EXHIBIT 3.6


                               COMMERCIAL GUARANTY



         COMMERCIAL GUARANTY (this "Agreement") made and entered into as of May
24, 2002 by CCBM, INC., a Delaware corporation (hereinafter referred to as
"Guarantor"), in favor of HIBERNIA NATIONAL BANK, a national banking association
(the "Lender"), guarantying the Indebtedness (as such terms are hereinafter
defined) of CARRIZO OIL & GAS, INC., a Texas corporation (hereinafter referred
to as "Borrower").

                                   WITNESSETH:

         FOR VALUE RECEIVED, and in consideration of and for credit and
financial accommodations extended, to be extended, or continued to or for the
account of the above named Borrower, the undersigned Guarantor, hereby jointly,
severally and solidarily, agrees as follows:

         SECTION 1. CONTINUING GUARANTY OF BORROWER'S INDEBTEDNESS. Guarantor
hereby absolutely and unconditionally agrees to, and by these presents does
hereby, guarantee the prompt and punctual payment, performance and satisfaction
of any and all loans, extensions of credit and/or other obligations that
Borrower may now and/or in the future owe to and/or incur in favor of Lender
under or pursuant to that certain Credit Agreement dated of even date herewith,
by and among Borrower, Guarantor, and Lender, as the same may be amended and/or
restated from time to time and in effect (the "Credit Agreement"), including the
indebtedness of Borrower evidenced by that certain Revolving Note dated of even
date herewith, in the maximum aggregate principal amount of $30,000,000.00,
executed by Borrower pursuant to the Credit Agreement, and any and all renewals,
extensions, substitutions, modifications and replacements of said Revolving Note
from time to time and in effect, and whether such indebtedness and/or
obligations are absolute or contingent, liquidated or unliquidated, due or to
become due, secured or unsecured, and whether now existing or hereafter arising,
of any nature or kind whatsoever, up to a maximum principal amount outstanding
at any one or more times not to exceed THIRTY MILLION AND NO/100 DOLLARS (U.S.
$30,000,000.00), together with interest, costs and attorneys' fees thereon (with
all of Borrower's indebtedness and/or obligations being hereinafter individually
and collectively referred to under this Agreement as "Borrower's Indebtedness"
or the "Indebtedness").

         SECTION 2. LIMITATION ON LIABILITY. The liability of Guarantor
hereunder with respect to the Indebtedness shall be limited to the maximum
amount of liability that can be incurred without rendering this Commercial
Guaranty, as it relates to Guarantor, voidable under applicable law relating to
fraudulent conveyance or fraudulent transfer, and not for any greater amount.

         SECTION 3. JOINT, SEVERAL AND SOLIDARITY LIABILITY. Guarantor further
agrees that its obligations and liabilities for the prompt and punctual payment,
performance and satisfaction of all of Borrower's Indebtedness shall be on a
"joint and several" and "solidary" basis along with Borrower to the same degree
and extent as if Guarantor had been and/or will be



a co-borrower, co-principal obligor and/or co-maker of all of Borrower's
Indebtedness. In the event that there is more than one guarantor under this
Agreement, or in the event that there are other guarantors, endorsers or
sureties of all or any portion of Borrower's Indebtedness, Guarantor's
obligations and liabilities hereunder shall be on a "joint and several" and
"solidary" basis along with such other guarantor or guarantors, endorsers and/or
sureties.

         SECTION 4. DURATION; CANCELLATION OF AGREEMENT. This Agreement and
Guarantor's obligations and liabilities hereunder shall remain in full force and
effect until such time as each and every Indebtedness of Borrower shall be paid,
performed and/or satisfied in full, in principal, interest, costs and attorneys'
fees, or until such time as this Agreement may be cancelled or otherwise
terminated by Lender under a written cancellation instrument in favor of
Guarantor (subject to the automatic reinstatement provision hereinbelow). Unless
otherwise indicated under such a written cancellation instrument, Lender's
agreement to terminate or otherwise cancel this Agreement shall only effect and
shall be expressly limited to Guarantor's continuing obligations and liabilities
to guarantee the prompt and punctual payment, performance and satisfaction of
Borrower's Indebtedness incurred, originated and/or extended or committed to by
Lender after the date of such a written cancellation instrument; with Guarantor
remaining fully obligated and liable under this Agreement for the prompt and
punctual payment, performance and satisfaction of any and all of Borrower's then
outstanding Indebtedness together with continuing assessment of interest
thereon) that was incurred, originated, extended or committed to prior to the
date of such a written cancellation instrument. Nothing under this Agreement or
under any other agreement or understanding by and between Guarantor and Lender,
shall in any way obligate, or be construed to obligate, Lender to agree to the
subsequent termination or cancellation of Guarantor's obligations and
liabilities hereunder, it being fully understood and agreed by Guarantor that
Lender may, within their sole and uncontrolled discretion and judgment, refuse
to release Guarantor from any of its obligations and liabilities under this
Agreement for any reason whatsoever as long as any of Borrower's Indebtedness
remains unpaid and outstanding.

