Document:

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                                                                      EXHIBIT 10

                              SEPARATION AGREEMENT

         THIS SEPARATION AGREEMENT (this "Agreement") is entered into by and
between RELIANT ENERGY, INCORPORATED, a Texas corporation (said corporation,
together with its successors and assigns permitted under this Agreement,
hereinafter referred to as the "Company"), and LEE W. HOGAN ("Executive"), this
28th day of July, 2000.

                                   WITNESSETH:

         WHEREAS, effective as of July 28, 2000, the Executive shall terminate
employment with the Company; and

         WHEREAS, the Company and Executive desire to confirm and clarify their
agreements regarding the termination of Executive's employment, as well as to
provide for certain additional matters set forth herein;

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
herein contained, the parties hereto agree to the following:

1.   CERTAIN DEFINITIONS

         "AICP" shall mean the Company's Annual Incentive Compensation Plan, as
in effect from time to time, or any similar successor plan adopted by the
Company.

         "ANNUAL BASE SALARY" shall mean Executive's current annual base salary
of $550,000.

         "BOARD" shall mean the Board of Directors of the Company.

         "DATE OF TERMINATION" shall mean July 28, 2000.

         "DEFERRED COMPENSATION PLAN" shall mean each of the Deferred
Compensation Plan (amended and restated effective January 1, 1991), the Deferred
Compensation Plan (amended and restated effective January 1, 1989) and the
Deferred Compensation Plan (amended and restated effective September 1, 1985),
each of which is sponsored by the Company, as in effect from time to time.

         "LICP" shall mean the Company's Long-Term Incentive Compensation Plan,
as in effect from time to time, or any similar successor plan adopted by the
Company.

         "RELEASE DATE" shall mean the date that is seven (7) days after
Executive's execution and delivery of the Waiver and Release as described in
Section 5, provided that the Executive has not revoked the Waiver and Release
before such time.

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         "RETIREMENT PLAN" shall mean the Reliant Energy, Incorporated
Retirement Plan.

         "SERP" shall mean the Benefit Restoration Plan of the Company.

         "STOCK" shall mean the Common Stock, without par value, of the Company.

         "SUPPLEMENTAL PENSION AGREEMENT" shall mean the letter agreement
between the Company and Executive dated July 17, 1996 setting forth certain
agreements regarding supplemental pension payments by the Company.

2.   TERMINATION OF EMPLOYMENT. Executive's employment with the Company shall
terminate on the Date of Termination. Through the Date of Termination, the
Company shall pay to Executive all accrued and unpaid Annual Base Salary in
accordance with the Company's normal payroll procedures.

3.   PAYMENTS AND BENEFITS UPON TERMINATION. In exchange for the Executive's
execution of a Waiver and Release as provided in Section 5 and performance of
the post-employment obligations set forth in Section 4, the Company shall pay or
provide the following amounts and benefits, as described below.

         A. As a severance payment, the Company shall pay to the Executive a
lump sum cash payment of $4,042,547, which is determined by the following
formula:

                  (i)   Three (3) times the Executive's Annual Base Salary, or
         $1,650,000, plus

                  (ii)  Three (3) times the Executive's target incentive
         opportunity under the AICP, or $1,155,000 (this amount is in addition
         to the payment described in Section 3.D. below), plus

                  (iii) A cash amount equal to the total target amount (a dollar
         amount based upon a percentage of the Executive's Annual Base Salary)
         granted to Executive as a Restricted Stock Award or Option under the
         LICP, or $1,237,547.

         The lump-sum severance payment pursuant to this Section 3.A. shall be
         made within 15 business days after the Release Date.

         B. Outstanding Restricted Stock Awards (as defined in the LICP) under
the LICP shall be treated in accordance with the terms of the LICP. Accordingly,
any Restricted Stock Award for the 2000-2002 Performance Cycle, as defined in
the LICP, will be forfeited, as the Executive's termination will occur in the
first year of this Performance Cycle. With respect to Restricted Stock Awards
for the 1998-2000 Performance Cycle and 1999-2001 Performance Cycle, the
Committee, as defined in the LICP, will make a determination as to the extent
that the performance goals for the relevant performance cycles are expected to
have been met. As soon as practicable after December 31, 2000, the Executive
shall be delivered a number of shares of

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Stock based on the Committee's determination and prorated based on the number of
days that have elapsed in each Performance Cycle as of the Date of Termination.

         C. Executive's outstanding Options (as defined in the LICP) under the
LICP shall be treated in accordance with the terms of the LICP. Accordingly, to
the extent Executive is vested in his existing Options, the Options shall remain
exercisable until the date that is three (3) years (or one (1) year, whichever
is applicable under the governing agreement and/or plan for the particular
Option) following the Date of Termination.

         D. For the year 2000, Executive shall receive a payment under the AICP
in an amount which is Executive's target award prorated based on the amount of
his Compensation (as defined in the AICP) earned in the year 2000 prior to the
Date of Termination. The payment pursuant to this Section 3.D. shall be made at
the same time as the severance payment made pursuant to Section 3.A.

         E. Executive's benefits under the Retirement Plan and SERP will
commence on the date, and in the amount(s), determined by the terms of such
plans. In addition, the Supplemental Pension Agreement shall be amended and
superceded, such that Executive or, in the event of his death, his beneficiary
under the Retirement Plan, shall be paid a supplemental pension determined in
the same manner as the pension payable under the Retirement Plan, but as if
Executive had achieved 30 years of service for all purposes under the Retirement
Plan and attained age 60 as of the Date of Termination; provided, however, that
should Executive elect to receive payments under the Retirement Plan prior to
attaining age 60, the supplemental pension will be reduced in the same manner as
provided in the Retirement Plan for an early pension that commences prior to age
60. Executive shall not be considered or treated as having achieved such age and
service credit for any other purpose. The supplemental pension shall be reduced
by any benefit actually received by Executive under the Retirement Plan or SERP.
The supplemental pension shall commence at the same time and in the same form as
Executive's benefits under the Retirement Plan and SERP. For pension purposes,
the severance payment pursuant to Section 3.A. shall not be included in
Executive's compensation. The amounts of the supplemental pension payments made
pursuant to this Section 3.E. (when added to the amounts payable under the
Retirement Plan and SERP) shall not be less than the amounts specified for the
applicable payment options and annuity starting dates specified on the attached
Schedule 3.E.

