EXHIBIT 10.2

                               COMMERCIAL GUARANTY



          COMMERCIAL  GUARANTY  (this  "Agreement")  made and entered into as of
September 30, 2004 by CCBM, Inc., a Delaware corporation  (hereinafter  referred
to as  "Guarantor"),  in favor of Hibernia  National  Bank,  a national  banking
association,  as Agent for itself and each of the  financial  institutions  (the
"Lenders")  which  now or  hereafter  become  a  party  to that  certain  Credit
Agreement (as defined below), guarantying the Indebtedness (as defined below) 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 Second Amended and Restated  Credit  Agreement
dated of even date herewith,  by and among Borrower,  Guarantor,  the Agent, and
Lenders,  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 certain Notes dated of even date herewith, in the maximum aggregate
principal amount of $100,000,000.00, executed by Borrower pursuant to the Credit
Agreement, and any and all renewals,  extensions,  substitutions,  modifications
and replacements of said Notes 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 ONE HUNDRED
MILLION AND NO/100 DOLLARS (U.S. $100,000,000.00), 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  Agent  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,  Agent'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
Agent and/or Lenders 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,  Agent,  and Lenders,  shall in any way obligate,  or be construed to
obligate,  Agent  and/or  Lenders  to agree  to the  subsequent  termination  or
cancellation  of Guarantor's  obligations and  liabilities  hereunder,  it being
fully  understood and agreed by Guarantor that Agent and/or Lenders 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 Agent 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 Agent 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.



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          SECTION 6.  GUARANTOR'S  SUBORDINATION  OF RIGHTS TO  LENDERS.  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 Agent and/or Lenders 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 Lenders or  otherwise,  shall in all  respects  be
subordinate,  inferior and junior to Agent's and/or  Lenders'  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 Agent's
and/or  Lenders'  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 Lenders is
fully paid and satisfied, in principal, interest, costs and attorneys' fees.

          SECTION 7. ADDITIONAL  COVENANTS.  Guarantor further agrees that Agent
and/or  Lenders may, at its/their  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
Agent and/or Lenders 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 Agent
and/or Lenders 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 Agent's and/or  Lenders'  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;



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               (F) Apply any sums paid to any of Borrower's  Indebtedness,  with
such payments  being applied in such priority or with such  preferences as Agent
and/or  Lenders may determine in its/their 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  Agent and  Borrower,
and/or the Lenders and Borrower (or any other  guarantor,  surety or endorser of
Borrower's  Indebtedness),  nor any failure or delay on the part of Agent and/or
Lenders to exercise any of its/their rights and remedies, or any other agreement
or agreements by and between Agent and Borrower  and/or Lenders and Borrower (or
any other  guarantor,  surety or endorser) shall have the affect of impairing or
releasing  Guarantor's  obligations  and  liabilities to Agent and Lenders or of
waiving any of Agent's and/or Lenders' rights and remedies. Any partial exercise
of any rights and remedies granted to Agent and/or Lenders shall furthermore not
constitute a waiver of any of Agent's and/or Lenders' other rights and remedies,
it being  Guarantor's  intent and agreement that Agent's and Lenders' 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 Agent  and/or  Lenders to pursue the rights and  remedies  available  to
Agent shall be binding  upon Agent and Lenders  only to the extent that  Lenders
specifically  agree to such  waiver  or  forbearance  in  writing.  A waiver  or
forbearance on the part of Agent and/or Lenders 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 Agent is held
to  constitute  a  preferential  transfer or a fraudulent  conveyance  under any
applicable  law, or for any reason,  Agent and/or Lenders are required to refund
such payment or pay such amount to Borrower or to any other person;



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

               (E) Any failure of Agent 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 Agent.

               (F) Apply any sums paid to any of Borrower's  Indebtedness,  with
such payments  being applied in such priority or with such  preferences as Agent
and/or  Lenders may  determine in its/their 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 Agent with respect to any
of Borrower's  Indebtedness  is rescinded or must otherwise be restored by Agent
and/or  Lenders   pursuant  to  any  insolvency,   bankruptcy,   reorganization,
receivership,  or any other  debt  relief  granted to  Borrower  or to any other
party.  In the event that  Agent  and/or  Lenders  must  rescind or restore  any
payment   received  by  Agent  and/or  Lenders  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 Agent,  Lenders 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 Agent and/or Lenders deem it necessary to file an
appropriate collection action to enforce Guarantor's obligations and liabilities
under this Agreement,  Agent 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.  In the event that Agent 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
Agent's and/or


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Lenders' rights  hereunder,  Guarantor (on a joint,  several and solidary basis)
agrees to reimburse  Agent  and/or  Lenders for the  reasonable  fees of such an
attorney.  Guarantor  additionally agrees that Agent and/or Lenders 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
Agent,  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 Agent, to obtain the full benefits of this Agreement.

