CORRESP 1 filename1.htm
Dirección General Paseo de la      Tel. 34 91 348 14 94
Económico Financiera Castellana, 278-280      Fax. 34 91 314 29 35
28046 Madrid      framirez@repsolypf.com
Director General España      www.repsolypf.com
     
    November 6, 2006
     

Re: Repsol YPF, S.A.
  Form 20-F for the fiscal year ended December 31. 2005
  File No. 1-10220

Mr. H. Roger Schwall
United States Securities and Exchange Commission
Division of Corporation Finance
100 F Street, N.W.
Washington, D.C. 20549-7410

Dear Mr. Schwall:

     Thank you for your letter dated September 28, 2006, 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”) to the annual report on Form 20-F for the year ended December 31, 2005 (the “2005 Form 20-F”) of Repsol YPF, S.A. (“Repsol 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 comment letter in italicized text.

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

  • Repsol 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 an action with respect to the filing; and

  • Repsol 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 Madrid at 011-34-91-348-14-94 or fax: 011-34-91-348-71-99, Manuel Arranz at 011-34-91-514-50-00 or Joel Osnoss at 212-436-33-52 of Deloitte, our external auditors, or our counsel, Michael J. Willisch of Davis Polk & Wardwell, at 011-34-91-702-2741 or fax: 011-34-91-702-2765.

Very truly yours,
 
 
/s/ Fernando Ramirez Mazarredo
Fernando Ramirez Mazarredo
Group Managing Director of Finance and
Corporate Services

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ANNEX A

1. Key Information about Repsol YPF, page 1

Comment 1: We note your statement on page two that “Under IFRS, Repsol YPF reflects excise and similar taxes on oil and gas production and/ or sales as both expenses and income”. Please tell us how you have applied the guidance in paragraph 8 of IAS 18, which indicates that the following are excluded from revenue, “Amounts collected on behalf of third parties such as sales taxes, goods and services taxes and value added taxes.” We note related disclosure on page F-36 that “As a result of the legislation on oil and gas retailing in force in the countries in which the Group operates, Repsol YPF reflects as both expenses and income the excise and similar taxes oil and gas production and/or sale.”

Response:

The amount of excise taxes recorded by Repsol YPF for the year ended December 31, 2005 (EUR 5,636 million) basically relates to the Spanish oil and gas excise tax.

According to Spanish law, this tax applies to oil & gas production and not to sales because such tax arises when the goods subject to the excise taxes leave (tax point) the plant or tax warehouse. The excise tax cannot be considered to constitute a “pass-through”, since once the tax point has arisen and the tax has been paid it cannot be recovered from the Spanish Treasury.

As a consequence, relating to paragraph 8 of IAS 18 mentioned in your comment, we believe that the Spanish excise tax is not a tax on sales or a tax paid on behalf of third party but is rather an inventory cost in accordance with paragraph 11 of IAS 2. In order to arrive at this conclusion we have taken into consideration the fact that this tax is not paid and collected on behalf of third parties but is directly paid by Repsol YPF, which is the primary obligor of this tax from a legal point of view.

The accounting treatment commented above has been discussed and accepted by the “Comisión Nacional del Mercado de Valores” (CNMV) in Spain.

Repsol YPF applies the same accounting treatment to excise taxes of a similar nature and with similar characteristics that are applicable in other countries in which the Group operates. Additionally, we disclose in our financial statements the amount of excise taxes recognised as expenses and income in each period, as it is a common practice in our industry.

3. Operating and Financial Review and Prospectus, page 94. No accounting consequences resulting from the reserve reduction.

Comment 2. We note your statements on page 98, with respect to your 25% total proved reserves reduction from that originally reported as of December 31, 2004, that “No restatement of the Repsol YPF’s balance sheets or statements of income included in

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[your] statutory consolidated financial statements for prior years is necessary.” We note similar disclosure on page F-55, where you state that “This adjustment of reserves did not have any effect on the depreciation and amortization charge for 2005, as a result of the application of the Group’s accounting policies described in Note 3.4. c.” We further note your disclosure on page F-55 that “Of these adjustments, (52%), 659 million BOE, relate to Bolivia, 509 million BOE (41%) relate to Argentina and 86 million BOE relate to the rest of the world.” Given that 93% of these adjustments occurred in the geographical segment you define as ABB, representing approximately 38% of total assets at December 31, 2005, please provide us with a detailed analysis that supports your conclusion that there were no accounting consequences resulting from this reserve reduction, other than a net asset impairment charge of €23 million, by addressing the following:

a) Expand your disclosures throughout your document to more fully describe the specific facts and circumstances which triggered the reserve revision and restatement. In this regard, we note your disclosure on page 188 indicating that you did not properly apply SEC rules for reserve determinations all time from 1999 to 2004.

Repsol YPF made significant changes in 2005 that greatly improved the reserves process, including by expanding the Board of Director's role in the reserves reporting function, separating the reserves function from the business units, instituting a new reserves reporting manual (the RRM) and engaging in extensive training efforts. Repsol YPF believes that these improvements in the reserves process were primarily responsible for the identification by Repsol YPF senior management, in connection with the determination of reserves as of December 31, 2005, that a reduction to previously reported reserve amounts was necessary.

In that connection, Repsol YPF announced on January 26, 2006 that it would reduce it prior proved reserve estimates by 1,254 million barrels of oil equivalent. It also announced on such date that its Audit and Control Committee would undertake an independent review of the facts and circumstances of the reduction of the proved reserve estimates. Following the conclusion of the independent review in June 2006, Repsol YPF concluded that a reserves restatement should be made for Argentina in respect of 2003 and 2004 and for Bolivia in respect of years 1999 to 2004.

The restatement in respect of 2003 and 2004 in Argentina was due to the fact that reported volumes at the gas-condensate reservoir of Loma La Lata--Sierras Blancas, which had originally been booked on the basis of computer reservoir simulation modelling, were not sufficiently supported by actual reservoir performance. This restatement in respect of Loma La Lata-Sierras Blancas was made using a conservative approach, as recommended by the SEC, pursuant to which the restatement was made in respect of periods following the last date for which Repsol YPF had received an external certification in respect of such reservoir (as of December 31, 2002).

The restatement in respect of years 1999 to 2004 in Bolivia was due to the fact that the treatment during such years was inadequate due to a different interpretation of the commercial aspects of the exportation of gas to Brazil.

The facts and circumstances regarding the reserves revisions in respect of 2005 are described on pages 22-25 of the 2005 20-F.

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Repsol YPF has included extensive disclosure regarding the reserves restatement and revision on pages 20 - 25 and pages 121 - 122 of the 2005 20-F. Repsol YPF also has highlighted the reserves restatement and revision in the initial pages of the 2005 20-F (see page v) and in the operating and financial review and prospects section of the 2005 20-F (see page 98). Repsol YPF does not believe that expanding its disclosure regarding the reserves restatement and revision would provide investors with any material additional information.

b) Provide us with a schedule that lists, by country, the quantity of proved reserves on a field by field basis which were in place immediately prior to and after the reserve restatement for those fields affected by the restatement. Please quantify the carrying and fair values of each field immediately prior to and after the reserve restatement.

Please see the below table:

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Country Field Year
Ending
Proved Reserves
(thousands of boe)
Carrying Value
(millions of USD)
(1)
Fair Value (Millions of
USD)(2)
Impairment (million
of USD)
Impairment (million
of Euros)
Original Restated Original Restated Original Restated        
Argentina Loma La Lata 2003 990 650 2,881 2,881 4,429 3,210
2004 829 575 1,930 1,930 2,089 1,913 17(3) 14(3)
Bolivia Sábalo 2003 425 203 254 254 2,719 1,207
2004 505 206 239 239 789 590
San Alberto 2003 522 240 164 164 1,879 1,272
2004 447 230 163 163 408 377
Grigota (Rio Grande) 2003 85 74 129 129 245 240
2004 112 108 124 124 158 157
SB II (Sirari y Vibora) 2003 94 70 93 93 171 151
2004 66 66 86 86 110 104
SB III (Yapacani) 2003 85 64 60 60 181 130
2004 103 88 58 58 130 126
Margarita 2003 33 17 56 56 1,834 930
2004 47 47 141 141 378 378
(1) Carrying value of the reporting unit has been calculated in accordance with the GAAP applied for each period presented in the 2005 Form 20-F. Regarding the table above, the Group applies Spanish GAAP and IFRS for 2004.
(2) Fair value has been calculated in accordance with the GAAP applied for each period presented in the 2005 Form 20-F. Regarding the table above, the Group applies Spanish GAAP (1° step undiscounted cash flows until year 2003) and IFRS (Discounted cash flows after tax) for 2004.
(3) If it had considered the DD&A effect in Loma la Lata (See response 2.c. below) as a minor restated carrying value, the impairment would have been zero.
 

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c) Provide us with your quantitative analysis demonstrating the effect on depreciation, depletion and amortization (DD&A) and accumulated DD&A balances for all periods presented had the restated reserves been used to calculate DD&A expense.

An additional amount of depreciation, depletion and amortization (DD&A) is associated with the described reserves restatement. After performing detailed calculations and further analysis Repsol YPF concluded that corresponding DD&A effects were not quantitatively and qualitatively significant. Consequently those effects were not recognized within presented financial statements. We confirm to SEC Staff that we have applied the applicable literature in SAB 99 in order to arrive at our conclusion on this specific issue. As mentioned in SAB 99, “the omission or misstatement of an item in a financial report is material if, in the light of surrounding circumstances, the magnitude of the item is such that it is probable that the judgment of a reasonable person relying upon the report would have been changed or influenced by the inclusion or correction of the item”. We have quantitatively concluded that the calculated amount of any corrected misstatement is below the 5% numerical threshold and additionally we have carefully taken into account to arrive at our conclusion on materiality all of the qualitative considerations mentioned in SAB 99 that may render material a quantitatively small misstatement of a financial statement item.

The following table sets forth DD&A amounts before and after the reserves restatement and its corresponding effect over Repsol YPF’s net income:

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Million of Euros
  2003 2004 2005
Net income attributable to shareholders of the parent(1) 2,020 2,414 3,120
       
Original DD&A charge 22 213 227
Restated DD&A charge 36 297 312
       
Increase in DD&A 15 84 85
Increase in DD&A after tax and minority interest 7 52 56
       
% over net income attributable to shareholders of the parent 0.35% 2.14% 1.81%
 
(1) Amounts for 2003 are presented in accordance with Spanish GAAP. For 2004 and 2005 the amounts presented are prepared under IFRS.


As a consequence of the revision of the reserves mentioned on Page F-55 of our Form 20-F, no additional differences to those explained above arise since January 1, 2006.

d) Compare and contrast the accounting effects regarding asset decommissioning obligations as a result of the reserve revisions, if any. For example, state whether revisions to estimates affecting decommissioning obligations were affected by the restatement and the related accounting impact.

The estimated settlement period or amount of the well abandonment obligation corresponding to Loma La Lata, San Antonio, San Alberto, Grigota, Sara Boomerang II and III and Margarita fields have not been affected by the restatement of reserves. The reserve revision did not affect the estimated well abandonment dates. Consequently, no accounting effect is related to well decommissioning obligation of fields affected by the restatement of reserves.

3.6.2 Capital Investments and Divestitures, page 118

Comment 3. We note your statement on page 120 that the amount of proceeds you present for divestitures “does not include the gain on the sale, which is accounted for as operating income, in accordance with the method used for transactions of this type and with standard practice in the industry in which the Group operates.” Please tell us what method you use to record these types of transactions and what you mean by “standard practice in the industry in which the Group operates.” In this regard, tell us if the standard practice used in this industry differs from that proscribed by IFRS or US GAAP.

Response:

We confirm to the Staff that there is a mistake in the text on page 120. The method used by Repsol YPF to record divestment transactions is that established by IFRS.

We indicate below the corrected text which we intend to include in future filings with the SEC. New text is underlined for the Staff’s convenience:

 

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“The principal financial divestments in 2005 relate to PBBPolisur (€123.8 million) and Enagás (€125.3 million). These figures include the gain on the sale, which is accounted for as operating income, in accordance with IFRS.

The main income from divestitures in 2005 came from fixed and financial assets, among which the following are noteworthy: the sale of certain assets in Trinidad & Tobago (€56 million) and in Mexico (€49 million), the sale of YPF’s stake in PBB Polisur (€88 million), and the sale of Gas Natural SDG’s stake in Enagás (€36 million), which is accounted for as operating income, in accordance with IFRS.

The main income from divestitures in 2004 came from financial assets, among which the following are noteworthy: the sale of Gas Natural SDG’s stake in Enagás (€88 million), the sale of Global Companies LLC (€35 million) and the sale of certain assets in Indonesia (€31 million), which figures include the gain on the sale, which is accounted for as operating income, in accordance with IFRS”.