         F. Without further action on his part (other than completion of
necessary enrollment forms), upon the Date of Termination, Executive shall be
treated as a retiree and Executive shall be eligible for retiree coverage under
Company group insurance plans including, without limitation, medical,
prescription, dental, group life, accidental death and travel accident insurance
plans and programs to the extent applicable generally to other similarly
situated senior executives of the Company, if coverage is available under the
terms of such insurance plans, and such coverage shall be subject to all terms
and conditions of such plans and policies, including the Company's right to
amend or terminate such plans or policies at any time. Executive shall bear the
expense of any such coverage on the same basis as other retirees eligible for
welfare continuation coverage from the Company.

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         G. Executive's payments pursuant to the Deferred Compensation Plan
shall commence as of the date, and in the amount(s), determined by the terms of
such plan.

         H. Following the Date of Termination, Executive shall continue to
participate in the Company's Executive Life Insurance Plan on the same basis as
he participates in such plan as of the Date of Termination.

         I. As soon as practicable after the Date of Termination, the Company
will reimburse Executive for business expenses which were incurred before the
Date of Termination in the ordinary course of his duties with the Company and
which are reimbursable under the Company's normal reimbursement policies and
procedures. In addition, the Company shall transfer to Executive the laptop
computer and Palm Pilot personal digital assistant currently used by Executive
in the course of his duties, along with the software (and accompanying licenses)
currently installed on such devices; provided, however, that (i) the Company
shall be under no obligation to transfer to Executive network-based software or
data that is merely accessed by Executive via his laptop or personal digital
assistant and not locally installed on such devices and (ii) Executive shall
submit his laptop computer and Palm Pilot for review by qualified Company
personnel. Following review pursuant to subparagraph (ii) above, material
contained on the hard drive of his laptop computer or resident in the Palm
Pilot's memory that is deemed by the Company to be Confidential Information
shall be wiped from memory. However, the Palm Pilot datebook and address data
shall be exempted from this process and Executive shall be permitted to retain
such software and data.

         J. Within 60 days after the Date of Termination, the Company will
reimburse Executive's legal and accounting fees and expenses incurred in the
review and negotiation of this Agreement. The Company's reimbursement obligation
will not extend to any disputes arising under this Agreement following
execution, except to the extent set forth in Section 9.E.

         K. Executive shall be entitled to receive the benefits to which he is
otherwise entitled pursuant to the terms of any employee benefit plan of the
Company or its affiliates based upon his service with the Company through the
Date of Termination.

         L. In lieu of providing Executive with office space, the Company will
pay to Executive a lump sum of $70,000 as an allowance for office space for two
years. In addition, the Company agrees to continue to provide at its sole
expenses the services of Executive's current assistant full-time until the
earlier of (a) Executive accepting an offer of employment or (b) the second
anniversary of the Date of Termination. If Executive's current assistant is
unwilling to fill this position, the Company will pay to Executive a lump sum of
$130,000.

4.   POST-EMPLOYMENT OBLIGATIONS:

         A. The Company has provided Executive with Confidential Information
regarding the Company and the Company's business and has agreed to make certain
payments pursuant to Section 3 hereof. In return for this and the other
consideration provided under this Agreement, Executive agrees that he will not
disclose or make available to any other person or entity, or use for his own
personal gain, any Confidential Information, except for such disclosures as
required

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(i) by law or legal process, (ii) in the performance of Executive's obligations
hereunder, (iii) in connection with the enforcement of Executive's rights under
this Agreement, or (iv) in connection with the defense or settlement of any
claim, suit or action brought against Executive by the Company. For purposes of
this Agreement, "Confidential Information" shall mean any and all information,
data and knowledge that has been created, discovered, developed or otherwise
become known to the Company or in which property rights have been assigned or
otherwise conveyed to the Company, which information, data or knowledge has
commercial value in the business in which the Company is engaged, except such
information, data or knowledge as is or becomes known to the public without
violation of the terms of this Agreement. By way of illustration, but not
limitation, Confidential Information includes business trade secrets, secrets
concerning the Company's plans and strategies, nonpublic information concerning
material market opportunities, technical trade secrets, processes, formulas,
know-how, improvements, discoveries, developments, designs, inventions,
techniques, marketing plans, manuals, records of research, reports, memoranda,
computer software, strategies, forecasts, new products, unpublished financial
statements or parts thereof, budgets or other financial information,
projections, licenses, prices, costs, and employee, customer information,
customer lists and supplier lists or parts thereof.

         B. Executive agrees that as of the Date of Termination he will deliver
to the Company (and will not keep in his possession, recreate or deliver to
anyone else) all Confidential Information as well as all other devices, records,
data, notes, reports, proposals, lists, correspondence, specifications,
drawings, blueprints, sketches, materials, equipment (except as specifically set
forth in Section 3.I.), customer or client lists or information, or any other
documents or property (including all reproductions of the aforementioned items)
belonging to the Company, regardless of whether such items were prepared by
Executive.

         C. Executive acknowledges that a significant portion of the Company's
business is conducted in the counties located (or partially located) within a
100-mile radius of the Greater Houston, Texas area (such counties are herein
referred to as the "Business Area"). Executive further acknowledges that the
skills, processes and Confidential Information developed at the Company could be
utilized to the Company's detriment with any other business in the Business Area
involved in the power generation, wholesale or retail business (a "Competitive
Product"). Accordingly, for consideration provided to Executive pursuant to this
Agreement, Executive agrees to be bound by the following restrictive covenants:

                  1. For a period of one (1) year after the Date of Termination,
         Executive shall not, acting alone or in conjunction with others,
         directly or indirectly, invest or engage, directly or indirectly, in
         any business in the Business Area involved in researching, developing,
         or marketing a Competitive Product or accept employment with or render
         services to such a business as a director, officer, agent, employee,
         independent contractor or consultant, or take any action inconsistent
         with the fiduciary relationship of an employee to his employer;
         provided, however, that the beneficial ownership by Executive of up to
         5% of the voting stock of any corporation subject to the periodic
         reporting requirements of the Securities Exchange Act of 1934 shall not
         violate this Section 4.C.