          SECTION  11.  TRANSFER  OF  INDEBTEDNESS.  This  agreement  is for the
benefit of Lenders 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 Sections 16.7, 16.8, and 16.9 of the Credit Agreement, it being understood
that,  upon  the  transfer  or  assignment  by  Lenders  of  any  of  Borrower's
Indebtedness hereby guaranteed, the legal holder of such Indebtedness shall have
all the rights granted to Lenders under this Agreement.

          Guarantor hereby  recognizes and agrees that Lenders 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 Sections 16.7 and/or 16.8
of the Credit Agreement.  Guarantor specifically agrees and consents to all such
transfers and assignments in accordance with Sections 16.7, 16.8, and/or 16.9 of
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 Lenders from whom the  syndication  interest was  purchased  under the
Credit  Agreement.  Guarantor  further waives any right of offset that Guarantor
may have  against  Lenders  and/or  any  purchaser  of such a  participation  or
syndication  interest in Borrower's  Indebtedness and Guarantor  unconditionally
agrees  that  either  Lenders  or  such  a  purchaser  may  enforce  Guarantor's
obligations and liabilities under this Agreement, irrespective of the failure or
insolvency of Lenders or any such purchaser. Guarantor further agrees that, upon
any transfer, in accordance with Sections 16.7 and 16.9 of the Credit Agreement,
of all or any  portion of  Borrower's  Indebtedness,  Lenders 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
Sections 16.7. 16.8, and/or



                                       6


16.9 of the Credit Agreement, Lenders 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.

          SECTION 12. RIGHT OF OFFSET. As collateral  security for the repayment
of Guarantor's  obligations  and  liabilities  under this  Agreement,  Guarantor
hereby grants  Lenders,  as well as their  successors and assigns,  the right to
apply, upon the occurrence of an Event of Default under the Credit Agreement and
the  expiration  of any  applicable  grace  period  allowed to cure the Event of
Default,  any and all funds that  Guarantor  may then have on deposit with or in
the  possession or control of any Lender and its successors or assigns (with the
exception  of funds  deposited  in IRA,  pension or other  tax-deferred  deposit
accounts),  towards repayment of any of Borrower's  Indebtedness subject to this
Agreement.

          SECTION 13. CONSTRUCTION. The provisions of this Agreement shall be in
addition to and  cumulative of, and not in  substitution,  novation or discharge
of,  any and all  prior  or  contemporaneous  guaranty  or other  agreements  by
Guarantor,  in favor of Agent or assigned to Agent by others, all of which shall
be construed as complementing each other. Nothing herein contained shall prevent
Agent from  enforcing  any and all such  guaranties  or agreements in accordance
with their respective terms.

          SECTION 14. AMENDMENT. No amendment,  modification,  consent or waiver
of any provision of this Agreement, and no consent to any departure by Guarantor
therefrom,  shall be effective unless the same shall be in writing signed by the
Agent,  and then shall be effective  only to the  specific  instance and for the
specific purpose for which given.

          SECTION 15. SUCCESSORS AND ASSIGNS BOUND.  Guarantor's obligations and
liabilities  under this Agreement shall be binding upon Guarantor's  successors,
heirs, legatees,  devisees,  administrator executors and assigns. The rights and
remedies  granted to Agent and Lenders under this Agreement  shall also inure to
the benefit of Agent's and Lenders'  successors  and assigns,  as well as to any
and all subsequent holder or holders of any of Borrower's  Indebtedness  subject
to this Agreement.

          SECTION 16. CAPTION  HEADING.  Caption headings of the section of this
Agreement are for convenience  purposes only and are not to be used to interpret
or to define  their  provisions.  In this  Agreement,  whenever  the  context so
requires,  the  singular  includes  the plural and the plural also  includes the
singular.

          SECTION 17.  GOVERNING  LAW.  THIS  AGREEMENT  SHALL BE  GOVERNED  AND
CONSTRUED IN ACCORDANCE WITH THE SUBSTANTIVE LAWS OF THE STATE OF LOUISIANA.

          SECTION 18.  SEVERABILITY.  If any provision of this Agreement is held
to be illegal,  invalid or unenforceable  under present or future laws effective
during the term hereof; such provision shall be fully severable,  this Agreement
shall be construed and enforceable as if the illegal,  invalid or  unenforceable
provision had never comprised a part of it, and the remaining provisions of this
Agreement shall remain in full force and effect and shall not be affected by the



                                       7


illegal,  invalid  or  unenforceable  provision  or by its  severance  herefrom.
Furthermore,  in lieu of such illegal, invalid or unenforceable provision, there
shall be added automatically as a part of this Agreement, a provision as similar
in terms to such illegal,  invalid or unenforceable provision as may be possible
and legal, valid and enforceable.

          IN WITNESS WHEREOF,  Guarantor has executed this Agreement in favor of
Agent for the ratable benefit of the Lenders on the day,  month,  and year first
written above.

                                            GUARANTOR:
                                            CCBM, INC.
                                            a Delaware corporation

                                            By:
                                            Name:
                                            Title: