October 12, 2007

Re: YPF Sociedad Anónima Form 20-F for the year ended December 31, 2006 File No. 001-12102

Mr. H. Roger Schwall

United States Securities and Exchange Commission

Division of Corporation Finance

100 F Street, N.E.

Washington, D.C. 20549-7410

Dear Mr. Schwall:

Thank you for your letter dated September 10, 2007 setting forth comments of the staff of the Division of Corporation Finance (the “Staff”) of the United States Securities and Exchange Commission (the “SEC” or “Commission”) on the annual report on Form 20-F for the year ended December 31, 2006 (the “2006 Form 20-F”) of YPF Sociedad Anónima (“YPF”, also referred to in this letter as the “Company” and “we”).

We appreciate your understanding in affording us the time necessary to prepare our responses, which we set forth in Annex A hereto. To facilitate the Staff’s review, we have reproduced the captions and numbered comments from the Staff’s September 10, 2007 comment letter in bold text.

In providing these responses, and in response to the Staff’s prior request, we hereby acknowledge that:

· YPF is responsible for the adequacy and accuracy of the disclosure in its filings with the Commission;

· Staff comments or changes to this disclosure in response to Staff comments do not foreclose the Commission from taking any action with respect to the filing; and

· YPF may not assert Staff comments as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

We would like to express our appreciation for your cooperation in these matters, and we are available to discuss any of our responses with you at your convenience. In that connection, please do not hesitate to contact the undersigned in Buenos Aires at 54-11-5071-2850 or fax: 54-11-4329-2113; Ricardo C. Ruiz and Manuel Arranz Alonso of Deloitte, our external auditors, at 54-11-4320-2700 (ext. 2221) and 34-915-14-50-00

(ext. 2072), or our counsel, Nicholas A. Kronfeld of Davis Polk & Wardwell, at 212-450-4950 or fax: 212-450-3950.

Very truly yours,

/s/ Walter Cristian Forwood

Walter Cristian Forwood

Chief Financial Officer

ANNEX A

Form 20-F for Fiscal Year Ended December 31, 2006

Notes to Consolidated Financial Statements, page F-8

Note 15. Additional U.S. GAAP Disclosures, page F-46

c) Hydrocarbon well abandonment obligations, page F-46

1. We note that you have recorded revisions in estimated cash flows related to your hydrocarbon well abandonment obligations in 2006, 2005 and 2004, that represented 58%, 107% and 72%, respectively, of the beginning of year obligations under US GAAP.  Considering the magnitude of these revisions, please describe the reasons for the revisions and identify the changes in prior estimates that caused revision to the timing or amount of the original estimate of undiscounted cash flows.  In addition, tell us what impact the revisions had on your financial position and results of operations.

Response

Variations in estimates related to abandonment obligations are mainly due to changes in estimates of amounts related to such tasks, which in turn are mainly due to the following:

­- New estimates are made as of the closing date of the fiscal year for which the annual financial statements are submitted (December 31), based on actual costs incurred during the year. As new information appears in each year (e.g., more complexity in abandonment activities as a result of wells abandoned during the year, new requirements of the Secretariat of Energy, and changes in suppliers in light of new or more complex abandonment activities), the average estimated cost per well is affected;

­- Increase in petroleum activities: WTI (West Texas Intermediate) price increases during the period under analysis provide for a greater demand for existing equipment (most of which is the same as that used for well abandonment activities), as a result of the increases in investments/repairs by companies in this industry, thus increasing their average cost with a direct impact on abandonment costs; and

­- General increase in salaries and prices in the economy.

Work related to abandonment obligations is usually carried out by many suppliers because it comprises different activities, geographical locations and working conditions. The main variations in the past have been cost increases in the following items (jobs):

­- Profiler

­- DTA (Disassembly, Transportation and Assembly)

­- Cement jobs

These revisions in estimates had the following impact on our financial position: assets and liabilities increased by 840 million Argentine pesos, 693 million Argentine pesos and 251 million Argentine pesos as of the closing date of each of the 2006, 2005 and 2004 fiscal years, respectively. Such increases in 2005 and 2004 represented an effect of 141 million Argentine pesos and 39 million Argentine pesos, respectively, in the net income for each of the 2006 and 2005 fiscal years, respectively.

Supplemental Information on Oil and Gas Producing Activities, page F-54

Standardized measure of discounted future net cash flows, page F-57

2. Please remove the subtotal of “Future net cash flows, before income taxes” as this item is not an explicit component of the standardized measure of discounted future net cash flows.  Refer to paragraph 30 and Illustration 5 of SFAS 69.

Response

We acknowledge the Staff’s comment and confirm that in future filings we will remove the subtotal of “Future net cash flows, before income taxes” in the standardized measure of discounted future net cash flows.

Engineering Comments

Oil and Gas Terms, page 3

3. Expand your definition of a “reserve audit” to provide more details on the procedures conducted in a reserves audit or provide a cross-reference to such discussion elsewhere in your filing.

Response

A Reserves Audit is the process of reviewing certain factual matters and assumptions on which an estimate of reserves and/or reserves information prepared by others has been based and the rendering of an opinion about (1) the appropriateness of the methodologies employed, (2) the adequacy and quality of the data relied upon, (3) the depth and thoroughness of the reserves estimation process, (4) the classification of reserves appropriate to the relevant definitions used, and (5) the reasonableness of the estimated reserves quantities and/or the reserves information. The term “reasonableness” cannot be defined with precision but reflects a quantity and/or value difference as contemplated under “Internal Control on Reserves and Reserves Audits” on page 31 of the 2006 Form 20-F. Often a reserves audit includes a detailed review of certain critical assumptions and independent assessments with acceptance of other information less critical to the reserves estimation. Typically, a reserves audit letter should be of sufficient rigor to determine the appropriate reserves classification for all reserves in the property set evaluated and to clearly state the reserves classification

system being utilized. In contrast to the term “audit” as used in a financial sense, a reserves audit is generally less rigorous than a reserves report.

On page F-55 of the 2006 Form 20-F, we disclose that the estimation of reserves and other reserves information is an imprecise science due to the many unknown geological and reservoir factors that can only be estimated through sampling techniques. Since reserves are therefore only estimates, they cannot be audited for the purpose of verifying exactness. Instead, reserves information is audited for the purpose of reviewing in sufficient detail the policies, procedures, methods and data used by YPF in estimating its reserves information so that the Reserves Auditors may express an opinion as to whether, in the aggregate, the reserves information furnished by YPF is reasonable within established and predetermined tolerances and has been estimated and presented in conformity with generally accepted petroleum engineering and evaluation principles and within the rules and regulations of the Securities and Exchange Commission.

In some cases, the auditing procedure may require independent estimates of reserves information for some or all properties. The desirability of such re-estimation will be determined by the Reserves Auditor exercising his or her professional judgment in arriving at an opinion as to the reasonableness of YPF’s reserves information. In those cases, an external reservoir engineer makes an independent comprehensive evaluation of reserves by interpreting and assessing all the pertinent data to generate such engineer’s own cash flow analysis and proved reserves estimate. The degree of assurance of such independent estimates cannot usually be provided with numeric precision.

The main product of these external engineering evaluations is a report that includes the engineer’s actual proved reserves estimates and economic evaluation. This report may also, at YPF’s request, include maps, logs, or other technical backup used by the external reservoir engineer, with an opinion letter that includes the auditor’s findings, conformance or not with the applicable principles, definitions and procedures for estimating reserves. This opinion may also, at YPF’s request, include conclusions and recommendations. In the aforementioned case where the auditor performs an independent estimate of reserves information, we at YPF will call it an external reserves certification. This concept is further described under “Internal Control on Reserves and Reserves Audits” on page 30 of the 2006 Form 20-F.

In all cases, in the opinion letter or report issued by the auditor, the auditor states his or her professional standing and professional affiliation as a registered or certified professional from an appropriate governmental authority or professional organization.

The meaning of the terms “reserves audit”, “reserves report”, “external reserves certification” among others may not be comparable to other similar terms used by other companies in respect of proved reserves.

Further information on reserves audits is also included on pages 30-32 of the 2006 Form 20-F. We also confirm that in future filings we will add disclosure

substantially similar to the disclosure in this response and include a cross reference to such disclosure from the definition of “reserve audit”.

4. In your definition of the term “plausible” you refer to “an independent qualified reserves auditor.”  Define that term and describe your standard for independence.  If it is different than the independence standard for an accountant, address those differences.

Response

An Independent Qualified Reserves Auditor is a professional who has sufficient educational background, professional training and professional experience to enable him or her to exercise prudent professional judgment while in charge of the conduct of an audit of reserves information estimated by others. The determination of whether a Reserves Auditor is professionally qualified is made on an individual-by-individual basis with reference to the recognition and respect of his or her peers. A Reserves Auditor would normally be considered by us to be qualified if he or she (i) has a minimum of 10 years’ practical experience in petroleum engineering or petroleum production geology, with at least 5 years of such experience in charge of the estimations and evaluation of reserves information; and (ii) either (A) has obtained, from a college or university of recognized stature, a bachelor’s or advanced degree in petroleum engineering, geology or other discipline of engineering or physical science, or (B) has received, and is maintaining in good standing, a registered or certified professional engineer’s license or a registered or certified professional geologist’s license, or the equivalent thereof, from an appropriate governmental authority or professional organization.

YPF’s standard of independence for Consulting Reserves Auditors is that he or she must not have any financial interest in the properties under evaluation. This is in order that there is no incentive for his or her reports to be outcome-oriented because there is no direct economic benefit for him or her as a consequence of the results of his or her work. The Independent Qualified Reserves Auditor’s compensation is based only on professional services carried out to deliver an unbiased analysis suitable for the public and financial communities. YPF also requires that a statement of such independence is included in the auditor’s report.

We also confirm to the Staff that in future filings we will include disclosure substantially similar to the disclosure in this response relating to the definition of an “Independent Qualified Reserves Auditor”.

Risk Factors, page 11

We may not be able to replace our reserves, page 16

5. Risk factors should be as specific to you as possible.  Please revise your document to expand this risk factor to include the fact that, even after your restatement of reserves, in the last two years your proved reserves have

declined by approximately 33% and you only replaced 11% of your production last year.

Response

We acknowledge the Staff’s comment and confirm that in future filings we will revise this risk factor to read substantially as follows:

We May Not Be Able to Replace Our Reserves

The rate of production from oil and gas properties generally declines as reserves are depleted. Without successful exploration and development activities or reserve acquisitions, our proved reserves will decline as oil and gas are produced from our existing proved developed reserves. Because YPF mainly has mature fields, it is difficult to replace developed proved reserves from other categories of reserves. Consequently, in the last two years our proved reserves declined by approximately 33% and we replaced 11% of our production last year. Although, YPF is developing efforts to increase reserves, these exploration, development and acquisition activities may not result in significant additional reserves.

Exploration and Production, Reserves, page 25

Restatement of Previously Reported Reserves as of December 31, 2004, page 25

6. You indicated on January 26, 2006 that you would revise your proved reserves estimates by 509 million barrels of oil equivalent.  However, you indicate, on page 27, that, at December 31, 2004 you restated your proved reserves by 254 million barrels of oil equivalent.  Explain the discrepancy between the two numbers.

Response

The 254 million barrels of oil equivalent corresponds only to the restatement for Loma La Lata Sierras Blanca reservoir – LLL-SB. The 509 million barrels of oil equivalent corresponds to the total downward reserves revision as of December 31, 2005, that, in addition to LLL-SB, also includes other fields not subject to restatement as disclosed in the 2006 20-F.

Revisions of Previous Estimates, Changes in YPF estimated proved reserves during 2005, page 27

7. You discuss a number of fields which you indicate were “certified” by an external auditor.  In reasonable detail, explain what you mean by that term and how it differs from a reserves “audit” and describe the procedures followed by the external consultant.

Response

In the 2006 20-F the terms “certified by an external auditor” and “externally audited” should be construed as the definition of and procedures carried out in connection with, “reserves audit” as defined in “Oil and Gas Terms”, on page 4, and described in “Internal Controls on Reserves and Reserves Audit” on page 31 in the paragraph beginning “For those areas audited by independent firms,…”, in the 2006 Form 20-F, and also as further explained in our response to the Staff´s Comment No. 3. All these terms as used by YPF may not be comparable to other similar terms used by other companies in respect of proved reserves.

8. Please provide us with supplemental information to better explain the negative revision of 49% of proved reserves in the Troncoso Inferior/Agrio+Avile reservoir in the Chihuido de la Sierra Negra (CHSN) field.  Please tell us if these reserves had been certified by an independent engineer prior to the negative revision and if so which one.

Response

CHSN Troncoso Inferior/Agrio+Avilé is a mature oil field under secondary recovery by water injection. It belongs to the Chihuido Sierra Negra reserve area located in the Neuquina basin in Argentina. YPF is the operator with a 100% share. The negative revision in this field was principally due to two factors:

a. Contractual revisions: reserves declared as proved in previous years based on the 10 year extension of the Concessions, established by the Hydrocarbons Law, were reclassified as non-proved since there was no reasonable certainty at December 31, 2005 that concessions would be renewed, considering many facts such as the competition from state-owned energy companies such as Empresa Argentina Sociedad Anónima and other companies owned by Argentine provinces which  operate in the oil and gas industry; the intense competition in bidding for production blocks (especially those blocks with the most attractive crude oil and natural gas reserves); and the proposed legislation to transfer the hydrocarbon properties from the National Government to the provinces in Argentina, finally implemented by Law No. 26.197 in January 2007. All these facts and circumstances led us to conclude that the renewal of our concessions would become more difficult to obtain in the future. The effect of this revision was 31.6 millions of barrels of oil equivalent.

b. Several technical revisions: In fiscal years prior to 2005, proved reserves of this oil field were estimated by the linear extrapolation method “Log WOR vs. Np”, globally applied to all the oil field and considering a constant fluid production. Although such estimates were always affected by intervention works and new wells, in the past they had provided reasonable predictions without any need for significant adjustments.

However, between the end of 2004 and the beginning of 2005 there was a considerable loss in injection and therefore, in the total fluid production. A gradual and sustained increase of the system pressure due to the use of a surfactant bactericide led to wellhead clogging. In turn, this clogging led to breakage of deeply corroded lines and reduction in injection performance. In addition, a workers’ strike resulted in a complete cessation of activity at the field that frustrated the repair of the lost injectors. In addition, the total cessation of activities caused precipitation of solids in the system which resulted in the collapse of new injectors.

The effect of this revision was 40.2 millions of barrels of oil equivalent. The effect of these events was not evident by the time the forecast as of December 31, 2004 was prepared.

These negative deviations in the estimations of the proven reserves were considered by DeGolyer and Mac Naughton (“D&M”) in their certification of the reserves as of December 31, 2005.

Prior to December 31, 2005, the last audit of the reserves of these areas was by Gaffney, Cline & Associates (“GCA”) in December 2002.

9. Please provide us with supplemental information regarding the negative revision totaling 39% of total proved reserves in the Ramos/Chango Norte-Porcelana gas condesate field.  Please tell us the justification for Gaffney Cline & Associates certifying these reserves as proved in 2004.

Response

Ramos/Chango Norte-Porcelana is a gas condensate field, located in the Northwest basin in Argentina, and its geological structure is in the Ramos concessions, where YPF has a 50.7% share and Aguaragüe, where YPF has a 30.0% share. None of the concessions is operated by YPF.

The revision of proven reserves of this field was based on the updated analysis of the production-pressure data of the Huamampampa formation through the material balance method, incorporating the latest static pressure data available in the years 2004 and 2005. The study resulted in a reduction of the estimated GIIP (Gas Initially In Place) as well as the applied recovery factor. The respective adjustment of net proven reserves as of December 31, 2004 presumed a reduction of 94,952 Mscf of gas and 3,132 kstb of condensate, gasoline and LPG in the Ramos concession and 23,223 Mscf of gas and 747 kstb of condensate, gasoline and LPG in the Aguaragüe concession.

These areas were certified by GCA as of December 31, 2004. At the time of the study, the data registered in the 2005 pressure campaign were not available because the data survey described above was registered after the certification. Therefore, without these production-pressure points showing a departure from the linear p/z vs Gp established in the previous analysis, the auditor was unable to identify the GIIP reduction which was established one year later.

10. Also please provide us with supplemental information regarding the negative revisions in:

• the Porton/Chihuido of the Salina/Chihuido of the Salina Sur reserve area.  Tell us if these reserves had been certified by an independent engineer prior to the negative revision and if so, which one;

• the Aguada Toledo-Sierra Barrosa reservoir and tell us if these reserves had been certified by an independent engineer prior to the negative revision and if so which one;

• the Lomas del Cuy/Los Perales reserve areas and tell us the justification for Gaffney Cline & Associates certifying these reserves, which were revised downward a year later, as proved in 2004.

Response

· Also please provide us with supplemental information regarding the negative revisions in The Porton/Chihuido of the Salina/Chihuido of the Salina Sur reserve area. Tell us if those reserves had been certified by an independent engineer prior to the negative revision and if so, which one;

We respectfully submit to the Staff that the information available regarding technical and contractual revisions for these areas is included on page 28 of the 2006 Form 20-F. Additionally, we confirm to the Staff that GCA audited the reserves of these areas in December 2002.

· Also please provide us with supplemental information regarding the negative revisions in The Aguada Toledo-Sierra Barrosa reservoir and tell us if these reserves had been certified by an independent engineer prior to the negative revision and if so which one;

We respectfully submit to the Staff that the information available regarding technical and contractual revisions for these areas is included on page 28 of the 2006 Form 20-F. Additionally, we confirm to the Staff that GCA audited the reserves of these areas on December 2003.

· Also please provide us with supplemental information regarding the negative revisions in The Lomas del Cuy/Los Perales reserve areas and tell us the justification for Gaffney Cline & Associates certifying these reserves, which were revised downward a year later, as proved in 2004.

The negative revision in this field was principally due to the increased exponential decline used by GCA as of December 31, 2005, to estimate the proved reserves, for the primary recovery, of wells drilled before 2001 in Los Perales and Lomas del Cuy. The reserves of secondary recovery projects which temporarily suffered losses in 2005 in injection due to mechanical problems in the injection wells (El Guadal Sur) have been reclassified as probable reserves. Furthermore, the reserves of secondary

projects developing worse in 2005 than originally expected (La Itala, Las Mesetas Oeste y Las Mesetas Norte) have also been reclassified as probable reserves.

GCA did not audit the reserves of these areas in 2004 but did so in December 2005.

Changes in YPF estimated net proved reserves during 2006, page 28

11. You state that the reserves of all the productive areas were externally audited by GCA and D&M.  Please revise your document to provide more information on the work performed by these independent engineers.  This should include but is not limited to:

• Disclose which systems, controls and approvals they reviewed in order to arrive at an opinion and what parameters they did not independently verify.

• Disclose what their opinion letter stated.

• Disclose the difference between a reserve audit that they performed and a reserve determination.

• Explain how these audits raise the confidence that the reserves reported meet the definition of proved reserves and are reasonably certain to be produced in the future.

Response

We refer the Staff to our responses to Staff comments Nos. 3, 4 and 7. The procedures for all work done by our external auditors were based on the guides and definitions established by Rule 4-10(a) of Regulations S-X, and are disclosed in their reports, copies of which we have attached as Attachments A and B.

As to “reserve audit”, we refer the Staff to our response to Staff comment No. 3. Regarding “reserve determination” we use the term “determination” to refer to reserves on page 70 of the 2006 20 F, in accounting policies for the cost of drilling exploratory wells, in accordance with paragraph 19 of FAS 19 “Financial Accounting and Reporting by Oil and Gas Producing Companies”.

Each of GCA and D&M, as an external independent engineering firm hired by YPF for the purpose of auditing its proved reserves, must comply with Rule 4-10(a) of Regulation S-X under the SEC. Past performances, and CVs provided by the firms, are thoroughly reviewed to assess their level of experience and professional qualifications. Additionally, YPF through its Reserves Control Group holds regular meetings with the independent engineering firms during the course of the audits, to test for such compliance.  If any discrepancy (i.e., in used estimations, methodologies, among others)appears, it must be indicated in the report and properly documented. The work performed by these external auditors represents a qualified second opinion that is used by YPF, as a double check to enhance the quality in its proved reserves estimates as described under “Internal Control and Reserves Audit” on page 31 of the 2006 Form 20-F.

12. At the bottom of page 31, you indicate that “D&M audited the main areas” in which you operate.  Quantify or describe what you mean by “main areas”.  Also, clarify what you mean in the next paragraph by “minor areas”.

Response

By “main areas” we are referring to the areas with greater volumes of reserves for each Economic Unit in Argentina, so as to achieve a total amount audited equivalent to 1/3 of the total reserves of Repsol YPF, in accordance with the objective to audit 100% of group reserves in a 3-year cycle. The amount of 1/3 of Repsol YPF’s total reserves equals approximately 80% of the total reserves of YPF in Argentina. We refer to the rest of the areas operated by YPF in Argentina as “minor areas” and “non operated areas”, which represent the remaining approximately 20%.

We confirm to the Staff that in future filings we will provide disclosures, similar to those included in the foregoing paragraph, to clarify our definition of main and minor areas.

Exploration and Development Properties and Production, page 35

13. For your principal oil and gas fields please include all the information required by Item 4D for Form 20-F.  This includes as a minimum production, reserves, nature of your interest, location and development of these fields.  Please see Instruction to Item 4D for reference.

Response

We confirm to the Staff that in future filings we will add information about our principal oil and gas fields as required by Item 4D of Form 20-F. Additionally, we include below a table with information related to our main areas for the year ended December 31, 2006:

Areas	Interest	Production of the year (thousands of boe)	Reserves as of December 31, 2006 (thousands of boe)	Basin	Development of the area
LOMA LA LATA (1)	100%	70,773	445,819	Neuquina	Mature Field
EL PORTON-CHIHUIDO LA SALINA (1)	100%	22,600	142,550	Neuquina	Mature Field
LOS PERALES (1)	100%	12,323	56,954	Golfo San Jorge	Mature Field
CHIHUIDO SIERRA NEGRA (1)	100%	12,568	52,737	Neuquina	Mature Field
AGUADA TOLEDO-SIERRA BARROSA (1)	100%	8,661	49,780	Neuquina	Mature Field
MANANTIALES BEHR (1)	100%	6,494	31,455	Golfo San Jorge	Mature Field
SECO LEON (1)	100%	4,765	28,233	Golfo San Jorge	Mature Field
VIZCACHERAS (1)	100%	4,061	28,213	Cuyana	Mature Field
BARRANCA BAYA (1)	100%	4,721	22,609	Golfo San Jorge	Mature Field
BARRANCAS (1)	100%	2,438	19,420	Cuyana	Mature Field
LOMAS DEL CUY (1)	100%	3,597	18,860	Golfo San Jorge	Mature Field
SEÑAL PICADA (1)	100%	2,064	16,307	Neuquina	Mature Field
LA VENTANA (1)	(2)	2,159	15,178	Cuyana	Mature Field
EL TREBOL (1)	100%	2,398	14,397	Golfo San Jorge	Mature Field
PASO BARDAS NORTE (1)	100%	1,356	13,083	Neuquina	Mature Field
CERRO FORTUNOSO (1)	100%	2,124	10,121	Neuquina	Mature Field

(1) Exploitation concessions

(2) 69.6% for Crude Oil and 60% for Liquids, Natural Gas Liquids and Natural Gas

Oil and Gas Reserves, page F-56

14. You indicate that gas production volumes do not include volumes that were flared or vented.  Please tell us if these volumes were included as part of proved reserves and, are therefore, now included as negative revisions.

Response

We confirm to the Staff that proved reserves do not include gas volumes projected to be vented or flared. If volumes in excess of those projected are flared or vented, such excess is reflected in negative revisions.

ATTACHMENT A

Gaffney, Cline & Associates

Digital Copy

CRUDE OIL AND NATURAL GAS

RESERVE AUDIT AND CERTIFICATION

OF SIX FIELDS IN SAN JORGE BASIN

EFFECTIVE DECEMBER 31, 2005

Prepared for

REPSOL YPF S.A.

JANUARY 2006

Repsol YPF

C1191.00

SECTIONS

·   INTRODUCTORY LETTER

·   RESERVE STATEMENTS

·   TECHNICAL EXPLANATIONS

·   SUMMARY SHEET OF TOTALS

GCA

Gaffney, Cline & Associates Inc.

Technical and Management Advisers to the Petroleum Industry Internationally Since 1962

Four Oaks Place

1360 Post Oak Boulevard, Suite 2500

Houston, Texas 77056 

Principals William B. Cline

Peter D. Gaffney

Telephone: (713) 850-9955

Facsimile: (713) 850-9966

e-Mail: gcah@gaffney-cline.com

C1191.00/IASF/ralo/LT1371  January 19, 2006

Ing. Guillermo García Alvarez-Valle

Repsol YPF S.A.

Avenida Pte. Roque Sáenz Peña 777

Oficina 930 D

1364 Buenos Aires, Argentina

CRUDE OIL AND NATURAL GAS RESERVE AUDIT CERTIFICATION

OF SIX FIELDS IN SAN JORGE BASIN EFFECTIVE DECEMBER 31, 2005

Dear Ing. García:

Gaffney, Cline & Associates (GCA) has examined the crude oil and natural gas reserve estimates rendered by Repsol YPF S.A. (RY) in respect of six San Jorge Basin fields, four of them in the province of Santa Cruz and two in the province of Chubut. On the basis of production performance data and other technical information made available to us concerning these property units, we hereby certify the oil and gas reserve volumes as summarized by property unit in the tables below and by the individual property specific statements that are attached to this letter.

It is our considered opinion that the following total estimates of remaining recoverable oil, natural gas and natural gas liquids volumes at December 31, 2005, are, in the aggregate, reasonable. Proved reserves have been prepared in accordance with the definitions set out in Rule 4-10 of Regulation S-X of the United States Securities and Exchange Commission. Probable and Possible reserves have been prepared in accordance with the reserve definitions approved by the Society of Petroleum Engineers and World Petroleum Congresses in March 1997.