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                  2. Executive acknowledges that these restrictive covenants
         under this Section 4, for which he received consideration from the
         Company as provided in this Section 4, are ancillary to otherwise
         enforceable provisions of this Agreement and that these restrictive
         covenants contain limitations as to time, geographical area, and scope
         of activity to be restrained that are reasonable and do not impose a
         greater restraint than is necessary to protect the goodwill or other
         business interests of the Company, such as the Company's need to
         protect its Confidential Information. Executive acknowledges that in
         the event of a breach by Executive of these restrictive covenants,
         money damages will not be a sufficient remedy, and the covenants may be
         enforced by temporary restraining order, preliminary or temporary
         injunction, and permanent injunction. In that connection, Executive
         acknowledges that, in the event of a breach, the Company will suffer
         irreparable injury for which there is no adequate legal remedy, in part
         because damages caused by the breach may be difficult to prove with any
         reasonable degree of certainty.

                  3. Notwithstanding any provision of this Agreement to the
         contrary, for purposes of the obligations of this Section 4, "Company"
         means the Company or an Affiliate or any successor to the Company or an
         Affiliate and "employment" means employment as an employee with the
         Company, any Affiliate or any such successor. For purposes of this
         Agreement, the term "Affiliate" means (i) any corporation or other
         entity in which the shares or other measure of ownership owned or
         controlled directly or indirectly by the Company shall represent 40% or
         more of the voting power of the issued and outstanding stock or other
         measure of ownership of such corporation or entity and (ii) any other
         company or organization controlled by, controlling or under common
         control with the Company within the meaning of Section 414 of the
         Internal Revenue Code of 1986, as amended.

         D. As a material inducement to the Company to enter into this
Agreement, Executive agrees that he will not (i) publicly criticize or disparage
the Company or any Related Party, or privately criticize or disparage the
Company or any Related Party in a manner intended or reasonably calculated to
result in public embarrassment to, or injury to the reputation of, the Company
or any Related Party in any community in which the Company or any Related Party
is engaged in business; (ii) commit damage to the property of the Company or any
Related Party or otherwise engage in any misconduct which is injurious to the
business or reputation of the Company or any Related Party; or (iii) take any
other action, or assist any person in taking any other action, that is
materially adverse to the interests of the Company or any Related Party or
inconsistent with fostering the goodwill of the Company or any Related Party. As
used in this section, the term "Related Party" means the Company, any
subsidiary, Affiliate or successor to the Company or any Affiliate, any officer,
director or executive of the Company or any subsidiary, and any former officer,
director or executive of the Company or any subsidiary.

         E. As a material inducement to Executive to enter into this Agreement,
the Company agrees that it will not publicly criticize or disparage Executive or
privately criticize or disparage Executive in a manner intended or reasonably
calculated to result in public embarrassment to, or

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injury to the reputation of, Executive in any community in which Executive is
employed or conducts business.

         F. Executive agrees that for a period of one year after the Date of
Termination, Executive will furnish such information and proper assistance as
may be reasonably necessary in connection with any business of the Company or an
Affiliate or any litigation in which the Company or any Affiliate is then or may
become involved. If called upon to furnish such assistance, the Company will
promptly pay or reimburse Executive for any expenses incurred in providing any
such information or assistance, including, but not limited to, his travel and
legal expenses, and will pay all costs of Executive's legal representation
should his provision of such information or assistance cause him to be named as
a party litigant, to be served with subpoenas or other legal process, or
otherwise cause him to become entangled in Company litigation.

         G. If it is determined by a court of competent jurisdiction in Texas
that any restriction in this Section 4 is excessive in duration or scope or is
unreasonable or unenforceable under the laws of Texas, it is the intention of
the parties that such restriction may be modified or amended by the court to
render it enforceable to the maximum extent permitted by the laws of Texas.

         H. The Company does not currently intend to issue a press release
regarding the circumstances of Executive's termination, and agrees that it will
not issue such a press release without Executive's approval and consent to the
contents of such release.

         I. The Company agrees to indemnify Executive for any claims, including
associated legal fees and expenses, that may be asserted against Executive
account of Executive's good-faith execution of his employment with the Company,
but only to the extent that Executive was indemnified by the Company against
such claims during his employment with the Company. The Company shall provide
for a period of 6 years continued coverage to Executive under the Company's
officers and directors liability insurance policies relating to the period
during which Executive was a director and/or officer as is maintained for others
who were directors and officers during such period or continue to be directors
and officers.

         J. The Company and Executive agree and acknowledge that the separation
covered by this Agreement is not in connection with or in anticipation of a
change of control of the Company. Notwithstanding the foregoing, in the event
that any payment, benefit or distribution by the Company to or for the benefit
of the Executive as provided in this Agreement ("Payments") would be subject to
the excise tax imposed by Section 4999 of the Internal Revenue Code of 1986, as
amended, or any interest or penalties incurred by Executive in respect of such
excise tax, then the Executive shall be entitled to receive an additional gross
up amount such that after payment by Executive of all taxes (including any
interest or penalties imposed with respect to such taxes) imposed upon the gross
up payment, the Executive retains an amount of the gross up payment equal to the
excise tax imposed on the Payments.

5.   WAIVER AND RELEASE: As a condition precedent to the receipt of the benefits
under this Agreement, Executive shall execute a waiver and release of claims, in
substantially the form attached hereto as Exhibit A.

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6.   SUCCESSORS:

         A. This Agreement is personal to Executive and without the prior
written consent of the Company shall not be assignable by Executive otherwise
than by will or the laws of descent and distribution. This Agreement shall inure
to the benefit of and be enforceable by Executive's legal representatives.

         B. This Agreement shall inure to the benefit of and be binding upon the
Company and its successors and assigns.

         C. The Company will require any successor (whether direct or indirect,
by purchase, merger, consolidation or otherwise) to all or substantially all of
the business and/or assets of the Company to assume expressly and agree to
perform this Agreement in the same manner and to the same extent that the
Company would be required to perform it if no such succession had taken place.