8.4 Available information, page 172

Comment 4. Please note that our address is now 100 F Street, NE., Washington, D.C. 20549.

Response:

We confirm to the Staff that in future filings with the SEC we will address our correspondence to the address referred above.

12. Control Procedures, page 188

Comment 5. We note your representation that your disclosure controls and procedures were effective as of December 31, 2005. Additionally, we note your disclosure in which you announced your reserve restatement on January 26, 2006 and the subsequent independent review of your reserves by the Audit and Control Committee. Please clarify for us whether or not your disclosure controls and procedures were changed as a result of the restatement.

Response:

As stated on page 188, we believe that our disclosure controls and procedures were effective at the reasonable assurance level at December 31, 2005. Prior to that time, Repsol YPF had undertaken numerous and effective organizational changes which remedied in large measure the circumstances that primarily gave rise to the reserves revision. In January 2006, Repsol YPF's Audit and Control Committee undertook an independent review in connection with the revisions to prior reserve estimates, which review was concluded in June 2006. Such review led to certain recommendations, all of which were accepted by Repsol YPF's Board of Directors. These recommendations generally relate to improvements to the group's reserves reporting manual, improved training, better record keeping, increased staffing (including a change in leadership in the reserves area), better testing and monitoring procedures at the fields, certification requirements, and increased integration between the legal department and the commercialization group. These recommendations have been implemented or are in the

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process of being implemented by Repsol YPF's management. Although these recommendations were made in June 2006 and thus had no impact on our disclosure controls and procedures as of December 31, 2005, Repsol YPF believes that the implementation of these recommendations strengthens and reinforces its disclosure controls and procedures already in place as of December 31, 2005.

Comment 6. We note your disclosure indicates that “Other than as described above, there has been no change in Repsol YPF’s internal controls over financial reporting.” Please revise to clarify, if true, without such limiting language, that there were changes in your internal control over financial reporting that occurred during the period covered by the annual report that has materially affected, or is reasonably likely to materially affect, your internal control over financial reporting. If changes were made subsequent to the period covered by the annual report, please describe the facts and circumstances that led to the changes and the nature of the changes that were implemented.

Response:

As indicated in the second paragraph under Section 12 “Controls and Procedures”, of the 2005 Form 20-F, Repsol YPF undertook numerous and effective organizational changes in 2005 which remedied in large measure the circumstances that primarily gave rise to the reserves revision. These were the only changes to Repsol YPF's internal control over financial reporting that occurred during 2005 (the period covered by the 2005 Form 20-F) that materially affected, or were reasonably likely to materially affect, Repsol YPF's internal control over financial reporting and, accordingly, are the only items identified in such paragraph as having occurred in 2005.

We believe that by stating in the third paragraph under Section 12 “Controls and Procedures” that "other than as described above, there has been no change in Repsol YPF's internal control over financial reporting. . .", our disclosure adequately indicates the extent of the changes to our internal control over financial reporting during 2005, the period covered by the 2005 Form 20-F.

As discussed in our response to comment 5, we are in the process of implementing the recommendations that arose out of the independent review conducted by Repsol YPF's Audit and Control Committee in connection with the revisions to prior reserve estimates. Such recommendations were made in June 2006 and have been implemented or are in the process of being implemented. As discussed in our response to comment 5, they generally relate to improvements to the group's reserves reporting manual, improved training, better record keeping, increased staffing (including a change in leadership in the reserves area), better testing and monitoring procedures at the fields, certification requirements, and increased integration between the legal department and the commercialization group.

Consolidated Cash Flow Statements, page F-6

Comment 7. Please tell us why you use “Profit from continuing operations before finance costs” as the starting point to adjust for the effects of transactions for operating activities. In this regard, we note paragraph 18(b) of IAS 7 defines the indirect method as a method “whereby profit or loss is adjusted for the effects of transactions of a non

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cash nature, any deferrals or accruals of past or future operating cash receipts or payments, and items of income or expense associated with investing or financing cash flows.”

Response:

We acknowledge the SEC Staff interpretation. However, we noted that paragraph 31 of IAS 7 requires that interest and dividends both paid and received be separately disclosed, and paragraph 35 of IAS 7 requires that taxes paid be separately disclosed. In that context we also noted that the starting point of the indirect method cash flow statement example in Appendix A to IAS 7 is “Profit before taxation”. Consequently, we believe that similar to the example in the Standard it was acceptable to separately disclose these three amounts in the appropriate captions of our cash flow statement as required by the Standard and eliminate them from the starting point of our indirect method cash flow statement avoiding showing the non cash impacts regarding these items. Our aim was to provide a clearer and fair view presentation for the user of the cash flow statements.

(1.2) Adoption of international Financial Reporting Standards (IFRSs), page F- 11

c) Asset impairment losses, page F-13

Comment 8. We note your statement that “Under IFRSs, the calculation is made in a single stage: the discounted cash flows from the asset are compared with the carrying amount of the asset and, if the latter is higher, an impairment loss is recognized as an expense for the difference.” Please confirm, if true, that the amount you compare to the carrying amount represents recoverable amount, as defined by paragraph 18 of IAS 36 or otherwise advise.

Response:

We confirm to the Staff that the amount we compare to the carrying amount represents the recoverable amount as defined by paragraph 18 of IAS 36. We intend to clarify this statement in future filings.

3.4) Property, Plant and Equipment, page F-24

Comment 9. We note your disclosure indicating that you capitalize borrowing costs directly related to the acquisition or production of property, plant and equipment. Please clarify what you mean by “production” and expand your disclosure to specifically address when you commence, suspend and cease capitalization of borrowing costs in relation to your oil and gas, refining and storage infrastructure construction. Refer to paragraphs 20-29 of NIC 23. Additionally, please disclose how you define a “substantial period of time” to get an asset ready for its intended use and the types of assets used in your operations which typically qualify for this categorization.

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Response:

The method used by Repsol YPF to capitalise borrowing costs is based on the requirements established by IAS 23.

In this connection, only those assets defined in paragraph 4 of IAS 23 are capitalized: “A qualifying asset is an asset that necessarily takes a substantial period of time to get ready for its intended use or sale”. One year is the substantial period of time considered by Repsol YPF.

In addition Repsol YPF considers that in accordance with paragraph 12 of IAS 23 some borrowing costs related with the production of property, plant and equipment are capitalized:

“Borrowing costs that are directly attributable to the acquisition, construction or production of a qualifying asset shall be capitalised as part of the cost of that asset. The amount of borrowing costs eligible for capitalisation shall be determined in accordance with this Standard”.

When we mention “production” on page F-24 paragraph 3.4. , we were reproducing literally the wording in paragraph 12 of IAS 23. Therefore, we confirm to the Staff that in 2005 and 2004 no borrowing costs were capitalized in relation to in-house production performed in a period exceeding one year.

For information purposes we bring to the Staff’s attention that the amount capitalized are not significant to us. In 2005 and 2004, EUR 19 million and EUR 17 million, respectively were capitalized in this connection.

Therefore, in view of the degree of significance of the figures referred to in the preceding paragraph, the Group did not consider expanding the related disclosures in the financial statements.

c) ii. Recognition of Oil and Gas Exploration and Production Transactions, F-25

Comment 10: Please clarify the nature of the costs included in acquiring “interests on exploration permits”.

Response:

The costs of acquiring interests on exploration permits consists of the entry vouchers paid in order to be able to operate in these areas which are capitalized in accordance with paragraph 15 of SFAS 19 which also applies under IFRS.

v) i. Recognition of Oil and Gas Exploration and Production Transactions. F-26

Comment 11: We note your disclosure suggesting that you amortize investments in the acquisition of proved reserves on a method substantially similar to the units-of production method in which you appear to use total proved reserves by field. If true, please explain why you believe it is more systematic and rational to amortize development costs using total proved reserves as opposed to total proved developed

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reserves, or otherwise advise. Please quantify the accounting impact had you used proved developed reserves for IFRS and U.S. GAAP and cite the authoritative guidance supporting your use of a method substantially similar to the units-of-production method. Refer to paragraph 35 of SFAS 19 for U.S. GAAP.

Response:

Repsol YPF amortizes development costs over the estimated commercial life of the field on the basis of the production for the year as a proportion of the proved developed reserves of the field at the beginning of the amortization period.

In this connection, we advise the Staff that the text included in Repsol YPF’s 2005 Form 20-F is incomplete due to a mistake in the translation of the financial statements prepared in Spanish and that we have used proved developed reserves for IFRS and US GAAP.

We propose to amend this translation mistake in future filings with the SEC.

(3.6) Goodwill, page F-27

Comment 12: We note your disclosure with respect to impairment testing for goodwill that you allocate goodwill among cash-generating units and that “the recoverable amount thereof is estimated by discounting the estimate future cash flows from each unit;” and if “the recoverable amount of a cash-generating unit is lower than that of the discounted future cash flows, a loss is recognized.” Please tell us how you have applied the guidance in paragraph 104 of IAS 36, which states that an impairment loss is recognized for a cash-generating unit “if, and only if, the recoverable amount of the unit (group of units) is less than the carrying amount of the unit (group of units).”

Response:

We confirm to the Staff that Repsol YPF applies paragraph 104 of IAS 36. The wording included in Repsol YPF’s 2005 Form 20-F is incorrect. Therefore, we propose to revise the text in future filings with the SEC as follows. New text is underlined for the Staff’s convenience.

“…To perform this test, the goodwill is allocated among the cash-generating units that benefit from the synergies of a business combination and the recoverable amount thereof is estimated by discounting the estimated future cash flows from each unit. If the recoverable amount of the cash-generating units is lower than that of the carrying amount of the units, a loss is recognised with a charge to the profit for the year en which it arises. An impairment loss recognised for goodwill must not be reversed in a subsequent period”.

3.23) Revenue and expense recognition, page F-35

Comment 13: Please tell us whether or not you earn revenue from royalties and expand your disclosure, if material, to explain how royalty revenue is recognized in accordance with IAS 18.

Response:

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Repsol YPF has recorded royalties as revenue for the year ending December 31, 2005 amounting to EUR 73 million, mainly in Libya. Since this amount represents an immaterial percentage of Repsol YPF’s total revenues (less than 0.2%), we considered that it was not necessary to make additional disclosures in this connection.

Comment 14: We note your disclosure on page F-36 indicating that you reflect both the expenses and income associated with excise and similar taxes on oil and gas production and/or sales. Please describe to us in further detail the nature of these taxes and quantify these taxes to distinguish between taxes on production and taxes on sales. Additionally, briefly describe the related contractual arrangements, if any, associated with these taxes.

Response:

Please refer to the response provided for comment 1. The excise taxes mentioned in F-36 are the same as explained in comment 1. There are no contractual arrangements related to these taxes.

Comment 15: Please expand your disclosures to indicate how you account for oil and gas over and under-lifts.

Response:

We do not disclose the accounting method used for these costs since we do not have material items related to these. The amounts recorded at 31 December 2005 in this connection were the following:

  o      Overlift: EUR 6.6 million
 
  o      Underlift: EUR 18.4 million

We do not believe that any further comment is required in light of the amounts involved.

(3.24) Financial derivatives, page F-36

(c) Hedges of net investments in a foreign operation, page F-37

Comment 16. We note your disclosure that “The hedges of net investments defined by Repsol YPF with mixed exchange rate and interest rate swaps are forward foreign exchange hedges and, therefore, the total change in the fair value of these instruments at the balance sheet date is recognized in equity.” Please tell us how you considered the guidance surrounding embedded derivatives as contemplated in paragraph 11 of IAS 39 given the components of the derivative financial instruments you describe.

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Response:

Repsol YPF uses “Cross Currency Swaps” (mixed exchange rate and interest rate swaps as refer above), as the hedging instrument to hedge its investments in USD as it is described on pages F-108 and F-109. The hedged net investments referred to in the mentioned paragraph are net investments denominated in USD. We confirm to the Staff that there are no embedded derivatives as contemplated by paragraph 11 of IAS 39 in these investments.

We will clarify the wording to describe this accounting policy in future filings.

(3.24) Financial derivatives, page F-36

Comment 17: We note that you enter into long-term purchase and sale commitments as disclosed on page F-95. Please address the following:

a) Tell us whether any of these contracts are denominated in currencies other than the applicable functional currency and whether or not the pricing terms are based on a price or a commodity or index other than the commodity being delivered.
 
  Response:
 
  We confirm to the Staff that:
 
 
  • None of these contracts are denominated in currencies other than the applicable functional currency of each party in accordance with paragraph AG33 (d) of IAS 39.
     