Natural gas volumes represent those volumes to be sold or used internally for operations. Net volumes reflect RY’s working interest in the concession. This interest has not been reduced for royalties, which under customary Argentine accounting practice are treated as an operating expense. Proved gas volumes are based on firm and existing gas contracts, and on the reasonable expectation that such gas sales contracts will be renewed on similar terms in the future.

Crude Oil Net Reserves Volumes for RY (10³ m³)

Property-Field	Proved Developed		Proved Undeveloped		Total Proved		Probable		Possible
Barranca Baya		3,170		708		3,878		389		1,096
Los Perales		4,650		3,976		8,626		1,720		631
Lomas del Cuy		1,983		1,160		3,143		1,307		70
Seco Leon		2,471		1,592		4,063		625		467
Manantiales Behr		3,665		1,142		4,807		1,812		1,875
El Trebol		2,347		441		2,788		177		747
TOTAL		18,286		9,019		27,305		6,030		4,886

Natural Gas Net Reserves Volumes for RY (10⁶ m³)

Property-Field	Proved Developed		Proved Undeveloped		Total Proved		Probable		Possible
Barranca Baya		62		14		76		8		21
Los Perales		1,336		870		2,206		1,619		1,839
Lomas del Cuy		220		129		349		145		8
Seco Leon		495		319		814		125		180
Manantiales Behr		385		105		490		221		172
El Trebol		30		0		30		2		10
TOTAL		2,528		1,437		3,965		2,120		2,230

This audit examination was based on reserve estimates and other information provided by RY to GCA through December 31, 2005, and included such tests, procedures and adjustments as were considered necessary. All questions that arose during the course of the certification process were resolved to GCA’s satisfaction. The reported hydrocarbon reserve is an estimate based on professional engineering judgment and is subject to future revisions, upward or downward, as a result of future operations or as additional information becomes available.

GCA served as independent reserve auditors. The firm’s Senior Partners, officers, and employees have no direct or indirect interest holding in RY. GCA’s remuneration was not in any way contingent upon reported reserve estimates. No representations are made herein in respect of property title or encumbrances thereon. This report has been prepared for RY and should not be used for purposes other than those for which it is intended.

Very truly yours,

GAFFNEY, CLINE & ASSOCIATES, INC.

/s/ Ivan Simões Filho

Ivan Simões Filho

Southern Cone Area Manager

Attn.

Gaffney, Cline & Associates

RESERVE STATEMENTS

Repsol YPF C1191.00

Gaffney, Cline & Associates

TABLE OF CONTENTS

Total	1
Barranca Baya	2
Los Perales	3
Lomas del Cuy	4
Seco León	5
Manantiales Behr	6
El Trébol	7
Repsol YPF	C1191.00

TOTAL

(Field / Area Name)

Crude Oil and Natural Gas Reserve Statement

Audit Certification @ December 31st, 2005

Supporting Sub-unit Data Sheet

		Operator Name:	Repsol YPF S.A.
Sub-unit Name:	TOTAL	Repsol YPF Oil Interest:	0.00%
Country:	Argentina	Repsol YPF Gas Interest:	0.00%
Province:	Santa Cruz/Chubut	Sales Gas as % of Total Gross Gas:	0.00%
		Fuel Gas as % of Total Gross Gas:	0.00%

A. Cumulative Production to December 31st, 2005

Oil			Cond.	Gasoline	LPG	Gas
Primary Mm³	Secondary Mm³	Total Mm³	Mm³	Mm³	Mm³	Solution MMm³	Total MMm³

B. Gross Field Volumes @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		10,263		8,023		18,286		0		0		0		2,130		2,504
Developed Non-Prod.		0		0		0		0		0		0		0		24
Undeveloped		4,393		4,626		9,019		0		0		0		1,410		1,437
Sub-total Proved		14,656		12,649		27,305		0		0		0		3,540		3,965
Probable		4,739		1,291		6,030		0		0		0		812		2,120
Possible		4,168		718		4,886		0		0		0		525		2,230

C. Respsol YPF Net Interest Reserves @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		10,263		8,023		18,286		0		0		0		2,130		2,504
Developed Non-Prod.		0		0		0		0		0		0		0		24
Undeveloped		4,393		4,626		9,019		0		0		0		1,410		1,437
Sub-total Proved		14,656		12,649		27,305		0		0		0		3,540		3,965
Probable		4,739		1,291		6,030		0		0		0		812		2,120
Possible		4,168		718		4,886		0		0		0		525		2,230

D. Notes:

GCA Auditor:	VSW
Approved:	DKM
Date:	19-Jan-06

Barranca Baya

(Field / Area Name)

Crude Oil and Natural Gas Reserve Statement

Audit Certification @ December 31st, 2005

		Operator Name:	Repsol YPF S.A.
Sub-unit Name:	San Jorge	Repsol YPF Oil Interest:	100.00%
Country:	Argentina	Repsol YPF Gas Interest:	100.00%
Province:	Santa Cruz	Sales Gas as % of Total Gross Gas:	0.00%
		Fuel Gas as % of Total Gross Gas:	100.00%

A. Cumulative Production to December 31st, 2005

Oil			Cond.	Gasoline	LPG	Gas
Primary Mm³	Secondary Mm³	Total Mm³	Mm³	Mm³	Mm³	Solution MMm³	Total MMm³

B. Gross Field Volumes @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		1,624		1,546		3,170		0		0		0		62		62
Developed Non-Prod.		0		0		0		0		0		0		0		0
Undeveloped		290		418		708		0		0		0		14		14
Sub-total Proved		1,914		1,964		3,878		0		0		0		76		76
Probable		302		87		389		0		0		0		8		8
Possible		1,041		55		1,096		0		0		0		21		21

C. Respsol YPF Net Interest Reserves @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		1,624		1,546		3,170		0		0		0		62		62
Developed Non-Prod.		0		0		0		0		0		0		0		0
Undeveloped		290		418		708		0		0		0		14		14
Sub-total Proved		1,914		1,964		3,878		0		0		0		76		76
Probable		302		87		389		0		0		0		8		8
Possible		1,041		55		1,096		0		0		0		21		21

D. Notes:

GCA Auditor:	VSW
Approved:	DKM
Date:	19-Jan-06

Seco Leon

(Field / Area Name)

Crude Oil and Natural Gas Reserve Statement

Audit Certification @ December 31st, 2005

		Operator Name:	Repsol YPF S.A.
Sub-unit Name:	San Jorge	Repsol YPF Oil Interest:	100.00%
Country:	Argentina	Repsol YPF Gas Interest:	100.00%
Province:	Santa Cruz	Sales Gas as % of Total Gross Gas:	71.00%
		Fuel Gas as % of Total Gross Gas:	29.00%

A. Cumulative Production to December 31st, 2005

Oil			Cond.	Gasoline	LPG	Gas
Primary Mm³	Secondary Mm³	Total Mm³	Mm³	Mm³	Mm³	Solution MMm³	Total MMm³

B. Gross Field Volumes @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		1,041		1,430		2,471		0		0		0		495		495
Developed Non-Prod.		0		0		0		0		0		0		0		0
Undeveloped		193		1,399		1,592		0		0		0		319		319
Sub-total Proved		1,234		2,829		4,063		0		0		0		814		814
Probable		316		309		625		0		0		0		125		125
Possible		417		50		467		0		0		0		180		180

C. Respsol YPF Net Interest Reserves @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		1,041		1,430		2,471		0		0		0		495		495
Developed Non-Prod.		0		0		0		0		0		0		0		0
Undeveloped		193		1,399		1,592		0		0		0		319		319
Sub-total Proved		1,234		2,829		4,063		0		0		0		814		814
Probable		316		309		625		0		0		0		125		125
Possible		417		50		467		0		0		0		180		180

D. Notes:

GCA Auditor:	VSW
Approved:	DKM
Date:	19-Jan-06

Lomas del Cuy

(Field / Area Name)

Crude Oil and Natural Gas Reserve Statement

Audit Certification @ December 31st, 2005

		Operator Name:	Repsol YPF S.A.
Sub-unit Name:	San Jorge	Repsol YPF Oil Interest:	100.00%
Country:	Argentina	Repsol YPF Gas Interest:	100.00%
Province:	Santa Cruz	Sales Gas as % of Total Gross Gas:	0.00%
		Fuel Gas as % of Total Gross Gas:	100.00%

A. Cumulative Production to December 31st, 2005

Oil			Cond.	Gasoline	LPG	Gas
Primary Mm³	Secondary Mm³	Total Mm³	Mm³	Mm³	Mm³	Solution MMm³	Total MMm³

B. Gross Field Volumes @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		1,120		863		1,983		0		0		0		220		220
Developed Non-Prod.		0		0		0		0		0		0		0		0
Undeveloped		375		785		1,160		0		0		0		129		129
Sub-total Proved		1,495		1,648		3,143		0		0		0		349		349
Probable		1,144		163		1,307		0		0		0		145		145
Possible		20		50		70		0		0		0		8		8

C. Respsol YPF Net Interest Reserves @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		1,120		863		1,983		0		0		0		220		220
Developed Non-Prod.		0		0		0		0		0		0		0		0
Undeveloped		375		785		1,160		0		0		0		129		129
Sub-total Proved		1,495		1,648		3,143		0		0		0		349		349
Probable		1,144		163		1,307		0		0		0		145		145
Possible		20		50		70		0		0		0		8		8

D. Notes:

GCA Auditor:	VSW
Approved:	DKM
Date:	19-Jan-06

Los Perales

(Field / Area Name)

Crude Oil and Natural Gas Reserve Statement

Audit Certification @ December 31st, 2005

		Operator Name:	Repsol YPF S.A.
Sub-unit Name:	San Jorge	Repsol YPF Oil Interest:	100.00%
Country:	Argentina	Repsol YPF Gas Interest:	100.00%
Province:	Santa Cruz	Sales Gas as % of Total Gross Gas:	0.00%
		Fuel Gas as % of Total Gross Gas:	100.00%

A. Cumulative Production to December 31st, 2005

Oil			Cond.	Gasoline	LPG	Gas
Primary Mm³	Secondary Mm³	Total Mm³	Mm³	Mm³	Mm³	Solution MMm³	Total MMm³

B. Gross Field Volumes @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		2,575		2,075		4,650		0		0		0		986		1,336
Developed Non-Prod.		0		0		0		0		0		0		0		0
Undeveloped		2,736		1,240		3,976		0		0		0		843		870
Sub-total Proved		5,311		3,315		8,626		0		0		0		1,829		2,206
Probable		1,603		117		1,720		0		0		0		365		1,619
Possible		570		61		631		0		0		0		134		1,839

C. Respsol YPF Net Interest Reserves @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		2,575		2,075		4,650		0		0		0		986		1,336
Developed Non-Prod.		0		0		0		0		0		0		0		0
Undeveloped		2,736		1,240		3,976		0		0		0		843		870
Sub-total Proved		5,311		3,315		8,626		0		0		0		1,829		2,206
Probable		1,603		117		1,720		0		0		0		365		1,619
Possible		570		61		631		0		0		0		134		1,839

D. Notes:

GCA Auditor:	VSW
Approved:	DKM
Date:	19-Jan-06

Manatiales Behr

(Field / Area Name)

Crude Oil and Natural Gas Reserve Statement

Audit Certification @ December 31st, 2005

		Operator Name:	Repsol YPF S.A.
Sub-unit Name:	San Jorge	Repsol YPF Oil Interest:	100.00%
Country:	Argentina	Repsol YPF Gas Interest:	100.00%
Province:	Chubut	Sales Gas as % of Total Gross Gas:	7.00%
		Fuel Gas as % of Total Gross Gas:	93.00%

A. Cumulative Production to December 31st, 2005

Oil			Cond.	Gasoline	LPG	Gas
Primary Mm³	Secondary Mm³	Total Mm³	Mm³	Mm³	Mm³	Solution MMm³	Total MMm³

B. Gross Field Volumes @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		3,229		436		3,665		0		0		0		337		361
Developed Non-Prod.		0		0		0		0		0		0		0		24
Undeveloped		799		343		1,142		0		0		0		105		105
Sub-total Proved		4,028		779		4,807		0		0		0		442		490
Probable		1,279		533		1,812		0		0		0		167		221
Possible		1,875		0		1,875		0		0		0		172		172

C. Respsol YPF Net Interest Reserves @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		3,229		436		3,665		0		0		0		337		361
Developed Non-Prod.		0		0		0		0		0		0		0		24
Undeveloped		799		343		1,142		0		0		0		105		105
Sub-total Proved		4,028		779		4,807		0		0		0		442		490
Probable		1,279		533		1,812		0		0		0		167		221
Possible		1,875		0		1,875		0		0		0		172		172

D. Notes:

GCA Auditor:	VSW
Approved:	DKM
Date:	19-Jan-06

El Trebol

(Field / Area Name)

Crude Oil and Natural Gas Reserve Statement

Audit Certification @ December 31st, 2005

		Operator Name:	Repsol YPF S.A.
Sub-unit Name:	San Jorge	Repsol YPF Oil Interest:	100.00%
Country:	Argentina	Repsol YPF Gas Interest:	100.00%
Province:	Chubut	Sales Gas as % of Total Gross Gas:	0.00%
		Fuel Gas as % of Total Gross Gas:	100.00%

A. Cumulative Production to December 31st, 2005

Oil			Cond.	Gasoline	LPG	Gas
Primary Mm³	Secondary Mm³	Total Mm³	Mm³	Mm³	Mm³	Solution MMm³	Total MMm³

B. Gross Field Volumes @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		674		1,673		2,347		0		0		0		30		30
Developed Non-Prod.		0		0		0		0		0		0		0		0
Undeveloped		0		441		441		0		0		0		0		0
Sub-total Proved		674		2,114		2,788		0		0		0		30		30
Probable		95		82		177		0		0		0		2		2
Possible		245		502		747		0		0		0		10		10

C. Respsol YPF Net Interest Reserves @ December 31st, 2005

	Oil						Cond.		Gasoline		LPG		Gas
	Primary Mm³		Secondary Mm³		Total Mm³		Mm³		Mm³		Mm³		Solution MMm³		Total MMm³
Proved
Developed Prod.		674		1,673		2,347		0		0		0		30		30
Developed Non-Prod.		0		0		0		0		0		0		0		0
Undeveloped		0		441		441		0		0		0		0		0
Sub-total Proved		674		2,114		2,788		0		0		0		30		30
Probable		95		82		177		0		0		0		2		2
Possible		245		502		747		0		0		0		10		10

D. Notes:

GCA Auditor:	VSW
Approved:	DKM
Date:	19-Jan-06

Gaffney, Cline & Associates

TECHNICAL EXPLANATIONS

Repsol YPF C1191.00

Gaffney, Cline & Associates

Technical Explanations of the Audit/Engineering Review of the Argentina Sur Main Fields

REPSOL-YPF AUDIT PROCESS

The fields being audited have been undergoing primary and secondary recovery for many years and are very mature. The Repsol YPF (RY) reserves declaration contains both proved primary and proved secondary projects that are at various stages of development.

1.           Proved Reserves Audit

Primary Reserves

Proved Developed Producing (PDP) Audit

The audit approach to producing reserves was to utilize RY’s Oilfield Manager (OFM) database, extract the primary production and compare it with the production curve presented by RY. After confirmation that the production data extracted was the same or very near the same, all production from “new” wells (drilled since 1/1/2001) was extracted. From this, a PDP decline was determined for continued operations, assuming no further drilling would occur. In cases where GCA’s estimated decline rate was considered to be more representative, GCA then estimated the PDP reserves. The decline rate was applied to the current production and extrapolated to 31/12/2017. The reserves were calculated from the estimated production rates between 1/1/2006 and 31/12/2017.

The only significant differences in oil volume estimates between RY and GCA occurred in the primary recovery in the Los Perales and the Lomas Del Cuy fields. The reasons for both fields are the same: a difference in interpretation and application of the time decline rate. For both fields GCA adopted a steeper (more conservative) decline rate, which was based on overall historical performance, while RY’s decline was based on a more recent trend (2001 forward). The reason presented by RY for the “flattening” of the decline was the stabilization of the number of primary wells either through restoring shut-in wells to production or from slowing or stopping the conversions of producers to injectors. As the type and amount of data necessary to support the continuation of this flatter decline was not available, the Primary PDP reserves estimated by GCA for these fields reflects the original decline rate forecast (28.8%/yr at Los Perales and 25.5%/yr at Lomas del Cuy’ see Figures 1 and 2). The estimated dissolved gas volumes were reduced accordingly by applying an average GOR to the estimated oil volumes.

There was also a significant difference between RY and GCA in the free gas estimate for Los Perales. RY had recognized that free gas production was likely to exceed reserves during 2005. In addition to some minor volumes re-categorization due to workovers, RY transferred volumes from the Probable category in an amount sufficient to account for approximately two more years of production at current rates, with the understanding that the Los Perales free gas will be the subject of study during 2006. GCA accepted this transfer but only for a volume sufficient to account for one additional year of production, subject to review once the results of the gas study are available.

The differences between GCA’s estimates and RY’s declarations are presented in the accompanying “Summary Sheet of Totals”.

Proved Developed Non-Producing (PDNP) Reserve Audit

RY made no representations of PDNP reserves, and GCA concurs.

Proved Undeveloped (PUD) Reserve Audit

The audit approach to PUD reserves was to utilize RY’s OFM database and extract the primary production from all wells drilled since 1/1/2001. The new wells were then normalized to zero time and the average production for each month was divided by the wells producing that month. This resulted in a 4 to 5 year normalized production graph. The production was extrapolated on a straight-line semi-log decline until 31/12/2017. The cumulative production volume was added to the extrapolated volume to provide an estimated average recovery per completion

for the new wells. This value was compared with the estimated per well recovery of RY’s PUD representation. In all cases the GCA estimated recovery was greater than or very near to RY’s estimates. The primary production maps were reviewed to assess the location of the PUD wells. The locations of the PUD wells were all basically one-well step-out locations and the PUD reserves were accepted.

Secondary Reserves

Proved Developed Producing (PDP) Audit

The primary objective of this audit was to assess RY’s estimates in respect to the current production performance and assure that the proper reserve categorization was made according to SPE standards.

Production performance behavior was analyzed by the following methods:

1. Total projected oil production, primary production, secondary production, associated gas production, water production, water injection, number of producing wells (total, primary and secondary) and the number of injection wells were extracted from the OFM database to the extent that this data existed. The secondary oil production was compared to the secondary oil graph used by RY to extrapolate future secondary recovery.

2. From the data extracted, the project performance for secondary oil and, where necessary, total project oil performance was plotted versus time on a semi-log graph. The graph includes daily oil rate, oil cumulative, monthly oilcut, GOR, daily water production, daily water injection, number of producing and injection wells. The oil production graph was analyzed in detail to determine if an exponential decline could represent the estimated future PDP recovery of the project.

3. In addition to the total project performance analysis, graphs of oilcut versus cumulative production, type-well performance, pseudo fractional flow diagrams of watercut versus percent cumulative recovery and; watercut and percent oil recovery versus a pseudo net pore volume of water injection were analyzed. The two later graphs are not explicit, but were created to view the recovery behavior of the project. Extrapolations of oilcut versus cumulative oil were made to assess the recovery estimated by normal exponential decline analysis.

4. The estimated recovery by exponential extrapolation was compared to RY’s declination and if in reasonable agreement, the PDP reserves were accepted.

Proved Developed Non-Producing (PDNP) Reserve Audit

RY made no representations of PDNP reserves and GCA concurs.

Proved Undeveloped (PUD) Reserve Audit

The audit approach to PUD reserves was to clarify that the secondary PUD reserves presented by RY were properly categorized. Secondary projects which have not been implemented but have sufficient supporting technical studies, analogs, economic evaluation and are planned to be implemented within a reasonable time frame by SEC standards, can be classified as secondary PUD projects. Secondly, if a relatively new PUD project is being or has been fully implemented then reserves may be transferred from PUD to PDP as performance supports the estimated volumes. All of RY’s PUD projects fell into the guidelines of these two definitions. All the technical studies on the unimplemented projects were reviewed and found to be acceptable. There were several new projects that have been implemented or are being implemented that have reserves remaining in the PUD category. Each of these projects was reviewed, and the distinctions between PDP and PUD were found to be reasonable.

2.           Probable and Possible Reserves Audit

Essentially the same methodologies were applied to probable and possible reserve categories, with the only variable being related to uncertainty.

Primary

Primary probable and possible reserves are similar to primary PUD reserves, with more uncertainty. The audit approach to these reserves was to compare the average recovery per PUD well since 2001 with the estimated per well recovery of RY’s probable/possible representation. In all cases, GCA’s estimated recovery was greater than or very near to RY’s estimates. Also, in all cases RY’s average recovery per well was less for probable than for PUD. The locations of the probable/possible wells were all basically one-well step-out locations from and around the PDP plus PUD areas, and the reserves were accepted.

Secondary

The probable and possible secondary reserves were generally related to secondary expansion (new wells and/or injection pattern expansion) and/or higher recovery potential. Current operations and/or performance can not support the movement of these reserves to a higher category. In all cases, RY provided technical studies that supported these reserves and, overall, GCA accepted these reserves.

There were a few projects in which current performance and operations do not support the PDP reserves. In these isolated cases some reserves were transferred to PUD and/or probable categories.

Gaffney, Cline & Associates

Figure 1

Repsol YPF C1191.00

Gaffney, Cline & Associates

Figure 2

Repsol YPF C1191.00

Gaffney, Cline & Associates

SUMMARY SHEET OF TOTALS

Repsol YPF C1191.00

GCA Results	Repsol Reserves										GCA Reserves										Difference (GCA – Repsol)
Summary Sheet of Totals	CDEP		CDNP		CND		Pr		Po		CDEP		CDNP		CND		Pr		Po		CDEP			CDNP		CND		Pr		Po
31 December 2005	E3m3		E3m3		E3m3		E3m3		E3m3		E3m3		E3m3		E3m3		E3m3		E3m3		E3m3			E3m3		E3m3		E3m3		E3m3
BARRANCA BAYA FIELD
Primary Reserves		1,624		—		290		302		1,041		1,624		—		290		302		1,041		—			—		—		—		—
Primary Proved		1,914										1,914										—
Secondary Totals		1,546		—		418		87		55		1,546		—		418		87		55		—			—		—		—		—
Secondary Proved		1,964										1,964										—
Dissolved Gas Reserves – E6m3		62		—		14		8		21		62		—		14		8		21		—			—		—		—		—
LOS PERALES FIELD
Primary Reserves		3,984		—		2,736		1,603		570		2,575		—		2,736		1,603		570		(1,409	)		—		—		—		—
Primary Proved		6,720										5,311										(1,409	)		—		—		—		—
Secondary Totals		2,232		—		1,200		—		61		2,075		—		1,240		117		61		(157	)		—		40		117		—
Secondary Proved		3,432										3,315										(117	)		—		—		—		—
Dissolved Gas Reserves – E6m3		1,317		—		836		340		134		986		—		843		365		134		(332	)		—		8		25		—
Free Gas Reserves – E6m3		773		—		27		840		1,705		350				27		1,254		1,705		(423	)		—		—		414		—
LOMAS DEL CUY FIELD
Primary Reserves		1,549		—		375		1,144		20		1,120		—		375		1,144		20		(429	)		—		—		—		—
Primary Proved		1,923										1,495										(428	)		—		—		—		—
Secondary Totals		863		—		785		163		50		863		—		785		163		50		—			—		—		—		—
Secondary Proved		1,648										1,648										—			—		—		—		—
Dissolved Gas Reserves – E6m3		268		—		129		145		8		220		—		129		145		8		(48	)		—		—		—		—
SECO LEON FIELD																									—
Primary Reserves		1,041		—		193		316		417		1,041		—		193		316		417		—			—		—		—		—
Primary Proved		1,234										1,234										—
Secondary Totals		1,430		—		1,399		309		50		1,430		—		1,399		309		50		—			—		—		—		—
Secondary Proved		2,829										2,829
Dissolved Gas Reserves – E6m3		495		—		319		125		180		495		—		319		125		180		—			—		—		—		—
MANANTIALES BEHR FIELD
Primary Reserves 3,229		3,229		—		799		1,279		1,875		3,229		—		799		1,279		1,875		—			—		—		—		—
Primary Proved		4,028										4,028										—
Secondary Totals		436		—		343		533		—		436		—		343		533		—		—			—		—		—		—
Secondary Proved		779										779										—
Dissolved Gas Reserves – E6m3		337		—		105		167		172		337		—		105		167		172		—			—		—		—		—
Free Gas Reserves – E6m3		24		24		—		54		—		24		24		—		54		—		—			—		—		—		—
EL TREBOL FIELD
Primary Reserves		674		—		—		95		245		674		—		—		95		245		—			—		—		—		—
Primary Proved		674										674										—

Secondary Totals	1,673	—	441	82	502	1,673	—	441	82	502	—		—	—	—	—
Secondary Proved	2,114					2,114					—
Dissolved Gas Reserves – E6m3	30	—	—	2	10	30	—	—	2	10	—		—	—	—	—
TOTAL RESERVES
Primary Reserves	12,100	—	4,393	4,739	4,168	10,263	—	4,393	4,739	4,168	(1,838	)	—	—	—	—
Primary Proved	16,493					14,656					(1,837	)
Secondary Totals	8,180	—	4,586	1,174	718	8,023	—	4,626	1,291	718	(157	)	—	40	117	—
Secondary Proved	12,766					12,649					(117	)
Dissolved Gas Reserves – E6m3	2,509	—	1,403	786	526	2,130	—	1,409	811	525	(380	)	—	8	25	—
Free Gas Reserves – E6m3	797	24	27	894	1,705	374	24	27	1,308	1,705	(423	)	—	—	414	—

Checked: VSW

Approved: DKM

C1191.00

Attachment B

This CD-ROM contains digital representation of a DeGolyer and MacNaughton report.

The files on this CD-ROM are intended to be manifestations of certain data in the subject report and as such are subject to the same conditions thereof. The information and data contained in this CD-ROM maybe subject to misinterpretation; therefore, the signed and bound copy of this report should be considered the only authoritative source of such information.