7.   SOURCE OF PAYMENTS: All payments provided in this Agreement shall, unless
the plan or program pursuant to which they are made provides otherwise, be paid
in cash from the general funds of the Company, and no special or separate funds
shall be established and no other segregation of assets shall be made to assure
payment. Executive shall have no right, title or interest whatever in or to any
investments which the Company may make to aid the Company in meeting its
obligations hereunder. Nothing contained in this Agreement, and no action taken
pursuant to this provision, shall create or be construed to create a trust of
any kind, or a fiduciary relationship, between the Company and Executive or any
other person. To the extent that any person acquires a right to receive payments
from the Company hereunder, such right shall be no greater than the right of an
unsecured creditor of the Company.

8.   CONSOLIDATION, MERGER OR SALE OF ASSETS: Nothing in this Agreement shall
preclude the Company from consolidating or merging into or with, or transferring
all or substantially all of its assets to, another corporation which assumes
this Agreement and all obligations and undertakings of the Company hereunder;
provided that no such action shall diminish the Executive's rights hereunder.
Upon such a consolidation, merger or transfer of assets and assumption, the term
"Company" as used herein shall mean such other corporation.

9.   MISCELLANEOUS:

         A. This Agreement shall be governed by and construed in accordance with
the laws of the State of Texas, without reference to principles of conflict of
laws. Further, Executive agrees that any legal proceeding to enforce the
provisions of this Agreement shall be brought in Houston, Harris County, Texas,
and hereby waives his right to any pleas regarding subject matter or personal
jurisdiction and venue. The captions of this Agreement are not part of the
provisions hereof and shall have no force or effect. This Agreement may not be
amended or modified otherwise than by a written agreement executed by the
parties hereto or their respective successors and legal representatives.

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         B. All notices and other communications hereunder shall be in writing
and shall be given by hand delivery to the other party or by registered or
certified-mail, return receipt requested, postage prepaid, addressed as follows:

                 If to the Executive:  Lee W. Hogan
                                       5312 Bayou Glen
                                       Houston, Texas  77056

                 If to the Company:    Reliant Energy, Incorporated
                                       P.O. Box 4567
                                       Houston, Texas  77210

                                       ATTENTION:  Mr. Hugh Rice Kelly
                                                   Executive Vice President,
                                                   General Counsel and Secretary

or to such other address as either party shall have furnished to the other in
writing in accordance herewith. Notice and communications shall be effective
when actually received by the addressee.

         C. The invalidity or unenforceability of any provision of this
Agreement shall not affect the validity or enforceability of any other provision
of this Agreement.

         D. The Company may withhold from any amounts payable under this
Agreement such Federal, state or local taxes as shall be required to be withheld
pursuant to any applicable law or regulation.

         E. In the event that Executive makes a demand upon the Company for any
benefits or amounts due hereunder and the Company rejects such demand, and
Executive ultimately prevails in litigation resulting therefrom, the Company
shall reimburse Executive for reasonable attorney fees incurred by Executive in
enforcing rights to which Executive shall have become entitled pursuant to this
Agreement.

         F. Except as specifically contemplated by this Agreement, this
Agreement constitutes the entire agreement between the parties with respect to
the subject matter hereof and supersedes any and all prior written or oral
agreements, arrangements or understandings between the Company and Executive.

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         IN WITNESS WHEREOF, each of the parties hereto has hereunto set its
hand and has caused these presents to be executed in its name and on its behalf,
all on the day and year first above written, but effective as of the Date of
Termination.

                                    RELIANT ENERGY, INCORPORATED

                                    By  /s/ R. S. LETBETTER
                                      ------------------------------------------
                                       R. S. Letbetter, Chief Executive Officer

                                    EXECUTIVE

                                    /s/ LEE W. HOGAN
                                    --------------------------------------------
                                    Lee W. Hogan

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                                                                     EXHIBIT 4.2

                                 TENTH AMENDMENT
                                       TO
              FIRST AMENDED, RESTATED, AND COMBINED LOAN AGREEMENT
                              DATED AUGUST 28, 1997
                     BY AND BETWEEN CARRIZO OIL & GAS, INC.
                                AND COMPASS BANK

      This Tenth Amendment to the Loan Agreement (this "Tenth Amendment") by and
between CARRIZO OIL & GAS, INC., a Texas corporation (the "Borrower"), and
COMPASS BANK, an Alabama state chartered bank, formerly a Texas chartered bank
(the "Bank"), is entered into on this 3rd day of November 2000.

                             W I T N E S S E T H:

      Borrower and Bank entered into a First Amended, Restated, and Combined
Loan Agreement dated August 28, 1997, as amended by the First Amendment thereto
dated December 23, 1997, the Second Amendment thereto dated December 30, 1997,
the Third Amendment thereto dated July 30, 1998, the Fourth Amendment thereto
dated September 24, 1998, the Fifth Amendment thereto dated March 22, 1999, the
Sixth Amendment thereto dated April 23, 1999, the Seventh Amendment thereto
dated August 27, 1999, the Eighth Amendment thereto dated November 11, 1999 and
the Ninth Amendment thereto dated December 15, 1999 (collectively, the "Loan
Agreement").

      Borrower has requested that the Loan Agreement be further amended and that
Bank make available certain guidance line letters of credit under the Loan
Agreement, and Bank has agreed to such requests, subject to the terms and
conditions set forth in this Tenth Amendment.

      Capitalized terms used, but not defined herein, shall have the meanings
prescribed therefor in the Loan Agreement.

      NOW, THEREFORE, in consideration of the mutual promises herein contained,
and for other good and valuable consideration, the receipt and sufficiency of
which are acknowledged by Borrower and Bank, and each intending to be legally
bound hereby, the parties agree as follows:

1.    Specific Amendments to Loan Agreement.

      Article I, Definitions, is hereby amended by adding the following
definitions thereto:

            "Borrower's Hedge Obligations" means all obligations and liabilities
      of Borrower to third party counter-parties pursuant to Hedging
      Transactions.

            "Guidance Line LOC" means letters of credit to be issued by Bank for
      the account of Borrower pursuant to Section 2.26,
<PAGE>   2
      in the form acceptable to Bank, and all extensions, renewals and
      modifications thereof.

            "Tenth Amendment" means the Tenth Amendment to this Agreement
      executed by Borrower and Bank on November 3, 2000.