         SECTION 5. DEFAULT OF BORROWER. Upon the occurrence of an Event of
Default as provided in the Credit Agreement, Guarantor unconditionally and
absolutely agrees to pay in full the then unpaid amount of all of Borrower's
Indebtedness guaranteed hereunder, in principal interest, costs and reasonable
attorneys' fees. Such payment or payments shall be made immediately following
demand by Lender at its offices at 313 Carondelet Street, New Orleans, Louisiana
70130. Other than the demand referred to in the immediately preceding sentence,
Guarantor hereby waives notice of acceptance of this Agreement and of any
Indebtedness to which it applies or may apply. Guarantor further waives
presentation and demand for payment of Borrower's Indebtedness, notice of
dishonor and of nonpayment, notice of intention to accelerate, notice of
acceleration, protest and notice of protest, collection or institution of any
suit or other action by Lender in collection thereof, including any notice of
default in payment thereof or other notice to, or demand for payment thereof on
any party. Guarantor additionally waives any and all rights and pleas of
division and discussion as provided under Louisiana law, as well as, to the
degree applicable, any similar rights as may be provided under the laws of any
other state.



                                      -2-


         SECTION 6. GUARANTOR'S SUBORDINATION OF RIGHTS TO LENDER. In the event
that Guarantor should for any reason (i) make any payment for and on behalf of
Borrower under any of Borrower's Indebtedness, and/or (ii) make any payments to
Lender in total or partial satisfaction of Guarantor's obligations and
liabilities hereunder, Guarantor hereby agrees that any and all rights that
Guarantor may have or acquire to collect or to be reimbursed by Borrower (or by
any guarantor, endorser or surety of Borrower's Indebtedness), whether
Guarantor's rights of collection or reimbursement arise by way of subrogation to
the rights of Lender or otherwise, shall in all respects be subordinate,
inferior and junior to Lender' rights to collect and enforce payment,
performance and satisfaction of Borrower's then remaining Indebtedness, until
such time as all of Borrower's Indebtedness is fully paid and satisfied. Upon
the occurrence and continuance of an Event of Default (as defined in the Credit
Agreement) any and all amounts owed by Borrower to Guarantor shall in all
respects be subordinate, inferior and junior to Lender' rights to collect and
enforce payment, performance and satisfaction of Borrower's then remaining
Indebtedness, until such time as all of Borrower's Indebtedness is fully paid
and satisfied. Guarantor further agrees to refrain from attempting to collect
and/or enforce any of Guarantor's aforesaid rights against Borrower (or any
other guarantor, surety or endorser of Borrower's Indebtedness), arising by way
of subrogation or otherwise, until such time as all of Borrower's then remaining
Indebtedness in favor of Lender is fully paid and satisfied, in principal,
interest, costs and attorneys' fees.

         SECTION 7. ADDITIONAL COVENANTS. Guarantor further agrees that Lender
may, at its sole option, at any time, and from time to time, without the consent
of or notice to Guarantor, or to any other party, and without incurring any
responsibility to Guarantor or to any other party (other than the Borrower to
the extent provided in the Loan Documents as such term is defined in the Credit
Agreement), and without impairing or releasing the obligations of Guarantor
under this Agreement

                  (A) Discharge or release any party (including, but not limited
to, Borrower or any guarantor under this Agreement) who is or may be liable to
Lender for any of Borrower's Indebtedness;

                  (B) Sell, exchange, release, surrender, realize upon or
otherwise deal with, in any manner and in any order, any collateral directly or
indirectly securing repayment of any of Borrower's Indebtedness;

                  (C) Change the manner, place or terms of payment, or change or
extend the time of payment of or renew, as often and for such periods as Lender
may determine, or after, any of Borrower's Indebtedness;

                  (D) Settle or compromise any of Borrower's Indebtedness;

                  (E) Subordinate and/or agree to subordinate the payment of all
or any of Borrower's Indebtedness or Lender's security rights in and/or to any
collateral directly or indirectly securing any such indebtedness, to the payment
and/or security rights of any other present and/or future creditors of Borrower;



                                      -3-


                  (F) Apply any sums paid to any of Borrower's Indebtedness,
with such payments being applied in such priority or with such preferences as
Lender may determine in its sole discretion, regardless of what Indebtedness of
Borrower remains unpaid;

                  (G) Take or accept any other security for any or all of
Borrower's Indebtedness; and/or

                  (H) Enter into, deliver, modify, amend or waive compliance
with, any instrument or arrangement (other than this Agreement) evidencing,
securing or otherwise affecting, all or any part of Borrower's Indebtedness.