REPORT

as of

DECEMBER 31, 2005

on

RESERVES

of

CERTAIN PROPERTIES

in

ARGENTINA

attributable to

REPSOL YPF

2

TABLE OF CONTENTS

Page

FOREWARD	1
Scope of Investigation	1
Authority	1
Source of Information	2
CLASSIFICATION OF RESERVES	2
ESTIMATION OF RESERVES	5
SUMMARY AND CONCLUSIONS	7

TABLES
Table	1	–	Properties Evaluated
SUMMARY of RESERVES
Table	2	–	Summary of Gross Proved Reserves
Table	3	–	Summary Gross Probable and Possible Reserves
Table	4	–	Summary of Net Reserves
PROJECTIONS of GROSS RESERVES
MENDOZA BLOCK
Table	5	–	Mendoza Block Total
Table	6	–	Barrancas Area Total
Table	7	–	Fld-Seg: Barrancas Sur
Table	8	–	Fld-Seg: Barrancas-C.R.I.
Table	9	–	Fld-Seg: Barrancas-Cabras / B. Verde
Table	10	–	Fld-Seg: Barrancas-Cabras-Potrerillos
Table	11	–	Fld-Seg: Barrancas-Cabras-Villavicencio
Table	12	–	Guanaco Blanco Area
			Fld-Seg: Guanaco Blanco LRB
Table	13	–	La Ventana Area
			Fld-Seg: La Ventana-Barrancas/Rio Blanco
Table	14	–	La Ventana Central Area Total
Table	15	–	Fld-Seg: Rio Viejas
Table	16	–	Fld-Seg: Zona Central BRC
Table	17	–	Fld-Seg: Zona Central LRB
Table	18	–	Fld-Seg: Zona Central TRC
Table	19	–	Fld-Seg: Zona Central VC
Table	20	–	La Ventana-Caflada Dura Area
			Fld-Seg: La Ventana-Cañada Dura
Table	21	–	Vizcacheras-Caflada Dura Area
			Fld-Seg: Vizcacheras-Canada Dura
Table	22	–	Vizcacheras Area Total
Table	23	–	Fld-Seg: Vizcacheras-Barrancas
Table	24	–	Fld-Seg: Vizcacheras-Papagayos

Table	25	–	Cerro Fortunoso Area Total
Table	26	–	Fld-Seg: Cerro Fortunoso
Table	27	–	Fld-Seg: Cerro Fortunoso Stir
EL PORTÓN BLOCK
Table	28	–	El Portón Block Total
Table	29	–	Chihuido La Salina Area Total
Table	30	–	Fld-Seg: Chihuido La Salina Norte-Troncoso Inf.
Table	31	–	Fld-Seg: Chihuido La Salina-Centro Norte-Troncoso Inf.
Table	32	–	Fld-Seg: Chihuido La Salina-Centro Sur-Troncoso Info.
Table	33	–	Fld-Seg: Chihuido La Salina-Mulichinco
Table	34	–	Chihuido La Salina Sur Area Total
Table	35	–	Fld-Seg: Bajo Los Lobos-Troncoso Inf.
Table	36	–	Fld-Seg: Chihuido La Salina-Troncoso Inf.-Escama Intermedia
Table	37	–	Fld-Seg: Chihuido La Salina-Troncoso Inf.-Escama Principal
Table	38	–	Fld-Seg: Chihuido La Salina-Troncoso Inf.-Escama Superior
Table	39	–	Fld-Seg: Rincon de Correa
Table	40	–	Fld-Seg: Rincon de Correa Sur
Table	41	–	El Portón Area Total
Table	42	–	Fld-Seg: El Portón Norte
Table	43	–	Fld-Seg: El Portón Sur
RDLS BLOCK
Table	44	–	RDLS Block Total
Table	45	–	Chihuido Sierra Negra Area Total
Table	46	–	Fld -Seg: Chihuido Sierra Negra-Rayoso
Table	47	–	Fld -Seg: Chihuido-Roca Ignea / La Tosca
Table	48	–	Fld-Seg: Chihuido Sierra Negra-Troncoso Inf. / Agrio+Avile
Table	49	–	Fld-Seg: Lomita Norte
Table	50	–	Fld-Seg: Lomita-Rayoso
Table	51	–	Paso Bardas Norte Area Total
Table	52	–	Fld-Seg: Paso Bardas Norte-Grupo Neuquen
Table	53	–	Fld-Seg: Paso Bardas Norte-Huitrin (La Tosca)
Table	54	–	Fld-Seg: Paso Bardas Norte-Mulichinco
Table	55	–	Señal Picada Area Total
Table	56	–	Fld-Seg: Señal Picada-Centenario
Table	57	–	Fld-Seg: Señal Picada-Quintuco
LOMA LA LATA BLOCK
Table	58	–	Loma La Lata Block Total
Table	59	–	Aguada Toledo-Sierra Barrosa Area Total
Table	60	–	Fld-Seg: Aguada Toledo-Sierra Barrosa
Table	61	–	Fld-Seg: Barrosa Norte
Table	62	–	Fld-Seg: Barrosa Oeste
Table	63	–	Fld-Seg: Cupen Mahuida-Precuyano
Table	64	–	Fld-Seg: Cupen Mahuida Norte-Precuyano
Table	65	–	Fld-Seg: Cupen-Centenario

4

Table	66	–	Fld-Seg: El Cordon-Lajas
Table	67	–	Fld-Seg: El Cordon-Lotena
Table	68	–	Fld-Seg: El Triangulo
Table	69	–	Fld-Seg: Sierra Barrosa Este
Table	70	–	Loma La Lata Area Total
Table	71	–	Fld-Seg: Barr. Colorados-Sierras Blancas
Table	72	–	Fld-Seg: Quintuco
Table	73	–	Fld-Seg: Sierras Blancas
Table	74	–	Fld-Seg: Lotena
MEGAPLANT
Table	75	–	Mega Plant: El Portón Block, Loma La Lata Block

5

REPORT

as of

DECEMBER 31, 2005

on

RESERVES

of

CERTAIN PROPERTIES

in

ARGENTINA

attributable to

REPSOL YPF

FOREWARD

Scope of Investigation

This report presents estimates of the proved, probable, and possible crude oil, condensate, natural gas liquids (NGL), and natural gas reserves, as of December 31, 2005, of certain properties in Argentina owned by REPSOL YPF as listed in Table 1.

Estimates of proved reserves presented in this report have been prepared in compliance with the regulations promulgated by the United States Securities and Exchange Commission (SEC). Estimates of probable and possible reserves presented in this report have been prepared according to the reserves definitions approved by the Society of Petroleum Engineers (SPE) and the World Petroleum Congresses (WPC). These reserves definitions are discussed in detail in the Classification of Reserves section of this report.

Reserves estimated in this report are expressed as gross and net reserves. Gross reserves are defined as the total estimated petroleum to be produced from the properties after December 31, 2005. Net reserves are defined as that portion of the gross reserves attributable to the interests of REPSOL YPF after deducting interests owned by others. Tables 2 through 4 are summaries of the reserves estimated in this report.

Estimates of oil, condensate, NGL, and gas reserves should be regarded only as estimates that may change as further production history and additional information become available. Not only are such reserves estimates based on that information which is currently available, but such estimates are also subject to the uncertainties inherent in the application of judgmental factors in interpreting such information.

Authority

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

1

This report was authorized by Mr. Guillermo J. Garcia Alvarez-Valle, Director Control de Reservas, REPSOL YPF.

Source of Information

Information used in the preparation of this report was obtained from REPSOL YPF. In the preparation of this report we have relied, without independent verification, upon information furnished by REPSOL YPF with respect to its property interests, production from such properties, current costs of operation and development, current prices for production, agreements relating to current and future operations and sale of production, and various other information and data that were accepted as represented. A field examination of the properties was not considered necessary for the purposes of this report.

CLASSIFICATION of RESERVES

Petroleum reserves included in this report that are classified as proved are judged to be economically producible in future years from known reservoirs under existing economic and operating conditions and assuming continuation of current regulatory practices using conventional production methods and equipment. In the analyses of production-decline curves, reserves were estimated only to the limit of economic rates of production under existing economic and operating conditions using prices and costs as of the date the estimate is made, including consideration of changes in existing prices provided only by contractual arrangements but not including escalations based upon future conditions. Proved reserves classifications used in this report are in accordance with the reserves definitions of Rules 4–10(a) (1)–(13) of Regulation S–X of the SEC of the United States. The petroleum reserves are classified as follows:

Proved oil and gas reserves – Proved oil and gas reserves are the estimated quantities of crude oil, natural gas, and natural gas liquids which geological and engineering data demonstrate with reasonable certainty to be recoverable in future years from known reservoirs under existing economic and operating conditions, i.e., prices and costs as of the date the estimate is made. Prices include consideration of changes in existing prices provided only by contractual arrangements, but not on escalations based upon future conditions.

(i) Reservoirs are considered proved if economic producibility is supported by either actual production or conclusive formation test. The area of a reservoir considered proved includes (A) that portion delineated by drilling and defined by gas-oil and/or oil-water contacts, if any; and (B) the immediately adjoining portions not yet drilled, but which can be reasonably judged as economically productive on the basis of available geological and engineering data. In the absence of information on fluid contacts, the lowest known structural

2

occurrence of hydrocarbons controls the lower proved limit of the reservoir.

(ii) Reserves which can be produced economically through application of improved recovery techniques (such as fluid injection) are included in the “proved” classification when successful testing by a pilot project, or the operation of an installed program in the reservoir, provides support for the engineering analysis on which the project or program was based.

(iii) Estimates of proved reserves do not include the following: (A) oil that may become available from known reservoirs but is classified separately as “indicated additional reserves”; (B) crude oil, natural gas, and natural gas liquids, the recovery of which is subject to reasonable doubt because of uncertainty as to geology, reservoir characteristics, or economic factors; (C) crude oil, natural gas, and natural gas liquids, that may occur in undrilled prospects; and (D) crude oil, natural gas, and natural gas liquids, that may be recovered from oil shales, coal, gilsonite, and other such sources.

Proved developed oil and gas reserves – Proved developed oil and gas reserves are reserves that can be expected to be recovered through existing wells with existing equipment and operating methods. Additional oil and gas expected to be obtained through the application of fluid injection or other improved recovery techniques for supplementing the natural forces and mechanisms of primary recovery should be included as “proved developed reserves” only after testing by a pilot project or after the operation of an installed program has confirmed through production response that increased recovery will be achieved.

Proved undeveloped reserves – Proved undeveloped oil and gas reserves are reserves that are expected to be recovered from new wells on undrilled acreage, or from existing wells where a relatively major expenditure is required for recompletion. Reserves on undrilled acreage shall be limited to those drilling units offsetting productive units that are reasonably certain of production when drilled. Proved reserves for other undrilled units can be claimed only where it can be demonstrated with certainty that there is continuity of production from the existing productive formation. Under no circumstances should estimates for proved undeveloped reserves be attributable to any acreage for which an application of fluid injection or other improved recovery technique is

3

contemplated, unless such techniques have been proved effective by actual tests in the area and in the same reservoir.

The probable and possible reserves presented in this report have been prepared in accordance with reserves definitions approved in March 1997 by the SPE and the WPC. Probable and possible reserves are based on geologic and/or engineering data similar to that used in estimates of proved reserves; but technical, contractual, economic, or regulatory uncertainties preclude such reserves being classified as proved. They may be estimated assuming future economic conditions different from those prevailing at the time of the estimate. The effect of possible future improvements in economic conditions and technological developments can be expressed by allocating appropriate quantities of reserves to the probable and possible classifications.

Probable Reserves – Probable reserves are those unproved reserves which analysis of geological and engineering data suggests are more likely than not to be recoverable. In this context, when probabilistic methods are used, there should be at least a 50-percent probability that the quantities actually recovered will equal or exceed the sum of estimated proved plus probable reserves.

In general, probable reserves may include (1) reserves anticipated to be proved by normal step-out drilling where sub-surface control is inadequate to classify these reserves as proved, (2) reserves in formations that appear to be productive based on well log characteristics but lack core data or definitive tests and which are not analogous to producing or proved reservoirs in the area, (3) incremental reserves attributable to infill drilling that could have been classified as proved if closer statutory spacing had been approved at the time of the estimate, (4) reserves attributable to improved recovery methods that have been established by repeated commercially successful applications when (a) a project or pilot is planned but not in operation and (b) rock, fluid, and reservoir characteristics appear favorable for commercial application, (5) reserves in an area of the formation that appears to be separated from the proved area by faulting and the geologic interpretation indicates the subject area is structurally higher than the proved area, (6) reserves attributable to a future workover, treatment, re-treatment, change of equipment, or other mechanical procedures, where such procedure has not been proved successful in wells which exhibit similar behavior in analogous reservoirs, and (7) incremental reserves in proved reservoirs where an alternative interpretation of performance or volumetric data indicates more reserves than can be classified as proved.

4

Possible Reserves – Possible reserves are those unproved reserves which analysis of geological and engineering data suggests are less likely to be recoverable than probable reserves. In this context, when probabilistic methods are used, there should be at least a 10-percent probability that the quantities actually recovered will equal or exceed the sum of estimated proved plus probable plus possible reserves.

In general, possible reserves may include (1) reserves which, based on geological interpretations, could possibly exist beyond areas classified as probable, (2) reserves in formations that appear to be petroleum bearing based on log and core analysis but may not be productive at commercial rates, (3) incremental reserves attributed to infill drilling that are subject to technical uncertainty, (4) reserves attributed to improved recovery methods when (a) a project or pilot is planned but not in operation and (b) rock, fluid, and reservoir characteristics are such that a reasonable doubt exists that the project will be commercial, and (5) reserves in an area of the formation that appears to be separated from the proved area by faulting and geological interpretation indicates the subject area is structurally lower than the proved area.

The extent to which probable and possible reserves ultimately may be reclassified as proved reserves is dependent upon future drilling, testing, and well performance. The degree of risk to be applied in evaluating probable and possible reserves is influenced by economic and technological factors as well as the time element. Probable and possible reserves in this report have not been adjusted in consideration of these additional risks and therefore are not comparable with proved reserves.

ESTIMATION of RESERVES

Estimates of reserves were prepared by the use of standard geological and engineering methods generally accepted by the petroleum industry. The method or combination of methods utilized in the analysis of each reservoir was tempered by experience with similar reservoirs, stage of development, quality and completeness of basic data, and production history.

Where applicable, the volumetric method was used to determine the original quantities of petroleum in place. Estimates were made by using various types of logs, core analyses, and other available data. Formation tops, gross thickness, and representative values for net pay thickness, porosity, and interstitial fluid saturations were used to prepare structural maps to delineate each reservoir and isopachous maps to determine reservoir volumes. Where adequate data were available and where circumstances justified, material-balance and other engineering methods were used to estimate the original petroleum in place.

5

Estimates of ultimate recovery were obtained by applying recovery efficiency factors to the original quantities of petroleum in place. These factors were based on consideration of the type of energy inherent in the reservoir, analysis of the fluid and rock properties, the structural position of the properties, and the production history. In some instances, comparisons were made with similar producing reservoirs in the area where more complete data were available.

Where adequate data were available and where circumstances justified, material-balance and other engineering methods were used to estimate recovery factors. In these instances, reservoir performance parameters such as cumulative production, producing rate, reservoir pressure, gasoil ratio behavior, and water production were considered in estimating recovery efficiencies used in determining gross ultimate recovery.

For depletion-type reservoirs or other reservoirs where performance has disclosed a reliable decline in producing-rate trends or other diagnostic characteristics, reserves were estimated by the application of appropriate decline curves or other performance relationships. In analyzing decline curves, reserves were estimated to the calculated economic limits based on current economic conditions. Proved reserves were limited to the economic limit, the expiration date of a production license or, in the case of gas reserves, the expiration of applicable gas sales contracts, whichever occurs first.

In certain cases where the previously named methods could not be used, reserves were estimated by analogy with similar reservoirs where more complete data were available.

The reserves estimates presented herein were based on consideration of monthly production data through August 2005. Other data available through December 31, 2005, were used to prepare estimates for this report. However, reserves estimates for the Loma La Lata Block, Chihuido Sierra Negra-Troncoso Inferior/Agrio+Auile, in the Rincon de los Sauces Block were based on monthly production data through October 2005. Where applicable, estimated cumulative production, as of December 31, 2005, was deducted from the gross ultimate recovery to determine the estimated gross reserves.

Gas reserves reported herein are expressed as separator-gas and marketable-gas volumes. The gas reserves are expressed at a temperature base of 60 degrees Fahrenheit (°F) and at a pressure base of 14.696 pounds per square inch absolute (psia). Separator gas is defined as the gas remaining after field separation but prior to gas processing and shrinkage for fuel use or flare. Marketable-gas reserves were calculated from separator-gas reserves after deduction for flare, plant processing, and removal of inerts, but prior to deduction for fuel usage. NGL reserves credited to each field have been estimated on the basis of the quantities of liquids recovered from Repsol YPF’s share of gas delivered to a gas plant for processing. The NGL reserves included herein are reported as either liquefied petroleum gas (LPG) or natural gasoline. The LPG and natural gasoline estimated herein are defined as propane and butanes fractions and pentanes and heavier fractions, respectively. Oil and condensate reserves reported herein are to be recovered by normal field separation.

6

The estimated gross and net proved, probable, and possible reserves from the properties evaluated in this report, as of December 31, 2005, are summarized as follows, expressed in thousands of barrels (Mbbl) and millions of cubic feet (MMcf):

	Gross Reserves								Net Reserves
	Oil, Condensate, and Natural Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Natural Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)
Proved
Developed		238,202		15,338		84,360		2,154,192		230,551		15,131		84,360		2,153,107
Undeveloped		23,507		49		28,846		901,675		23,128		37		28,846		901,624
Total Proved		261,709		15,387		113,206		3,055,867		253,679		15,168		113,206		3,054,731
Probable*		108,148		88		32,101		1,038,424		104,273		59		32,101		1,037,969
Possible*		17,378		6		8,214		614,982		17,007		6		8,214		614,941

* Probable and possible reserves have not been adjusted for risk.

Tables 2 and 3 list the gross reserves of the fields evaluated in this report, while Table 4 lists the net reserves. Tables 5 through 74 are projections of gross proved and proved-plus-probable reserves by block, area, and field-segment. Table 75 contains the projections for the Mega plant.

In our opinion, the information relating to estimated proved reserves of crude oil, condensate, NGL, and natural gas reserves contained in this report has been prepared in accordance with Paragraphs 10—13 and 15 of Statement of Financial Accounting Standards No. 69 (November 1982) of the Financial Accounting Standards Board and Rules 4—10(a) (1)—( 13) of Regulation S—X of the Securities and Excange Commission (SEC); provided, however, that certain estimated data have not been provided with respect to changes in reserves information. These rules and regulations also contain specific provisions that prohibit the reporting of probable and possible reserves; therefore, the reporting and filing with the SEC of the probable and possible reserves contained herein would not be in conformity with such rules and regulations and should not, under any circumstances, be used or relied upon to meet the requirements thereof.

To the extent that the above-enumerated rules, regulations, and statements require determinations of an accounting or legal nature or information beyond the scope of this report, we are necessarily unable to express an opinion as to whether the above-described information is in accordance therewith or sufficient therefor.

SUMMARY and CONCLUSIONS

This report evaluates REPSOL YPF’s interests in proved, probable, and possible oil, condensate, NGL, and gas reserves in certain properties located in Argentina.

7

The estimated gross and net proved, probable, and possible reserves, as of December 31, 2005, for the properties listed in Table 1 and described in this report are summarized as follows, expressed in thousands of barrels (Mbbl) or millions of cubic feet (MMcf):

	Gross Reserves								Net Reserves
	Oil, Condensate, and Natural Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Natural Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)
Proved
Developed		238,202		15,338		84,360		2,154,192		230,551		15,131		84,360		2,153,107
Undeveloped		23,507		49		28,846		901,675		23,128		37		28,846		901,624
Total Proved		261,709		15,387		113,206		3,055,867		253,679		15,168		113,206		3,054,731
Probable*		108,148		88		32,101		1,038,424		104,273		59		32,101		1,037,969
Possible*		17,378		6		8,214		614,982		17,007		6		8,214		614,941

* Probable and possible reserves have not been adjusted for risk.

Submitted,

/s/ DeGOLYER and MacNAUGHTON

DeGOLYER and MacNAUGHTON

SIGNED: February 24, 2006

	/s/ R.M. Shuck, P.E.
	R. M. Shuck, P.E. Senior Vice President DeGolyer and MacNaughton

8

TABLE 1

PROPERTIES EVALUATED

as of

DECEMBER 31, 2005

for

REPSOL YPF

in

ARGENTINA

Block Area Field-Segment	Net Oil, Condensate and Nat. Gasoline Revenue Interest			Net Gas and LPG Revenue Interest
Mendoza Block
Barrancas Area
Barrancas Sur		100.0	%		100.0	%
Barrancas-C.R.I.		100.0	%		100.0	%
Barrancas-Cabras / B. Verde		100.0	%		100.0	%
Barrancas-Cabras-Potrerillos		100.0	%		100.0	%
Barrancas-Cabras-Villavicencio		100.0	%		100.0	%
Guanaco Blanco Area
Guanaco Blanco LRB		69.6	%		60.0	%
La Ventana Area
La Ventana-Barrancas / Rio Blanco		69.6	%		60.0	%
La Ventana Central Area
Rio Viejas		69.6	%		60.0	%
Zona Central BRC		69.6	%		60.0	%
Zona Central LRB		69.6	%		60.0	%
Zona Central TRC		69.6	%		60.0	%
Zona Central VC		69.6	%		60.0	%
La Ventana-Caflada Dura Area
La Ventana-Canada Dura		69.6	%		60.0	%
Vizcacheras-Caflada Dura Area
Vizcacheras-Caflada Dura		100.0	%		100.0	%
Vizcacheras Area
Vizcacheras-Barrancas		100.0	%		100.0	%
Vizcacheras-Papagayos		100.0	%		100.0	%
Cerro Fortunoso Area
Cerro Fortunoso		100.0	%		100.0	%
Cerro Fortunoso Sur		100.0	%		100.0	%
El Portón Block
Chihuido La Salina Area
Chihuido La Sauna Norte-Troncoso Inf.		100.0	%		100.0	%
Chihuido La Salina-Centro Norte-Troncoso Inf.		100.0	%		100.0	%
Chihuido La Salina-Centro Sur-Troncoso Inf.		100.0	%		100.0	%
Chihuido La Salina-Mulichinco		100.0	%		100.0	%
Chihuido La Sauna Sur Area
Bajo Los Lobos-Troncoso Inf.		100.0	%		100.0	%
Chthuido La Salina-Troncoso Inf.-Escama Intermedia		100.0	%		100.0	%
Chihuido La Salina-Troncoso Inf.-Escama Principal		100.0	%		100.0	%
Chihuido La Salina-Troncoso Inf.-Escama Superior		100.0	%		100.0	%
Rincon de Correa		100.0	%		100.0	%
Rincon de Correa Sur		100.0	%		100.0	%

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 1 – PROPERTIES EVALUATED – (Continued)

Block Area Field-Segment	Net Oil, Condensate and Nat. Gasoline Revenue Interest			Net Gas and LPG Revenue Interest
El Portón Area
El Portón Norte		100.0	%		100.0	%
El Portón Sur		100.0	%		100.0	%
Rincon de los Sauces Block
Chihuido Sierra Negra Area
Chihuido Sierra Negra-Rayoso		100.0	%		100.0	%
Chihuido -Roca Ignea / La Tosca		100.0	%		100.0	%
Chihuido Sierra Negra-Troncoso Inf. / Agrio+Avile		100.0	%		100.0	%
Lomita Norte		100.0	%		100.0	%
Lomita-Rayoso		100.0	%		100.0	%
Paso Bardas Norte Area
Curri Cura-Rayoso		100.0	%		100.0	%
Paso Bardas Norte-Grupo Neuquen		100.0	%		100.0	%
Paso Bardas Norte-Huitrin (La Tosca)		100.0	%		100.0	%
Paso Bardas Norte-Mulichinco		100.0	%		100.0	%
Señal Picada Area
Señal Picada-Centenario		100.0	%		100.0	%
Señal Picada-Quintuco		100.0	%		100.0	%
Loma La Lata Block
Aguada Toledo-Sierra Barrosa Area
Aguada Toledo-Sierra Barrosa		100.0	%		100.0	%
Barrosa Norte		100.0	%		100.0	%
Barrosa Oeste		100.0	%		100.0	%
Cupen Mahuida-Precuyano		100.0	%		100.0	%
Cupen Mahuida Norte-Precuyano		100.0	%		100.0	%
Cupen-Centenario		100.0	%		100.0	%
El Cordon-Lajas		100.0	%		100.0	%
El Cordon-Lotena		100.0	%		100.0	%
El Triangulo		100.0	%		100.0	%
Sierra Barrosa Este		100.0	%		100.0	%
Loma La Lata Area
Barr. Colorados-Sierras Blancas		100.0	%		100.0	%
Quintuco		100.0	%		100.0	%
Sierras Blancas		100.0	%		100.0	%
Lotena		100.0	%		100.0	%