      Article I, Definitions, is hereby further amended by revising the
following definition in its entirety to read as follows:

            "Hedging Transaction" means any (i) interest rate or currency swap,
      rate cap, rate collar, forward agreement and other exchange or rate
      protection agreements or any option with respect to any such transaction
      and (ii) any swap agreement, cap, collar, floor, exchange transaction,
      forward agreement or exchange or protection agreement related to oil
      and/or gas or any option with respect to such transaction.

            "Obligations" means all obligations, indebtedness, and liabilities
      of Borrower to Bank, now existing or hereafter arising, including, but not
      limited to, the indebtedness evidenced by the Guidance Line LOCs and the
      Notes, whether direct, indirect, related, unrelated, fixed, contingent,
      specified, unspecified, joint, several, or joint and several, and all
      interest and fees accruing thereon and all attorneys' fees and other
      expenses incurred in the enforcement or collection thereof.

      Article I, Definitions, is hereby further amended by rewording the
definition of "Second Term Loan Note" to read "Second Term Note."

      Section 2.15 is hereby amended by revising the reference to the dollar
amount of "One Million Dollars ($1,000,000.00)" with the dollar amount of "Two
Million Dollars ($2,000,000.00)."

      Section 2.17 is hereby amended by revising that section in its entirety to
read as follows:

            2.17 Letter of Credit and Guidance Line LOC Fees. As consideration
      for the issuance by the Bank of Letters of Credit and Guidance Line LOCs
      for the account of Borrower, Borrower agrees to pay to the Bank a fee of
      one percent (1.0%), per annum, of the amount of each such Letter of Credit
      or Guidance Line LOC (subject to a $300.00 minimum fee per year on each
      such Letter of Credit and Guidance Line LOC), the first such per annum fee
      for each such Letter of Credit and Guidance Line LOC to be payable in
      advance of the issuance of such Letter of Credit and Guidance Line LOC,
      with successive per annum fees to be paid in advance of the anniversary
      date of the issuance of such Letter of Credit and Guidance Line LOC if it
      is to remain in effect beyond such anniversary date.

      Article II, The Loan, is hereby amended by adding the following sections
thereto:

            2.26 Guidance Line LOC. Subject to the terms and conditions of this
      Agreement, Bank may issue standby Guidance Line LOCs for the account of
      the Borrower from time to

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      time to cover Borrower's Hedge Obligations. If Borrower desires a Guidance
      Line LOC, Borrower shall submit a written request three (3) Business Days
      prior to the requested date of issuance in such amount as the Borrower
      may request in an aggregate amount of up to Two Million Dollars
      ($2,000,000.00). Bank will require in connection with the issuance of
      any Guidance Line LOC under this Section 2.26 that Borrower execute
      Bank's then-current form of application for a letter of credit, but if
      there is any conflict between the terms of any such application and the
      terms of this Agreement, the terms of this Agreement shall control. No
      Guidance Line LOC shall have an expiration date that is later than one
      year from the date of its issuance, or, if sooner, beyond the Maturity
      Date.

            2.27 Repayment of Guidance Line LOC. If drawn upon by the
      beneficiary of a Guidance Line LOC, all amounts so drawn shall be due and
      payable by the Borrower immediately upon receipt of Bank's statement
      therefor. If Borrower fails to pay such drawn amounts within one (1)
      Business Day of such receipt by Borrower, Bank shall have the right, but
      not the obligation, and Borrower hereby expressly authorizes Bank, to
      repay any amount drawn under a Guidance Line LOC as an advance under the
      Revolving Commitment; provided, however, that Bank's right to repay such
      Guidance Line LOC as an advance under the Revolving Commitment shall not
      be limited by any maximum limits applicable to Borrower and any Loan
      Excess resulting from the repayment by Bank of a Guidance Line LOC shall
      be subject to Section 2.09 hereof.

      Section 5.31, as added to the Loan Agreement by the Seventh Amendment, is
hereby amended by revising that section in its entirety to read as follows:

            5.31 Aged Accounts Reports. Deliver to Bank, on or before the
      forty-fifth (45th) day after the end of each calendar quarter, a detailed
      aging accounts receivable report and a detailed aging accounts payable
      report effective as of the end of such calendar quarter, all such reports
      to be prepared in accordance with GAAP.

      Section 5.35, as added to the Loan Agreement by the Seventh Amendment, is
hereby amended by revising that section in its entirety to read as follows:

      [This section is intentionally omitted.]

      Subsection 7.01(b) of the Loan Agreement is hereby amended by revising
that section in its entirety to read as follows:

            (b) Default shall be made by Borrower in the payment of any
      installment of interest on the Note, or any fees or other monetary
      obligation payable hereunder, including without limitation, under the
      Letters of Credit and Guidance Line LOCs, and such default shall remain
      unremedied in excess of three (3) days after notice being given by Bank,

                                       3
<PAGE>   4
2.    Amendments to Security Instruments. Borrower acknowledges that it has
executed various Security Instruments in favor of Bank, including, without
limitation, those Security Instruments described on Exhibit "A" attached to this
Tenth Amendment, to secure the obligations of Borrower to Bank. Borrower and
Bank hereby agree that any reference to the definitions of the "Obligations,"
"Indebtedness," or any other generic definition of Borrower's liabilities to
Bank in any such Security Instruments (whether such terms are capitalized or
not) shall be deemed to include the Obligations of Borrower, as defined in the
Loan Agreement, as hereby amended. Furthermore, Borrower and Bank hereby agree
that any reference to the definitions of the "Collateral" or "Mortgaged
Property" in the Security Instruments shall include all amounts owing Borrower
pursuant to any and all Hedging Transactions regardless of whether or not such
amounts owing to Borrower relate to, arise from or are in connection with the
"Collateral," "Property," "Leases," "Lands" or "Mortgaged Property" as such
terms are defined in the Security Instruments.

3.    Conditions Precedent in Connection with the Tenth Amendment.  The Tenth
Amendment shall not be binding on the Bank until satisfaction of the following
conditions precedent:

            (a) Receipt of Tenth Amendment and Compliance Certificate. Bank
      shall have received multiple fully executed counterparts of the Tenth
      Amendment, as requested by Bank, and the Compliance Certificate duly
      executed by an authorized officer for Borrower.