     
  • The pricing terms of these contracts are based on a price of the commodity being delivered, which are the commonly used in contracts to purchase or sell non-financial items in the economic environment in which the transaction takes place, therefore the pricing adjustment is always closely related to the host contract.
     
    b) Clarify whether these contracts host embedded derivatives and how you have applied the guidance in paragraph 11 of IAS 39.
     
      Response:
     
      Repsol YPF reviews long term contracts in order to determine if any clause in the contract would meet the definition of a derivative and if that is the case, if the combined instrument is not measured at fair value with changes in profit or loss. In the case that an embedded derivative exists, Repsol YPF reviews whether the economic characteristics and risks of the embedded derivative are not closely related to the economic characteristics and risks of the host contract in accordance with Guides AG-30 and AG-33 of IAS 39.
     
      Although some of our contracts host embedded derivatives, our conclusion after the revision process performed by us is that we haven’t found any long-term contracts
     

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      contain embedded derivatives which require separation in accordance with paragraph 11 of IAS 39.
     
    c)      Clarify for us whether these purchase and sale contracts may be net settled. Refer to paragraph 5 of IAS 39.
     
      Response:
     
      All the purchase and sale contracts disclosed on page F-95 refer to commercial contracts which are entered into and continue to be held for the purpose of the receipt or delivery of a non-financial item in accordance with our expected purchase, sale or usage requirements and, additionally, Repsol YPF has no past practice of settling similar contracts net or trading the underlying.

    (4) Financial risk management and definition of hedges, page F-38

    Comment 18. Please tell us how you have complied with the disclosure requirements of paragraphs 34 through 42 of IFRS 7 or otherwise advise where such disclosure in made within the filing.

    Response:

    We have disclosed on pages F-41 and F-42 that we did not early adopt IFRS 7. This IFRS is effective for annual periods beginning on or after 1 January 2007.

    (9) Goodwill page F-46

    Comment 19: Please expand your disclosure in footnote (4) to disclose the main events and circumstances that led to the recognition of impairment losses in accordance with paragraph 131(b) of IAS 36 or otherwise advise where such disclosure is made within the filing.

    Response:

    We believe that the mentioned disclosure is made within the filing as discussed below.

    The detail of impairment on goodwill arising in 2005 and 2004 is as follows:

    • 2005 impairment goodwill: EUR 6 million (relating to Refinaría de Petróleos de Manguinhos).

    • 2004 impairment goodwill: EUR 4 million (relating to Repsol YPF Distribuidora, S.A.).

    Please refer to pages F-55 and F-56 (Note 14 “Asset impairment”) for a detailed explanation of both impairments. Note 14 discloses the carrying amount of intangible assets, property, plant and equipment and other non-current assets, including goodwill.

    F-55: “…In the case of Refinaria de Petróleos Manguinhos, the specific price conditions in the internal fuel market in Brazil and the low refining capacity have made refining,

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    the company’s main business, unviable, although the company is continuing with its marketing operations. The consolidated income statement for 2005 reflects an impairment loss of EUR 15 million to reduce the carrying amount of the assets to their recoverable amount”. The total EUR 15 million includes EUR 6 million of goodwill.

    F-56: “…Also, in 2004, as a result of the performance of the Brazilian market, an impairment loss of EUR 58 million was recognised in relation to the service station business in Brazil”. The total EUR 58 million includes EUR 4 million of goodwill.

    Testing goodwill for impairment, page F-47

    Comment 20: We note you have disclosed that you use a value-in-use model to determine the recoverable amounts of the goodwill allocated to your cash-generating units. Please expand your disclosure as required by paragraph 134(d) of IAS 36 or otherwise advise where such disclosure in made within the filing.

    Response:

    On pages F-37 and F-38 under the section “Methodology for estimating fair value” we disclose the methodology for estimating the fair value of assets, including goodwill, and financial derivatives. We believe that the disclosure required by paragraph 134 (d) of IAS 36 is contained in such section.

    Comment 21. We note your disclosure indicating that you identified cash-generating units based on the business to which they belong. Please expand your disclosure to clarify the unit or group of units within each business that you have identified cash generating units to which you attribute goodwill and the basis on which you have aggregated cash-generating units. Refer to paragraph 68 and 134(a) of IAS 36.

    Response:

    We respectfully indicate to the Staff that we are disclosing on page F-47 the goodwill allocation for impairment test purposes as of December 31, 2005 and 2004 as required by paragraph 134 (a) of IAS 36. For purpose of impairment testing we have allocated goodwill in accordance with paragraph 80 of IAS 36. Therefore, we have allocated goodwill for impairment test purposes through some businesses (Group of cash generating units) that are expected to benefit from the synergies of the combination and represent the level by which this goodwill is monitored for internal management purposes, which is not larger than a segment.

    10) Other intangible assets, page F-48

    Comment 22: We note that you have capitalized internally generated assets. Please tell us whether or not you have considered the guidance in paragraphs 51 through 67 of IAS 38 with respect to developing your accounting policy for recording internally generated intangible assets.

    15






    Response:

    We confirm to the Staff that Repsol YPF has considered the guidance contained in paragraphs 51 through 67 of IAS 38. Additional information regarding accounting policies related to other intangible assets has not been provided due to their insignificancy. The internally generated assets amount as of December 31, 2005 to EUR 6 million (net of amortization).

    (12) Investments accounted for using the equity method, page F-50

    Comment 23: Please disclose the reasons why you believe you have significant influence for the companies identified on page F-51 in which you have an ownership interest of less than 20% as required by paragraph 37(c) of IAS 28 or otherwise advise where such disclosure in made within the filing.

    Response:

    We confirm to the Staff that we have enough representation and management rights to exercise significant influence on the board of directors to meet the requirements of paragraph 7 of IAS 28 for all the entities that are disclosed on page F-51.

    We propose to include the following revised text in our future filings with the SEC. New text is underlined for the Staff’s convenience.

    “The following companies were accounted for using the equity method, based on the fact that the Group has enough representation on the board of directors and management rights to exercise significant influence despite having an ownership interest of less than 20%:”

    (18) Preference shares, page F-60

    Comment 24. We note your disclosure indicating that your preference shares include an “early redemption” feature which suggests that there is an explicit redemption date. Please expand your disclosures to c1arify the specific redemption date and terms. In the event the preference shares do not require cash redemption, please c1arify why you believe these instruments qualify for liability classification under IFRS and U.S. GAAP and cite the authoritative literature supporting your view. In this regard, we note your disclosure on page F-14 indicating that these instruments were classified as liabilities “in view of the obligation to pay dividends if the issuer reports a distributable profit.” Refer to paragraphs 17 and 18 of IAS 32.

    Response:

    As we disclose on page F-60, the terms of the 3 series of preference shares issued by Repsol International Capital is “perpetual”. By early redemption, we wanted to point out the fact that the issuer has the option to redeem these preference shares from the fifth year or the tenth year onwards at face value (see page F-60).

    Our preferred security transactions are based on the following model:

    16






    • Repsol YPF issues its debentures to Repsol International Capital (the issuer of preference shares).

    • Repsol International Capital issues both preferred securities and common shares. The preferred securities are acquired by 3rd party investors and Repsol International Capital has the option to redeem these preferred securities after a certain period of time. The common shares are held by Repsol YPF.

    • Repsol International Capital uses cash from interest payment from Repsol YPF to pay dividends to investors.

    • Repsol YPF guarantees payments on the preferred securities.

    According to SIC 12, the issuer should be consolidated because it is controlled by Repsol YPF. Additionally, we have classified the three series of preference shares issued by Repsol International Capital Limited as liabilities based on the relevant accounting literature discussed below.

    Paragraph AG25 of IAS 32 specifies that “an option of the issuer to redeem the shares for cash does not satisfy the definition of a financial liability because the issuer does not have a present obligation to transfer financial assets to the shareholders”. In this case, the redemption of the shares is solely at the discretion of the issuer which in principle could imply that the preference shares would be considered as equity.

    Paragraph AG26 of IAS 32 states:

    “When preference shares are non-redeemable, the appropriate classification is determined by the other rights that attach to them. Classification is based on an assessment of the substance of the contractual arrangements and the definitions of a financial liability and an equity instrument. When distributions to holders of the preference shares, whether cumulative or non-cumulative, are at the discretion of the issuer, the shares are equity instruments”.

    Repsol International Capital's preference shares include the following clause: "Dividends are payable only to the extent that the Distributable Profits of Repsol YPF, S.A. for the preceding fiscal year are sufficient to cover the payment of dividends on the preference shares, together with any dividends previously paid in the current fiscal year and any dividends proposed to be paid during the current calendar quarter, on either the preference shares or any other preference shares of Repsol YPF or any affiliate ranking pari passu with the preference shares".

    It is our understanding that such clause cannot be interpreted as providing any degree of discretion to Repsol International Capital in respect of the payment of dividends on the preference shares. Accordingly, we have concluded that since such discretion does not exist, the preference shares must be classified as liability.

    Under US GAAP, our conclusion is that we should not consolidate Repsol International Capital as we are not the primary beneficiary under paragraph 2(d) of Interpretation FIN 46R. We believe that as sponsor of Repsol International Capital, we neither have a

    17






    significant residual interest held (since our common shares are not viewed as equity at risk because they do not suppose to participate significantly in profit or losses), nor the loan payable to Repsol International Capital would be considered variable interests (since they assume variability). In addition, the fact that we have unconditionally guaranteed the trust preferred securities is not relevant, since in substance, we are guaranteeing our own obligations.

    We have accounted for the investment in the common stock of the Repsol International Capital as an equity-method investment in accordance with APB Opinion No. 18, The Equity Method of Accounting for Investments in Common Stock.

    (21) Provision for pensions and similar obligations, page F-65

    Comment 25: Please include a narrative description of the basis used to determine the overall expected rate of return on assets, including the effect of the major categories of plan assets in accordance with paragraph 120A(1) of IAS 19 or otherwise advise where such disclosure in made within the filing. In addition, please address the disclosures required by paragraph 120A(o) of IAS 19.

    Response:

    As of December 2005, the actual breakdown of the assets plan was Domestic Equity (S&P 500 Index Fund and Mid Cap Value Fund) 54.3%, International Equity Fund (Euro Pacific Growth Fund) 15.6%, Fixed Income Fund (Northern Trust Bond Index) 30.1% and Cash 0%.

    The basis used to determine the overall expected rate of return on assets are the following:

    • The expected return assumptions for each category of assets were 10.05%, 10.75%, 11%, 5.75% and 3%, respectively based on the financial capital market assumptions and the current and projected asset mix. Therefore, the target weighted return on average was approximately 9%.
    • When statistical models were applied to the asset mix, the expected rat of return for the 25th to 75th percentiles was in the range of 4.25% to 8.5%.
    • The actual rate of return for 2004 was 12.67%:
    Assets 2004
    S&P 500 Index Fund 10.83%
    Mid Cap Value Fund 21.98%
    Euro Pacific Growth Fund 19.70%
    Northern Trust bond index 4.4%
    Cash 0%
    Total weighted
    return
    12.67%

    18






    Consequently based on all the information above provided by both, the Financial Advisor of the Management Committee and the actuary of the plan, we decided that the expected rate of return was 8.5%.

    Regarding the disclosures required by paragraph 120A(o) of IAS 19, we confirm to the Staff that we have included such disclosures on page F-141 of the Form 20-F.

    (23) Obligations under finance leases, page F-69

    Comment 26: Please tell us how you have complied with the disclosure requirement of paragraph 3l (a) of IAS 17.

    Response:

    The disclosures referred to in your comment are provided in Section 7 “Property, plant and equipment” on page F-45 (item 6) which details all the assets held under finance leases by Repsol YPF.

    (25) Tax matters, page F-70

    Comment 27: Please provide an explanation of the relationship between tax expense (income) and accounting profit in either of the forms prescribed by paragraph 81(c) of IAS 12 or otherwise advise where such disclosure is made within the filing.

    Response:

    We believe that the information required under paragraph 81.c) of IAS 12 is included in pages F-70 and F-71.

    The heading "Income Tax Expense for Accounting Purposes" on page F-71 includes a reconciliation of the accounting profit before taxes to the income tax expenses for the year, broken down by the main geographical areas. Also, page F-70 includes information relating to the tax rates applicable in these jurisdictions. Accordingly, we consider that, with the information included in these pages, the reconciliation of the income tax expense to the result of multiplying the accounting profit before taxes by the tax rates applicable, as required under paragraph 81. c) of IAS 12, using alternative (i) of this paragraph, has been adequately covered.

    (28) Finance income and costs, page F-77

    Comment 28: Please tell us what type of expense is recorded in the line item Expenses relating to preference shares.

    Response:

    We confirm to the Staff that this heading includes the expenses accrued for the preferred shares coupon, i.e. the interest arising from the preferred shares, and the allocation in the year of the expenses which initially arose on the issuance (Transaction costs).