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 2

PROVED GROSS RESERVES

as of

DECEMBER 31, 2005

of

CERTAIN PROPERTIES

with interests owned by

REPSOL YPF

in

ARGENTINA

	Reserves
	Proved Developed								Proved Undeveloped								Total Proved
Block Area Field Segment	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)
Mendoza Block
Barrancas Area
Barrancas Sur		364		0		0		0.0		1,604		0		0		0.0		1,868		0		0		0.0
Barrancas-C.R.I.		8,264		262		0		340.8		943		15		0		47.1		9,207		277		0		387.9
Barrancas-Cabras / B. Verde		11,203		0		0		461.7		79		0		0		3.4		11,282		0		0		465.1
Barrancas-Cabras-Potrerillos		664		0		0		27.1		0		0		0		0.5		664		0		0		27.1
Barrancas-Cabras-Villavicencio		54		0		0		3.4		8		0		0		0.0		54		0		0		3.4
Subtotal-Barrancas Area		20,549		262		0		833.0		2,626		15		0		50.5		23,175		277		0		883.5
Guanaco Blanco Area
Guanaco Blanco LRB		84		0		0		0.0		0		0		0		0.0		84		0		0		0.0
La Ventana Area
La Ventana-Barrancas / Rio Blanco		3,212		0		0		348.7		0		0		0		0.0		3,212		0		0		348.7
La Ventana Central Area
Rio Viejas		2,174		51		0		236.0		283		7		0		30.7		2,457		58		0		266.7
Zona Central BRC		1,601		132		0		607.9		228		7		0		25.0		5,829		139		0		632.9
Zona Control LRB		272		7		0		29.5		0		0		0		0.0		272		7		0		25.5
Zona Central TRC		7,580		180		0		822.7		448		10		0		48.7		8,028		190		0		871.4
Zona Central VC		6,155		147		0		668.1		227		5		0		24.5		6,382		512		0		692.6
Subtotal-La Ventana Cent. Area		21,782		517		0		2,364.2		1,186		29		0		128.9		22,968		546		0		2,493.1
La Ventana-Cañada Dura Area
La Ventana-Cañada Dura		90		0		0		0.0		64		0		0		0.0		154		0		0		0.0
Vizcacheras-Cañada Dura Area
Vizcacheras-Cañada Dura		4,244		0		0		232.0		0		0		0		0.0		4,244		0		0		232.0
Vizcacheras Area
Vizcacheras-Barrancas		8,032		118		0		698.4		74		0		0		6.4		8,106		116		0		704.8
Vizcacheras-Papagayos		17,903		259		0		1,556.9		284		5		0		24.5		18,187		264		0		1,581.4
Subtotal-Vizcacheras Area		25,935		377		0		2,255.3		358		5		0		30.9		26,293		382		0		2,286.2
Cerro Fortunoso Area
Cerro Fortunoso		13,120		0		0		0.0		865		0		0		0.0		13,989		0		0		0.0
Cerro Fortunoso Sur		44		0		0		0.0		5		0		0		0.0		44		0		0		0.0
Subtotal-Cerro Fortunoso Area		13,164		0		0		0.0		869		0		0		0.0		14,033		0		0		0.0
Total-Mendoza Block		89,060		1,156		0		6,033.2		5,103		49		0		210.3		94,163		1,205		0		6,243.5
El Portón Black
Chihuido La Salina Area
Chihuido La Salina Norte-Troncoso Inf.		8,629		0		0		12,190.6		2,704		0		0		0.0		11,333		0		0		12,190.6
Chihuido La Salina-Centro Norte-Troncoso Inf.		15,424		0		0		62,828.8		2,828		0		0		0.0		18,252		0		0		82,828.8
Chihuido La Salina-Centro Sur-Troncoso Inf.		4,057		0		0		164,868.0		0		0		0		0.0		4,057		0		0		154,868.0
Chihuido La Solina-Mulichinco		0		0		0		0.0		5		0		0		0.0		0		0		0		0.0
Subtotal-Chihuido La Salina Area		28,110		0		0		239,887.4		5,532		0		0		0.0		33,642		0		0		239,887.4
Chihuido La Salina Sur Area
Bajo Los Lobos-Troncoso Inf.		125		0		0		8,757.0		0		0		0		0.0		125		0		0		8,757.0
Chihuido La Salina-Troncoso Inf.-Escama Intermedia		483		0		0		5,876.6		741		0		0		0.5		1,224		0		0		5,976.6
Chihuido La Salina-Troncoso Inf.-Escama Principal		3,918		0		0		29,270.9		691		0		0		0.0		4,609		0		0		29,270.9
Chihuido La Salina-Troncoso Inf.-Escama Superior		1,560		0		0		24,825.8		0		0		0		0.0		1,560		0		0		24,825.8
Rincon de Correa		257		0		0		0.0		220		0		0		0.0		477		0		0		0.0
Rincon de Correa Sur		188		0		0		0.0		315		0		0		0.0		503		0		0		0.0
Subtotal-Chihuido La Salina Sur Area		6,531		0		0		68,830.3		1,967		0		0		0.0		8,498		0		0		68,830.3

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 2 – PROVED GROSS RESERVES – (Continued)

	Reserves
	Proved Developed								Proved Undeveloped								Total Proved
Block Area Field Segment	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)
El Portón Area
El Portón Norte		4,006		0		0		100,421.4		1,040		0		0		0.0		5,046		0		0		100,421.4
El Portón Sur		3,460		0		0		73,017.3		0		0		0		0.0		3,460		0		0		73,017.3
Subtotal-El Portón Ares		7,466		0		0		173,438.7		1,040		0		0		0.0		8,506		0		0		173,438.7
Total-El Portón, Block		42,107		14,182		22,934		482,156.4		8,539		0		0		0.0		50,646		14,182		22,934		482,156.4
Rincon do los Sauces Black
Chihuido Sierra Negra Area
Chihuido Sierra Negra-Rayoso		565		0		0		66.9		139		0		0		16.5		704		0		0		83.4
Chihuido .Roca Ignea / La Tosca		757		0		0		126.9		0		0		0		0.0		757		0		0		126.9
Chihuido Sierra Negra-Troncoso Inf. /Agrio+Avile		59,857		0		0		7,341.9		0		0		0		0.0		59,857		0		0		7,341.9
Lomita Norte		590		0		0		56.0		0		0		0		0.0		590		0		0		56.0
Lomita-Rayoso		1,088		0		0		103.3		0		0		0		0.0		1,088		0		0		103.3
Subtotal-Chihuido Sierra Negra Area		62,857		0		0		7,695.0		139		0		0		16.5		62,996		0		0		7,711.5
Paso Bardas Norte Area
Paso Bardas Norte-Grupo Neuquen		0		0		0		5,914.1		0		0		0		64,779.6		0		0		0		70,693.7
Paso Bardas Norte-Huitrin (La Tosca)		177		0		0		3,910.9		0		0		0		0.0		177		0		0		3,910.9
Paso Bardas Norte-Mulichinco		0		0		0		0.0		0		0		0		0.0		0		0		0		0.0
Subtotal-Paso Bardas Norte Area		177		0		0		9,825.0		0		0		0		64,779.6		177		0		0		74,604.6
Señal Picada Area
Señal Picada-Centenario		46		0		0		0.0		0		0		0		0.0		46		0		0		0.0
Señal Picada-Quintuco		16,816		0		0		749.9		0		0		0		0.0		16,816		0		0		749.9
Subtotal-Señal Picada Area		16,862		0		0		749.9		0		0		0		0.0		16,862		0		0		749.9
Total-Rincon de los Sauces Block		79,896		0		0		18,269.9		139		0		0		64,796.1		80,035		0		0		83,066.0
																		0		0				0.0
Loma La Lata Block
Aguada Toledo-Sierra Barrosa Area
Aguada Toledo-Sierra Barrosa		7,955		0		0		105,622.8		1,050		0		0		0.0		9,005		0		0		105,622.8
Barrosa Norte		0		0		0		5,462.8		0		0		0		20,082.6		0		0		0		25,545.4
Barrosa Oeste		67		0		0		1,451.3		0		0		0		10,128.6		67						11,579.9
Cupen Mahuida-Precuyano		0		0		0		26,474.1		0		0		0		35,624.8		0						62,098.9
Cupen Mahuida Norte-Precuyano		0		0		5		3,318.0		0		0		0		2,235.9		0						5,553.9
Cupen-Centenario		0		0		0		5,717.4		0		0		0		970.1		0						6,687.5
El Cordon-Lajas		0		0		0		0.0		0		0		0		0.0		0						0.0
El Cordon-Lotena		0		0		0		0.0		0		0		0		0.0		0						0.0
El Triangulo		24		6		0		7,769.7		5		0		0		0.0		24		0		0		7,769.7
Sierra Barrosa Este		0		0		0		0.0		0		0		0		0.0		0		0		0		0.0
Subtotal-Aguada Toledo-Sierra Barrosa Area		8,046		0		0		155,816.1		1,050		0		0		69,042.0		9,096		0		0		224,858.1
Loma La Lata Area
Barr. Colorados-Sierras Blancas		32		0		0		1,080.7		0		0		0		0.0		32		0		0		1,080.7
Quintuco		410		0		0		339.9		0		0		0		0.0		410		0		0		339.9
Sierras Blancas		18,651		0		61,426		1,444,092.6		8,676		0		28,846		680,994.8		27,327		0		90,272		2,125,087.4
Lotena		0		0		0		46,403.5		0		0		0		86,631.9		0		0		0		133,035.4
Subtotal-Loma La Lata Area		19,093		0		61,426		1,491,916.7		8,676		0		28,846		767,626.7		27,769		0		90,272		2,259,543.4
Total-Loma La Lata Block		27,139		0		61,426		1,647,732.8		9,726		0		28,846		836,668.7		36,865		0		90,272		2,484,401.5
Total		238,202		15,338		84,360		2,154,192.3		23,507		49		28,846		901,675.1		261,709		15,387		113,206		3,055,867.4

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 3

PROBABLE and POSSIBLE GROSS RESERVES

as of

DECEMBER 31, 2005

of

CERTAIN PROPERTIES

with interests owned by

REPSOL YPF

in

ARGENTINA

	Reserves
	Probable								Possible
Block Area Field-Segment	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)
Mendoza Block
Barrancas Area
Barrancas Sur		4,325		0		0		0.0		0		0		0		0.0
Barrancas-C.R.I.		5,134		8		0		119.0		0		0		0		0.0
Barrancas-Cabras / B. Verde		4,379		0		0		180.4		0		0		0		0.0
Barrancas-Cabras-Potrerillos		265		0		0		10.1		0		0		0		0.0
Barrancas-Cabras-Villavicencio		0		0		0		0.0		0		0		0		0.0
Subtotal-Barrancas Area		14,103		8		0		309.5		0		0		0		0.0
Guanaco Blanco Area
Guanaco Blanco LRB		0		0		0		0.0		0		0		0		0.0
La Ventana Area
La Ventana-Barrancas/ Rio Blanco		1,336		0		0		102.4		0		0		0		0.0
La Ventana Central Area
Rio Viejas		1,048		4		0		88.5		94		0		0		13.0
Zona Central BRC		2,647		21		0		248.1		453		0		0		0.0
Zona Central LRB		822		0		0		88.9		0		0		0		0.0
Zona Central TRC		3,705		31		0		331.8		0		0		0		0.0
Zona Central VC		3,189		18		0		278.7		673		0		0		88.0
Subtotal-La Ventana Cent. Area		11,411		74		0		1,036.0		1,220		0		0		101.0
La Ventana-Cañada Dura Area
La Ventana-Cañada Dura		0		0		0		0.0		0		0		0		0.0
Vizcacheras-Cañada Dura Area
Vizcacheras-Cañada Dura		1,298		0		0		71.0		881		0		0		52.1
Vizcacheras Area
Vizcacheras-Barrancas		4,269		3		0		371.3		0		0		0		0.0
Vizcacheras-Papagayos		6,771		3		0		589.1		434		6		0		39.0
Subtotal-Vizcacheras Area		11,040		6		0		960.4		434		6		0		39.0
Cerro Fortunoso Area
Cerro Fortunoso		4,195		0		0		0.0		0		0		0		0.0
Cerro Fortunoso Sur		105		0		0		0.0		0		0		0		0.0
Subtotal-Cerro Fortunoso Area		4,300		0		0		0.0		0		0		0		0.0
Total-Mendoza Block		43,488		88		0		2,479.3		2,535		6		0		192.1
El Portón Block
Chihuido La Salina Area
Chihuido La Salina Norte-Troncoso Inf.		2,391		0		0		0.0		1,195		0		0		0.0
Chihuido La Salina-Centro Norte-Troncoso Inf.		3,359		0		0		0.0		2,516		0		0		0.0
Chihuido La Salina-Centro Sur-Troncoso Inf.		427		0		0		0.0		0		0		0		0.0
Chihuido La Salina-Mulichinco		0		0		0		0.0		0		0		0		0.0
Subtotal-Chihuido La Salina Area		6,177		0		0		0.0		3,711		0		0		0.0
Chihuido La Salina Sur Area
Bajo Los Lobos-Troncoso Inf.		133		0		0		9,000.4		0		0		0		0.0
Chihuido La Salina-Troncoso Inf.-Escama Intermedi		627		0		0		0.0		440		0		0		0.0
Chihuido La Salina-Troncoso Inf.-Escama Principal		2,354		0		0		0.0		1,629		0		0		0.0
Chihuido La Salina-Troncoso Inf.-Escama Superior		0		0		0		0.0		0		0		0		0.0
Rincon de Correa		0		0		0		0.0		220		0		0		0.0
Rincon de Correa Sur		630		0		0		0.0		943		0		0		0.0
Subtotal-Chihuido La Salina Sur Area		3,744		0		0		9,000.4		3,232		0		0		0.0

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 3 – PROBABLE and POSSIBLE GROSS RESERVES (Continued)

	Reserves
	Probable								Possible
Block Area Field-Segment	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)
El Portón Area
El Portón Norte		0		0		0		0.0		0		0		0		0.0
El Portón Sur		264		0		0		0.0		3,604		0		0		0.0
Subtotal-El Portón Area		264		0		0		0.0		3,604		0		0		0.0
Total-El Portón Block		10,185		0		0		9,000.4		10,547		0		0		0.0
Rincon de los Sauces Block
Chihuido Sierra Negra Area
Chihuido Sierra Negra-Rayoso		1,132		0		0		134.8		0		0		0		0.0
Chihuido -Roca Ignea / La Tosca		542		0		0		91.1		755		0		0		70.6
Chihuido Sierra Negra-Troncoso Inf. /Agrio+Avile		36,635		0		0		4,495.7		0		0		0		22,633.2
Lomita Norte		1,284		0		0		125.2		0		0		0		0.0
Lomita-Rayoso		630		0		0		59.9		629		0		0		0.0
Subtotal-Chihuido Sierra Negra Area		40,223		0		0		4,906.7		1,384		0		0		22,703.8
Paso Bardas Norte Area
Paso Bardas Norte-Grupo Neuquen		0		0		0		19,633.1		0		0		0		0.0
Paso Bardas Norte-Huitrin (La Tosca)		0		0		0		0.0		0		0		0		0.0
Paso Bardas Norte-Mulichinco		835		0		0		167.9		440		0		0		5,085.3
Subtotal-Paso Bardas Norte Area		835		0		0		19,801.0		440		0		0		5,085.3
Señal Picada Area
Señal Picada-Centenario		0		0		0		0.0		0		0		0		0.0
Señal Picada-Quintuco		2,445		0		0		109.2		0		0		0		0.0
Subtotal-Señal Picada Area		2,445		0		0		109.2		0		0		0		0.0
Total-Rincon de los Sauces Block		43,503		0		0		24,816.9		1,824		0		0		27,789.1
Loma La Lata Block
Aguada Toledo-Sierra Barrosa Area
Aguada Toledo-Sierra Barrosa		0		0		0		33,520.6		0		0		0		0.0
Barrosa Norte		0		0		0		0.0		0		0		0		85,496.8
Barrosa Oeste		0		0		0		8,906.9		0		0		0		1,589.2
Cupen Mahuida-Precuyano		0		0		0		46,975.6		0		0		0		204,260.0
Cupen Mahuida Norte-Precuyano		0		0		0		7,789.0		0		0		0		26,556.6
Cupen-Centenario		0		0		0		3,691.4		0		0		0		2,648.6
El Cordon-Lajas		0		0		0		0.0		0		0		0		44,461.2
El Cordon-Lotena		0		0		0		0.0		0		0		0		27,969.2
El Triangulo		0		0		0		0.0		0		0		0		0.0
Sierra Barrosa Este		0		0		0		4,610.2		0		0		0		0.0
Subtotal-Aguada Toledo-Sierra Barrosa Area		0		0		0		105,493.7		0		0		0		392,981.6
Loma La Lata Area
Barr. Colorados-Sierras Blancas		490		0		0		19,089.3		0		0		0		0.0
Quintuco		830		0		0		327.6		0		0		0		0.0
Sierras Blancas		9,652		0		32,101		758,098.8		2,472		0		8,214		194,018.8
Lotena		0		0		0		119,118.3		0		0		0		0.0
Subtotal-Loma La Lata Area		10,972		0		32,101		896,634.0		2,472		0		8,214		194,018.8
Total-Loma La Lata Block		10,972		0		32,101		1,002,127.7		2,472		0		8,214		587,000.4
Total		108,148		88		32,101		1,038,424.3		17,378		6		8,214		614,981.6

Note:  Probable and possible reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 4

PROVED, PROBABLE, and POSSIBLE NET RESERVES

as of

DECEMBER 31, 2005

of

CERTAIN PROPERTIES

attributable to

REPSOL YPF

in

ARGENTINA

	Reserves
	Proved Developed								Proved Undeveloped								Total Proved								Probable								Possible
Block Area Field-Segment	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil and Condensate(Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)
Mendoza Block
Barrancas Area
Barrancas Sur		364		0		0		0.0		1,604		0		0		0.0		1,968		0		0		0.0		4,325		0		0		0.0		0		0		0		0.0
Barrancas-C.R.I.		8,264		262		0		340.8		943		15		0		47.1		9,207		277		0		387.9		5,134		8		0		119.0		0		0		0		0.0
Barrancas-Cabras / B. Verde		11,203		0		0		461.7		79		0		0		3.4		11,282		0		0		465.1		4,379		0		0		180.4		0		0		0		0.0
Barrancas-Cabras-Potrerillos		664		0		0		27.1		0		0		0		0.0		664		0		0		27.1		265		0		0		10.1		0		0		0		0.0
Barrancas-Cabras-Villavicencio		54		0		0		3.4		0		0		0		0.0		54		0		0		3.4		0		0		0		0.0		0		0		0		0.0
Subtotal-Barrancas Area		20,549		262		0		833.0		2,626		15		0		50.5		23,175		277		0		883.5		14,103		8		0		309.5		0		0		0		0.0
Guanaco Blanco Area
Guanaco Blanco LRB		58		0		0		0.0		0		0		0		0.0		58		0		0		0.0		0		0		0		0.0		0		0		0		0.0
La Ventana Area
La Ventana-Barrancas/ Rio Blanco		2,236		0		0		209.2		0		0		0		0.0		2,236		0		0		209.2		930		0		0		61.4		0		0		0		0.0
La Ventana Central Area
Rio Viejas		1,513		31		0		141.6		197		4		0		18.4		1,710		35		0		160.0		729		2		0		53.1		66		0		0		7.8
Zona Central BRC		3,898		79		0		364.7		159		4		0		15.0		4,057		83		0		379.7		1,842		13		0		148.9		315		0		0		0.0
Zona Central LRB		189		4		0		17.7		0		0		0		0.0		189		4		0		17.7		572		0		0		53.3		0		0		0		0.0
Zona Central TRC		5,276		108		0		493.6		312		6		0		29.2		5,588		114		0		522.8		2,579		19		0		199.1		0		0		0		0.0
Zona Central VC		4,284		88		0		400.9		158		3		0		14.7		4,442		91		0		415.6		2,220		11		0		167.2		468		0		0		52.8
Subtotal-La Ventana Cent. Area		15,160		310		0		1,418.5		826		17		0		77.3		15,986		327		0		1,495.8		7,942		45		0		621.6		849		0		0		60.6
La Ventana-Cañada Dura Area
La Ventana-Cañada Dura		63		0		0		0.0		45		0		0		0.0		108		0		0		0.0		0		0		0		0.0		0		0		0		0.0
Vizcacheras-Cañada Dura Area
Vizcacheras-Cañada Dura		4,244		0		0		232.0		0		0		0		0.0		4,244		0		0		232.0		1,298		0		0		71.0		881		0		0		52.1
Vizcacheras Area
Vizcacheras-Barrancas		8,032		118		0		698.4		74		0		0		6.4		8,106		118		0		704.8		4,269		3		0		371.3		0		0		0		0.0
Vizcacheras-Papagayos		17,903		259		0		1,556.9		284		5		0		24.5		18,187		264		0		1,581.4		6,771		3		0		589.1		434		6		0		39.0
Subtotal-Vizcacheras Area		25,935		377		0		2,255.3		358		5		0		30.9		26,293		382		0		2,286.2		11,040		6		0		960.4		434		6		0		39.0
Cerro Fortunoso Area
Cerro Fortunoso		13,120		0		0		0.0		869		0		0		0.0		13,989		0		0		0.0		4,195		0		0		0.0		0		0		0		0.0
Cerro Fortunoso Sur		44		0		0		0.0		0		0		0		0.0		44		0		0		0.0		105		0		0		0.0		0		0		0		0.0
Subtotal-Cerro Fortunoso Area		13,164		0		0		0.0		869		0		0		0.0		14,033		0		0		0.0		4,300		0		0		0.0		0		0		0		0.0
Total-Mendoza Block		81,409		949		0		4,948.0		4,724		37		0		158.7		86,133		986		0		5,106.7		39,613		59		0		2,023.9		2,164		0		0		151.7
El Portón Block
Chihuido La Salina Area
Chihuido La Salina Norte-Troncoso Inf.		8,629		0		0		12,190.6		2,704		0		0		0.0		11,333		0		0		12,190.6		2,391		0		0		0.0		1,195		0		0		0.0
Chihuido La Salina-Centro Norte-Troncoso Inf.		15,424		0		0		62,828.8		2,828		0		0		0.0		18,252		0		0		62,828.8		3,359		0		0		0.0		2,516		0		0		0.0
Chihuido La Salina-Centro Sur-Troncoso Inf.		4,057		0		0		164,868.0		0		0		0		0.0		4,057		0		0		164,868.0		427		0		0		0.0		0		0		0		0.0
Chihuido La Salina-Mulichinco		0		0		0		0.0		0		0		0		0.0		0		0		0		0.0		0		0		0		0.0		0		0		0		0.0
Subtotal-Chihuido La Salina Area		28,110		0		0		239,887.4		5,532		0		0		0.0		33,642		0		0		239,887.4		6,177		0		0		0.0		3,711		0		0		0.0
Chihuido La Salina Sur Area
Bajo Los Lobos-Troncoso Inf.		125		0		0		8,757.0		0		0		0		0.0		125		0		0		8,757.0		133		0		0		9,000.4		0		0		0		0.0
Chihuido La Salina-Troncoso Inf.-Escama Intermeda		483		0		0		5,976.6		741		0		0		0.0		1,224		0		0		5,976.6		627		0		0		0.0		440		0		0		0.0
Chihuido La Salina-Troncoso Inf.-Escama Principal		3,918		0		0		29,270.9		691		0		0		0.0		4,609		0		0		29,270.9		2,354		0		0		0.0		1,629		0		0		0.0
Chihuido La Salina-Troncoso Inf.-Escama Superior		1,560		0		0		24,825.8		0		0		0		0.0		1,560		0		0		24,825.8		0		0		0		0.0		0		0		0		0.0
Rincon de Correa		257		0		0		0.0		220		0		0		0.0		477		0		0		0.0		0		0		0		0.0		220		0		0		0.0
Rincon de Correa Sur		188		0		0		0.0		315		0		0		0.0		503		0		0		0.0		630		0		0		0.0		943		0		0		0.0
Subtotal-Chihuido La Salina Sur Area		6,531		0		0		68,830.3		1,967		0		0		0.0		8,498		0		0		68,830.3		3,744		0		0		9,000.4		3,232		0		0		0.0

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 4 – PROVED, PROBABLE, and POSSIBLE NET RESERVES – (Continued)