            (b) Accuracy of Representations and Warranties and No Event of
      Default. After giving effect to the Tenth Amendment, the representations
      and warranties contained in Article IV of the Loan Agreement shall be true
      and correct in all material respects on the date of the Tenth Amendment
      with the same effect as though such representations and warranties had
      been made on such date; and after giving effect to the Tenth Amendment, no
      Event of Default shall have occurred and be continuing or will have
      occurred upon the execution of the Tenth Amendment.

            (c) Legal Matters Satisfactory to Special Counsel to Bank. All legal
      matters incident to the consummation of the transactions contemplated by
      the Tenth Amendment shall be satisfactory to the firm of Porter & Hedges,
      L.L.P., special counsel for Bank.

                                       4
<PAGE>   5
            (d) Legal Fees. All reasonable legal fees and expenses owed by Bank
      to Porter & Hedges, L.L.P. in connection with the Loan Agreement shall
      have been paid by Borrower.

            (e) No Material Adverse Change. No material adverse change shall
      have occurred since the date of the Loan Agreement in the condition,
      financial or otherwise, of Borrower.

4.    Reaffirmation of Representations and Warranties. To induce Bank to enter
into this Tenth Amendment, Borrower hereby reaffirms, as of the date hereof,
after giving effect to the Tenth Amendment, its representations and warranties
contained in Article IV of the Loan Agreement and in all other documents
executed pursuant thereto, and additionally represents and warrants as follows:

            A. The execution and delivery of this Tenth Amendment and the
      performance by Borrower of its obligations under this Tenth Amendment are
      within Borrower's power, have been duly authorized by all necessary
      corporate action, have received all necessary governmental approval (if
      any shall be required), and do not and will not contravene or conflict
      with any provision of law or of the articles of incorporation, charter or
      bylaws of Borrower or of any agreement binding upon Borrower.

            B. The Loan Agreement as amended by this Tenth Amendment, represents
      the legal, valid and binding obligations of Borrower, enforceable against
      Borrower in accordance with its terms, subject as to enforcement only to
      bankruptcy, insolvency, reorganization, moratorium or other similar laws
      affecting the enforcement of creditors' rights generally.

            C. No Event of Default or Unmatured Event of Default has occurred
      and is continuing as of the date hereof.

5.    Defined Terms. Except as amended hereby, terms used herein that are
defined in the Loan Agreement shall have the same meanings in this Tenth
Amendment.

6.    Reaffirmation of Loan Agreement. This Tenth Amendment shall be deemed to
be an amendment to the Loan Agreement, and the Loan Agreement, as further
amended hereby, is hereby ratified, approved and confirmed in each and every
respect. All references to the Loan Agreement herein and in any other document,
instrument, agreement or writing shall hereafter be deemed to refer to the Loan
Agreement as amended hereby.

                                       5
<PAGE>   6
7.    Entire Agreement. The Loan Agreement, as hereby further amended,
embodies the entire agreement between Borrower and Bank and supersedes all prior
proposals, agreements and understandings relating to the subject matter hereof.
Borrower certifies that it is relying on no representation, warranty, covenant
or agreement except for those set forth in the Loan Agreement as hereby further
amended and the other documents previously executed or executed of even date
herewith.

8.    Governing Law. THIS TENTH AMENDMENT SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS AND THE APPLICABLE LAWS OF THE
UNITED STATES OF AMERICA. This Tenth Amendment has been entered into in Harris
County, Texas, and it shall be performable for all purposes in Harris County,
Texas. Courts within the State of Texas shall have jurisdiction over any and all
disputes between Borrower and Bank, whether in law or equity, including, but not
limited to, any and all disputes arising out of or relating to this Tenth
Amendment or any other Loan Document; and venue in any such dispute whether in
federal or state court shall be laid in Harris County, Texas.

9.    Severability. Whenever possible each provision of this Tenth Amendment
shall be interpreted in such manner as to be effective and valid under
applicable law, but if any provision of this Tenth Amendment shall be prohibited
by or invalid under applicable law, such provision shall be ineffective to the
extent of such prohibition or invalidity, without invalidating the remainder of
such provision or the remaining provisions of this Tenth Amendment.

10.   Execution in Counterparts. Each party hereto acknowledges that this
Agreement may be executed in several counterparts by each party at different
times and in different locations; that each separate counterpart bearing the
signature of any party may be effectively delivered to the other parties by the
delivery of an electronic facsimile sent via telecopier; that each party so
delivering any such counterpart shall be bound by its facsimile signature
thereon; and that the signature pages from counterparts signed by each party may
be collated into one or more copies of this agreement, which shall constitute
one and the same agreement among all parties hereto.

11.   Section Captions. Section captions used in this Tenth Amendment are for
convenience of reference only, and shall not affect the construction of this
Tenth Amendment.

12.   Successors and Assigns. This Tenth Amendment shall be binding upon
Borrower and Bank and their respective successors and assigns,

                                       6
<PAGE>   7
and shall inure to the benefit of Borrower and Bank, and the respective
successors and assigns of Bank.

13.   Non-Application of Chapter 346 of Texas Finance Codes. In no event shall
Chapter 346 of the Texas Finance Code (which regulates certain revolving loan
accounts and revolving tri-party accounts) apply to this Loan Agreement as
hereby further amended or any other Loan Documents or the transactions
contemplated hereby.

14.   Notice. THIS TENTH AMENDMENT TOGETHER WITH THE LOAN AGREEMENT, AND THE
OTHER LOAN DOCUMENTS REPRESENT THE FINAL AGREEMENT BETWEEN THE PARTIES AND MAY
NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS OR SUBSEQUENT ORAL
AGREEMENTS OF THE PARTIES. THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE
PARTIES.

                           [SIGNATURE PAGE FOLLOWS]

                                       7
<PAGE>   8
      IN WITNESS WHEREOF, the parties hereto have caused this Tenth Amendment to
be duly executed as of the day and year first above written.

BANK                                      BORROWER

COMPASS BANK                              CARRIZO OIL & GAS, INC.