    19






    (31) Business combinations, page F-80

    Comment 29. Please expand your disclosure under this heading to describe the factors that contributed to a cost that results in the recognition of goodwill as contemplated by paragraph 67(h) of IFRS 3 or otherwise advise where such disclosure is made within the filing.

    Response:

    The factors that contributed to a cost that results in the recognition of goodwill as contemplated by paragraph 67(h) of IFRS 3 are disclosed in the second paragraph of note 3.6 Goodwill (page F-27).

    Comment 30: Additionally, please reconcile for us the increase in goodwill from December 31, 2004 to December 31, 2005.

    Response:

    The movement in goodwill for both years is disclosed in Note 9 “Goodwill”, page F-46.

    (37) Contingent liabilities and obligations, page F-93

    Comment 31: With respect to the asset swap with Petrobras, we note your statement that “The accompanying consolidated financial statements include all the accounting effects for the Group of the terms of this Agreement.” Please explain what accounting effects you have recognized for this asset swap and expand your disclosure as necessary so that the reader understands the implications of this Agreement on your financial statements.

    Response:

    The accounting effects of the Revision Settlement Agreement entered into by Repsol YPF Brasil, S.A. and some Petrobras Group companies led to the recognition of a total provision amounting to EUR 54 million as of December 31, 2005. In 2004 the provision was calculated by applying the correction mechanisms provided for in the contract, amounting to EUR 61 million. That amount represented the best estimation of the loss on termination of the asset swap contract. The difference of EUR 7 million between the provision for 2005 and 2004 is due to the exchange rate differences and minor adjustments regarding the mentioned Agreement.

    In addition, related to the asset swap contract mentioned above, Repsol YPF and Petrobras signed an Intention Protocol regarding certain pending environmental issues as of December 29, 2005. Therefore, due to the modification introduced by the Intention Protocol, the Group recorded an additional provision amounting to EUR 16 million as of December 31, 2005.

    Finally, we confirm to the Staff that during 2006, Repsol YPF has paid the EUR 54 million to Petrobras mentioned above and the rest is pending to be paid in the following months. We do not expect significant differences between the amounts of the provision

    20






    recorded as of December 31, 2005 which are still pending to be paid and the cash flows to be paid related to the asset swap contract.

    Comment 32: We note your statement on page F-106 that “The Company’s directors consider that the provisions recorded adequately cover the risks arising from the contingencies described above.” Please confirm, if true, that the amounts recognized as provisions for the contingencies described represent the best estimate of the expenditure required to settle the present obligation at the balance sheet date as contemplated by paragraph 36 of IAS 37 or otherwise advise.

    Response:

    We confirm to the Staff that the amounts recognized as provisions for the contingencies described in the financial statements represent the best estimate of the expenditure required to settle the present obligation at the balance sheet date as contemplated by paragraph 36 of IAS 37.

    (38) Derivative transactions, page F-106

    (38.1) Fair value hedges, page F-106

    Comment 33. Please tell us how you have complied with the disclosure required by paragraphs 24 and 27 of IFRS 7.

    Response:

    Please refer to the response provided to comment 18.

    (38.2) Cash flow hedges, page F-107

    Comment 34. Please tell us where you have disclosed the information required by paragraph 23 of IFRS 7.

    Response:

    Please refer to the response provided to comment 18.

    (40) Fees Paid to the Auditors, page F-114

    Comment 35: Please expand your disclosures to describe in detail and separately quantify the “other services” rendered by your auditors. Refer to Item 16C(d) of Form 20-F.

    Response:

    We believe that we have complied with the disclosures required by item 16C (d) on page 189 (Item 13C) of our Form 20-F 2005. The mentioned disclosures are not required under IFRS. Therefore, in order to prepare our IFRS Financial Statements we followed the disclosures required in this respect by Spanish law.

    21






    42) Differences Between IFRS and U.S. GAAP, F-l16

    (16) Compensation arrangements, F-127

    Comment 36. We note your disclosure stating that you have used “The quote of the Repsol YPF share at December 3lst…” as a component assumption in applying the Black-Scholes option pricing model in valuing medium term incentive awards. Please clarify whether December 31, 2005 and 2004 were the dates the incentive awards were granted or tell us how you concluded these were the appropriate dates for measuring compensation cost in accordance with U.S. GAAP.

    Response:

    We confirm that December 31, 2005 and 2004 were not the dates the incentives awards were granted. Repsol YPF has incentive plans tied to the appreciation of Repsol YPF shares (liability awards) which are evaluated at the end of each reporting period both under IFRS and US GAAP.

    These incentive plans have been considered as compensatory variable plans, under U.S. GAAP. Therefore we have considered the intrinsic value of the options, as required by paragraphs 10(b), 13, 27 and 28 of APB Opinion 25, by using the quoted market price of the stock at the end of each period.

    For further details of our incentive plans tied to the appreciation of Repsol YPF shares please refer to page F-84.

    Comment 37: We note your disclosure indicating that you attribute expense associated with share based payments on a straight-line basis for the term remaining until the end of the plan. Please explain how this accounting differs from attributing expense over the period for which services are performed and quantify the accounting effect, if any, for each period presented. Refer to paragraph 30 of SFAS 123.

    Response:

    For our incentive plans tied to the appreciation of Repsol YPF shares, attributing expense associated with share based payments on a straight-line basis for the term remaining until the end of the plan does not differ from attributing expense over the period for which services are performed, because both are the same period.

    The expenses are accounted for over the vesting period to reflect the services rendered, or expected to be rendered at grant date, as required by paragraph 32 of IFRS 2. Regarding Repsol YPF there is no GAAP difference with paragraph 30 of SFAS 123, but we would like to mention that Repsol YPF applies APB 25 under US GAAP as explained above.

    22






    Additional Disclosures Required Under U.S. GAAP, page F- 131

    g)FIN 46, page F-134

    Comment 38: We note your disclosure indicating that you have determined that Repsol International Capital (“RIC”) should be deconsolidated. Please clarify for us how you arrived at this conclusion. In this regard, we note your disclosure on page F-171 appears to indicate that you own and control 100% of the interest in this subsidiary. Additionally, please provide us with your analysis supporting that Repsol YPF, S.A. is not the primary beneficiary)’ of RIC, as defined by paragraph 2(d) of FIN 46(R).

    Response:

    Please refer to the response provided to comment 24.

    Supplementary Information On Oil and Gas Exploration and Production Activities, page F-155

    General

    Comment 39: Please expand your disclosures to separately present reserve quantities, capitalized costs, costs incurred, results of operations and the standardized measure of discounted future net cash flows for entities accounted for by the equity method for U.S. GAAP purposes, or tell us why you believe this disclosure is not required. Refer to paragraphs 14(c), 20, 23, 29, and 32 of SFAS 69.

    Response:

    Repsol YPF believes that the disclosures required under SFAS 69 should be made in accordance with the consolidation methods established under its primary GAAP, i.e. IFRS. In this connection, the supplementary information on oil and gas exploration and production activities as described on page F-155 has been compiled in accordance with this method. Accordingly, we have not included separately supplemental information in respect of companies accounted for using the equity method under US GAAP as those reserves have been included in our disclosures as part of the disclosure that includes proportionally consolidated entities under IFRS.

    Present value of future net income, page F-164

    Comment 40: Please revise your caption of “Present value of future net income” to “Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserve Quantities” as this item is specifically defined under SFAS 69 and is not intended to represent a measure of future net income.

    Response:

    We note the Staff’s comment and will revise in future filings with the SEC.

    23






    Comment 41: Please remove the subtotals of ”Future net cash flows before taxes” as this item is not an explicit component of the standardized measure of discounted future net cash flows. Refer to Illustration 5 of SFAS 69.

    Response:

    We note the Staff’s comment and we will revise this caption in future filings with the SEC.

    Engineering Comments

    Risk Factors. page 3

    Political instability and the negative regulatory environment and outlook for the oil and gas industry in Bolivia… page 6

    Comment 42: You report on May 1, 2006 by Supreme Decree Bolivia nationalized all natural hydrocarbon resources and they will take control and direction of production, transportation, refining, storage, and distribution of all hydrocarbons. Please tell us the current status of your production sharing agreements in Bolivia and if you will be able to participate in the oil and gas industry in Bolivia in the future.

    Response:

    In May 2005, the National Congress of Bolivia approved a new Hydrocarbon Law that stipulated a new legal framework for, and affected various aspects of, the legal regime under which the Repsol YPF Group and all oil and gas companies had been operating, which, among others, included the imposition of an additional 32% tax on oil and gas production (IDH), and the obligation for those companies operating in Bolivia under Risk Sharing Agreements (“Contratos de Riesgo Compartido”) to convert their agreements to any of the three possible agreements contemplated by the new Hydrocarbons Law, namely: i) Contrato de Producción Compartida (Production Sharing Contract); ii) Contrato de Operación (Operating Contract); and iii) Contrato de Asociación (Association Contract). The Hydrocarbon Law transfers the ownership of all hydrocarbons in the well head to the Bolivian State. In its ruling of June 2, 2006, the Bolivian Constitutional Court confirmed the constitutionality of the Hydrocarbon Law.

    Supreme Decree 28.701 (the Supreme Decree), published on May 1, 2006, has declared the nationalization of all of Bolivian’s natural hydrocarbon resources and the Bolivian State, through Yacimientos Petrolíferos Bolivianos (“YPFB”), the Bolivian oil company, including the commercialization of the internal market as well as the industrialization and exportation of hydrocarbons. In accordance with the text of the Supreme Decree the Bolivian State will take control and direction of production, transportation, refining, storage, distribution, commercialization and industrialization of all hydrocarbons in Bolivia. Moreover, the Supreme Decree establishes that, within a period of 180 days from its publication, private companies in Bolivia must adjust their activities in Bolivia through the negotiation and execution of new agreements in accordance with the new Hydrocarbons Law and the Bolivian Constitutional regime.

    24






    The Supreme Decree states that any company that fails to comply with this time limit will be prohibited from continuing its activities in Bolivia. Repsol YPF has indicated its willingness to negotiate with the Bolivian government, though Repsol YPF also intends to pursue all available legal rights. Moreover, the Bolivian Government has issued different administrative resolutions as part of the implementation of the Supreme Decree, including but not limited to an increase of taxation over the two most productive fields in Bolivia (San Antonio and San Alberto). This notwithstanding, up to the present Repsol YPF, as well as the other oil and gas companies operating in Bolivia, is still conducting its operations as it is established by the Risk Sharing Agreements (“Contratos de Riesgo Compartido”) with the limitations imposed by the new legal framework.

    On October 28, 2006 Repsol YPF signed with YPFB Operating Contracts over Caipipendi, San Antonio and San Alberto Blocks, converting its previous Risk Sharing Agreements. This notwithstanding, up to the present, some of the exhibits of these agreements are still pending of signature. Moreover, both Repsol YPF and Andina S.A. expect to sign Operating Contracts in relation with the rest of their blocks in Bolivia in similar contractual terms as those contemplated for the above mentioned blocks. It is worth to mention that, in accordance with the Hydrocarbons Law, the Bolivian Congress has to approve these contracts, so YPFB should deliver the signed agreements to the Congress for their final approval.

    Operations, page 17

    Oil and Gas Reserves, page 18

    Comment 43: You state that the reserves in all production areas were externally certified by independent engineers. Please tell us the meaning of “certified.”

    Response:

    Repsol YPF uses the term “certified” as related to reserves to mean an external reservoir engineer has made an independent, comprehensive review of all the pertinent data required to prepare a reserves estimate and determined the estimate was made in accordance with SEC requirements.

    Comment 44: You state that the gas condensate reservoir of Loma La Lata-Sierras Blancas had originally been booked on the basis of a computer reservoir simulation model. Please tell us the extent of testing and production history data you had at the time of the completion of the model and the booking of the reserves as proved. Please tell us the recovery factor you used and if you based it on the results of the simulation. You indicate that these reserves had been “certified” by an independent engineer at the time they were booked as proved. Please provide to us the letter or report by the independent engineer that so “certified” these reserves.

    Response:

    Loma La Lata field, one of the largest gas fields of South America, is located in the Neuquina basin, Argentina. Discovered in 1977, Loma La Lata was put on production in 1978. The gas-condensate reservoir Sierra Blancas (LLL-SB) accounts for about

    25






    95% of the total field reserves. Through 1996 LLL-SB reserves were estimated using a combination of volumetric and material balance calculations. Reservoir numerical simulation was used for the first time to book proved reserves in 1997. At the time of the completion of the original model, the extent of production history data available for the history match was 2.9 trillion scf of gas from LLL-SB.