	Proved Developed								Proved Undeveloped								Total Proved								Probable								Possible
Block Area Field-Segment	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil and Condensat		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Mega Plant NGL (Mbbl)		Marketable Gas (MMcf)
El Portón Area
El Portón Norte		4,006		0		0		100,421.4		1,040		0		0		0.0		5,046		0		0		100,421.4		0		0		0		0.0		0		0		0		0.0
El Portón Sur		3,460		0		0		73,017.3		0		0		0		0.0		3,460		0		0		73,017.3		264		0		0		0.0		3,604		0		0		0.0
Subtotal-El Portón Area		7,466		0		0		173,438.7		1,040		0		0		0.0		8,506		0		0		173,438.7		264		0		0		0.0		3,604		0		0		0.0
Total-El Portón Block		42,107		1,4182		22,934		482,156.4		8,539		0		0		0.0		50,646		14,182		22,934		482,156.4		10,185		0		0		9,000.4		10,547		0		0		0.0
Rincon de los Sauces Block
Chihuido Sierra Negra Area
Chihuido Sierra Negra-Rayoso		565		0		0		66.9		139		0		0		16.5		704		0		0		83.4		1,132		0		0		134.8		0		0		0		0.0
Chihuido -Roca Ignea / La Tosca		757		0		0		126.9		0		0		0		0.0		757		0		0		126.9		542		0		0		91.1		755		0		0		70.6
Chihuido Sierra Negra-Troncoso Inf. /Agrio+Avile		59,857		0		0		7,341.9		0		0		0		0.0		59,857		0		0		7,341.9		36,635		0		0		4,495.7		0		0		0		22,633.2
Lomita Norte		590		0		0		56.0		0		0		0		0.0		590		0		0		56.0		1,284		0		0		125.2		0		0		0		0.0
Lomita-Rayoso		1,088		0		0		103.3		0		0		0		0.0		1,088		0		0		103.3		630		0		0		59.9		629		0		0		0.0
Subtotal-Chihuido Sierra Negra Area		62,857		0		0		7,695.0		139		0		0		16.5		62,996		0		0		7,711.5		40,223		0		0		4,906.7		1,384		0		0		22,703.8
Paso Bardas Norte Area
Paso Bardas Norte-Grupo Neuquen		0		0		0		5,914.1		0		0		0		64,779.6		0		0		0		70,693.7		0		0		0		19,633.1		0		0		0		0.0
Paso Bardas Norte-Huitrin (La Tosca)		177		0		0		3,910.9		0		0		0		0.0		177		0		0		3,910.9		0		0		0		0.0		0		0		0		0.0
Paso Bardas Norte-Mulichinco		0		0		0		0.0		0		0		0		0.0		0		0		0		0.0		835		0		0		167.9		440		0		0		5,085.3
Subtotal-Paso Bardas Norte Area		177		0		0		9,825.0		0		0		0		64,779.6		177		0		0		74,604.6		835		0		0		19,801.0		440		0		0		5,085.3
Señal Picada Area
Señal Picada-Centenario		46		0		0		0.0		0		0		0		0.0		46		0		0		0.0		0		0		0		0.0		0		0		0		0.0
Señal Picada-Quintuco		16,816		0		0		749.9		0		0		0		0.0		16,816		0		0		749.9		2,445		0		0		109.2		0		0		0		0.0
Subtotal-Señal Picada Area		16,862		0		0		749.9		0		0		0		0.0		16,862		0		0		749.9		2,445		0		0		109.2		0		0		0		0.0
Total-Rincon de los Sauces Block		79,896		0		0		18,269.9		139		0		0		64,796.1		80,035		0		0		83,066.0		43,503		0		0		24,816.9		1,824		0		0		27,789.1
Loma La Lata Block
Aguada Toledo-Sierra Barrosa Area
Aguada Toledo-Sierra Barrosa		7,955		0		0		105,622.8		1,050		0		0		0.0		9,005		0		0		105,622.8		0		0		0		33,520.6		0		0		0		0.0
Barrosa Norte		0		0		0		5,462.8		0		0		0		20,082.6		0		0		0		25,545.4		0		0		0		0.0		0		0		0		85,496.8
Barrosa Oeste		67		0		0		1,451.3		0		0		0		10,128.6		67		0		0		11,579.9		0		0		0		8,906.9		0		0		0		1,589.2
Cupen Mahuida-Precuyano		0		0		0		26,474.1		0		0		0		35,624.8		0		0		0		62,098.9		0		0		0		46,975.6		0		0		0		204,260.0
Cupen Mahuida Norte-Precuyano		0		0		0		3,318.0		0		0		0		2,235.9		0		0		0		5,553.9		0		0		0		7,789.0		0		0		0		26,556.6
Cupen-Centenario		0		0		0		5,717.4		0		0		0		970.1		0		0		0		6,687.5		0		0		0		3,691.4		0		0		0		2,648.6
El Cordon-Lajas		0		0		0		0.0		0		0		0		0.0		0		0		0		0.0		0		0		0		0.0		0		0		0		44,461.2
El Cordon-Lotena		0		0		0		0.0		0		0		0		0.0		0		0		0		0.0		0		0		0		0.0		0		0		0		27,969.2
El Triangulo		24		0		0		7,769.7		0		0		0		0.0		24		0		0		7,769.7		0		0		0		0.0		0		0		0		0.0
Sierra Barrosa Este		0		0		0		0.0		0		0		0		0.0		0		0		0		0.0		0		0		0		4,610.2		0		0		0		0.0
Subtotal-Aguada Toledo-Sierra Barrosa Area		8,046		0		0		155,816.1		1,050		0		0		69,042.0		9,096		0		0		224,858.1		0		0		0		105,493.7		0		0		0		392,981.6
Lorna La Lata Area
Barr. Colorados-Sierras Blancas		32		0		0		1,080.7		0		0		0		0.0		32		0		0		1,080.7		490		0		0		19,089.3		0		0		0		0.0
Quintuco		410		0		0		339.9		0		0		0		0.0		410		0		0		339.9		830		0		0		327.6		0		0		0		0.0
Sierras Blancas		18,651		0		61,426		1,444,0926		8,676		0		28,846		680,994.8		27,327		0		90,272		2,125,087.4		9,652		0		32,101		758,098.8		2,472		0		8,214		194,018.8
Lotena		0		0		0		46,403.5		0		0		0		86,631.9		0		0		0		133,035.4		0		0		0		119,118.3		0		0		0		0.0
Subtotal-Loma La Lata Area		19,093		0		61,426		1491,916.7		8,676		0		28,846		767,626.7		27,769		0		90,272		2,259,543.4		10,972		0		32,101		896,634.0		2,472		0		8,214		194,018.8
Total-Loma La Lata Block		27,139		0		61,426		1,647,732.8		9,726		0		28,846		836,668.7		36,865		0		90,272		2,484,401.5		10,972		0		32,101		1,002,127.7		2,472		0		8,214		587,000.4
Total		230,551		15,131		84,360		2,153,107.1		23,128		37		28,846		901,623.5		253,679		15,168		113,206		3,054,730.6		104,273		59		32,101		1,037,968.9		17,007		6		8,214		614,941.2

Note:  Probable and possible reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 5

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		11,507		146		750.8		11,911		150		774.4		12,423		155		784.6
2007		10,332		133		686.7		11,321		143		722.0		12,579		153		748.1
2008		9,403		123		633.3		10,308		130		668.6		12,310		145		712.6
2009		8,587		113		582.6		9,311		119		612.9		11,545		132		677.9
2010		7,916		105		539.2		8,479		110		563.3		10,415		120		637.2
2011		7,314		97		500.0		7,739		102		518.6		9,275		109		586.5
2012		6,804		90		466.4		7,130		93		479.9		8,307		100		533.8
2013		6,311		82		433.3		6,556		85		442.6		7,469		90		485.4
2014		5,873		74		404.4		6,077		78		412.9		6,798		82		446.9
2015		5,483		70		377.6		5,647		71		384.0		6,198		75		410.1
2016		5,132		65		354.7		5,235		66		358.2		5,657		68		376.6
2017		4,398		58		304.2		4,449		58		306.1		5,076		60		340.9
2018		0		0		0.0		0		0		0.0		3,871		1		306.9
2019		0		0		0.0		0		0		0.0		3,609		1		284.8
2020		0		0		0.0		0		0		0.0		3,373		1		264.4
2021		0		0		0.0		0		0		0.0		3,146		1		245.2
2022		0		0		0.0		0		0		0.0		2,949		0		228.6
2023		0		0		0.0		0		0		0.0		2,766		0		195.3
2024		0		0		0.0		0		0		0.0		2,611		0		182.7
2025		0		0		0.0		0		0		0.0		2,457		0		99.3
2026		0		0		0.0		0		0		0.0		2,325		0		93.9
2027		0		0		0.0		0		0		0.0		2,066		0		81.1
2028		0		0		0.0		0		0		0.0		426		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		89,060		1,156		6,033.2		94,163		1,205		6,243.5		137,651		1,293		8,722.8

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 6

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – BARRANCAS

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		2,495		36		99.2		2,693		37		111.6		2,803		38		106.5
2007		2,295		32		91.8		2,837		35		98.9		3,215		36		102.4
2008		2,122		29		85.5		2,595		31		91.3		3,554		33		94.5
2009		1,961		26		79.2		2,328		28		84.6		3,317		29		87.1
2010		1,823		24		74.1		2,097		25		78.2		2,820		26		80.5
2011		1,702		22		69.3		1,901		23		72.5		2,427		23		74.4
2012		1,595		20		65.1		1,754		21		67.9		2,140		21		69.7
2013		1,493		18		61.0		1,620		19		63.6		1,907		19		65.3
2014		1,403		16		57.5		1,507		17		59.8		1,721		17		61.4
2015		1,323		14		54.2		1,410		15		56.4		1,571		16		57.8
2016		1,253		13		51.5		1,312		14		52.9		1,435		14		54.2
2017		1,084		12		44.6		1,121		12		45.8		1,309		13		50.9
2018		0		0		0.0		0		0		0.0		1,119		0		46.1
2019		0		0		0.0		0		0		0.0		1,063		0		43.8
2020		0		0		0.0		0		0		0.0		1,015		0		41.8
2021		0		0		0.0		0		0		0.0		964		0		39.7
2022		0		0		0.0		0		0		0.0		920		0		38.0
2023				0		0.0		0		0		0.0		879		0		18.1
2024		0		0		0.0		0		0		0.0		843		0		17.1
2025		0		0		0.0		0		0		0.0		805		0		16.1
2026		0		0		0.0		0		0		0.0		772		0		15.2
2027		0		0		0.0		0		0		0.0		679		0		12.4
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		20,549		262		833.0		23,175		277		883.5		37,278		285		1,193.0

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 7

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – BARRANCAS

FIELD-SEGMENT – BARRANCAS SUR

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		96		0		0.0		195		0		0.0		226		0		0.0
2007		72		0		0.0		443		0		0.0		736		0		0.0
2008		53		0		0.0		385		0		0.0		1,266		0		0.0
2009		40		0		0.0		279		0		0.0		1,208		0		0.0
2010		29		0		0.0		202		0		0.0		869		0		0.0
2011		22		0		0.0		146		0		0.0		625		0		0.0
2012		16		0		0.0		106		0		0.0		449		0		0.0
2013		12		0		0.0		77		0		0.0		323		0		0.0
2014		9		0		0.0		56		0		0.0		232		0		0.0
2015		7		0		0.0		40		0		0.0		167		0		0.0
2016		5		0		0.0		28		0		0.0		119		0		0.0
2017		3		0		0.0		11		0		0.0		73		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		364		0		0.0		1,968		0		0.0		6,293		0		0.0

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 8

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – BARRANCAS

FIELD-SEGMENT – BARRANCAS-C.R.I.

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		904		36		37.3		991		37		49.2		1,070		38		44.1
2007		852		32		35.1		1,009		35		41.6		1,094		36		45.1
2008		807		29		33.3		937		31		38.6		1,015		33		41.8
2009		762		26		31.4		880		28		36.3		940		29		38.8
2010		724		24		29.9		817		25		33.7		873		26		36.0
2011		690		22		28.4		759		23		31.3		806		23		33.2
2012		660		20		27.2		723		21		29.8		766		21		31.6
2013		630		18		26.0		688		19		28.4		729		19		30.1
2014		604		16		24.9		658		17		27.1		696		17		28.7
2015		580		14		23.9		631		15		26.0		665		16		27.4
2016		559		13		23.1		593		14		24.4		625		14		25.7
2017		492		12		20.3		521		12		21.5		594		13		24.5
2018		0		0		0.0		0		0		0.0		518		0		21.3
2019		0		0		0.0		0		0		0.0		500		0		20.6
2020		0		0		0.0		0		0		0.0		485		0		20.0
2021		0		0		0.0		0		0		0.0		468		0		19.3
2022		0		0		0.0		0		0		0.0		453		0		18.7
2023		0		0		0.0		0		0		0.0		440		0		0.0
2024		0		0		0.0		0		0		0.0		428		0		0.0
2025		0		0		0.0		0		0		0.0		414		0		0.0
2026		0		0		0.0		0		0		0.0		403		0		0.0
2027		0		0		0.0		0		0		0.0		359		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		8,264		262		340.8		9,207		277		387.9		14,341		285		506.9

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 9

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – BARRANCAS

FIELD-SEGMENT – BARRANCAS-CABRAS / B. VERDE

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		1,393		0		57.4		1,405		0		57.9		1,405		0		57.9
2007		1,281		0		52.8		1,295		0		53.4		1,295		0		53.4
2008		1,183		0		48.7		1,194		0		49.2		1,194		0		49.2
2009		1,088		0		44.8		1,098		0		45.3		1,098		0		45.3
2010		1,006		0		41.5		1,014		0		41.8		1,014		0		41.8
2011		932		0		38.4		938		0		38.7		938		0		38.7
2012		866		0		35.7		872		0		35.9		872		0		35.9
2013		803		0		33.1		807		0		33.3		807		0		33.3
2014		747		0		30.8		750		0		30.9		750		0		30.9
2015		696		0		28.7		699		0		28.8		699		0		28.8
2016		651		0		26.8		653		0		26.9		653		0		26.9
2017		557		0		23.0		557		0		23.0		607		0		25.0
2018		0		0		0.0		0		0		0.0		568		0		23.4
2019		0		0		0.0		0		0		0.0		532		0		21.9
2020		0		0		0.0		0		0		0.0		500		0		20.6
2021		0		0		0.0		0		0		0.0		468		0		19.3
2022		0		0		0.0		0		0		0.0		440		0		18.2
2023		0		0		0.0		0		0		0.0		414		0		17.1
2024		0		0		0.0		0		0		0.0		391		0		16.1
2025		0		0		0.0		0		0		0.0		368		0		15.1
2026		0		0		0.0		0		0		0.0		347		0		14.3
2027		0		0		0.0		0		0		0.0		301		0		12.4
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		11,203		0		461.7		11,282		0		465.1		15,661		0		645.5

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 10

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – BARRANCAS

FIELD-SEGMENT – BARRANCAS-CABRAS-POTRERILLOS

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		88		0		3.6		88		0		3.6		88		0		3.6
2007		79		0		3.2		79		0		3.2		79		0		3.2
2008		71		0		2.9		71		0		2.9		71		0		2.9
2009		64		0		2.6		64		0		2.6		64		0		2.6
2010		59		0		2.4		59		0		2.4		59		0		2.4
2011		54		0		2.2		54		0		2.2		54		0		2.2
2012		50		0		2.0		50		0		2.0		50		0		2.0
2013		46		0		1.9		46		0		1.9		46		0		1.9
2014		43		0		1.8		43		0		1.8		43		0		1.8
2015		40		0		1.6		40		0		1.6		40		0		1.6
2016		38		0		1.6		38		0		1.6		38		0		1.6
2017		32		0		1.3		32		0		1.3		35		0		1.4
2018		0		0		0.0		0		0		0.0		33		0		1.4
2019		0		0		0.0		0		0		0.0		31		0		1.3
2020		0		0		0.0		0		0		0.0		30		0		1.2
2021		0		0		0.0		0		0		0.0		28		0		1.1
2022		0		0		0.0		0		0		0.0		27		0		1.1
2023		0		0		0.0		0		0		0.0		25		0		1.0
2024		0		0		0.0		0		0		0.0		24		0		1.0
2025		0		0		0.0		0		0		0.0		23		0		1.0
2026		0		0		0.0		0		0		0.0		22		0		0.9
2027		0		0		0.0		0		0		0.0		19		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		664		0		27.1		664		0		27.1		929		0		37.2

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 11

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – BARRANCAS

FIELD-SEGMENT – BARRANCAS-CABRAS-VILLAVICENCIO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		14		0		0.9		14		0		0.9		14		0		0.9
2007		11		0		0.7		11		0		0.7		11		0		0.7
2008		8		0		0.6		8		0		0.6		8		0		0.6
2009		7		0		0.4		7		0		0.4		7		0		0.4
2010		5		0		0.3		5		0		0.3		5		0		0.3
2011		4		0		0.3		4		0		0.3		4		0		0.3
2012		3		0		0.2		3		0		0.2		3		0		0.2
2013		2		0		0.0		2		0		0.0		2		0		0.0
2014		0		0		0.0		0		0		0.0		0		0		0.0
2015		0		0		0.0		0		0		0.0		0		0		0.0
2016		0		0		0.0		0		0		0.0		0		0		0.0
2017		0		0		0.0		0		0		0.0		0		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		54		0		3.4		54		0		3.4		54		0		3.4

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 12

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – GUANACO BLANCO

FIELD-SEGMENT – GUANACO BLANCO LRB

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		13		0		0.0		13		0		0.0		13		0		0.0
2007		12		0		0.0		12		0		0.0		12		0		0.0
2008		10		0		0.0		10		0		0.0		10		0		0.0
2009		9		0		0.0		9		0		0.0		9		0		0.0
2010		8		0		0.0		8		0		0.0		8		0		0.0
2011		7		0		0.0		7		0		0.0		7		0		0.0
2012		6		0		0.0		6		0		0.0		6		0		0.0
2013		5		0		0.0		5		0		0.0		5		0		0.0
2014		4		0		0.0		4		0		0.0		4		0		0.0
2015		4		0		0.0		4		0		0.0		4		0		0.0
2016		3		0		0.0		3		0		0.0		3		0		0.0
2017		3		0		0.0		3		0		0.0		3		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		84		0		0.0		84		0		0.0		84		0		0.0

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 13

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – LA VENTANA

FIELD-SEGMENT – LA VENTANA-BARRANCAS / RIO BLANCO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		388		0		42.2		388		0		42.2		388		0		42.2
2007		360		0		39.0		360		0		39.0		360		0		39.0
2008		334		0		36.3		334		0		36.3		334		0		36.3
2009		309		0		33.6		309		0		33.6		309		0		33.6
2010		288		0		31.2		288		0		31.2		288		0		31.2
2011		268		0		29.1		268		0		29.1		268		0		29.1
2012		251		0		27.2		251		0		27.2		251		0		27.2
2013		233		0		25.4		233		0		25.4		233		0		25.4
2014		218		0		23.7		218		0		23.7		218		0		23.7
2015		205		0		22.2		205		0		22.2		205		0		22.2
2016		193		0		20.9		193		0		20.9		193		0		20.9
2017		165		0		17.9		165		0		17.9		180		0		19.5
2018		0		0		0.0		0		0		0.0		156		0		17.0
2019		0		0		0.0		0		0		0.0		147		0		16.0
2020		0		0		0.0		0		0		0.0		139		0		15.1
2021		0		0		0.0		0		0		0.0		131		0		14.3
2022		0		0		0.0		0		0		0.0		125		0		13.5
2023		0		0		0.0		0		0		0.0		118		0		12.8
2024		0		0		0.0		0		0		0.0		112		0		12.1
2025		0		0		0.0		0		0		0.0		106		0		0.0
2026		0		0		0.0		0		0		0.0		101		0		0.0
2027		0		0		0.0		0		0		0.0		95		0		0.0
2028		0		0		0.0		0		0		0.0		91		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		3,212		0		348.7		3,212		0		348.7		4,548		0		451.1

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 14

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – LA VENTANA CENTRAL

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		2,717		64		294.8		2,755		66		298.9		2,777		69		301.3
2007		2,495		59		270.8		2,677		64		290.6		2,799		72		303.8
2008		2,303		55		250.0		2,518		59		273.3		2,825		70		306.8
2009		2,117		51		229.9		2,307		54		250.5		2,835		66		307.8
2010		1,957		47		212.3		2,114		51		229.5		2,734		60		296.9
2011		1,809		43		196.2		1,935		47		210.0		2,517		54		273.3
2012		1,682		41		182.7		1,777		43		192.9		2,247		49		243.9
2013		1,559		36		169.3		1,621		38		176.0		1,993		43		216.2
2014		1,451		33		157.5		1,507		36		163.7		1,801		39		195.6
2015		1,349		32		146.4		1,388		32		150.6		1,615		35		175.3
2016		1,262		30		137.0		1,281		30		139.1		1,441		32		156.2
2017		1,081		26		117.3		1,088		26		118.0		1,242		27		134.9
2018		0		0		0.0		0		0		0.0		1,076		1		116.8
2019		0		0		0.0		0		0		0.0		973		1		105.7
2020		0		0		0.0		0		0		0.0		877		1		95.1
2021		0		0		0.0		0		0		0.0		791		1		85.8
2022		0		0		0.0		0		0		0.0		718		0		77.8
2023		0		0		0.0		0		0		0.0		652		0		70.9
2024		0		0		0.0		0		0		0.0		599		0		65.0
2025		0		0		0.0		0		0		0.0		551		0		0.0
2026		0		0		0.0		0		0		0.0		510		0		0.0
2027		0		0		0.0		0		0		0.0		471		0		0.0
2028		0		0		0.0		0		0		0.0		335		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		21,782		517		2,364.2		22,968		546		2,493.1		34,379		620		3,529.1

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 15

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – LA VENTANA CENTRAL

FIELD-SEGMENT – RIO VIEJAS

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		267		6		29.0		280		7		30.3		280		7		30.3
2007		247		6		26.8		303		7		32.9		331		7		35.9
2008		229		5		24.9		292		7		31.7		339		7		36.8
2009		212		5		23.0		256		6		27.8		289		6		31.4
2010		196		5		21.3		228		5		24.7		252		5		27.4
2011		182		4		19.7		207		5		22.5		225		5		24.5
2012		169		4		18.4		188		4		20.4		202		4		21.9
2013		157		4		17.0		169		4		18.4		180		4		19.5
2014		146		3		15.8		158		4		17.2		166		4		18.0
2015		135		3		14.7		142		3		15.4		147		3		16.0
2016		126		3		13.7		126		3		13.7		129		3		13.9
2017		108		3		11.7		108		3		11.7		118		3		12.8
2018		0		0		0.0		0		0		0.0		109		1		11.9
2019		0		0		0.0		0		0		0.0		101		1		11.0
2020		0		0		0.0		0		0		0.0		94		1		10.2
2021		0		0		0.0		0		0		0.0		87		1		9.4
2022		0		0		0.0		0		0		0.0		81		0		8.7
2023		0		0		0.0		0		0		0.0		75		0		8.1
2024		0		0		0.0		0		0		0.0		69		0		7.5
2025		0		0		0.0		0		0		0.0		64		0		0.0
2026		0		0		0.0		0		0		0.0		60		0		0.0
2027		0		0		0.0		0		0		0.0		55		0		0.0
2028		0		0		0.0		0		0		0.0		52		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		2,174		51		236.0		2,457		58		266.7		3,505		62		355.2

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 16

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – LA VENTANA CENTRAL

FIELD-SEGMENT – ZONA CENTRAL BRC

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		730		17		79.2		736		17		79.9		736		18		79.9
2007		667		16		72.4		699		17		75.9		699		19		75.9
2008		612		15		66.4		650		15		70.6		680		18		73.9
2009		558		13		60.6		596		14		64.7		698		18		75.7
2010		511		12		55.4		542		13		58.9		662		16		71.9
2011		468		11		50.7		493		12		53.5		639		14		69.4
2012		429		10		46.6		448		11		48.7		583		13		63.3
2013		392		9		42.6		405		10		43.9		514		11		55.8
2014		359		8		39.0		372		9		40.4		460		10		50.0
2015		326		8		35.4		332		8		36.1		398		9		43.2
2016		298		7		32.4		305		7		33.1		353		8		38.3
2017		251		6		27.2		251		6		27.2		310		6		33.7
2018		0		0		0.0		0		0		0.0		266		0		28.9
2019		0		0		0.0		0		0		0.0		239		0		26.0
2020		0		0		0.0		0		0		0.0		214		0		23.2
2021		0		0		0.0		0		0		0.0		191		0		20.7
2022		0		0		0.0		0		0		0.0		172		0		18.7
2023		0		0		0.0		0		0		0.0		156		0		17.0
2024		0		0		0.0		0		0		0.0		143		0		15.5
2025		0		0		0.0		0		0		0.0		131		0		0.0
2026		0		0		0.0		0		0		0.0		121		0		0.0
2027		0		0		0.0		0		0		0.0		111		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		5,601		132		607.9		5,829		139		632.9		8,476		160		881.0

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 17

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – LA VENTANA CENTRAL

FIELD-SEGMENT – ZONA CENTRAL LRB

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		35		1		3.7		35		1		3.7		35		1		3.7
2007		31		1		3.4		31		1		3.4		31		1		3.4
2008		29		1		3.1		29		1		3.1		75		1		8.1
2009		26		1		2.9		26		1		2.9		168		1		18.3
2010		24		1		2.6		24		1		2.6		195		1		21.2
2011		22		1		2.4		22		1		2.4		147		1		15.9
2012		21		1		2.3		21		1		2.3		99		1		10.8
2013		19		0		2.1		19		0		2.1		78		0		8.4
2014		18		0		2.0		18		0		2.0		64		0		6.9
2015		17		0		1.8		17		0		1.8		55		0		5.9
2016		16		0		1.7		16		0		1.7		42		0		4.5
2017		14		0		1.5		14		0		1.5		35		0		3.8
2018		0		0		0.0		0		0		0.0		19		0		2.0
2019		0		0		0.0		0		0		0.0		16		0		1.8
2020		0		0		0.0		0		0		0.0		14		0		1.5
2021		0		0		0.0		0		0		0.0		12		0		1.3
2022		0		0		0.0		0		0		0.0		7		0		0.7
2023		0		0		0.0		0		0		0.0		2		0		0.2
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		272		7		29.5		272		7		29.5		1,094		7		118.4

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 18

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – LA VENTANA CENTRAL

FIELD-SEGMENT – ZONA CENTRAL TRC

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		998		24		108.3		1,004		24		109.0		1,004		26		109.0
2007		906		21		98.3		975		23		105.8		997		27		108.2
2008		826		20		89.7		902		21		97.9		989		26		107.4
2009		750		18		81.4		820		19		89.0		966		24		104.9
2010		685		16		74.3		748		18		81.2		937		22		101.7
2011		626		15		67.9		676		16		73.4		864		19		93.8
2012		575		14		62.4		613		15		66.5		769		17		83.5
2013		526		12		57.1		551		13		59.8		676		15		73.4
2014		483		11		52.5		502		12		54.5		603		13		65.5
2015		445		11		48.3		458		11		49.7		536		12		58.2
2016		412		10		44.7		424		10		46.1		484		11		52.5
2017		348		8		37.8		355		8		38.5		406		9		44.1
2018		0		0		0.0		0		0		0.0		357		0		38.7
2019		0		0		0.0		0		0		0.0		320		0		34.7
2020		0		0		0.0		0		0		0.0		284		0		30.8
2021		0		0		0.0		0		0		0.0		253		0		27.5
2022		0		0		0.0		0		0		0.0		231		0		25.1
2023		0		0		0.0		0		0		0.0		211		0		23.0
2024		0		0		0.0		0		0		0.0		196		0		21.2
2025		0		0		0.0		0		0		0.0		181		0		0.0
2026		0		0		0.0		0		0		0.0		168		0		0.0
2027		0		0		0.0		0		0		0.0		156		0		0.0
2028		0		0		0.0		0		0		0.0		145		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		7,580		180		822.7		8,028		190		871.4		11,733		221		1,203.2