By:                                       By:
   ---------------------------------         ---------------------------------
      Kathleen J. Bowen                         Frank A. Wojtek
      Vice President                            Vice President

                                       8
<PAGE>   9

THE STATE OF TEXAS          ss.
                            ss.
COUNTY OF HARRIS            ss.

      BEFORE ME, the undersigned authority, on this day personally appeared
Frank A. Wojtek, Vice President of Carrizo Oil & Gas, Inc., a Texas corporation,
known to me to be the person whose name is subscribed to the foregoing
instrument, and acknowledged to me that he executed the same for the purposes
and consideration therein expressed, as the act and deed of such corporation,
and in the capacity therein stated.

      GIVEN UNDER MY HAND AND SEAL OF OFFICE this 3rd day of November, 2000.

                                          -------------------------------
                                          NOTARY PUBLIC, STATE OF TEXAS

THE STATE OF TEXAS          ss.
                            ss.
COUNTY OF HARRIS            ss.

      BEFORE ME, the undersigned authority, on this day personally appeared
Kathleen J. Bowen, Vice President of Compass Bank, known to me to be the person
whose name is subscribed to the foregoing instrument, and acknowledged to me
that she executed the same for the purposes and consideration therein expressed,
as the act and deed of such bank, and in the capacity therein stated.

      GIVEN UNDER MY HAND AND SEAL OF OFFICE this ___ day of November, 2000.

                                          -------------------------------
                                          NOTARY PUBLIC, STATE OF TEXAS

                                       9
<PAGE>   10
                            COMPLIANCE CERTIFICATE

            I, Frank A. Wojtek, Vice President of CARRIZO OIL & GAS, INC. (the
"Company"), pursuant to Article III(a) of the Tenth Amendment to the First
Amended, Restated, and Combined Loan Agreement dated as of August 28, 1997, by
and among COMPASS BANK ("Bank") and the Company (the "Agreement") do hereby
certify, as of the date hereof, that to my knowledge:

      1.    After giving effect to the Ninth Amendment, no Event of Default (as
            defined in the Agreement) has occurred and is continuing, and no
            Unmatured Event of Default (as defined in the Agreement) has
            occurred and is continuing;

      2.    No material adverse change has occurred in the business prospects,
            financial condition, or the results of operations of the Company
            since the date of the previous Financial Statements (as defined in
            the Agreement) provided to Bank;

      3.    After giving effect to the Ninth Amendment, each of the
            representations and warranties of the Company contained in Article
            IV of the Agreement is true and correct in all respects.

            This certificate is executed this 3rd day of November 2000.

                                                ------------------------------
                                                Frank A. Wojtek

<PAGE>   11
                                   EXHIBIT "A"
<TABLE>
<CAPTION>
====================================================================================================================================
DATE           DOCUMENT                                                           RECORDING                   JURISDICTION
                                                                                  INFORMATION
====================================================================================================================================
<S>            <C>                                                                <C>                         <C>
6/26/96        Deed of Trust, Mortgage, Security Agreement, Financing             7/2/96                      Brooks County, TX
               Statement and Assignment of Production from Encinitas              Vol.164/Page 357
               Partners Ltd. (as predecessor to Carrizo) for the benefit of
               Compass Bank                                                       7/2/96                      Victoria County, TX
                                                                                  Vol. 227/Page 554
               ---------------------------------------------------------------------------------------------------------------------
               UCC-1 Financing Statement from Encinitas Partners Ltd.             7/1/96 #96130338            TX Secretary of State
               (as predecessor to Carrizo) for the benefit of Compass Bank                                    State
------------------------------------------------------------------------------------------------------------------------------------
12/6/96        Deed of Trust, Mortgage, Security Agreement, Financing             12/11/96 #188820            Starr County, TX
               Statement and Assignment of Production                             Vol 0769/Pg 661
               UCC-1 Financing Statement                                          12/12/96 #245276            TX Secretary of State
               ---------------------------------------------------------------------------------------------------------------------
               Security Agreement                                                 N/A                         N/A
------------------------------------------------------------------------------------------------------------------------------------
3/4/97         Deed of Trust, Mortgage, Security Agreement, Financing             3/10/97 #059214             Duval County, TX
               Statement and Assignment of Production                             Vol. 220/Pg 509
               UCC-1 Financing Statement                                          3/10/97 #97-046906          TX Secretary of State
               ---------------------------------------------------------------------------------------------------------------------
               Security Agreement                                                 N/A                         N/A
------------------------------------------------------------------------------------------------------------------------------------
12/5/97        Deed of Trust, Mortgage, Security Agreement, Financing             12/15/97                    Live Oak County,
               Statement and Assignment of Production                             Vol 347/Pg 266              TX
------------------------------------------------------------------------------------------------------------------------------------
7/30/98        Deed of Trust, Mortgage, Security Agreement, Financing             8/6/98 Vol 42/Pg 230        DeWitt County, TX
               Statement and Assignment of Production
                                                                                  --------------------------------------------------
                                                                                  8/6/98 #464754              San Patricio County,
                                                                                                              TX
                                                                                  --------------------------------------------------
               UCC-1 Financing Statement                                          8/6/98 #98-160378           TX Secretary of State
------------------------------------------------------------------------------------------------------------------------------------
9/29/98        Deed of Trust, Mortgage, Security Agreement, Financing             11/10/98 #199824            Starr County, TX
               Statement and Assignment of Production                             Vol 0819/Pg 299
               ---------------------------------------------------------------------------------------------------------------------
               UCC-1 Financing Statement                                          11/9/98 #98-224598          TX Secretary of State
               ---------------------------------------------------------------------------------------------------------------------
               Mortgage, Collateral Assignment, Security Agreement                12/4/98 #844100             Lafourche Parish, LA
               and Financing Statement                                            COB 1370/Folio 227
                                                                                  MOB 795/Folio 508
               ---------------------------------------------------------------------------------------------------------------------
               UCC-1 Financing Statement                                          12/4/98 #844101             Lafourche Parish, LA
------------------------------------------------------------------------------------------------------------------------------------
12/11/98       Deed of Trust, Mortgage, Security Agreement, Financing             12/11/98 #191639            Wharton County, TX
               Statement and Assignment of Production                             Vol 304/Pg 887
               ---------------------------------------------------------------------------------------------------------------------
</TABLE>