    The recovery factor used to book proved reserves was based on the results of the simulation from 1997 through 2004. Simulation results in 2005 indicated a 73% recovery factor, though it was at this point in the field life that it was concluded the volume in the reservoir numerical simulator was no longer all going to be produced with reasonable certainty as required by SEC for classifying proved reserves. At year-end 2005, LLL-SB proved reserves were based on a global material balance of a smaller gas-initially-in-place than used in the reservoir numerical simulation model. The material balance model estimates 89% recovery factor under volumetric depletion based on results from nodal analysis and the surface operating conditions.

    The report of the independent engineer who reviewed such reservoir is attached hereto.

    Comment 45: Please revise your filing to include production costs per unit of production.

    Response:

    We traditionally have disclosed the amount of lifting cost (see the information disclose in page 18 of Form 20-F). The average production cost may be estimated through the volumes and production cost disclose in the “Supplementary information on oil and gas exploration and production activities”, however we note SEC comment and we believe that this information can be useful for investors, therefore we propose to include the following table in future filings with the SEC:

    AVERAGE PRODUCTION COSTS

    (Figures on €/bbl) 2005
     
       Total Spain Africa and
    Middle East
    Argentina Central and
    South America
    Rest of the
    World
     
    Lifting costs 1.97 6.14 1.77 2.29 1.32  
    Royalties, local taxes and withholding on exports 3.15 0.08 10.10 2.58 3.01  
    Transportation and other costs 0.55 3.32 1.20 0.12 1.23 16.93
     
                       Average production costs 5.67 9.54 13.07 4.99 5.56 16.93
     


    (Figures on €/bbl) 2004
     
       Total Spain Africa and
    Middle East
    Argentina Central and
    South America
    Rest of the
    World
     
    Lifting costs 1.57 3.97 1.63 1.69 1.20  
    Royalties, local taxes and withholding on exports 2.28 0.15 6.22 2.17 1.75  
    Transportation and other costs 0.59 3.17 0.85 0.09 1.67 27.01
     





                       Average production costs 4.44 7.29 8.70 3.95 4.62 27.01
     






    26




    Exploration, Development, Acquisitions and Production, page 29

    Peru, page 38

    Comment 46: It appears that your reserve to production life in Peru is over 250 years. Please explain to us the justification for booking so many reserves as proved when production is so low.

    Response:

    Net petroleum production in Peru, all from Block 88, was only from the last 16 days of 2005 and was 0.08 million barrels of oil equivalent (an average of 5.1 thousand barrels of oil equivalent per day). Net proved oil and gas reserves in Peru at December 31, 2005 were 20.2 million barrels of oil equivalent. The reserves have been determined according to SEC rules. The reserves to production ratio at December 31, 2005 taking into account a full year of production would have been 10.9 years on an oil equivalent basis.

    Repsol YPF reinforces its presence in the Gulf of Mexico, page 124

    Comment 47: You state that additional phases for the Southern Flank of the Shenzi field include the completion of oil-bearing shallower reservoirs and water injection. Please tell us how many reserves have been attributed to this field and how many reserves you attributed to each of the aggregate of the shallower reservoirs and then to water injection. Finally, tell us the recovery factor you assumed for the attribution of proved reserves and the basis for that assumption.

    Response:

    Repsol acquired the 28% interest in Shenzi from BP plc in July 2006. No reserves have been booked as of December 31, 2005. Therefore, the information referring to this investment is included under the caption “Recent Developments” on page 124.

    Results of Oil and Gas Production Activities, page F-156

    Comment 48: Your footnote indicates that production costs include royalties. Please tell us the nature of these royalties and why you believe that they represent a production expense under IFRS and US GAAP. It is our understanding that the payment of royalty is payment of oil that is not net to you and therefore, should not be reported as your revenue or reserves. Please tell us if your reported oil and gas production and revenues are gross or net of royalties. We may have further comments. Refer to paragraph 24 of SFAS 19 for US GAAP.

    Response:

    Repsol YPF applies paragraph 24 of SFAS 19 with respect to production cost. However, with respect to royalties we apply SEC Securities Act Industry Guides and the FORM 20-F Guideline, Appendix A to Item 4.D: Oil and Gas, “Generally, net production should include only production that is owned by the registrant and produced to its interest, less royalties and production due others. However, in special situations (e.g.,

    27






    foreign production) net production before royalties may be provided if more appropriate”.

    In foreign countries where the company takes legal title of the oil and royalty and/or taxes can be paid in-cash and the government has formally elected to receive payment in cash, Repsol YPF’s share of production and proved reserves are reported including these royalty volumes. Such in-cash payments are treated as a production cost in the qualifying proved reserve economic limit test.

    Comment 49: Please tell us if all of your proved reserves are re-determined every year.

    Response:

    All proved reserves from operated properties are internally re-determined every year. All proved reserves from non-operated properties are reviewed every year with data from the operator and the reserves are either internally estimated or the operator’s estimates are accepted after an internal review.

    Apart from that, Repsol YPF has chosen to engage external independent reserves auditors to review reserves such that each oil and gas field of the company is externally reviewed every 3 years.

    Comment 50: Please tell us how much of your reserve restatement in each of the years 2003, 2004 and 2005 was due to increasing oil and gas prices causing a reduction of the reserves from your production sharing agreements.

    Response:

    The reserves restatement of fields in Argentina and Bolivia were not associated with any production sharing agreements and as a consequence the restatement due to changes in year-end pricing was zero.

    Present Value of Future Net Income, page F165

    Comment 51: In future filings please include a separate line item for future development costs if they are significant. See FASB 69 paragraph 30b for guidance.

    Response:

    We note the Staff’s comment and will consider its applicability in future filings with the SEC.

    28







    Gaffney, Cline & Associates
       
      Digital Copy

     

    CRUDE OIL AND NATURAL GAS

    RESERVE AUDIT CERTIFICATION

    CERTAIN ARGENTINE PROPERTY UNITS

    EFFECTIVE DECEMBER 31, 2002

    Prepared for

    YPF S.A.

     

     

     

    JANUARY 2003

     

     

    YPF S.A.
      C877







    Gaffney, Cline & Associates

     

    TABLE OF CONTENTS

    CERTIFICATION LETTER
    RESERVE STATEMENTS
    APPENDIX 1 - a) SPE/WPC PETROLEUM RESERVES DEFINITIONS
        b) SEC DEFINITIONS FOR OIL AND GAS RESERVES

     

                          

     

     

     

     

    YPF S.A.
      C877





    Gaffney, Cline & Associates   Four Oaks Place
    Technical and Management Advisers to the Petroleum Industry Internationally   1360 Post Oak, Suite 2500
    Houston, Texas 77056
     Principals Telephone: (713) 850-9955
     William B. Cline Facsimile: (713) 850-9966
     Peter D. Gaffney e-Mail: gcah@gaffney-cline.com

     RMB/jk/C877.00/2876    January 10, 2003
         
     Ing. Guillermo García Alvarez-Valle    
     YPF S.A.    
     Avenida Pte. Roque Sáenz Peña 777 Oficina 930 D    
     1364 Buenos Aires    

    CRUDE OIL AND NATURAL GAS RESERVE AUDIT CERTIFICATION
    EFFECTIVE DECEMBER 31
    ST, 2002

    Gentlemen:

         Gaffney, Cline & Associates (GCA) has examined the crude oil and natural gas reserve estimates rendered by YPF S.A. (YPF) in respect of 12 property units in Argentina containing 40 fields. 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 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, 2002, 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.

    YPF S.A.
    Oil and Condensate Net Reserve Estimates
    For Certain Argentine Property Units
    as of December 31
    st, 2002

    Area Proved
    Developed

    Mm3
    Proved
    Undeveloped

    Mm3
    Total Proved
    Mm3
    Probable
    Mm3
    Possible
    Mm
    3
    La Ventana 4,356 205 4,561 934 745
    Vizcacheras 9,205 98 9,303 762 2,236
    Cerro Fortunoso 2,671 810 3,481 1,207 125
    Chihuido de la Salina 9,611 287 9,898 2,301 0
    Chihuido de la Salina Sur 1,697 138 1,835 1,070 50
    El Portón 1,401 457 1,858 250 0
    Chihuido de la Sierra Negra 30,692 568 31,260 5,750 2,770
    Señal Picada 3,199 45 3,244 157 0
    Loma La Lata 4,272 778 5,050 122 284
    Manatiales Behr 3,929 1,018 4,947 2,101 5,663
    Seco León 3,531 1,329 4,860 711 1,137
    Los Perales 9,227 4,843 14,070 3,373 2,372
    Total 83,791 10,576 94,367 18,738 14,382
                                   Oil and condensate volumes are reported in thousand (103 ) cubic meters.



    UNITED KINGDOM UNITED STATES SINGAPORE AUSTRALIA ARGENTINA BRAZIL VENEZUELA







    Gaffney, Cline & Associates
    RMB/jk/C877.00/2876  
    YPF S.A.  
    January 10, 2003 Page 2

    YPF S.A.
    Natural Gas Net Reserve Estimates
    For Certain Argentine Property Units
    as of December 31
    st, 2002

    Area Proved
    Developed

    Mm3
    Proved
    Undeveloped

    Mm3
    Total Proved
    Mm3
    Probable
    Mm3
    Possible
    Mm
    3
    La Ventana 84.7 4.4 89.1 19.9 16.0
    Vizcacheras 176.1 2.1 178.2 11.7 34.8
    Cerro Fortunoso 0.0 0.0 0.0 0.0 0.0
    Chihuido de la Salina 1,937.9 7,508.0 9,445.9 252.4 0.0
    Chihuido de la Salina Sur 903.9 1,894.2 2,798.1 551.9 5.0
    El Portón 643.8 6,264.2 6,908.0 27.5 0.0
    Chihuido de la Sierra Negra 2,552.8 52.4 2,605.2 592.7 87.4
    Señal Picada 81.0 0.5 81.5 18.4 0.0
    Loma La Lata 112,446.4 24,701.3 137,147.7 6,731.6 14,758.5
    Manatiales Behr 298.3 85.6 383.9 224.6 522.7
    Seco León 866.8 192.1 1,058.9 25.4 213.8
    Los Perales 2,784.3 1,159.5 3,943.8 2,423.3 2,063.8
    Total 122,776.0 41,864.3 164,640.3 10,879.4 17,702.0
                                   Natural gas volumes are reported in million (106) cubic meters at standard conditions of 14.7 psia and 60° Fahrenheit

    YPF S.A.
    Natural Gas Liquids Net Reserve Estimates
    For Certain Argentine Property Units
    as of December 31st, 2002

    Area Proved
    Developed

    Mm3
    Proved
    Undeveloped

    Mm3
    Total Proved
    Mm3
    Probable
    Mm3
    Possible
    Mm
    3
    La Ventana 71 4 75 13 6
    Vizcacheras 0 0 0 7 31
    Cerro Fortunoso 0 0 0 0 0
    Chihuido de la Salina 0 2,771 2,771 0 0
    Chihuido de la Salina Sur 0 955 955 0 0
    El Portón 0 2,044 2,044 0 0
    Chihuido de la Sierra Negra 0 0 0 0 0
    Señal Picada 0 0 0 0 0
    Loma La Lata 27,179 5,981 33,160 0 2,241
    Manatiales Behr 0 0 0 0 0
    Seco León 0 0 0 0 0
    Los Perales 0 0 0 0 0
    Total 27,250 11,755 39,005 20 2,278
                                   NGL volumes are reported in thousand (103 ) cubic meters.

         Natural gas volumes represent those volumes to be sold or used internally for operations net of shrinkage due to condensate and NGL extraction. Net volumes reflect YPF’s working interest in the concession, which is 100% in all property units except La Ventana (69.6% of oil and condensate, and 60% of NGL and natural gas). This interest has not been reduced for royalties, which under customary Argentine accounting practice are treated as an operating

    YPF S.A.
      C877







    Gaffney, Cline & Associates
    RMB/jk/C877.00/2876  
    YPF S.A.  
    January 10, 2003 Page 3


    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. The client also confirmed that the ten-year extensions to area concessions will be automatically approved by the government.

         The economic tests for December 31, 2002, Proved Developed and Total Proved reserve volumes were based on a reference price for West Texas Intermediate (WTI) crude of US$31.23/barrel as of December 31, 2002, corrected for location and quality to a wellhead price of between US$25.80/barrel and US$28.78/barrel, depending on the field. There are three gas contract groups in place, each with gas prices pegged to a heating value of 9,300 Kcal/m3; Cuyana at US$0.04388/m3, Neuquina at US$0.02606/m3, and Golfo San Jorge at US$0.01743/m3. Actual heating value of the gas ranges from a high of 10,000 Kcal/m3 and a low of 9,000 Kcal/m3. The gas prices that were used in the economic test assumed that the above US$ prices have been converted to Argentine Pesos at 3.35 Pesos/US$, resulting in base gas prices for the above three gas contract groups of US$0.01310/m3, US$0.00778/m 3 and US$0.005203/m3, respectively.