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 19

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – LA VENTANA CENTRAL

FIELD-SEGMENT – ZONA CENTRAL VC

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		687		16		74.6		700		17		76.0		722		17		78.4
2007		644		15		69.9		669		16		72.6		741		18		80.4
2008		607		14		65.9		645		15		70.0		742		18		80.6
2009		571		14		62.0		609		14		66.1		714		17		77.5
2010		541		13		58.7		572		14		62.1		688		16		74.7
2011		511		12		55.5		537		13		58.2		642		15		69.7
2012		488		12		53.0		507		12		55.0		594		14		64.4
2013		465		11		50.5		477		11		51.8		545		13		59.1
2014		445		11		48.2		457		11		49.6		508		12		55.2
2015		426		10		46.2		439		10		47.6		479		11		52.0
2016		410		10		44.5		410		10		44.5		433		10		47.0
2017		360		9		39.1		360		9		39.1		373		9		40.5
2018		0		0		0.0		0		0		0.0		325		0		35.3
2019		0		0		0.0		0		0		0.0		297		0		32.2
2020		0		0		0.0		0		0		0.0		271		0		29.4
2021		0		0		0.0		0		0		0.0		248		0		26.9
2022		0		0		0.0		0		0		0.0		227		0		24.6
2023		0		0		0.0		0		0		0.0		208		0		22.6
2024		0		0		0.0		0		0		0.0		191		0		20.8
2025		0		0		0.0		0		0		0.0		175		0		0.0
2026		0		0		0.0		0		0		0.0		161		0		0.0
2027		0		0		0.0		0		0		0.0		149		0		0.0
2028		0		0		0.0		0		0		0.0		138		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		6,155		147		668.1		6,382		152		692.6		9,571		170		971.3

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 20

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – LA VENTANA CAÑADA DURA

FIELD-SEGMENT – LA VENTANA CAÑADA DURA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		15		0		0.0		25		0		0.0		25		0		0.0
2007		12		0		0.0		28		0		0.0		28		0		0.0
2008		10		0		0.0		23		0		0.0		23		0		0.0
2009		9		0		0.0		19		0		0.0		19		0		0.0
2010		8		0		0.0		15		0		0.0		15		0		0.0
2011		7		0		0.0		12		0		0.0		12		0		0.0
2012		6		0		0.0		9		0		0.0		9		0		0.0
2013		5		0		0.0		5		0		0.0		5		0		0.0
2014		5		0		0.0		5		0		0.0		5		0		0.0
2015		5		0		0.0		5		0		0.0		5		0		0.0
2016		4		0		0.0		4		0		0.0		4		0		0.0
2017		4		0		0.0		4		0		0.0		4		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		90		0		0.0		154		0		0.0		154		0		0.0

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 21

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – VIZCACHERAS-CAÑADA DURA

FIELD-SEGMENT – VIZCACHERAS-CAÑADA DURA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		787		0		43.0		787		0		43.0		822		0		44.9
2007		609		0		33.3		609		0		33.3		631		0		34.5
2008		495		0		27.1		495		0		27.1		508		0		27.8
2009		413		0		22.6		413		0		22.6		422		0		23.1
2010		354		0		19.4		354		0		19.4		366		0		20.0
2011		308		0		16.8		308		0		16.8		312		0		17.0
2012		273		0		14.9		273		0		14.9		273		0		14.9
2013		244		0		13.3		244		0		13.3		244		0		13.3
2014		220		0		12.0		220		0		12.0		220		0		12.0
2015		201		0		11.0		201		0		11.0		201		0		11.0
2016		184		0		10.1		184		0		10.1		184		0		10.1
2017		156		0		8.5		156		0		8.5		169		0		9.3
2018		0		0		0.0		0		0		0.0		157		0		8.5
2019		0		0		0.0		0		0		0.0		146		0		8.0
2020		0		0		0.0		0		0		0.0		136		0		7.5
2021		0		0		0.0		0		0		0.0		128		0		7.0
2022		0		0		0.0		0		0		0.0		120		0		6.6
2023		0		0		0.0		0		0		0.0		113		0		6.2
2024		0		0		0.0		0		0		0.0		108		0		5.9
2025		0		0		0.0		0		0		0.0		101		0		5.5
2026		0		0		0.0		0		0		0.0		97		0		5.3
2027		0		0		0.0		0		0		0.0		84		0		4.6
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		4,244		0		232.0		4,244		0		232.0		5,542		0		303.0

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 22

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – VIZCACHERAS

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		3,123		46		271.6		3,205		47		278.7		3,331		48		289.7
2007		2,894		42		251.8		2,992		44		260.2		3,087		45		268.4
2008		2,695		39		234.4		2,767		40		240.6		2,842		42		247.2
2009		2,499		36		217.3		2,549		37		221.6		2,602		37		226.3
2010		2,327		34		202.2		2,358		34		205.0		2,398		34		208.6
2011		2,169		32		188.6		2,188		32		190.2		2,216		32		192.7
2012		2,029		29		176.5		2,035		29		177.0		2,048		30		178.1
2013		1,891		28		164.3		1,891		28		164.3		1,900		28		165.2
2014		1,767		25		153.7		1,767		25		153.7		1,773		26		154.2
2015		1,654		24		143.8		1,654		24		143.8		1,654		24		143.8
2016		1,554		42		135.2		1,554		22		135.2		1,554		22		135.2
2017		1,333		20		115.9		1,333		20		115.9		1,452		20		126.3
2018		0		0		0.0		0		0		0.0		1,363		0		118.5
2019		0		0		0.0		0		0		0.0		1,280		0		111.3
2020		0		0		0.0		0		0		0.0		1,206		0		104.9
2021		0		0		0.0		0		0		0.0		1,132		0		98.4
2022		0		0		0.0		0		0		0.0		1,066		0		92.7
2023		0		0		0.0		0		0		0.0		1,004		0		87.3
2024		0		0		0.0		0		0		0.0		949		0		82.6
2025		0		0		0.0		0		0		0.0		894		0		77.7
2026		0		0		0.0		0		0		0.0		845		0		73.4
2027		0		0		0.0		0		0		0.0		737		0		64.1
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		25,935		377		2,255.3		26,293		382		2,286.2		37,333		388		3,246.6

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 23

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – VIZCACHERAS

FIELD-SEGMENT – VIZCACHERAS BARRANCAS

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		936		14		81.4		967		14		84.1		1,043		15		90.7
2007		865		13		75.3		887		13		77.2		938		14		81.5
2008		807		12		70.2		822		12		71.5		860		13		74.8
2009		752		11		65.4		758		11		65.9		783		11		68.1
2010		706		10		61.3		706		10		61.3		724		10		63.0
2011		665		10		57.8		665		10		57.8		677		10		58.9
2012		630		9		54.8		630		9		54.8		630		9		54.8
2013		596		9		51.8		596		9		51.8		596		9		51.8
2014		566		8		49.2		566		8		49.2		566		8		49.2
2015		540		8		46.9		540		8		46.9		540		8		46.9
2016		517		7		45.0		517		7		45.0		517		7		45.0
2017		452		7		39.3		452		7		39.3		493		7		42.9
2018		0		0		0.0		0		0		0.0		473		0		41.1
2019		0		0		0.0		0		0		0.0		454		0		39.5
2020		0		0		0.0		0		0		0.0		438		0		38.1
2021		0		0		0.0		0		0		0.0		421		0		36.6
2022		0		0		0.0		0		0		0.0		406		0		35.3
2023		0		0		0.0		0		0		0.0		392		0		34.1
2024		0		0		0.0		0		0		0.0		380		0		33.1
2025		0		0		0.0		0		0		0.0		367		0		31.9
2026		0		0		0.0		0		0		0.0		356		0		30.9
2027		0		0		0.0		0		0		0.0		321		0		27.9
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		8,032		118		698.4		8,106		118		704.8		12,375		121		1,076.1

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 24

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – VIZCACHERAS

FIELD-SEGMENT – VIZCACHERAS-PAPAGAYOS

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		2,187		32		190.2		2,238		33		194.6		2,288		33		199.0
2007		2,029		29		176.5		2,105		31		183.0		2,149		31		186.9
2008		1,888		27		164.2		1,945		28		169.1		1,982		29		172.4
2009		1,747		25		151.9		1,791		26		155.7		1,819		26		158.2
2010		1,621		24		140.9		1,652		24		143.7		1,674		24		145.6
2011		1,504		22		130.8		1,523		22		132.4		1,539		22		133.8
2012		1,399		20		121.7		1,405		20		122.2		1,418		21		123.3
2013		1,295		19		112.5		1,295		19		112.5		1,304		19		113.4
2014		1,201		17		104.5		1,201		17		104.5		1,207		18		105.0
2015		1,114		16		96.9		1,114		16		96.9		1,114		16		96.9
2016		1,037		15		90.2		1,037		15		90.2		1,037		15		90.2
2017		881		13		76.6		881		13		76.6		959		13		83.4
2018		0		0		0.0		0		0		0.0		890		0		77.4
2019		0		0		0.0		0		0		0.0		826		0		71.8
2020		0		0		0.0		0		0		0.0		768		0		66.8
2021		0		0		0.0		0		0		0.0		711		0		61.8
2022		0		0		0.0		0		0		0.0		660		0		57.4
2023		0		0		0.0		0		0		0.0		612		0		53.2
2024		0		0		0.0		0		0		0.0		569		0		49.5
2025		0		0		0.0		0		0		0.0		527		0		45.8
2026		0		0		0.0		0		0		0.0		489		0		42.5
2027		0		0		0.0		0		0		0.0		416		0		36.2
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		17,903		259		1,556.9		18,187		264		1,581.4		24,958		267		2,170.5

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 25

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – CERRO FORTUNOSO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		1,969		0		0.0		2,045		0		0.0		2,264		0		0.0
2007		1,655		0		0.0		1,806		0		0.0		2,447		0		0.0
2008		1,434		0		0.0		1,566		0		0.0		2,214		0		0.0
2009		1,270		0		0.0		1,377		0		0.0		2,032		0		0.0
2010		1,151		0		0.0		1,245		0		0.0		1,786		0		0.0
2011		1,044		0		0.0		1,120		0		0.0		1,516		0		0.0
2012		962		0		0.0		1,025		0		0.0		1,333		0		0.0
2013		881		0		0.0		937		0		0.0		1,182		0		0.0
2014		805		0		0.0		849		0		0.0		1,056		0		0.0
2015		742		0		0.0		780		0		0.0		943		0		0.0
2016		679		0		0.0		704		0		0.0		843		0		0.0
2017		572		0		0.0		579		0		0.0		717		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		13,164		0		0.0		14,033		0		0.0		18,333		0		0.0

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 26

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – CERRO FORTUNOSO

FIELD-SEGMENT – CERRO FORTUNOSO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		1,956		0		0.0		2,032		0		0.0		2,239		0		0.0
2007		1,642		0		0.0		1,793		0		0.0		2,422		0		0.0
2008		1,428		0		0.0		1,560		0		0.0		2,195		0		0.0
2009		1,264		0		0.0		1,371		0		0.0		2,013		0		0.0
2010		1,145		0		0.0		1,239		0		0.0		1,767		0		0.0
2011		1,044		0		0.0		1,120		0		0.0		1,510		0		0.0
2012		962		0		0.0		1,025		0		0.0		1,327		0		0.0
2013		881		0		0.0		937		0		0.6		1,176		0		0.0
2014		805		0		0.0		849		0		0.0		1,050		0		0.0
2015		742		0		0.0		780		0		0.0		937		0		0.0
2016		679		0		0.0		704		0		0.0		837		0		0.0
2017		572		0		0.0		579		0		0.0		711		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		13,120		0		0.0		13,989		0		0.0		18,184		0		0.0

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 27

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – MENDOZA

AREA – CERRO FORTUNOSO

FIELD-SEGMENT – CERRO FORTUNOSO SUR

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		13		0		0.0		13		0		0.0		25		0		0.0
2007		13		0		0.0		13		0		0.0		25		0		0.0
2008		6		0		0.0		6		0		0.0		19		0		0.0
2009		6		0		0.0		6		0		0.0		19		0		0.0
2010		6		0		0.0		6		0		0.0		19		0		0.0
2011		0		0		0.0		0		0		0.0		6		0		0.0
2012		0		0		0.0		0		0		0.0		6		0		0.0
2013		0		0		0.0		0		0		0.0		6		0		0.0
2014		0		0		0.0		0		0		0.0		6		0		0.0
2015		0		0		0.0		0		0		0.0		6		0		0.0
2016		0		0		0.0		0		0		0.0		6		0		0.0
2017		0		0		0.0		0		0		0.0		6		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		44		0		0.0		44		0		0.0		149		0		0.0

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 28

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		9,623		1,157		49,827.2		10,542		1,157		49,827.2		10,630		1,157		49,827.2
2007		7,112		1,164		51,001.9		8,935		1,164		51,001.9		9,573		1,164		51,001.9
2008		5,300		1,107		48,755.8		6,742		1,107		48,755.8		7,731		1,107		49,216.9
2009		4,094		1,025		44,422.3		5,185		1,025		44,422.3		6,460		1,025		46,531.4
2010		3,267		1,050		42,066.3		4,102		1,050		42,066.3		5,460		1,050		43,747.0
2011		2,660		1,283		44,195.4		3,296		1,283		44,195.4		4,436		1,283		45,506.7
2012		2,159		1,396		45,036.7		2,636		1,396		45,036.7		3,578		1,396		46,069.1
2013		1,748		1,182		39,238.7		2,125		1,182		39,238.7		2,912		1,182		40,057.1
2014		1,442		1,157		33,377.5		1,718		1,157		33,377.5		2,385		1,157		34,031.3
2015		1,177		1,107		26,499.1		1,398		1,107		26,499.1		1,936		1,107		27,019.5
2016		961		799		18,845.5		1,124		799		18,845.5		1,566		799		19,258.7
2017		774		579		13,342.8		890		579		13,342.8		1,247		579		13,342.8
2018		560		384		8,254.9		642		384		8,254.9		956		384		8,254.9
2019		471		314		6,764.2		527		314		6,764.2		798		314		6,764.2
2020		407		258		5,645.0		426		258		5,645.0		635		258		5,645.0
2021		352		220		4,883.1		358		220		4,883.1		528		220		4,883.1
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		42,107		14,182		482,156.4		50,646		14,182		482,156.4		60,831		14,182		491,156.8

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 29

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – CHIHUIDO LA SALINA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		5,881		0		20,534.6		6,396		0		20,534.6		6,396		0		20,534.6
2007		4,459		0		21,082.8		5,515		0		21,082.8		5,900		0		21,082.8
2008		3,465		0		20,528.0		4,352		0		20,528.0		4,906		0		20,528.0
2009		2,749		0		19,657.4		3,448		0		19,657.4		4,031		0		19,657.4
2010		2,215		0		18,654.4		2,768		0		18,654.4		3,359		0		18,654.4
2011		1,830		0		21,473.5		2,264		0		21,473.5		2,856		0		21,473.5
2012		1,535		0		25,987.9		1,874		0		25,987.9		2,427		0		25,987.9
2013		1,239		0		22,235.7		1,509		0		22,235.7		2,025		0		22,235.7
2014		995		0		17,024.7		1,202		0		17,024.7		1,673		0		17,024.7
2015		831		0		13,150.7		1,001		0		13,150.7		1,409		0		13,150.7
2016		698		0		10,422.2		830		0		10,422.2		1,189		0		10,422.2
2017		591		0		8,316.6		698		0		8,316.6		1,006		0		8,316.6
2018		503		0		6,739.2		585		0		6,739.2		849		0		6,739.2
2019		428		0		5,524.2		484		0		5,524.2		717		0		5,524.2
2020		370		0		4,588.7		389		0		4,588.7		579		0		4,588.7
2021		321		0		3,966.8		327		0		3,966.8		497		0		3,966.8
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		28,110		0		239,887.4		33,642		0		239,887.4		39,819		0		239,887.4

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 30

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – CHIHUIDO LA SALINA

FIELD-SEGMENT – CHIHUIDO LA SALINA NORTE-TRONCOSO INF.

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		2,000		0		1,558.1		2,289		0		1,558.1		2,289		0		1,558.1
2007		1,547		0		1,585.1		2,050		0		1,585.1		2,422		0		1,585.1
2008		1,195		0		1,599.9		1,604		0		1,599.9		2,082		0		1,599.9
2009		925		0		1,615.4		1,252		0		1,615.4		1,616		0		1,615.4
2010		711		0		1,316.9		975		0		1,316.9		1,258		0		1,316.9
2011		547		0		1,206.5		761		0		1,206.5		981		0		1,206.5
2012		421		0		787.7		591		0		787.7		767		0		787.7
2013		327		0		615.7		465		0		615.7		591		0		615.7
2014		252		0		482.0		359		0		482.0		459		0		482.0
2015		195		0		375.0		283		0		375.0		359		0		375.0
2016		151		0		294.6		220		0		294.6		283		0		294.6
2017		113		0		229.6		170		0		229.6		220		0		229.6
2018		88		0		179.9		132		0		179.9		170		0		179.9
2019		69		0		141.6		94		0		141.6		126		0		141.6
2020		50		0		111.0		50		0		111.0		63		0		111.0
2021		38		0		91.6		38		0		91.6		38		0		91.6
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		8,629		0		12,190.6		11,333		0		12,190.6		13,724		0		12,190.6

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 31

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – CHIHUIDO LA SALINA

FIELD-SEGMENT – CHIHUIDO LA SALINA CENTRO NORTE-TRONCOSO INF.

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		3,057		0		2,953.4		3,283		0		2,953.4		3,283		0		2,953.4
2007		2,296		0		3,202.3		2,849		0		3,202.3		2,849		0		3,202.3
2008		1,786		0		2,396.5		2,264		0		2,396.5		2,315		0		2,396.5
2009		1,421		0		765.2		1,793		0		765.2		1,981		0		765.2
2010		1,164		0		312.3		1,453		0		312.3		1,730		0		312.3
2011		981		0		306.3		1,201		0		306.3		1,535		0		306.3
2012		837		0		8,597.0		1,006		0		8,597.0		1,346		0		8,597.0
2013		686		0		7,597.7		818		0		7,597.7		1,170		0		7,597.7
2014		579		0		6,732.6		679		0		6,732.6		1,019		0		6,732.6
2015		516		0		5,969.5		598		0		5,969.5		899		0		5,969.5
2016		459		0		5,305.0		522		0		5,305.0		786		0		5,305.0
2017		409		0		4,688.7		459		0		4,688.7		692		0		4,688.7
2018		365		0		4,156.6		403		0		4,156.6		604		0		4,156.6
2019		321		0		3,684.1		352		0		3,684.1		528		0		3,684.1
2020		289		0		3,274.1		308		0		3,274.1		459		0		3,274.1
2021		258		0		2,887.5		264		0		2,887.5		415		0		2,887.5
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		15,424		0		62,828.8		18,252		0		62,828.8		21,611		0		62,828.8

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 32

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – CHIHUIDO LA SALINA

FIELD-SEGMENT – CHIHUIDO LA SALINA CENTRO SUR-TRONCOSO INF.

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		824		0		16,023.1		824		0		16,023.1		824		0		16,023.1
2007		616		0		16,295.4		616		0		16,295.4		629		0		16,295.4
2008		484		0		16,531.6		484		0		16,531.6		509		0		16,531.6
2009		403		0		17,276.8		403		0		17,276.8		434		0		17,276.8
2010		340		0		17,025.2		340		0		17,025.2		371		0		17,025.2
2011		302		0		19,960.7		302		0		19,960.7		340		0		19,960.7
2012		277		0		16,603.2		277		0		16,603.2		314		0		16,603.2
2013		226		0		14,022.3		226		0		14,022.3		264		0		14,022.3
2014		164		0		9,810.1		164		0		9,810.1		195		0		9,810.1
2015		120		0		6,806.2		120		0		6,806.2		151		0		6,806.2
2016		88		0		4,822.6		88		0		4,822.6		120		0		4,822.6
2017		69		0		3,398.3		69		0		3,398.3		94		0		3,398.3
2018		50		0		2,402.7		50		0		2,402.7		75		0		2,402.7
2019		38		0		1,698.5		38		0		1,698.5		63		0		1,698.5
2020		31		0		1,203.6		31		0		1,203.6		57		0		1,203.6
2021		25		0		987.7		25		0		987.7		44		0		987.7
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		4,057		0		164,868.0		4,057		0		164,868.0		4,484		0		164,868.0

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 33

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – CHIHUIDO LA SALINA

FIELD-SEGMENT – CHIHUIDO LA SALINA-MULICHINCO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		0		0		0.0		0		0		0.0		0		0		0.0
2007		0		0		0.0		0		0		0.0		0		0		0.0
2008		0		0		0.0		0		0		0.0		0		0		0.0
2009		0		0		0.0		0		0		0.0		0		0		0.0
2010		0		0		0.0		0		0		0.0		0		0		0.0
2011		0		0		0.0		0		0		0.0		0		0		0.0
2012		0		0		0.0		0		0		0.0		0		0		0.0
2013		0		0		0.0		0		0		0.0		0		0		0.0
2014		0		0		0.0		0		0		0.0		0		0		0.0
2015		0		0		0.0		0		0		0.0		0		0		0.0
2016		0		0		0.0		0		0		0.0		0		0		0.0
2017		0		0		0.0		0		0		0.0		0		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		0		0		0.0		0		0		0.0		0		0		0.0

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 34

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – CHIHUIDO LA SALINA SUR

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		2,119		0		10,587.1		2,422		0		10,587.1		2,510		0		10,587.1
2007		1,396		0		10,769.4		1,911		0		10,769.4		2,132		0		10,769.4
2008		841		0		9,335.3		1,207		0		9,335.3		1,605		0		9,796.4
2009		528		0		6,457.6		781		0		6,457.6		1,435		0		8,566.7
2010		372		0		5,417.8		554		0		5,417.8		1,290		0		7,098.5
2011		277		0		5,423.6		403		0		5,423.6		919		0		6,734.9
2012		215		0		3,850.4		296		0		3,850.4		660		0		4,882.8
2013		169		0		3,296.7		232		0		3,296.7		484		0		4,115.1
2014		145		0		2,803.9		182		0		2,803.9		359		0		3,457.7
2015		113		0		2,360.8		139		0		2,360.8		257		0		2,881.2
2016		100		0		2,039.4		112		0		2,039.4		182		0		2,452.6
2017		88		0		1,760.0		91		0		1,760.0		134		0		1,760.0
2018		57		0		1,515.7		57		0		1,515.7		107		0		1,515.7
2019		43		0		1,240.0		43		0		1,240.0		81		0		1,240.0
2020		37		0		1,056.3		37		0		1,056.3		56		0		1,056.3
2021		31		0		916.3		31		0		916.3		31		0		916.3
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		6,531		0		68,830.3		8,498		0		68,830.3		12,242		0		77,830.7

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 35

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – CHIHUIDO LA SALINA SUR

FIELD-SEGMENT – BAJO LOS LOBOS-TRONCOSO INF.

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		50		0		3,258.2		50		0		3,258.2		50		0		3,258.2
2007		44		0		3,311.8		44		0		3,311.8		44		0		3,311.8
2008		31		0		2,187.0		31		0		2,187.0		38		0		2,648.1
2009		0		0		0.0		0		0		0.0		31		0		2,109.1
2010		0		0		0.0		0		0		0.0		25		0		1,680.7
2011		0		0		0.0		0		0		0.0		19		0		1,311.3
2012		0		0		0.0		0		0		0.0		13		0		1,032.4
2013		0		0		0.0		0		0		0.0		13		0		818.4
2014		0		0		0.0		0		0		0.0		13		0		653.8
2015		0		0		0.0		0		0		0.0		6		0		520.4
2016		0		0		0.0		0		0		0.0		6		0		413.2
2017		0		0		0.0		0		0		0.0		0		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		125		0		8,757.0		125		0		8,757.0		258		0		17,757.4

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 36

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – CHIHUIDO LA SALINA SUR

FIELD-SEGMENT – CHIHUIDO LA SALINA-TRONCOSO INF.-ESCAMA INTERMEDIA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		170		0		729.7		277		0		729.7		277		0		729.7
2007		113		0		743.4		308		0		743.4		308		0		743.4
2008		75		0		709.3		214		0		709.3		359		0		709.3
2009		50		0		643.8		145		0		643.8		296		0		643.8
2010		31		0		537.8		101		0		537.8		201		0		537.8
2011		19		0		539.3		63		0		539.3		132		0		539.3
2012		13		0		382.4		44		0		382.4		94		0		382.4
2013		6		0		328.9		31		0		328.9		69		0		328.9
2014		6		0		279.2		19		0		279.2		44		0		279.2
2015		0		0		233.4		13		0		233.4		31		0		233.4
2016		0		0		202.8		6		0		202.8		19		0		202.8
2017		0		0		176.0		3		0		176.0		9		0		176.0
2018		0		0		149.3		0		0		149.3		6		0		149.3
2019		0		0		122.5		0		0		122.5		6		0		122.5
2020		0		0		107.2		0		0		107.2		0		0		107.2
2021		0		0		91.6		0		0		91.6		0		0		91.6
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		483		0		5,976.6		1,224		0		5,976.6		1,851		0		5,976.6

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 37

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – CHIHUIDO LA SALINA SUR

FIELD-SEGMENT – CHIHUIDO LA SALINA-TRONCOSO INF.-ESCAMA PRINCIPAL

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		1,484		0		3,569.8		1,654		0		3,569.8		1,654		0		3,569.8
2007		931		0		3,634.4		1,094		0		3,634.4		1,145		0		3,634.4
2008		491		0		3,483.5		604		0		3,483.5		730		0		3,483.5
2009		289		0		3,143.9		371		0		3,143.9		761		0		3,143.9
2010		189		0		2,641.7		245		0		2,641.7		799		0		2,641.7
2011		132		0		2,641.9		170		0		2,641.9		560		0		2,641.9
2012		101		0		1,877.4		126		0		1,877.4		396		0		1,877.4
2013		75		0		1,606.3		94		0		1,606.3		277		0		1,606.3
2014		63		0		1,365.6		75		0		1,365.6		201		0		1,365.6
2015		50		0		1,151.7		57		0		1,151.7		138		0		1,151.7
2016		44		0		994.8		50		0		994.8		101		0		994.8
2017		38		0		857.0		38		0		857.0		75		0		857.0
2018		13		0		738.7		13		0		738.7		57		0		738.7
2019		6		0		604.7		6		0		604.7		38		0		604.7
2020		6		0		512.8		6		0		512.8		25		0		512.8
2021		6		0		446.7		6		0		446.7		6		0		446.7
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		3,918		0		29,270.9		4,609		0		29,270.9		6,963		0		29,270.9