                  In addition, no course of dealing between Lender and Borrower
(or any other guarantor, surety or endorser of Borrower's Indebtedness), nor any
failure or delay on the part of Lender to exercise any of Lender's rights and
remedies, or any other agreement or agreements by and between Lender and
Borrower (or any other guarantor, surety or endorser) shall have the affect of
impairing or releasing Guarantor's obligations and liabilities to Lender or of
waiving any of Lender's rights and remedies. Any partial exercise of any rights
and remedies granted to Lender shall furthermore not constitute a waiver of any
of Lender's other rights and remedies, it being Guarantor's intent and agreement
that Lender's rights and remedies shall be cumulative in nature. Guarantor
further agrees that, should Borrower default under any of its Indebtedness, any
waiver or forbearance on the part of Lender to pursue the rights and remedies
available to Lender shall be binding upon Lender only to the extent that Lender
specifically agree to such waiver or forbearance in writing. A waiver or
forbearance on the part of Lender as to one event of default shall not
constitute a waiver of forbearance as to any other default.

         SECTION 8. NO RELEASE OF GUARANTOR. Guarantor's obligations and
liabilities under this Agreement shall not be released, impaired, reduced or
otherwise affected by, and shall continue in full force and effect,
notwithstanding the occurrence of any event (other than performance hereunder),
including without limitation any one of the following events:

                  (A) Insolvency, bankruptcy, arrangement, adjustment,
composition, liquidation, disability, dissolution or lack of authority (whether
corporate, partnership or trust) of Borrower (or any person acting on Borrower's
behalf), or any other guarantor, surety or endorser of any of Borrower's
Indebtedness;

                  (B) Partial payment or payments of any amount due and/or
outstanding under any of Borrower's Indebtedness;

                  (C) Any payment of Borrower or any other party to Lender is
held to constitute a preferential transfer or a fraudulent conveyance under any
applicable law, or for any reason, Lender is required to refund such payment or
pay such amount to Borrower or to any other person;

                  (D) Any dissolution of Borrower or any sale, lease or transfer
of all or any part of Borrower's assets; and/or



                                      -4-


                  (E) Any failure of Lender to notify Guarantor of the
acceptance of this Agreement or of the making of loans or other extensions of
credit in reliance on this Agreement or of the failure of Borrower to make any
payment due by Borrower to Lender.

                  (F) Apply any sums paid to any of Borrower's Indebtedness,
with such payments being applied in such priority or with such preferences as
Lender may determine in its own discretion, regardless of what Indebtedness of
Borrower remains unpaid;

                  (G) Take or accept any other security for any or all of
Borrower's Indebtedness; and/or

                  (H) Enter into, deliver, modify, amend or waive compliance
with, any instrument or arrangement evidencing, securing or otherwise affecting,
all or any part of Borrower's Indebtedness.

                  This Agreement and Guarantor's obligations and liabilities
hereunder shall continue to be effective, and/or shall automatically and
retroactively be reinstated if a release or discharge has occurred, as the case
may be, if at any time any payment or part thereof to Lender with respect to any
of Borrower's Indebtedness is rescinded or must otherwise be restored by Lender
pursuant to any insolvency, bankruptcy, reorganization, receivership, or any
other debt relief granted to Borrower or to any other party. In the event that
Lender must rescind or restore any payment received by Lender in satisfaction of
Borrower's Indebtedness, any prior release or discharge from the terms of this
Agreement given to Guarantor shall be without effect, and this Agreement and
Guarantor's obligations and liabilities hereunder shall automatically be renewed
or reinstated and shall remain in full force and effect to the same degree and
extent as if such a release or discharge was never granted. It is the intention
of Lender and Guarantor that Guarantor's obligations and liabilities hereunder
shall not be discharged except by Guarantor's full and complete performance of
such obligations and liabilities and then only to the extent of such
performance.