         This audit examination was based on reserve estimates and other information provided by YPF to GCA through December 27, 2002, 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 our 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 YPF. 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 YPF and should not be used for purposes other than those for which it is intended.

    Very truly yours,
     
    GAFFNEY, CLINE & ASSOCIATES, INC.
    Richard M. Bateman
    Buenos Aires
    Area Manager

     

    YPF S.A.
      C877






    Gaffney, Cline & Associates

     

    RESERVE STATEMENTS


     

     

     

     

     

    YPF S.A.
      C877






    Gaffney, Cline & Associates


    TABLE OF CONTENTS
      Page Number
       
    La Ventana 1
                 Zona Central TRC 2
                 Zona Central BRC 3
                 Zona Central VC 4
                 Zona Central LRB 5
                 Río Viejas 6
                 La Ventana NGL 7
                 Barrancas – Río Blanco 8
                 Guanaco Blanco LRB 9
                 Cañada Dura 10
    Vizcachereas 11
                 Barrancas 12
                 Papagayos 13
                 Cañada Dura 14
    Cerro Fortunoso 15
                 Cerro Fortunoso 16
                 Cerro Fortunoso Sur 17
    El Portón 18
                 Sur 19
                 Norte 20
    Chihuido de la Salina 21
                 Norte – Troncoso Inf. 22
                 Centro Norte – Troncoso Inf. 23
                 Centro Sur – Troncoso Inf. 24
                 Mulichinco 25
    Chihuido de la Salina Sur 26
                 Bajo Los Lobos – Troncoso Inf. 27
                 Troncoso Inf. – Escama Intermedia 28
                 Troncoso Inf. – Escama Principal 29
                 Troncoso Inf. – Escama Superior 30
                 El Zaino - Mulichinco 31
                 Rincón de Correa 32
                 Rincón de Correa Sur 33
    Chihuido de la Sierra Negra 34
                 Lomita Norte 35
                 Troncoso Inf. / Agrio + Avilé 36
                 Rayoso 37
                 Lomita Rayoso 38
                 Aguada de la Cerda – Avilé 39
                 Roca Ignea / La Tosca 40
                 Faldeo Amarillo 41
    Señal Picada 42
                 Quintuco 43
                 Centenario 44
    Loma La Lata 45
                 Barreales Colorados – Sierras Blancas 46
                 Quintuco 47
                 Sierras Blancas 48
                 Lotena 49

    YPF S.A.
      C877






    Gaffney, Cline & Associates


    Manantiales Behr 50
    Seco León 51
    Los Perales 52

     

    YPF S.A.
      C877





    La Ventana

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002

    GCA Audit Code: 126 YPF S.A. Oil Interest: 69.60%

     
    Basin: Cuyana YPF S.A. Gas Interest: 60.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    48,087 21,404 69,491   29 1,543.3 1,543.3

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,242

    108
    5,017

    186
    6,259

    294
      119

    6
    141.2

    7.3
    141.2

    7.3
    Sub-total Proved 1,350 5,203 6,553   125 148.5 148.5
    Probable 616 725 1,341   22 33.2 33.2
    Possible 715 355 1,070   9 26.5 26.5

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    864

    75
    3,492

    130
    4,356

    205
      71

    4
    84.7

    4.4
    84.7

    4.4
    Sub-total Proved 939 3,622 4,561   75 89.1 89.1
    Probable 429 505 934   13 19.9 19.9
    Possible 498 247 745   6 16.0 16.0

    D. Notes:

     

    YPF_03.123 1 Gaffney, Cline & Associates






    La Ventana

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 126 YPF S.A. Oil Interest: 69.60%

     
    Sub-unit Name: Zona Central TRC YPF S.A. Gas Interest: 60.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
                 21,638                10,470      32,108                  711.8            711.8

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    130

    12
    2,395

    113
    2,525

    125
        49.3

    3.1
    49.3

    3.1
    Sub-total Proved 142 2,508 2,650     52.4 52.4
    Probable 41 158 199     4.9 4.9
    Possible   132 132     3.3 3.3

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    90

    8
    1,667

    79
    1,757

    87
        29.6

    1.9
    29.6

    1.9
    Sub-total Proved 98 1,746 1,844     31.5 31.5
    Probable 29 110 139     2.9 2.9
    Possible   92 92     2.0 2.0

    D. Notes:

     

    YPF_03.123 2 Gaffney, Cline & Associates





    La Ventana

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 126 YPF S.A. Oil Interest: 69.60%

     
    Sub-unit Name: Zona Central BRC YPF S.A. Gas Interest: 60.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
                   5,987                    6,867      12,854                6              306.0            306.0

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    76

    9
    1,610

    46
    1,686

    55
        42.0

    1.4
    42.0

    1.4
    Sub-total Proved 85 1,656 1,741     43.4 43.4
    Probable 43 284 327     7.9 7.9
    Possible 16 107 123     3.1 3.1

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    53

    6
    1,121

    32
    1,174

    38
        25.2

    0.8
    25.2

    0.8
    Sub-total Proved 59 1,153 1,212     26.0 26.0
    Probable 30 198 228     4.7 4.7
    Possible 11 74 85     1.9 1.9

    D. Notes:

     

    YPF_03.123 3 Gaffney, Cline & Associates





    La Ventana

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 126 YPF S.A. Oil Interest: 69.60%

     
    Sub-unit Name: Zona Central VC YPF S.A. Gas Interest: 60.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
                 10,506                    4,067      14,573                  287.5            287.5

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    178

    26
    1,012

    27
    1,190

    53
        29.5

    1.3
    29.5

    1.3
    Sub-total Proved 204 1,039 1,243     30.8 30.8
    Probable 137 248 385     9.6 9.6
    Possible 64 116 180     4.5 4.5

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
      Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    124

    18
    704

    19
    828

    37
        17.7

    0.8
    17.7

    0.8
    Sub-total Proved 142 723 865     18.5 18.5
    Probable 95 173 268     5.8 5.8
    Possible 45 81 126     2.7 2.7

    D. Notes:

     

    YPF_03.123 4 Gaffney, Cline & Associates





    La Ventana

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet

    GCA Audit Code: 126 YPF S.A. Oil Interest: 69.60%

     
    Sub-unit Name: Zona Central LRB YPF S.A. Gas Interest: 60.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    262              262                        7.3                7.3

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    80


      80


        2.0


    2.0


    Sub-total Proved 80   80     2.0 2.0
    Probable 112                            9 121     3.0 3.0
    Possible 184   184     4.6 4.6

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    56


      56


        1.2


    1.2


    Sub-total Proved 56   56     1.2 1.2
    Probable 78 6 84     1.8 1.8
    Possible 128   128     2.8 2.8

    D. Notes:

     

    YPF_03.123 5 Gaffney, Cline & Associates





    La Ventana

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 126 YPF S.A. Oil Interest: 69.60%

     
    Sub-unit Name: Río Viejas YPF S.A. Gas Interest: 60.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
                   2,885          2,885                    59.7              59.7

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³

    Proved
         Producing
         Non-producing
         Undeveloped

    183


      183


        4.1


    4.1


    Sub-total Proved 183   183     4.1 4.1
    Probable 94   94     2.5 2.5
    Possible 302   302     7.5 7.5

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    127


      127


        2.5


    2.5


    Sub-total Proved 127   127     2.5 2.5
    Probable 65   65     1.5 1.5
    Possible 210   210     4.5 4.5

    D. Notes:

     

    YPF_03.123 6 Gaffney, Cline & Associates





    La Ventana

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 126 YPF S.A. Oil Interest: 69.60%

     
    Sub-unit Name: La Ventana NGL YPF S.A. Gas Interest: 60.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
            23    

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
            119

    6
       
    Sub-total Proved         125    
    Probable         22    
    Possible         9    

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
            71

    4
       
    Sub-total Proved         75    
    Probable         13    
    Possible         6    

    D. Notes:

     

    YPF_03.123 7 Gaffney, Cline & Associates





    La Ventana

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 126 YPF S.A. Oil Interest: 69.60%

     
    Sub-unit Name: Barrancas / Río Blanco YPF S.A. Gas Interest: 60.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
                   6,748          6,748                  170.0            170.0

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    558

    21
      558

    21
        13.5

    0.5
    13.5

    0.5
    Sub-total Proved 579   579     14.0 14.0
    Probable 126 26 152     3.8 3.8
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    388

    15
      388

    15
        8.1

    0.3
                   8.1

                   0.3
    Sub-total Proved 403   403     8.4                8.4
    Probable 88 18 106     2.3                2.3
    Possible              

    D. Notes:

     

    YPF_03.123 8 Gaffney, Cline & Associates





    La Ventana

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet



    GCA Audit Code: 126 YPF S.A. Oil Interest: 69.60%

     
    Sub-unit Name: Guanaco Blanco LRB YPF S.A. Gas Interest: 60.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    43                43                        0.8                0.8

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    20


      20


        0.4


    0.4


    Sub-total Proved 20   20     0.4 0.4
    Probable 3   3     0.1 0.1
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    14


      14


        0.2


    0.2


    Sub-total Proved 14   14     0.2 0.2
    Probable 2   2     0.1 0.1
    Possible              

    D. Notes:

     

    YPF_03.123 9 Gaffney, Cline & Associates





    La Ventana

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 126 YPF S.A. Oil Interest: 69.60%

     
    Sub-unit Name: Cañada Dura YPF S.A. Gas Interest: 60.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    18                18                        0.2                0.2

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    17

    40
      17

    40
        0.4

    1.0
    0.4

    1.0
    Sub-total Proved 57   57     1.4 1.4
    Probable 60   60     1.4 1.4
    Possible 149   149     3.5 3.5

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    12

    28
      12

    28
        0.2

    0.6
    0.2

    0.6
    Sub-total Proved 40   40     0.8 0.8
    Probable 42   42     0.8 0.8
    Possible 104   104     2.1 2.1

    D. Notes:

     

    YPF_03.123 10 Gaffney, Cline & Associates





    Vizcacheras

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002


    GCA Audit Code: 109 YPF S.A. Oil Interest: 100.00%

     
    Basin: Cuyana YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    51,801 306 52,107     1,218.8 1,218.8

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    8,531

    81
    674

    17
    9,205

    98
        176.1

    2.1
    176.1

    2.1
    Sub-total Proved 8,612 691 9,303     178.2 178.2
    Probable 555 207 762   7 11.7 11.7
    Possible 1,616 620 2,236   31 34.8 34.8

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    8,531

    81
    674

    17
    9,205

    98
        176.1

    2.1
    176.1

    2.1
    Sub-total Proved 8,612 691 9,303     178.2 178.2
    Probable 555 207 762   7 11.7 11.7
    Possible 1,616 620 2,236   31 34.8 34.8

    D. Notes:


    YPF_03.123 11 Gaffney, Cline & Associates





    Vizcacheras

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 109 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Barrancas YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    13,879 306 14,185     330.0 330.0

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    2,435

    39
    674

    17
    3,109

    56
        66.2

    1.2
    66.2

    1.2
    Sub-total Proved 2,474 691 3,165     67.4 67.4
    Probable 112 48 160   7 3.4 3.4
    Possible 540 227 767   31 15.7 15.7

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    2,435

    39
    674

    17
    3,109

    56
        66.2

    1.2
    66.2

    1.2
    Sub-total Proved 2,474 691 3,165     67.4 67.4
    Probable 112 48 160   7 3.4 3.4
    Possible 540 227 767   31 15.7 15.7

    D. Notes:


    YPF_03.123 12 Gaffney, Cline & Associates






    Vizcacheras

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 109 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Papagayos YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    


    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    36,950   36,950     882.7 882.7

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    4,203

    42
      4,203

    42
        89.6

    0.9
    89.6

    0.9
    Sub-total Proved 4,245   4,245     90.5 90.5
    Probable 176   176     3.8 3.8
    Possible 311   311     6.6 6.6

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    4,203

    42
      4,203

    42
        89.6

    0.9
    89.6

    0.9
    Sub-total Proved 4,245   4,245     90.5 90.5
    Probable 176   176     3.8 3.8
    Possible 311   311     6.6 6.6

    D. Notes:


    YPF_03.123 13 Gaffney, Cline & Associates





    Vizcacheras

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 109 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Cañada Dura YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Norte    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    972   972     6.1 6.1

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,893


      1,893


        20.3


    20.3


    Sub-total Proved 1,893   1,893     20.3 20.3
    Probable 267 159 426     4.5 4.5
    Possible 765 393 1,158     12.5 12.5