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 38

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – CHIHUIDO LA SALINA SUR

FIELD-SEGMENT – CHIHUIDO LA SALINA-TRONCOSO INF.-ESCAMA SUPERIOR

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		296		0		3,029.4		296		0		3,029.4		296		0		3,029.4
2007		226		0		3,079.8		226		0		3,079.8		226		0		3,079.8
2008		182		0		2,955.5		182		0		2,955.5		182		0		2,955.5
2009		145		0		2,669.9		145		0		2,669.9		145		0		2,669.9
2010		120		0		2,238.3		120		0		2,238.3		120		0		2,238.3
2011		101		0		2,242.4		101		0		2,242.4		101		0		2,242.4
2012		88		0		1,590.6		88		0		1,590.6		88		0		1,590.6
2013		75		0		1,361.5		75		0		1,361.5		75		0		1,361.5
2014		63		0		1,159.1		63		0		1,159.1		63		0		1,159.1
2015		57		0		975.7		57		0		975.7		57		0		975.7
2016		50		0		841.8		50		0		841.8		50		0		841.8
2017		44		0		727.0		44		0		727.0		44		0		727.0
2018		38		0		627.7		38		0		627.7		38		0		627.7
2019		31		0		512.8		31		0		512.8		31		0		512.8
2020		25		0		436.3		25		0		436.3		25		0		436.3
2021		19		0		378.0		19		0		378.0		19		0		378.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		1,560		0		24,825.8		1,560		0		24,825.8		1,560		0		24,825.8

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 39

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK-EL PORTÓN

AREA – CHIHUIDO LA SALINA SUR

FIELD-SEGMENT – RINCON DE CORREA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		44		0		0.0		44		0		0.0		44		0		0.0
2007		38		0		0.0		107		0		0.0		107		0		0.0
2008		31		0		0.0		82		0		0.0		82		0		0.0
2009		25		0		0.0		57		0		0.0		57		0		0.0
2010		19		0		0.0		44		0		0.0		44		0		0.0
2011		19		0		0.0		38		0		0.0		38		0		0.0
2012		13		0		0.0		25		0		0.0		25		0		0.0
2013		13		0		0.0		19		0		0.0		19		0		0.0
2014		13		0		0.0		19		0		0.0		19		0		0.0
2015		6		0		0.0		6		0		0.0		6		0		0.0
2016		6		0		0.0		6		0		0.0		6		0		0.0
2017		6		0		0.0		6		0		0.0		6		0		0.0
2018		6		0		0.0		6		0		0.0		6		0		0.0
2019		6		0		0.0		6		0		0.0		6		0		0.0
2020		6		0		0.0		6		0		0.0		6		0		0.0
2021		6		0		0.0		6		0		0.0		6		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		257		0		0.0		477		0		0.0		477		0		0.0

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 40

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – CHIHUIDO LA SALINA SUR

FIELD-SEGMENT – RINCON DE CORREA SUR

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		75		0		0.0		101		0		0.0		189		0		0.0
2007		44		0		0.0		132		0		0.0		302		0		0.0
2008		31		0		0.0		94		0		0.0		214		0		0.0
2009		19		0		0.0		63		0		0.0		145		0		0.0
2010		13		0		0.0		44		0		0.0		101		0		0.0
2011		6		0		0.0		31		0		0.0		69		0		0.0
2012		0		0		0.0		13		0		0.0		44		0		0.0
2013		0		0		0.0		13		0		0.0		31		0		0.0
2014		0		0		0.0		6		0		0.0		19		0		0.0
2015		0		0		0.0		6		0		0.0		19		0		0.0
2016		0		0		0.0		0		0		0.0		0		0		0.0
2017		0		0		0.0		0		0		0.0		0		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0	0:0			0		0		0.0
Total		188		0		0.0		503		0		0.0		1,133		0		0.0

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 41

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – EL PORTÓN

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		1,623		0		18,705.5		1,724		0		18,705.5		1,724		0		18,705.5
2007		1,257		0		19,149.7		1,509		0		19,149.7		1,541		0		19,149.7
2008		994		0		18,892.5		1,183		0		18,892.5		1,220		0		18,892.5
2009		817		0		18,307.3		956		0		18,307.3		994		0		18,307.3
2010		680		0		17,994.1		780		0		17,994.1		811		0		17,994.1
2011		553		0		17,298.3		629		0		17,298.3		661		0		17,298.3
2012		409		0		15,198.4		466		0		15,198.4		491		0		15,198.4
2013		340		0		13,706.3		384		0		13,706.3		403		0		13,706.3
2014		302		0		13,548.9		334		0		13,548.9		353		0		13,548.9
2015		233		0		10,987.6		258		0		10,987.6		270		0		10,987.6
2016		163		0		6,383.9		182		0		6,383.9		195		0		6,383.9
2017		95		0		3,266.2		101		0		3,266.2		107		0		3,266.2
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		7,466		0		173,438.7		8,506		0		173,438.7		8,770		0		173,438.7

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 42

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – EL PORTÓN

FIELD-SEGMENT – EL PORTÓN NORTE

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		1,019		0		17,793.1		1,120		0		17,793.1		1,120		0		17,793.1
2007		748		0		18,238.4		1,000		0		18,238.4		1,000		0		18,238.4
2008		591		0		17,990.0		780		0		17,990.0		780		0		17,990.0
2009		484		0		17,420.1		623		0		17,420.1		623		0		17,420.1
2010		403		0		17,138.3		503		0		17,138.3		503		0		17,138.3
2011		264		0		6,640.9		340		0		6,640.9		340		0		6,640.9
2012		151		0		2,393.7		208		0		2,393.7		208		0		2,393.7
2013		107		0		988.7		151		0		988.7		151		0		988.7
2014		88		0		840.6		120		0		840.6		120		0		840.6
2015		63		0		525.1		88		0		525.1		88		0		525.1
2016		50		0		296.1		69		0		296.1		69		0		296.1
2017		38		0		156.4		44		0		156.4		44		0		156.4
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		4,006		0		100,421.4		5,046		0		100,421.4		5,046		0		100,421.4

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 43

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – EL PORTÓN

AREA – EL PORTÓN

FIELD-SEGMENT – EL PORTÓN SUR

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		604		0		912.4		604		0		912.4		604		0		912.4
2007		509		0		911.3		509		0		911.3		541		0		911.3
2008		403		0		902.5		403		0		902.5		440		0		902.5
2009		333		0		887.2		333		0		887.2		371		0		887.2
2010		277		0		855.8		277		0		855.8		308		0		855.8
2011		289		0		10,657.4		289		0		10,657.4		321		0		10,657.4
2012		258		0		12,804.7		258		0		12,804.7		283		0		12,804.7
2013		233		0		12,717.6		233		0		12,717.6		252		0		12,717.6
2014		214		0		12,708.3		214		0		12,708.3		233		0		12,708.3
2015		170		0		10,462.5		170		0		10,462.5		182		0		10,462.5
2016		113		0		6,087.8		113		0		6,087.8		126		0		6,087.8
2017		57		0		3,109.8		57		0		3,109.8		63		0		3,109.8
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		3,460		0		73,017.3		3,460		0		73,017.3		3,724		0		73,017.3

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 44

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		13,656		0		2,961.1		13,706		0		9,415.3		15,153		0		9,582.1
2007		11,313		0		2,484.4		11,345		0		12,096.5		13,309		0		14,430.0
2008		9,541		0		2,118.6		9,567		0		11,738.8		12,169		0		15,903.7
2009		8,111		0		1,820.2		8,130		0		11,451.2		10,924		0		15,636.4
2010		6,991		0		1,587.5		7,003		0		10,877.5		9,827		0		12,789.0
2011		6,085		0		1,400.9		6,085		0		8,774.0		8,763		0		10,840.4
2012		5,356		0		1,252.1		5,356		0		6,008.5		7,911		0		8,932.6
2013		4,718		0		1,123.0		4,718		0		4,140.4		7,166		0		6,175.6
2014		4,205		0		1,021.1		4,205		0		2,997.8		6,559		0		4,319.7
2015		3,760		0		935.1		3,760		0		2,570.5		6,034		0		3,356.1
2016		3,320		0		856.0		3,320		0		1,799.2		5,566		0		2,405.1
2017		2,840		0		709.9		2,840		0		1,196.3		5,075		0		1,665.0
2018		0		0		0.0		0		0		0.0		2,763		0		337.7
2019		0		0		0.0		0		0		0.0		2,593		0		317.0
2020		0		0		0.0		0		0		0.0		2,445		0		299.3
2021		0		0		0.0		0		0		0.0		2,283		0		280.1
2022		0		0		0.0		0		0		0.0		2,156		0		264.5
2023		0		0		0.0		0		0		0.0		1,178		0		144.5
2024		0		0		0.0		0		0		0.0		482		0		59.2
2025		0		0		0.0		0		0		0.0		447		0		54.8
2026		0		0		0.0		0		0		0.0		416		0		51.0
2027		0		0		0.0		0		0		0.0		319		0		39.1
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		79,896		0		18,269.9		80,035		0		83,066.0		123,538		0		107,882.9

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 45

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – CHIHUIDO SIERRA NEGRA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		11,776		0		1,442		11,826		0		1,448		13,088		0		1,598
2007		9,541		0		1,170		9,573		0		1,173		11,276		0		1,376
2008		7,862		0		964		7,888		0		967		10,167		0		1,240
2009		6,525		0		800		6,544		0		802		9,044		0		1,104
2010		5,487		0		672		5,499		0		674		8,049		0		983
2011		4,658		0		571		4,658		0		571		7,071		0		864
2012		3,998		0		489		3,998		0		489		6,291		0		769
2013		3,432		0		419		3,432		0		419		5,616		0		687
2014		2,982		0		364		2,982		0		364		5,067		0		620
2015		2,597		0		317		2,597		0		317		4,594		0		562
2016		2,211		0		270		2,211		0		270		4,171		0		511
2017		1,788		0		217		1,788		0		217		3,728		0		460
2018		0		0		0		0		0		0		2,752		0		338
2019		0		0		0		0		0		0		2,584		0		317
2020		0		0		0		0		0		0		2,440		0		299
2021		0		0		0		0		0		0		2,283		0		280
2022		0		0		0		0		0		0		2,156		0		265
2023		0		0		0		0		0		0		1,178		0		145
2024		0		0		0		0		0		0		482		0		59
2025		0		0		0.0		0		0		0.0		447		0		54.8
2026		0		0		0.0		0		0		0.0		416		0		51.0
2027		0		0		0.0		0		0		0.0		319		0		39.1
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		62,857		0		7,695.0		62,996		0		7,711.5		103,219		0		12,618.2

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 46

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – CHIHUIDO SIERRA NEGRA

FIELD-SEGMENT – CHIHUIDO SIERRA NEGRA-RAYOSO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		207		0		24.6		257		0		30.6		283		0		33.6
2007		134		0		16.0		166		0		19.7		346		0		41.1
2008		87		0		10.4		113		0		13.4		377		0		44.8
2009		57		0		6.7		76		0		9.0		283		0		33.6
2010		37		0		4.4		49		0		5.9		198		0		23.6
2011		24		0		2.9		24		0		2.9		129		0		15.3
2012		16		0		1.9		16		0		1.9		84		0		9.9
2013		3		0		0.0		3		0		0.0		54		0		6.5
2014		0		0		0.0		0		0		0.0		35		0		4.2
2015		0		0		0.0		0		0		0.0		23		0		2.7
2016		0		0		0.0		0		0		0.0		15		0		1.8
2017		0		0		0.0		0		0		0.0		9		0		1.1
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		565		0		66.9		704		0		83.4		1,836		0		218.2

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 47

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – CHIHUIDO SIERRA NEGRA

FIELD-SEGMENT – CHIHUIDO-ROCA IGNEA / LA TOSCA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		223		0		37.3		223		0		37.3		238		0		40.0
2007		158		0		26.6		158		0		26.6		190		0		31.9
2008		113		0		18.9		113		0		18.9		156		0		26.1
2009		80		0		13.4		80		0		13.4		130		0		21.8
2010		57		0		9.5		57		0		9.5		110		0		18.5
2011		40		0		6.8		40		0		6.8		95		0		16.0
2012		29		0		4.8		29		0		4.8		83		0		13.9
2013		20		0		3.4		20		0		3.4		73		0		12.3
2014		15		0		2.4		15		0		2.4		65		0		10.9
2015		10		0		1.7		10		0		1.7		58		0		9.8
2016		7		0		1.2		7		0		1.2		53		0		8.8
2017		5		0		0.9		5		0		0.9		48		0		8.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		757		0		126.9		757		0		126.9		1,299		0		218.0

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 48

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – CHIHUIDO SIERRA NEGRA

FIELD-SEGMENT – CHIHUIDO SIERRA NEGRA-TRONCOSO INF. / AGRIO+AVILE

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		10,929		0		1,340.7		10,929		0		1,340.7		11,928		0		1,463.4
2007		8,969		0		1,100.3		8,969		0		1,100.3		10,202		0		1,251.5
2008		7,462		0		915.5		7,462		0		915.5		9,176		0		1,125.7
2009		6,237		0		765.1		6,237		0		765.1		8,247		0		1,011.7
2010		5,273		0		646.9		5,273		0		646.9		7,414		0		909.5
2011		4,494		0		551.3		4,494		0		551.3		6,571		0		806.2
2012		3,867		0		474.4		3,867		0		474.4		5,887		0		722.2
2013		3,332		0		408.8		3,332		0		408.8		5,286		0		648.5
2014		2,897		0		355.5		2,897		0		355.5		4,792		0		587.9
2015		2,524		0		309.7		2,524		0		309.7		4,362		0		535.1
2016		2,145		0		263.1		2,145		0		263.1		3,973		0		487.4
2017		1,728		0		210.6		1,728		0		210.6		3,597		0		441.3
2018		0		0		0.0		0		0		0.0		2,752		0		337.7
2019		0		0		0.0		0		0		0.0		2,584		0		317.0
2020		0		0		0.0		0		0		0.0		2,440		0		299.3
2021		0		0		0.0		0		0		0.0		2,283		0		280.1
2022		0		0		0.0		0		0		0.0		2,156		0		264.5
2023		0		0		0.0		0		0		0.0		1,178		0		144.5
2024		0		0		0.0		0		0		0.0		482		0		59.2
2025		0		0		0.0		0		0		0.0		447		0		54.8
2026		0		0		0.0		0		0		0.0		416		0		51.0
2027		0		0		0.0		0		0		0.0		319		0		39.1
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		59,857		0		7,341.9		59,857		0		7,341.9		96,492		0		11,837.6

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 49

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – CHIHUIDO SIERRA NEGRA

FIELD-SEGMENT – LOMITA NORTE

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		258		0		24.5		258		0		24.5		354		0		33.7
2007		145		0		13.8		145		0		13.8		296		0		28.1
2008		82		0		7.8		82		0		7.8		248		0		23.6
2009		46		0		4.4		46		0		4.4		207		0		19.6
2010		26		0		2.5		26		0		2.5		173		0		16.4
2011		15		0		1.4		15		0		1.4		144		0		13.7
2012		8		0		0.8		8		0		0.8		121		0		11.5
2013		5		0		0.4		5		0		0.4		101		0		9.6
2014		3		0		0.2		3		0		0.2		84		0		8.0
2015		1		0		0.1		1		0		0.1		70		0		6.7
2016		1		0		0.1		1		0		0.1		57		0		5.6
2017		0		0		0.0		0		0		0.0		19		0		4.7
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		590		0		56.0		590		0		56.0		1,874		0		181.2

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 50

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – CHIHUIDO SIERRA NEGRA

FIELD-SEGMENT – LOMITA RAYOSO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		159		0		15.1		159		0		15.1		285		0		27.1
2007		135		0		12.9		135		0		12.9		242		0		23.0
2008		118		0		11.3		118		0		11.3		210		0		19.9
2009		105		0		9.9		105		0		9.9		177		0		16.9
2010		94		0		8.9		94		0		8.9		154		0		14.6
2011		85		0		8.1		85		0		8.1		132		0		12.6
2012		78		0		7.4		78		0		7.4		116		0		11.0
2013		72		0		6.8		72		0		6.8		102		0		9.7
2014		67		0		6.3		67		0		6.3		91		0		8.6
2015		62		0		5.9		62		0		5.9		81		0		7.7
2016		58		0		5.5		58		0		5.5		73		0		6.9
2017		55		0		5.2		55		0		5.2		55		0		5.2
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		1,088		0		103.3		1,088		0		103.3		1,718		0		163.2

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 51

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – PASO BARDAS NORTE

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		50		0		1,438.1		50		0		7,886.3		105		0		7,897.7
2007		36		0		1,237.9		36		0		10,846.3		157		0		12,971.2
2008		26		0		1,081.3		26		0		10,698.5		196		0		14,583.4
2009		19		0		951.0		19		0		10,579.7		147		0		14,455.7
2010		14		0		849.0		14		0		10,137.5		109		0		11,732.1
2011		10		0		767.3		10		0		8,140.4		81		0		9,904.8
2012		7		0		702.6		7		0		5,459.0		59		0		8,094.5
2013		5		0		646.5		5		0		3,663.9		44		0		5,421.8
2014		4		0		602.3		4		0		2,579.0		33		0		3,635.0
2015		3		0		566.0		3		0		2,201.4		25		0		2,731.0
2016		2		0		536.7		2		0		1,479.9		18		0		1,833.2
2017		1		0		446.3		1		0		932.7		13		0		1,145.2
2018		0		0		0.0		0		0		0.0		11		0		0.0
2019		0		0		0.0		0		0		0.0		9		0		0.0
2020		0		0		0.0		0		0		0.0		5		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		177		0		9,825.0		177		0		74,604.6		1,012		0		94,405.6

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 52

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – PASO BARDAS NORTE

FIELD-SEGMENT – PASO BARDAS NORTE-GRUPO NEUQUEN

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		0		0		551.2		0		0		6,999.4		0		0		6,999.4
2007		0		0		540.7		0		0		10,149.1		0		0		12,248.9
2008		0		0		531.9		0		0		10,149.1		0		0		13,998.7
2009		0		0		520.4		0		0		10,149.1		0		0		13,998.7
2010		0		0		510.6		0		0		9,799.1		0		0		11,374.0
2011		0		0		501.2		0		0		7,874.3		0		0		9,624.1
2012		0		0		493.1		0		0		5,249.5		0		0		7,874.3
2013		0		0		482.3		0		0		3,499.7		0		0		5,249.5
2014		0		0		473.1		0		0		2,449.8		0		0		3,499.7
2015		0		0		464.4		0		0		2,099.8		0		0		2,624.8
2016		0		0		456.7		0		0		1,399.9		0		0		1,749.8
2017		0		0		388.5		0		0		874.9		0		0		1,084.9
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		0		0		5,914.1		0		0		70,693.7		0		0		90,326.8

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 53

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – PASO BARDAS NORTE

FIELD-SEGMENT – PASO BARDAS NORTE-HUITRIN (LA TOSCA)

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		50		0		886.9		50		0		886.9		50		0		886.9
2007		36		0		697.2		36		0		697.2		36		0		697.2
2008		26		0		549.4		26		0		549.4		26		0		549.4
2009		19		0		430.6		19		0		430.6		19		0		430.6
2010		14		0		338.4		14		0		338.4		14		0		338.4
2011		10		0		266.1		10		0		266.1		10		0		266.1
2012		7		0		209.5		7		0		209.5		7		0		209.5
2013		5		0		164.2		5		0		164.2		5		0		164.2
2014		4		0		129.2		4		0		129.2		4		0		129.2
2015		3		0		101.6		3		0		101.6		3		0		101.6
2016		2		0		80.0		2		0		80.0		2		0		80.0
2017		1		0		57.8		1		0		57.8		1		0		57.8
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		177		0		3,910.9		177		0		3,910.9		177		0		3,910.9

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 54

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – PASO BARDAS NORTE

FIELD-SEGMENT – PASO BARDAS NORTE-MULICHINCO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		0		0		0.0		0		0		0.0		55		0		11.4
2007		0		0		0.0		0		0		0.0		121		0		25.1
2008		0		0		0.0		0		0		0.0		170		0		35.3
2009		0		0		0.0		0		0		0.0		128		0		26.4
2010		0		0		0.0		0		0		0.0		95		0		19.7
2011		0		0		0.0		0		0		0.0		71		0		14.6
2012		0		0		0.0		0		0		0.0		52		0		10.7
2013		0		0		0.0		0		0		0.0		39		0		8.1
2014		0		0		0.0		0		0		0.0		29		0		6.1
2015		0		0		0.0		0		0		0.0		22		0		4.6
2016		0		0		0.0		0		0		0.0		16		0		3.4
2017		0		0		0.0		0		0		0.0		12		0		2.5
2018		0		0		0.0		0		0		0.0		11		0		0.0
2019		0		0		0.0		0		0		0.0		9		0		0.0
2020		0		0		0.0		0		0		0.0		5		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		0		0		0.0		0		0		0.0		835		0		167.9

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 55

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – SEÑAL PICADA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		1,830		0		80.8		1,830		0		80.8		1,960		0		86.6
2007		1,736		0		76.9		1,736		0		76.9		1,876		0		83.2
2008		1,653		0		73.4		1,653		0		73.4		1,806		0		80.2
2009		1,567		0		69.7		1,567		0		69.7		1,733		0		77.1
2010		1,490		0		66.3		1,490		0		66.3		1,669		0		74.3
2011		1,417		0		63.1		1,417		0		63.1		1,611		0		71.8
2012		1,351		0		60.2		1,351		0		60.2		1,561		0		69.6
2013		1,281		0		57.1		1,281		0		57.1		1,506		0		67.2
2014		1,219		0		54.4		1,219		0		54.4		1,459		0		65.1
2015		1,160		0		51.7		1,160		0		51.7		1,415		0		63.1
2016		1,107		0		49.4		1,107		0		49.4		1,377		0		61.4
2017		1,051		0		46.9		1,051		0		46.9		1,334		0		59.5
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		16,862		0		749.9		16,862		0		749.9		19,307		0		859.1

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 56

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – SEÑAL PICADA

FIELD-SEGMENT – SEÑAL PICADA-CENTENARIO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		17		0		0.0		17		0		0.0		17		0		0.0
2007		11		0		0.0		11		0		0.0		11		0		0.0
2008		7		0		0.0		7		0		0.0		7		0		0.0
2009		5		0		0.0		5		0		0.0		5		0		0.0
2010		3		0		0.0		3		0		0.0		3		0		0.0
2011		2		0		0.0		2		0		0.0		2		0		0.0
2012		1		0		0.0		1		0		0.0		1		0		0.0
2013		0		0		0.0		0		0		0.0		0		0		0.0
2014		0		0		0.0		0		0		0.0		0		0		0.0
2015		0		0		0.0		0		0		0.0		0		0		0.0
2016		0		0		0.0		0		0		0.0		0		0		0.0
2017		0		0		0.0		0		0		0.0		0		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		46		0		0.0		46		0		0.0		46		0		0.0

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 57

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – RINCON DE LOS SAUCES

AREA – SEÑAL PICADA

FIELD-SEGMENT – SEÑAL PICADA-QUINTUCO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		1,813		0		80.8		1,813		0		80.8		1,943		0		86.6
2007		1,725		0		76.9		1,725		0		76.9		1,865		0		83.2
2008		1,646		0		73.4		1,646		0		73.4		1,799		0		80.2
2009		1,562		0		69.7		1,562		0		69.7		1,728		0		77.1
2010		1,487		0		66.3		1,487		0		66.3		1,666		0		74.3
2011		1,415		0		63.1		1,415		0		63.1		1,609		0		71.8
2012		1,350		0		60.2		1,350		0		60.2		1,560		0		69.6
2013		1,281		0		57.1		1,281		0		57.1		1,506		0		67.2
2014		1,219		0		54.4		1,219		0		54.4		1,459		0		65.1
2015		1,160		0		51.7		1,160		0		51.7		1,415		0		63.1
2016		1,107		0		49.4		1,107		0		49.4		1,377		0		61.4
2017		1,051		0		46.9		1,051		0		46.9		1,334		0		59.5
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		16,816		0		749.9		16,816		0		749.9		19,261		0		859.1

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 58

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		5,004		0		318,815.4		5,235		0		334,189.9		5,645		0		360,956.5
2007		4,174		0		273,333.0		4,722		0		304,871.2		5,207		0		341,193.5
2008		3,414		0		229,024.4		4,067		0		270,382.5		4,677		0		317,889.3
2009		2,837		0		193,894.3		3,501		0		233,697.6		4,150		0		288,320.7
2010		2,388		0		166,020.6		3,066		0		205,715.4		3,696		0		268,871.4
2011		2,012		0		142,085.6		2,579		0		175,329.3		3,183		0		231,846.7
2012		1,745		0		125,010.8		2,179		0		151,465.1		2,753		0		203,542.8
2013		1,484		0		107,646.5		1,816		0		128,745.8		2,364		0		177,829.7
2014		961		0		62,773.1		1,533		0		111,023.8		2,051		0		156,971.2
2015		360		0		5,665.3		1,279		0		93,395.3		1,804		0		140,196.1
2016		335		0		4,674.5		1,102		0		80,055.3		1,616		0		125,905.9
2017		311		0		3,861.4		950		0		68,358.5		1,455		0		113,433.0
2018		286		0		2,948.6		819		0		57,550.5		1,315		0		101,968.4
2019		266		0		2,461.1		709		0		48,846.4		1,194		0		93,013.5
2020		248		0		2,059.6		620		0		42,147.8		1,087		0		85,324.3
2021		229		0		1,702.3		539		0		36,349.0		993		0		78,935.8
2022		214		0		1,429.2		464		0		31,495.2		906		0		74,384.2
2023		199		0		1,197.3		415		0		28,027.5		843		0		70,644.0
2024		186		0		1,010.7		370		0		24,544.3		789		0		67,384.1
2025		173		0		850.1		332		0		21,806.5		741		0		64,699.5
2026		162		0		715.1		299		0		19,342.6		702		0		62,510.2
2027		151		0		553.9		269		0		17,062.0		666		0		60,708.4
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		27,139		0		1,647,732.8		36,865		0		2,484,401.5		47,837		0		3,486,529.2