                                       1
<PAGE>   12
<TABLE>

<S>            <C>                                                                <C>
               UCC-1Financing Statement                                           12/17/98 #98-250845         TX Secretary of State
------------------------------------------------------------------------------------------------------------------------------------
6/3/99         Deed of Trust, Mortgage, Security Agreement, Financing             Vol 369/Pg 158              Live Oak County, TX
               Statement and Assignment of Production                             6/9/99                      (undeveloped)
               ---------------------------------------------------------------------------------------------------------------------
               UCC-3 Amendment of original Financing Statement                    6/10/99 #99-701556          TX Secretary of
               #245276 filed 12/12/96                                                                         State
               ---------------------------------------------------------------------------------------------------------------------
               1st Amendment to Mortgage, Collateral Assignment,                  COB 1388/Folio 580          Lafourche Parish,
               Security Agreement and Financing Statement                         MOB 815/Folio 205           LA
                                                                                  #854267   6/10/99
               ---------------------------------------------------------------------------------------------------------------------
               UCC-3 Amendment of original Financing Statement                    6/10/99 #29-854268          Lafourche Parish,
               #844101 filed 12/4/98                                                                          LA
               ---------------------------------------------------------------------------------------------------------------------
               First Amendment to  Security Agreement                             N/A                         N/A
------------------------------------------------------------------------------------------------------------------------------------
11/11/99       Deed of Trust, Mortgage, Security Agreement, Financing             Vol 0620/Pg 209             Bee County, TX
               Statement and Assignment of Production                             #116370 11/19/99
                                                                                  --------------------------------------------------
                                                                                  Vol 00114/Pg 00151          Goliad County, TX
                                                                                  #0093272 11/18/99
                                                                                  --------------------------------------------------
                                                                                  Vol 561/Pg 601              Matagorda County,
                                                                                  #998088 11/18/99            TX
               ---------------------------------------------------------------------------------------------------------------------
               1st Amendment to Deed of Trust, Mortgage, Security                 Vol 64/Pg 892               DeWitt County, TX
               Agreement, Financing Statement and Assignment of                   #16829 11/19/99
               Production
                                                                                  --------------------------------------------------
                                                                                  #479162 11/19/99            San Patricio County,
                                                                                                              TX
               ---------------------------------------------------------------------------------------------------------------------
               UCC-3 Amendment of original Financing Statement #98-               #99-767907                  TX Secretary of
               160378 filed                                                       11/18/99                    State
               ---------------------------------------------------------------------------------------------------------------------
               2nd Amendment to Security Agreement                                N/A                         N/A
------------------------------------------------------------------------------------------------------------------------------------
4/20/00        Deed of Trust, Mortgage, Security Agreement, Financing             4/28/00  #2663-B            Chambers County,
               Statement and Assignment of Production                             Vol 00453/Pg 745            TX
               ---------------------------------------------------------------------------------------------------------------------
               1st Amendment to Deed of Trust, Mortgage, Security                 4/28/00 #002677             Matagorda County,
               Agreement, Financing Statement and Assignment of                   Vol 578/Pg 535              TX
               Production
               ---------------------------------------------------------------------------------------------------------------------
               UCC-3 Amendment of original Financing Statement                    4/28/00 #00-802172          TX Secretary of
               #98-160378 filed 8/6/98                                                                        State
------------------------------------------------------------------------------------------------------------------------------------
               3rd Amendment to Security Agreement                                N/A                         N/A
               ---------------------------------------------------------------------------------------------------------------------
               Collateral Assignment of Contracts                                 N/A                         N/A
------------------------------------------------------------------------------------------------------------------------------------
5/10/00        1st Amendment to Deed of Trust, Mortgage, Security                 5/17/00 #074115             Brooks County, TX
               Agreement, Financing Statement and Assignment of                   Vol 0209/Pg 787
               ---------------------------------------------------------------------------------------------------------------------
</TABLE>

                                       2
<PAGE>   13
<TABLE>
<S>            <C>                                                                <C>
               ---------------------------------------------------------------------------------------------------------------------
               Production
               ---------------------------------------------------------------------------------------------------------------------
               1st Amendment to Deed of Trust, Mortgage, Security                 5/17/00 #071211             Duval County, TX
               Agreement, Financing Statement and Assignment of                   Vol 0288/Pg 309
               Production
               ---------------------------------------------------------------------------------------------------------------------
               1st Amendment to Deed of Trust, Mortgage, Security                 5/19/00   #209189           Starr County, TX
               Agreement, Financing Statement and Assignment of                   Vol 0863/Pg 765
               Production
               ---------------------------------------------------------------------------------------------------------------------
               UCC-3 Amendment of original Financing Statement                    5/17/00 #00-810056          TX Secretary of
               #98-160378 filed 8/6/98                                                                        State
               ---------------------------------------------------------------------------------------------------------------------
               4th Amendment to Security Agreement                                N/A                         N/A
------------------------------------------------------------------------------------------------------------------------------------
10/16/00       2nd Amendment to Deed of Trust, Mortgage, Security                                             Starr County, TX
               Agreement, Financing Statement and Assignment of
               Production
               ---------------------------------------------------------------------------------------------------------------------
               1st Amendment to Deed of Trust, Mortgage, Security                                             Goliad County, TX
               Agreement, Financing Statement and Assignment of
               Production
               ---------------------------------------------------------------------------------------------------------------------
               1st Amendment to Deed of Trust, Mortgage, Security                                             Wharton County, TX
               Agreement, Financing Statement and Assignment of
               Production
               ---------------------------------------------------------------------------------------------------------------------
               Deed of Trust, Mortgage, Security Agreement, Financing                                         Liberty County, TX
               Statement and Assignment of Production
               ---------------------------------------------------------------------------------------------------------------------
               UCC-3 Amendment of original Financing Statement                                                TX Secretary of
               #98-160378 filed 8/6/98                                                                        State
               ---------------------------------------------------------------------------------------------------------------------
               5th Amendment to Security Agreement                                N/A                         N/A
               ---------------------------------------------------------------------------------------------------------------------
               1st Amendment to Collateral Assignment of Contracts                N/A                         N/A
------------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                       3

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