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,893


      1,893


        20.3


    20.3


    Sub-total Proved 1,893   1,893     20.3 20.3
    Probable 267 159 426     4.5 4.5
    Possible 765 393 1,158     12.5 12.5

    D. Notes:


    YPF_03.123 14 Gaffney, Cline & Associates





    Cerro Fortunoso

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002


    GCA Audit Code: 039 YPF S.A. Oil Interest: 100.00%

     
    Basin: Neuquina YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    


    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    3.164   3,164     562.5 562.5

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    2,671

    810
      2,671

    810
           
    Sub-total Proved 3,481   3,481        
    Probable 1,207   1,207        
    Possible 125   125        

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    2,671

    810
      2,671

    810
           
    Sub-total Proved 3,481   3,481        
    Probable 1,207   1,207        
    Possible 125   125        

    D. Notes:


    YPF_03.123 15 Gaffney, Cline & Associates





    Cerro Fortunoso

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 039 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Cerro Fortunoso YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    3,160   3,160     562.5 562.5

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    2,650

    760
      2,650

    760
           
    Sub-total Proved 3,410   3,410        
    Probable 1,057   1,057        
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    2,650

    760
      2,650

    760
           
    Sub-total Proved 3,410   3,410        
    Probable 1,057   1,057        
    Possible              

    D. Notes


    YPF_03.123 16 Gaffney, Cline & Associates





    Cerro Fortunoso

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 039 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Cerro Fortunoso Sur YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    4   4        

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    21

    50
     

    21

    50

           
    Sub-total Proved 71   71        
    Probable 150   150        
    Possible 125   125        

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    21

    50
     

    21

    50

           
    Sub-total Proved 71   71        
    Probable 150   150        
    Possible 125   125        

    D. Notes:


    YPF_03.123 17 Gaffney, Cline & Associates





    El Portón

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002


    GCA Audit Code: 157 YPF S.A. Oil Interest: 100.00%

     
    Basin: Neuquina YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    4,520   4,520     196.3 713.7

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,401


      1,401


    248
    209

    1,516
    528

    643.8


    643.8

    6,264.2
    Sub-total Proved 1,401   1,401 457 2,044 643.8 6,908.0
    Probable 250   250     27.5 27.5
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,401


      1,401


    248
    209

    1,516
    528

    643.8


    643.8

    6,264.2
    Sub-total Proved 1,401   1,401 457 2,044 643.8 6,908.0
    Probable 250   250     27.5 27.5
    Possible              

    D. Notes:


    YPF_03.123 18 Gaffney, Cline & Associates






    El Portón

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 157 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Sur YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    3,116   3,116     187.9 205.1

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped

    498

     

     

     

    498

     

    48
    76

    353
    122

    212.4


    212.4

    1,412.6

    Sub-total Proved 498   498 124 475 212.4 1,625.0
    Probable 250   250     27.5 27.5
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped

    498

     

     

     

    498

     

    48
    76

    353
    122

    212.4


    212.4

    1,412.6

    Sub-total Proved 498   498 124 475 212.4 1,625.0
    Probable 250   250     27.5 27.5
    Possible              

    D. Notes:


    YPF_03.123 19 Gaffney, Cline & Associates





    El Portón

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 157 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Norte YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza & Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    1,404   1,404     8.4 508.6

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    903


     

    903


    200
    133

    1,163
    406

    431.4


    431.4

    4,851.6

    Sub-total Proved 903   903 333 1,569 431.4 5,283.0
    Probable              
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    903


     

    903


    200
    133

    1,163
    406

    431.4


    431.4

    4,851.6

    Sub-total Proved 903   903 333 1,569 431.4 5,283.0
    Probable              
    Possible              

    D. Notes:


    YPF_03.123 20 Gaffney, Cline & Associates






    Chihuido de la Salina

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002


    GCA Audit Code: 158 YPF S.A. Oil Interest: 100.00%

     
    Basin: Neuquina YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    9,309 915 10,224     718.4 831.7

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    3,550


    6,061

    287

    9,611

    287

     

    2,049
    722

    1,937.9


    1,937.9

    7,508.0
    Sub-total Proved 3,550 6,348 9,898   2,771 1,937.9 9,445.9
    Probable 624 1,677 2,301     252.4 252.4
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    3,550


    6,061

    287

    9,611

    287

     

    2,049
    722

    1,937.9


    1,937.9

    7,508.0
    Sub-total Proved 3,550 6,348 9,898   2,771 1,937.9 9,445.9
    Probable 624 1,677 2,301     252.4 252.4
    Possible              

    D. Notes:


    YPF_03.123 21 Gaffney, Cline & Associates





    Chihuido de la Salina

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 158 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Norte - Troncoso Inf. YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    1,794 647 2,441     193.8 193.8

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    368


    1,498

    287

    1,866

    287
      116
    42
    354.1


    354.1

    181.7
    Sub-total Proved 368 1,785 2,153   158 354.1 535.8
    Probable              
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    368


    1,498

    287

    1,866

    287
      116
    42
    354.1


    354.1

    181.7
    Sub-total Proved 368 1,785 2,153   158 354.1 535.8
    Probable              
    Possible              

    D. Notes:


    YPF_03.123 22 Gaffney, Cline & Associates





    Chihuido de la Salina

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 158 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Centrol Norte - Troncoso Inf. YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    5,700 268 5,968     535.5 535.5

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,570


    4,563


    6,133


     

    562
    201

    825.9


    825.9

    1,781.5

    Sub-total Proved 1,570 4,563 6,133   763 825.9 2,607.4
    Probable   434 434        
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,570


    4,563


    6,133


     

    562
    201

    825.9


    825.9

    1,781.5

    Sub-total Proved 1,570 4,563 6,133   763 825.9 2,607.4
    Probable   434 434        
    Possible              

    D. Notes:


    YPF_03.123 23 Gaffney, Cline & Associates





    Chihuido de la Salina

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 158 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Centro Sur - Troncoso Inf. YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    1,739   1,739     (25.6) 87.7

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,612


      1,612


     

    1,371
    479

    757.9


    757.9

    5,544.8

    Sub-total Proved 1,612   1,612   1,850 757.9 6,302.7
    Probable 270 1,243 1,513     185.1 185.1
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,612


      1,612


     

    1,371
    479

    757.9


    757.9

    5,544.8

    Sub-total Proved 1,612   1,612   1,850 757.9 6,302.7
    Probable 270 1,243 1,513     185.1 185.1
    Possible              

    D. Notes:


    YPF_03.123 24 Gaffney, Cline & Associates





    Chihuido de la Salina

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 158 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Mulichinco YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    76   76     14.7 14.7

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                 
    Sub-total Proved              
    Probable 354   354     67.3 67.3
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                 
    Sub-total Proved              
    Probable 354   354     67.3 67.3
    Possible              

    D. Notes:


    YPF_03.123 25 Gaffney, Cline & Associates





    Chihuido de la Salina Sur

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002


    GCA Audit Code: 159 YPF S.A. Oil Interest: 100.00%

     
    Basin: Neuquina YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    1,961 21 1,982     214.3 214.3

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,306


    391

    138
    1,697

    138
      606
    349
    903.9

    16.5
    903.9

    1,894.2
    Sub-total Proved 1,306 529 1,835   955 920.4 2,798.1
    Probable 590 480 1,070     47.9 551.9
    Possible 50   50     5.0 5.0

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,306


    391

    138
    1,697

    138
      606
    349
    903.9

    16.5
    903.9

    1,894.2
    Sub-total Proved 1,306 529 1,835   955 920.4 2,798.1
    Probable 590 480 1,070     47.9 551.9
    Possible 50   50     5.0 5.0

    D. Notes:


    YPF_03.123 26 Gaffney, Cline & Associates





    Chihuido de la Salina Sur

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 159 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Bajo Los Lobos - Troncoso Inf. YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
                 

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                 
    Sub-total Proved              
    Probable 50   50     5.0 509.0
    Possible 50   50     5.0 5.0

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                 
    Sub-total Proved              
    Probable 50   50     5.0 509.0
    Possible 50   50     5.0 5.0

    D. Notes:


    YPF_03.123 27 Gaffney, Cline & Associates





    Chihuido de la Salina Sur

    (Field / Area Name)
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 159 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Troncoso Inf. - Escama Intermed YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    37   37     2.5 2.5

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    370


      370


      80
    28
    106.2


    106.2

    258.9
    Sub-total Proved 370   370   108 106.2 365.1
    Probable 210   210        
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    370


      370


      80
    28
    106.2


    106.2

    258.9
    Sub-total Proved 370   370   108 106.2 365.1
    Probable 210   210        
    Possible              

    D. Notes:


    YPF_03.123 28 Gaffney, Cline & Associates





    Chihuido de la Salina Sur

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 159 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Troncoso Inf. - Escama Principal YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    1,787 21 1,808     193.6 193.6

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    710


    391

    138
    1,101

    138
      341
    259
    758.7

    16.5
    758.7

    807.2
    Sub-total Proved 710 529 1,239   600 775.2 1,565.9
    Probable 330   330     42.9 42.9
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    710


    391

    138
    1,101

    138
      341
    259
    758.7

    16.5
    758.7

    807.2
    Sub-total Proved 710 529 1,239   600 775.2 1,565.9
    Probable 330   330     42.9 42.9
    Possible              

    D. Notes:


    YPF_03.123 29 Gaffney, Cline & Associates





    Chihuido de la Salina Sur

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 159 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Troncoso Inf. - Escama Superior YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    49   49     7.4 7.4

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    38


      38


      185

    62
    18.0


    18.0

    828.1
    Sub-total Proved 38   38   247 18.0 846.1
    Probable              
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    38


      38


      185

    62
    18.0


    18.0

    828.1
    Sub-total Proved 38   38   247 18.0 846.1
    Probable              
    Possible              

    D. Notes:


    YPF_03.123 30 Gaffney, Cline & Associates





    Chihuido de la Salina Sur

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 159 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: El Zaino - Mulichinco YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    4   4     1.3 1.3

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                 
    Sub-total Proved              
    Probable              
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                 
    Sub-total Proved              
    Probable              
    Possible              

    D. Notes:


    YPF_03.123 31 Gaffney, Cline & Associates





    Chihuido de la Salina Sur

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 159 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Rincón de Correa YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    21   21     3.1 3.1

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    50


      50


        6.0


    6.0


    Sub-total Proved 50   50     6.0 6.0
    Probable   180 180        
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    50


      50


        6.0


    6.0


    Sub-total Proved 50   50     6.0 6.0
    Probable   180 180        
    Possible              

    D. Notes:


    YPF_03.123 32 Gaffney, Cline & Associates






    Chihuido de la Salina Sur

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 159 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Rincón de Correa Sur YPF S.A. Gas Interest: 100.00%
     
     
    Province: Mendoza Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Mendoza Sur    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    63   63     6.4 6.4

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    138


      138


        15.0


    15.0


    Sub-total Proved 138   138     15.0 15.0
    Probable   300 300        
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    138


      138


        15.0


    15.0


    Sub-total Proved 138   138     15.0 15.0
    Probable   300 300        
    Possible              

    D. Notes:


    YPF_03.123 33 Gaffney, Cline & Associates





    Chihuido de la Sierra Negra

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002


    GCA Audit Code: 027 YPF S.A. Oil Interest: 100.00%

     
    Basin: Neuquina YPF S.A. Gas Interest: 100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Rincón de los Sauces    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    39,561 32,190 71,751     7,311.2 7,209.7

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    2,119

    335

    28,573

    233

    30,692

    568

       

    1,192.1

    52.4

    1,192.1
    1,360.7
    52.4
    Sub-total Proved 2,454 28,806 31,260     1,244.5 2,605.2
    Probable 1,974 3,776 5,750     405.4 592.7
    Possible 2,770   2,770     87.4 87.4

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    2,119

    335

    28,573

    233

    30,692

    568

       

    1,192.1

    52.4

    1,192.1
    1,360.7
    52.4
    Sub-total Proved 2,454 28,806 31,260     1,244.5 2,605.2
    Probable 1,974 3,776 5,750     405.4 592.7
    Possible 2,770   2,770     87.4 87.4

    D. Notes:


    YPF_03.123 34 Gaffney, Cline & Associates





    Chihuido de la Sierra Negra

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 027 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Lomita Norte YPF S.A. Gas Interest: 100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Rincón de los Sauces    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    1,216 328 1,544     165.6 165.6

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped

    103


    553


    656


        31.7


    31.7

    Sub-total Proved 103 553 656     31.7 31.7
    Probable 25   25     6.6 6.6
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped

    103


    553


    656


        31.7


    31.7

    Sub-total Proved 103 553 656     31.7 31.7
    Probable 25   25     6.6 6.6
    Possible              