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 59

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – AGUADA TOLEDO-SIERRA BARROSA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		746		0		35,456.5		778		0		42,925.3		778		0		49,106.3
2007		684		0		27,078.8		779		0		38,698.5		779		0		51,115.3
2008		631		0		20,457.3		788		0		33,858.3		788		0		49,580.1
2009		579		0		15,639.1		711		0		25,819.4		711		0		39,633.7
2010		534		0		12,152.5		647		0		19,616.3		647		0		31,054.5
2011		492		0		9,539.5		586		0		15,005.4		586		0		24,432.2
2012		456		0		7,561.4		538		0		11,569.3		538		0		19,293.6
2013		420		0		5,971.2		490		0		8,968.1		490		0		15,251.3
2014		390		0		4,729.1		446		0		6,985.7		446		0		11,935.8
2015		359		0		3,807.2		409		0		5,531.7		409		0		9,530.4
2016		334		0		3,053.4		378		0		4,276.2		378		0		7,477.6
2017		310		0		2,455.3		347		0		3,266.1		347		0		5,815.2
2018		285		0		1,723.6		316		0		1,958.6		316		0		3,802.5
2019		265		0		1,393.9		290		0		1,526.3		290		0		3,041.2
2020		247		0		1,128.2		266		0		1,183.8		266		0		2,433.2
2021		229		0		908.6		242		0		908.6		242		0		1,945.1
2022		214		0		737.5		214		0		737.5		214		0		1,468.0
2023		199		0		594.6		199		0		594.6		199		0		1,114.1
2024		186		0		484.4		186		0		484.4		186		0		837.3
2025		173		0		392.9		173		0		392.9		173		0		637.1
2026		162		0		316.7		162		0		316.7		162		0		457.9
2027		151		0		234.4		151		0		234.4		151		0		389.4
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		8,046		0		155,816.1		9,096		0		224,858.1		9,096		0		330,351.8

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 60

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA –  TOLEDO-SIERRA BARROSA

FIELD-SEGMENT – AGUADA TOLEDO-SIERRA BARROSA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		732		0		20,065.8		764		0		20,065.8		764		0		24,448.3
2007		672		0		16,294.2		767		0		16,294.2		767		0		22,004.6
2008		620		0		13,260.7		777		0		13,260.7		777		0		18,702.6
2009		569		0		10,735.7		701		0		10,735.7		701		0		14,962.8
2010		525		0		8,719.2		638		0		8,719.2		638		0		11,971.7
2011		485		0		7,080.6		579		0		7,080.6		579		0		9,577.3
2012		449		0		5,763.4		531		0		5,763.4		531		0		7,659.8
2013		414		0		4,665.1		484		0		4,665.1		484		0		6,127.1
2014		384		0		3,785.7		440		0		3,785.7		440		0		4,901.7
2015		356		0		3,075.9		406		0		3,075.9		406		0		3,923.5
2016		331		0		2,503.8		375		0		2,503.8		375		0		3,139.5
2017		307		0		2,027.1		344		0		2,027.1		344		0		2,510.9
2018		285		0		1,645.7		316		0		1,645.7		316		0		2,009.4
2019		265		0		1,338.4		290		0		1,338.4		290		0		1,606.8
2020		247		0		1,087.7		266		0		1,087.7		266		0		1,285.5
2021		229		0		879.3		242		0		879.3		242		0		1,084.2
2022		214		0		716.9		214		0		716.9		214		0		865.2
2023		199		0		579.2		199		0		579.2		199		0		692.2
2024		186		0		473.2		186		0		473.2		186		0		554.4
2025		173		0		384.9		173		0		384.9		173		0		445.0
2026		162		0		310.8		162		0		310.8		162		0		353.1
2027		151		0		229.5		151		0		229.5		151		0		317.8
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		7,955		0		105,622.8		9,005		0		105,622.8		9,005		0		139,143.4

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 61

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – AGUADA TOLEDO-SIERRA BARROSA

FIELD-SEGMENT – BARROSA NORTE

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		0		0		1,154.4		0		0		3,097.1		0		0		3,097.1
2007		0		0		928.8		0		0		4,069.3		0		0		4,069.3
2008		0		0		748.7		0		0		4,732.9		0		0		4,732.9
2009		0		0		600.3		0		0		3,628.6		0		0		3,628.6
2010		0		0		483.1		0		0		2,764.4		0		0		2,764.4
2011		0		0		388.8		0		0		2,108.3		0		0		2,108.3
2012		0		0		313.2		0		0		1,603.3		0		0		1,603.3
2013		0		0		251.4		0		0		1,223.7		0		0		1,223.7
2014		0		0		202.4		0		0		935.5		0		0		935.5
2015		0		0		162.8		0		0		710.9		0		0		710.9
2016		0		0		131.4		0		0		451.7		0		0		451.7
2017		0		0		97.5		0		0		219.7		0		0		219.7
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		0		0		5,462.8		0		0		25,545.4		0		0		25,545.4

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 62

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – AGUADA TOLEDO-SIERRA BARROSA

FIELD-SEGMENT – BARROSA OESTE

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		10		0		196.0		10		0		894.5		10		0		1,418.2
2007		9		0		177.3		9		0		1,707.1		9		0		2,982.0
2008		8		0		161.4		8		0		1,436.2		8		0		2,711.1
2009		7		0		145.8		7		0		1,420.7		7		0		2,695.6
2010		6		0		132.4		6		0		1,215.2		6		0		2,297.9
2011		5		0		120.1		5		0		1,042.1		5		0		1,908.4
2012		5		0		109.1		5		0		891.3		5		0		1,582.8
2013		4		0		98.5		4		0		762.1		4		0		1,314.1
2014		4		0		89.3		4		0		655.1		4		0		1,095.5
2015		3		0		80.9		3		0		604.9		3		0		957.7
2016		3		0		73.8		3		0		520.9		3		0		835.2
2017		3		0		66.7		3		0		429.8		3		0		688.3
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		67		0		1,451.3		67		0		11,579.9		67		0		20,486.8

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 63

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – AGUADA TOLEDO-SIERRA BARROSA

FIELD-SEGMENT – CUPEN MAHUIDA-PRECUYANO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		0		0		9,884.8		0		0		13,770.4		0		0		13,770.4
2007		0		0		5,942.7		0		0		12,044.0		0		0		14,843.6
2008		0		0		3,672.5		0		0		11,284.7		0		0		15,716.8
2009		0		0		2,312.5		0		0		7,856.0		0		0		13,359.3
2010		0		0		1,495.2		0		0		5,381.1		0		0		10,687.4
2011		0		0		987.0		0		0		3,672.8		0		0		8,549.9
2012		0		0		664.3		0		0		2,508.4		0		0		6,840.0
2013		0		0		452.0		0		0		1,751.9		0		0		5,471.9
2014		0		0		311.9		0		0		1,228.4		0		0		4,377.6
2015		0		0		218.3		0		0		864.4		0		0		3,502.0
2016		0		0		154.4		0		0		609.8		0		0		2,801.8
2017		0		0		109.3		0		0		434.8		0		0		2,241.6
2018		0		0		77.9		0		0		312.9		0		0		1,793.1
2019		0		0		55.5		0		0		187.9		0		0		1,434.4
2020		0		0		40.5		0		0		96.1		0		0		1,147.7
2021		0		0		29.3		0		0		29.3		0		0		860.9
2022		0		0		20.6		0		0		20.6		0		0		602.8
2023		0		0		15.4		0		0		15.4		0		0		421.9
2024		0		0		11.2		0		0		11.2		0		0		282.9
2025		0		0		8.0		0		0		8.0		0		0		192.1
2026		0		0		5.9		0		0		5.9		0		0		104.8
2027		0		0		4.9		0		0		4.9		0		0		71.6
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		0		0		26,474.1		0		0		62,098.9		0		0		109,074.5

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 64

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – AGUADA TOLEDO-SIERRA BARROSA

FIELD-SEGMENT – CUPEN MAHUIDA NORTE-PRECUYANO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		0		0		1,062.8		0		0		2,004.8		0		0		2,004.8
2007		0		0		730.3		0		0		1,288.4		0		0		2,497.2
2008		0		0		503.0		0		0		822.5		0		0		2,900.6
2009		0		0		344.4		0		0		526.3		0		0		1,982.8
2010		0		0		236.8		0		0		340.9		0		0		1,360.7
2011		0		0		162.8		0		0		222.1		0		0		934.6
2012		0		0		112.1		0		0		146.0		0		0		645.4
2013		0		0		76.8		0		0		96.4		0		0		445.7
2014		0		0		52.7		0		0		63.9		0		0		308.4
2015		0		0		36.3		0		0		42.6		0		0		203.3
2016		0		0		0.0		0		0		0.0		0		0		59.4
2017		0		0		0.0		0		0		0.0		0		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		0		0		3,318.0		0		0		5,553.9		0		0		13,342.9

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 65

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – AGUADA TOLEDO-SIERRA BARROSA

FIELD-SEGMENT – CUPEN-CENTENARIO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		0		0		1,418.0		0		0		1,418.0		0		0		1,418.0
2007		0		0		1,680.0		0		0		1,970.0		0		0		2,436.1
2008		0		0		1,054.8		0		0		1,265.1		0		0		3,040.4
2009		0		0		660.1		0		0		811.8		0		0		1,622.9
2010		0		0		412.1		0		0		521.8		0		0		893.6
2011		0		0		258.5		0		0		337.8		0		0		508.2
2012		0		0		160.6		0		0		218.2		0		0		296.6
2013		0		0		73.3		0		0		114.8		0		0		133.1
2014		0		0		0.0		0		0		30.0		0		0		30.0
2015		0		0		0.0		0		0		0.0		0		0		0.0
2016		0		0		0.0		0		0		0.0		0		0		0.0
2017		0		0		0.0		0		0		0.0		0		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		0		0		5,717.4		0		0		6,687.5		0		0		10,378.9

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 66

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – AGUADA TOLEDO-SIERRA BARROSA

FIELD-SEGMENT – EL CORDON-LAJAS

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		0		0		0.0		0		0		0.0		0		0		0.0
2007		0		0		0.0		0		0		0.0		0		0		0.0
2008		0		0		0.0		0		0		0.0		0		0		0.0
2009		0		0		0.0		0		0		0.0		0		0		0.0
2010		0		0		0.0		0		0		0.0		0		0		0.0
2011		0		0		0.0		0		0		0.0		0		0		0.0
2012		0		0		0.0		0		0		0.0		0		0		0.0
2013		0		0		0.0		0		0		0.0		0		0		0.0
2014		0		0		0.0		0		0		0.0		0		0		0.0
2015		0		0		0.0		0		0		0.0		0		0		0.0
2016		0		0		0.0		0		0		0.0		0		0		0.0
2017		0		0		0.0		0		0		0.0		0		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		0		0		0.0		0		0		0.0		0		0		0.0

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 67

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – AGUADA TOLEDO-SIERRA BARROSA

FIELD-SEGMENT – EL CORDON-LOTENA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		0		0		0.0		0		0		0.0		0		0		0.0
2007		0		0		0.0		0		0		0.0		0		0		0.0
2008		0		0		0.0		0		0		0.0		0		0		0.0
2009		0		0		0.0		0		0		0.0		0		0		0.0
2010		0		0		0.0		0		0		0.0		0		0		0.0
2011		0		0		0.0		0		0		0.0		0		0		0.0
2012		0		0		0.0		0		0		0.0		0		0		0.0
2013		0		0		0.0		0		0		0.0		0		0		0.0
2014		0		0		0.0		0		0		0.0		0		0		0.0
2015		0		0		0.0		0		0		0.0		0		0		0.0
2016		0		0		0.0		0		0		0.0		0		0		0.0
2017		0		0		0.0		0		0		0.0		0		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		0		0		0.0		0		0		0.0		0		0		0.0

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 68

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – AGUADA TOLEDO-SIERRA BARROSA

FIELD-SEGMENT – EL TRIANGULO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		4		0		1,674.7		4		0		1,674.7		4		0		1,674.7
2007		3		0		1,325.5		3		0		1,325.5		3		0		1,325.5
2008		3		0		1,056.2		3		0		1,056.2		3		0		1,056.2
2009		3		0		840.3		3		0		840.3		3		0		840.3
2010		3		0		673.7		3		0		673.7		3		0		673.7
2011		2		0		541.7		2		0		541.7		2		0		541.7
2012		2		0		438.7		2		0		438.7		2		0		438.7
2013		2		0		354.1		2		0		354.1		2		0		354.1
2014		2		0		287.1		2		0		287.1		2		0		287.1
2015		0		0		233.0		0		0		233.0		0		0		233.0
2016		0		0		190.0		0		0		190.0		0		0		190.0
2017		0		0		154.7		0		0		154.7		0		0		154.7
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		24		0		7,769.7		24		0		7,769.7		24		0		7,769.7

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 69

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – AGUADA TOLEDO-SIERRA BARROSA

FIELD-SEGMENT – SIERRA BARROSA ESTE

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		0		0		0.0		0		0		0.0		0		0		1,274.8
2007		0		0		0.0		0		0		0.0		0		0		957.0
2008		0		0		0.0		0		0		0.0		0		0		719.5
2009		0		0		0.0		0		0		0.0		0		0		541.4
2010		0		0		0.0		0		0		0.0		0		0		405.1
2011		0		0		0.0		0		0		0.0		0		0		303.8
2012		0		0		0.0		0		0		0.0		0		0		227.0
2013		0		0		0.0		0		0		0.0		0		0		181.6
2014		0		0		0.0		0		0		0.0		0		0		0.0
2015		0		0		0.0		0		0		0.0		0		0		0.0
2016		0		0		0.0		0		0		0.0		0		0		0.0
2017		0		0		0.0		0		0		0.0		0		0		0.0
2018		0		0		0.0		0		0		0.0		0		0		0.0
2019		0		0		0.0		0		0		0.0		0		0		0.0
2020		0		0		0.0		0		0		0.0		0		0		0.0
2021		0		0		0.0		0		0		0.0		0		0		0.0
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		0		0		0.0		0		0		0.0		0		0		4,610.2

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 70

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – LOMA LA LATA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		4,258		0		283,358.9		4,457		0		291,264.6		4,867		0		311,850.2
2007		3,490		0		246,254.2		3,943		0		266,172.7		4,428		0		290,078.2
2008		2,783		0		208,567.1		3,279		0		236,524.2		3,889		0		268,309.2
2009		2,258		0		178,255.2		2,790		0		207,878.2		3,439		0		248,687.0
2010		1,854		0		153,868.1		2,419		0		186,099.1		3,049		0		237,816.9
2011		1,520		0		132,546.1		1,993		0		160,323.9		2,597		0		207,414.5
2012		1,289		0		117,449.4		1,641		0		139,895.8		2,215		0		184,249.2
2013		1,064		0		101,675.3		1,326		0		119,777.7		1,874		0		162,578.4
2014		571		0		58,044.0		1,087		0		104,038.1		1,605		0		145,035.4
2015		1		0		1,858.1		870		0		87,863.6		1,395		0		130,665.7
2016		1		0		1,621.1		724		0		75,779.1		1,238		0		118,428.3
2017		1		0		1,406.1		603		0		65,092.4		1,108		0		107,617.8
2018		1		0		1,225.0		503		0		55,591.9		999		0		98,165.9
2019		1		0		1,067.2		419		0		47,320.1		904		0		89,972.3
2020		1		0		931.4		354		0		40,964.0		821		0		82,891.1
2021		0		0		793.7		297		0		35,440.4		751		0		76,990.7
2022		0		0		691.7		250		0		30,757.7		692		0		72,916.2
2023		0		0		602.7		216		0		27,432.9		644		0		69,529.9
2024		0		0		526.3		184		0		24,059.9		603		0		66,546.8
2025		0		0		457.2		159		0		21,413.6		568		0		64,062.4
2026		0		0		398.4		137		0		19,025.9		540		0		62,052.3
2027		0		0		319.5		118		0		16,827.6		515		0		60,319.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		19,093		0		1,491,916.7		27,769		0		2,259,543.4		38,741		0		3,156,177.4

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 71

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – LOMA LA LATA

FIELD-SEGMENT – BARR. COLORADOS-SIERRAS BLANCAS

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		5		0		180.1		5		0		180.1		28		0		954.2
2007		4		0		151.9		4		0		151.9		41		0		1,583.5
2008		4		0		127.1		4		0		127.1		55		0		2,121.0
2009		3		0		109.5		3		0		109.5		66		0		2,580.4
2010		3		0		91.8		3		0		91.8		56		0		2,191.6
2011		2		0		77.7		2		0		77.7		48		0		1,859.7
2012		2		0		67.1		2		0		67.1		40		0		1,573.3
2013		2		0		56.5		2		0		56.5		34		0		1,330.0
2014		1		0		49.4		1		0		49.4		29		0		1,131.8
2015		1		0		42.4		1		0		42.4		25		0		965.5
2016		1		0		35.3		1		0		35.3		21		0		821.1
2017		1		0		28.3		1		0		28.3		18		0		696.4
2018		1		0		24.7		1		0		24.7		15		0		586.9
2019		1		0		21.2		1		0		21.2		13		0		498.3
2020		1		0		17.7		1		0		17.7		11		0		430.8
2021		0		0		0.0		0		0		0.0		9		0		360.9
2022		0		0		0.0		0		0		0.0		7		0		255.0
2023		0		0		0.0		0		0		0.0		4		0		159.3
2024		0		0		0.0		0		0		0.0		2		0		70.3
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		32		0		1,080.7		32		0		1,080.7		522		0		20,170.0

Note: Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 72

PROJECTION of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – LOMA LA LATA

FIELD-SEGMENT – QUINTUCO

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		197		0		163.7		197		0		163.7		220		0		172.8
2007		103		0		85.7		103		0		85.7		169		0		111.8
2008		54		0		45.1		54		0		45.1		157		0		85.9
2009		28		0		23.6		28		0		23.6		140		0		67.9
2010		15		0		12.1		15		0		12.1		110		0		50.0
2011		8		0		6.4		8		0		6.4		89		0		38.5
2012		4		0		2.9		4		0		2.9		73		0		30.3
2013		1		0		0.4		1		0		0.4		60		0		23.7
2014		0		0		0.0		0		0		0.0		50		0		19.8
2015		0		0		0.0		0		0		0.0		43		0		16.9
2016		0		0		0.0		0		0		0.0		36		0		14.4
2017		0		0		0.0		0		0		0.0		31		0		12.3
2018		0		0		0.0		0		0		0.0		27		0		10.5
2019		0		0		0.0		0		0		0.0		20		0		7.8
2020		0		0		0.0		0		0		0.0		11		0		4.4
2021		0		0		0.0		0		0		0.0		4		0		0.5
2022		0		0		0.0		0		0		0.0		0		0		0.0
2023		0		0		0.0		0		0		0.0		0		0		0.0
2024		0		0		0.0		0		0		0.0		0		0		0.0
2025		0		0		0.0		0		0		0.0		0		0		0.0
2026		0		0		0.0		0		0		0.0		0		0		0.0
2027		0		0		0.0		0		0		0.0		0		0		0.0
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		410		0		339.9		410		0		339.9		1,240		0		667.5

Note: Probable reserves have not been adjusted for risk

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 73

PROJECTION of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – LOMA LA LATA

FIELD-SEGMENT – SIERRAS BLANCAS

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		4,056		0		276,736.8		4,255		0		282,116.8		4,619		0		299,393.5
2007		3,383		0		240,546.2		3,836		0		253,676.9		4,218		0		271,862.6
2008		2,725		0		203,616.6		3,221		0		219,103.0		3,677		0		243,170.5
2009		2,227		0		173,970.8		2,759		0		191,849.3		3,233		0		218,240.5
2010		1,836		0		150,147.4		2,401		0		170,539.1		2,883		0		198,713.9
2011		1,510		0		129,310.6		1,983		0		147,680.1		2,460		0		177,076.2
2012		1,283		0		114,626.4		1,635		0		129,322.0		2,102		0		159,118.7
2013		1,061		0		99,226.9		1,323		0		110,983.4		1,780		0		141,737.3
2014		570		0		55,910.9		1,086		0		96,679.9		1,526		0		127,687.7
2015		0		0		0.0		869		0		87,711.8		1,327		0		116,344.1
2016		0		0		0.0		723		0		70,700.9		1,181		0		106,677.7
2017		0		0		0.0		602		0		61,176.4		1,059		0		98,427.8
2018		0		0		0.0		502		0		52,898.8		957		0		91,379.9
2019		0		0		0.0		418		0		45,668.9		871		0		85,357.8
2020		0		0		0.0		353		0		39,811.6		799		0		80,216.2
2021		0		0		0.0		297		0		34,646.7		738		0		75,835.6
2022		0		0		0.0		250		0		30,066.0		685		0		71,969.5
2023		0		0		0.0		216		0		26,830.2		640		0		68,767.9
2024		0		0		0.0		184		0		23,533.6		601		0		65,950.2
2025		0		0		0.0		159		0		20,956.4		568		0		63,605.2
2026		0		0		0.0		137		0		18,627.5		540		0		61,653.9
2027		0		0		0.0		118		0		16,508.1		515		0		59,999.5
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		18,651		0		1,444,092.6		27,327		0		2,125,087.4		36,979		0		2,883,186.2

Note: Probable reserves have not been adjusted for risk

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 74

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

BLOCK – LOMA LA LATA

AREA – LOMA LA LATA

FIELD-SEGMENT – LOTENA

for

REPSOL YPF

in

ARGENTINA

	Proved Developed						Total Proved						Proved plus Probable
Year	Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)		Oil, Condensate, and Nat. Gasoline (Mbbl)		LPG (Mbbl)		Marketable Gas (MMcf)
2006		0		0		6,278.3		0		0		8,804.0		0		0		11,329.7
2007		0		0		5,470.4		0		0		12,258.2		0		0		16,520.3
2008		0		0		4,778.3		0		0		17,249.0		0		0		22,931.8
2009		0		0		4,151.3		0		0		15,895.8		0		0		27,798.2
2010		0		0		3,616.8		0		0		15,456.1		0		0		36,861.4
2011		0		0		3,151.4		0		0		12,559.7		0		0		28,440.1
2012		0		0		2,753.0		0		0		10,503.8		0		0		23,526.9
2013		0		0		2,391.5		0		0		8,737.4		0		0		19,487.4
2014		0		0		2,083.7		0		0		7,308.8		0		0		16,196.1
2015		0		0		1,815.7		0		0		6,109.4		0		0		13,339.2
2016		0		0		1,585.8		0		0		5,042.9		0		0		10,915.1
2017		0		0		1,377.8		0		0		3,887.7		0		0		8,481.3
2018		0		0		1,200.3		0		0		2,668.4		0		0		6,188.6
2019		0		0		1,046.0		0		0		1,630.0		0		0		4,108.4
2020		0		0		913.7		0		0		1,134.7		0		0		2,239.7
2021		0		0		793.7		0		0		793.7		0		0		793.7
2022		0		0		691.7		0		0		691.7		0		0		691.7
2023		0		0		602.7		0		0		602.7		0		0		602.7
2024		0		0		526.3		0		0		526.3		0		0		526.3
2025		0		0		457.2		0		0		457.2		0		0		457.2
2026		0		0		398.4		0		0		398.4		0		0		398.4
2027		0		0		319.5		0		0		319.5		0		0		319.5
2028		0		0		0.0		0		0		0.0		0		0		0.0
2029		0		0		0.0		0		0		0.0		0		0		0.0
2030		0		0		0.0		0		0		0.0		0		0		0.0
Total		0		0		46,403.5		0		0		133,035.4		0		0		252,153.7

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.

TABLE 75

PROJECTIONS of GROSS RESERVES

as of

DECEMBER 31, 2005

of

MEGA PLANT

BLOCKS – EL PORTÓN and LOMA LA LATA

for

REPSOL YPF

in

ARGENTINA

	Natural Gas Liquids
	Proved Developed						Total Proved						Proved plus Probable
Year	El Portón Block (Mbbl)		Loma La Lata Block (Mbbl)		Total (Mbbl)		El Portón Block (Mbbl)		Loma La Lata Block (Mbbl)		Total (Mbbl)		El Portón Block (Mbbl)		Loma La Lata Block (Mbbl)		Total (Mbbl)
2006		2,107		11,762		13,869		2,107		11,988		14,095		2,107		12,705		14,812
2007		2,384		10,227		12,611		2,384		10,774		13,158		2,384		11,529		13,913
2008		2,233		8,661		10,894		2,233		9,303		11,536		2,233		10,309		12,542
2009		1,736		7,403		9,139		1,736		8,145		9,881		1,736		9,252		10,988
2010		1,623		6,390		8,013		1,623		7,240		8,863		1,623		8,428		10,051
2011		2,434		5,504		7,938		2,434		6,271		8,705		2,434		7,510		9,944
2012		2,453		4,881		7,334		2,453		5,491		7,944		2,453		6,749		9,202
2013		2,082		4,227		6,309		2,082		4,717		6,799		2,082		6,019		8,101
2014		1,736		2,371		4,107		1,736		4,101		5,837		1,736		5,416		7,152
2015		1,346		0		1,346		1,346		3,472		4,818		1,346		4,938		6,284
2016		969		0		969		969		3,007		3,976		969		4,535		5,504
2017		698		0		698		698		2,598		3,296		698		4,176		4,874
2018		365		0		365		365		2,252		2,617		365		3,887		4,252
2019		302		0		302		302		1,944		2,246		302		3,629		3,931
2020		252		0		252		252		1,692		1,944		252		3,409		3,661
2021		214		0		214		214		1,472		1,686		214		3,220		3,434
2022		0		0		0		0		1,277		1,277		0		3,057		3,057
2023		0		0		0		0		1,138		1,138		0		2,918		2,918
2024		0		0		0		0		1,000		1,000		0		2,805		2,805
2025		0		0		0		0		893		893		0		2,705		2,705
2026		0		0		0		0		793		793		0		2,623		2,623
2027		0		0		0		0		704		704		0		2,554		2,554
2028		0		0		0		0		0		0		0		0		0
2029		0		0		0		0		0		0		0		0		0
2030		0		0		0		0		0		0		0		0		0
Total		22,934		61,426		84,360		22,934		90,272		113,206		22,934		122,373		145,307

Note:  Probable reserves have not been adjusted for risk.

These data accompany the report of DeGolyer and MacNaughton and are subject to its specific conditions.