         SECTION 9. ENFORCEMENT OF GUARANTOR'S OBLIGATIONS AND LIABILITIES.
Guarantor agrees that, should Lender deem it necessary to file an appropriate
collection action to enforce Guarantor's obligations and liabilities under this
Agreement, Lender may commence such a civil action against Guarantor without the
necessity of first (i) attempting to collect Borrower's Indebtedness from
Borrower or from any other guarantor, surety or endorser, whether through filing
of suit or otherwise, (ii) attempting to exercise against any collateral
directly or indirectly securing repayment of any of Borrower's Indebtedness,
whether through the filing of an appropriate foreclosure action or otherwise, or
(iii) including Borrower or any other guarantor, surety or endorser of any of
Borrower's Indebtedness as an additional party defendant in such a collection
action against Guarantor. If there is more than one guarantor under this
Agreement, each guarantor additionally agrees that Lender may file an
appropriate collection and/or enforcement action against any one or more of
them, without impairing the rights of Lender against any other guarantor under
this Agreement. In the event that Lender should ever deem it necessary to refer
this Agreement to an attorney-at-law for the purpose of enforcing Guarantor
obligations and liabilities hereunder, or of protecting or preserving Lender's
rights hereunder, Guarantor (and each of them, on a joint, several and solidary
basis) agrees to



                                      -5-


reimburse Lender for the reasonable fees of such an attorney. Guarantor
additionally agrees that Lender shall not be liable for failure to use diligence
in the collection of any of Borrower's Indebtedness or any collateral security
therefor, or in creating or preserving the liability of any person liable on any
such Indebtedness, or in creating, perfecting or preserving any security for any
such Indebtedness.

         SECTION 10. ADDITIONAL DOCUMENTS. Upon the reasonable request of
Lender, Guarantor will, at any time, and from time to time, duly execute and
deliver to Lender any and all such further instruments and documents, and supply
such additional information as may be reasonably necessary or advisable in the
opinion of Lender, to obtain the full benefits of this Agreement.

         SECTION 11. TRANSFER OF INDEBTEDNESS. This agreement is for the benefit
of Lender and for such other person or persons as may from time to time become
or be the holders of any of Borrower's Indebtedness hereby guaranteed and this
Agreement shall be transferable and negotiable, with the same force and effect
and to the same extent as Borrower's Indebtedness may be transferable under the
Credit Agreement, it being understood that, upon the transfer or assignment by
Lender of any of Borrower's Indebtedness hereby guaranteed, the legal holder of
such Indebtedness shall have all the rights granted to Lender under this
Agreement.

                  Guarantor hereby recognizes and agrees that Lender may, from
time to time, one or more times, transfer all or any portion of Borrower's
Indebtedness to one or more third parties. Such transfers may include, but are
not limited to, sales of a participation or syndication interest in such
Indebtedness in favor of one or more third parties in accordance with the Credit
Agreement. Guarantor specifically agrees and consents to all such transfers and
assignments in accordance with the Credit Agreement and Guarantor further waives
any subsequent notice of and right to consent to any such transfers and
assignments as may be provided under applicable Louisiana law. Guarantor
additionally agrees that the purchaser of a syndication interest in Borrower's
Indebtedness will be considered as the absolute owner of an interest in, or a
percentage interest of, such Indebtedness and that such a purchaser shall have
all of the rights granted to the purchaser under any agreement governing the
sale of such a syndication interest and all rights of Lender from whom the
syndication interest was purchased under the Credit Agreement. Guarantor further
waives any right of offset that Guarantor may have against Lender and/or any
purchaser of such a participation or syndication interest in Borrower's
Indebtedness and Guarantor unconditionally agrees that either Lender or such a
purchaser may enforce Guarantor's obligations and liabilities under this
Agreement, irrespective of the failure or insolvency of Lender or any such
purchaser. Guarantor further agrees that, upon any transfer, in accordance with
the Credit Agreement, of all or any portion of Borrower's Indebtedness, Lender
may transfer and deliver any and all collateral securing repayment of such
Indebtedness including, but not limited to, any collateral provided by
Guarantor) to the transferee of such Indebtedness and such collateral (again,
including but not limited to Guarantor's collateral) shall secure any and all of
Borrower's Indebtedness in favor of such transferee. Guarantor additionally
agrees that, after any such transfer or assignment has taken place in accordance
with of the Credit Agreement, Lender shall be fully discharged from any and all
liability and responsibility to Borrower (and Guarantor) with respect to such
collateral, and the transferee thereafter shall be vested with all the powers
and rights with respect to such collateral.



                                      -6-