    D. Notes:


    YPF_03.123 35 Gaffney, Cline & Associates





    Chihuido de la Sierra Negra

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 027 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Troncoso Inf. / Agrio + Avilé YPF S.A. Gas Interest: 100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Rincón de los Sauces    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    37,118 31,811 68,929     7,091.8 6,990.3

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,806

    125

    27,852

    185

    29,658

    310

        1,149.8

    41.5

    1,149.8
    1,360.7
    41.5

    Sub-total Proved 1,931 28,037 29,968     1,191.3 2,552.0
    Probable 1,450 1,492 2,942     307.6 494.9
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,806

    125

    27,852

    185

    29,658

    310

        1,149.8

    41.5

    1,149.8
    1,360.7
    41.5

    Sub-total Proved 1,931 28,037 29,968     1,191.3 2,552.0
    Probable 1,450 1,492 2,942     307.6 494.9
    Possible              

    D. Notes:


    YPF_03.123 36 Gaffney, Cline & Associates





    Chihuido de la Sierra Negra

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 027 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Rayoso YPF S.A. Gas Interest: 100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Rincón de los Sauces    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
      1 1        

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
      2

    48
    2

    48
       

    0.1

    1.3

    0.1

    1.3

    Sub-total Proved   50 50     1.4 1.4
    Probable   2,250 2,250     66.0 66.0
    Possible 2,500   2,500     75.0 75.0

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
      2

    48
    2

    48
       

    0.1

    1.3

    0.1

    1.3

    Sub-total Proved   50 50     1.4 1.4
    Probable   2,250 2,250     66.0 66.0
    Possible 2,500   2,500     75.0 75.0

    D. Notes:


    YPF_03.123 37 Gaffney, Cline & Associates





    Chihuido de la Sierra Negra

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 027 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Lomita-Rayoso YPF S.A. Gas Interest: 100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Rincón de los Sauces    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    198 50 248     21.0 21.0

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped

    60

     

    166

     

    226

     

       

    3.6

     

    3.6


    Sub-total Proved 60 166 226     3.6 3.6
    Probable 169 34 203     10.1 10.1
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped

    60

     

    166

     

    226

     

       

    3.6

     

    3.6


    Sub-total Proved 60 166 226     3.6 3.6
    Probable 169 34 203     10.1 10.1
    Possible              

    D. Notes:


    YPF_03.123 38 Gaffney, Cline & Associates





    Chihuido de la Sierra Negra

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 027 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Aguada de la Cerda Norte-Avilé YPF S.A. Gas Interest: 100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Rincón de los Sauces    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    27   27     12.7 12.7

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                 
    Sub-total Proved              
    Probable              
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                 
    Sub-total Proved              
    Probable              
    Possible              

    D. Notes:


    YPF_03.123 39 Gaffney, Cline & Associates





    Chihuido de la Sierra Negra

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 027 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Roca Ignea / La Tosca YPF S.A. Gas Interest: 100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Rincón de los Sauces    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    999   999     19.7 19.7

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped

    150

    210

      150

    210
       

    6.9

    9.6

    6.9

    9.6

    Sub-total Proved 360   360     16.5 16.5
    Probable 330   330     15.1 15.1
    Possible 270   270     12.4 12.4

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped

    150

    210

      150

    210
       

    6.9

    9.6

    6.9

    9.6

    Sub-total Proved 360   360     16.5 16.5
    Probable 330   330     15.1 15.1
    Possible 270   270     12.4 12.4

    D. Notes:


    YPF_03.123 40 Gaffney, Cline & Associates





    Chihuido de la Sierra Negra

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 027 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Faldeo Amarillo YPF S.A. Gas Interest: 100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Rincón de los Sauces    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    3   3     0.4 0.4

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                 
    Sub-total Proved              
    Probable              
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                 
    Sub-total Proved              
    Probable              
    Possible              

    D. Notes:


    YPF_03.123 41 Gaffney, Cline & Associates





    Señal Picada

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002


    GCA Audit Code: 038 YPF S.A. Oil Interest: 100.00%

     
    Basin: Neuquina YPF S.A. Gas Interest: 100.00%
     
     
    Province: Neuquén & Río Negro Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Rincón de los Sauces    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    10,087 8,248 18,335     830.5 839.5

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped

    12

     

    3,187

    45

    3,199

    45

       

    39.1

    0.5

    81.0

    0.5

    Sub-total Proved 12 3,232 3,244     39.6 81.5
    Probable 157   157     1.9 18.4
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped

    12

     

    3,187

    45

    3,199

    45

       

    39.1

    0.5

    81.0

    0.5

    Sub-total Proved 12 3,232 3,244     39.6 81.5
    Probable 157   157     1.9 18.4
    Possible              

    D. Notes:


    YPF_03.123 42 Gaffney, Cline & Associates





    Señal Picada

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 038 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Quintuco YPF S.A. Gas Interest: 100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Rincón de los Sauces    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    10,073 8,248 18,321     830.2 839.2

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    2


    3,187

    45

    3,189

    45

        38.5

    0.5

    80.4

    0.5

    Sub-total Proved 2 3,232 3,234   39.0 80.9
    Probable 157   157     1.9 18.4
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    2


    3,187

    45

    3,189

    45

        38.5

    0.5

    80.4

    0.5

    Sub-total Proved 2 3,232 3,234   39.0 80.9
    Probable 157   157     1.9 18.4
    Possible              

    D. Notes:


    YPF_03.123 43 Gaffney, Cline & Associates





    Señal Picada

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 038 YPF S.A. Oil Interest: 100.00%

     
    Sub-unit Name: Centenario YPF S.A. Gas Interest: 100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Rincón de los Sauces    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    14   14     0.3 0.3

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    10


     

    10

     

       

    0.6

     

    0.6

    Sub-total Proved 10   10     0.6 0.6
    Probable              
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    10


     

    10

     

       

    0.6

     

    0.6

    Sub-total Proved 10   10     0.6 0.6
    Probable              
    Possible              

    D. Notes:


    YPF_03.123 44 Gaffney, Cline & Associates





    Loma La Lata

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002


    GCA Audit Code: 032 YPF S.A. Oil Interest:  100.00%

     
    Basin: Neuquina YPF S.A. Gas Interest:  100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Loma La Lata    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    2,224   2,224 13,463 10,939 719.9 146,861.6

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    231


     


    231


    4,041

    778
    27,179

    5,981
    30.0


    111,646.4
    800.0
    24,701.3
    Sub-total Proved 231   231 4,819 33,160 30.0 137,147.7
    Probable       122     6,731.6
    Possible       284 2,241   14,758.5

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    231


     


    231


    4,041

    778
    27,179

    5,981
    30.0


    111,646.4
    800.0
    24,701.3
    Sub-total Proved 231   231 4,819 33,160 30.0 137,147.7
    Probable       122     6,731.6
    Possible       284 2,241   14,758.5

    D. Notes:


    YPF_03.123 45 Gaffney, Cline & Associates





    Loma La Lata

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 032 YPF S.A. Oil Interest:  100.00%

     
    Sub-unit Name: Barreales Colorados - Sierras Bl YPF S.A. Gas Interest:  100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Loma La Lata    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
          1     2.4

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                 
    Sub-total Proved              
    Probable       122     855.7
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                 
    Sub-total Proved              
    Probable       122     855.7
    Possible              

    D. Notes:


    YPF_03.123 46 Gaffney, Cline & Associates





    Loma La Lata

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 032 YPF S.A. Oil Interest:  100.00%

     
    Sub-unit Name: Quintuco YPF S.A. Gas Interest:  100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Loma La Lata    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    2,224   2,224     719.9 719.9

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    231


      231


        30.0


    30.0


    Sub-total Proved 231   231     30.0 30.0
    Probable              
    Possible              

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    231


      231


        30.0


    30.0


    Sub-total Proved 231   231     30.0 30.0
    Probable              
    Possible              

    D. Notes:


    YPF_03.123 47 Gaffney, Cline & Associates





    Loma La Lata

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 032 YPF S.A. Oil Interest:  100.00%

     
    Sub-unit Name: Sierras Blancas YPF S.A. Gas Interest:  100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Loma La Lata    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
          13,462 10,939   144,533.9

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
          4,041

    778
    27,179

    5,981
      108,586.7

    24,388.4
    Sub-total Proved       4,819 33,160   132,975.1
    Probable              
    Possible       284 2,241   9,170.5

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
          4,041

    778
    27,179

    5,981
      108,586.7

    24,388.4
    Sub-total Proved       4,819 33,160   132,975.1
    Probable              
    Possible       284 2,241   9,170.5

    D. Notes:


    YPF_03.123 48 Gaffney, Cline & Associates





    Loma La Lata

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002
    Supporting Sub-unit Data Sheet


    GCA Audit Code: 032 YPF S.A. Oil Interest:  100.00%

     
    Sub-unit Name: Lotena YPF S.A. Gas Interest:  100.00%
     
     
    Province: Neuquén Sales and Field Gas Usage: 100.00%
     
     
    Division: Oeste Operator Name: YPF S.A.


    Economic Unit: Loma La Lata    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
                1,605.4

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                3,029.7
    800.0
    312.9
    Sub-total Proved             4,142.6
    Probable             5,875.9
    Possible             5,588.0

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
                3,029.7
    800.0
    312.9
    Sub-total Proved             4,142.6
    Probable             5,875.9
    Possible             5,588.0

    D. Notes:


    YPF_03.123 49 Gaffney, Cline & Associates





    Manatiales Behr

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002


    GCA Audit Code: 160 YPF S.A. Oil Interest:  100.00%

     
    Basin: San Jorge YPF S.A. Gas Interest:  100.00%
     
     
    Province: Chubut Sales and Field Gas Usage: 100.00%
     
     
    Division: Sur Operator Name: YPF S.A.


    Economic Unit: Chubut - Cañadón Seco    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    15,517 788 16,305     28,886.1 28,886.1

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    3,521

    995
    345
    63
    23

    3,866
    63
    1,018

        298.3

    85.6
    298.3

    85.6
    Sub-total Proved 4,516 431 4,947     383.9 383.9
    Probable 1,768 333 2,101     132.6 224.6
    Possible 5,196 467 5,663     389.7 522.7

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    3,521

    995
    345
    63
    23

    3,866
    63
    1,018

        298.3

    85.6
    298.3

    85.6
    Sub-total Proved 4,516 431 4,947     383.9 383.9
    Probable 1,768 333 2,101     132.6 224.6
    Possible 5,196 467 5,663     389.7 522.7

    D. Notes:


    YPF_03.123 50 Gaffney, Cline & Associates






    Seco León

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002


    GCA Audit Code: 010 YPF S.A. Oil Interest:  100.00%

     
    Basin: San Jorge YPF S.A. Gas Interest:  100.00%
     
     
    Province: Santa Cruz Sales and Field Gas Usage: 100.00%
     
     
    Division: Sur Operator Name: YPF S.A.


    Economic Unit: Chubut - Cañadón Seco    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    44,281 8,307 52,588     18,082.8 18,082.8

    B. Gross Field Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,137

    207
    2,342
    52
    1,122
    3,479
    52
    1,329
        866.8

    192.1
    866.8

    192.1
    Sub-total Proved 1,344 3,516 4,860     1,058.9 1,058.9
    Probable 99 612 711     25.4 25.4
    Possible 897 240 1,137     213.8 213.8

    C. YPF S.A. Net Revenue Interest Reserves @ December 31st, 2002

      Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³
    Total
    MMm³
    Proved
         Producing
         Non-producing
         Undeveloped
    1,137

    207
    2,342
    52
    1,122
    3,479
    52
    1,329
        866.8

    192.1
    866.8

    192.1
    Sub-total Proved 1,344 3,516 4,860     1,058.9 1,058.9
    Probable 99 612 711     25.4 25.4
    Possible 897 240 1,137     213.8 213.8

    D. Notes:


    YPF_03.123 51 Gaffney, Cline & Associates





    Los Perales

    (Field / Area Name)
     
    Crude Oil and Natural Gas Reserve Statement
    Audit Certification @ December 31st, 2002


    GCA Audit Code: 016 YPF S.A. Oil Interest:  100.00%

     
    Basin: San Jorge YPF S.A. Gas Interest:  100.00%
     
     
    Province: Santa Cruz Sales and Field Gas Usage: 100.00%
     
     
    Division: Sur Operator Name: YPF S.A.


    Economic Unit: Las Heras    

    A. Cumulative Production to December 31st, 2002

         Oil Cond.


    Mm³
    NGL


    Mm³
    Gas
    Primary
    Mm³
    Secondary
    Mm³
    Total
    Mm³
    Solution
    MMm³