Exhibit 10.1

[Execution]

THIRD AMENDMENT TO CREDIT AGREEMENT

THIS THIRD AMENDMENT TO CREDIT AGREEMENT (herein called this "Amendment") is made as of the 31st day of May, 2002, by and among Key Production
Company, Inc. ("Borrower"), Bank of America, N.A. ("Agent"), and the Lenders under the Credit Agreement referred to below.

W I T N E S S E T H:

WHEREAS, Borrower, Agent, and Lenders have entered into that certain Credit Agreement dated as of November 12, 1999 (as amended, restated, or supplemented
to the date hereof, the "Original Agreement"), for the purposes and consideration therein expressed, pursuant to which Lenders made and became obligated to make loans to Borrower as therein provided;

WHEREAS,
Borrower, Agent, and Lenders desire to amend the Original Agreement for the purposes described herein;

NOW,
THEREFORE, in consideration of the premises and the mutual covenants and agreements contained herein and in the Original Agreement, in consideration of the loans which may hereafter
be made by Lenders to Borrower, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto do hereby agree as follows:

ARTICLE I.
Definitions and References

Section 1.1.Defined Terms. Unless the context otherwise requires or unless otherwise expressly defined herein,
the terms defined in the Original Agreement shall have the same meanings whenever used in this Amendment. As used herein, the following terms shall have the following meanings:

"Amendment" means this Third Amendment to Credit Agreement.

"Credit Agreement" means the Original Agreement as amended by this Amendment.

ARTICLE II.
Amendments and Consent

Section 2.1.Definitions. The definitions of "Commitment Fee Rate", "Commitment Period", "Eurodollar Margin",
"Eurodollar Rate" and "Maturity Date" contained in Section 1.1 of the Original Agreement are hereby amended in its entirety to read as follows:



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Section
2.2.Regularly Scheduled Principal Payments. Section 2.6 of the Original Agreement is hereby deleted.

Section
2.3.Prepayments. The second sentence of Section 2.7 of the Original Agreement is hereby deleted.

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ARTICLE III.
Conditions of Effectiveness

Section 3.1.Effective Date. This Amendment shall become effective as of the date first above written when Agent
shall have received all of the following:



ARTICLE IV.
Representations and Warranties

Section 4.1.Representations and Warranties of Borrower. In order to induce each Lender to enter into this
Amendment, Borrower represents and warrants on the date hereof and as of the Effective Date to each Lender that:



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ARTICLE V.
Miscellaneous

Section 5.1.Ratification of Agreements. The Original Agreement as hereby amended is hereby ratified and confirmed
in all respects. Any reference to the Credit Agreement in any Loan Document shall be deemed to be a reference to the Original Agreement as hereby amended. The Loan Documents, as they may be amended or
affected by this Amendment, are hereby ratified and confirmed in all respects. The execution, delivery and effectiveness of this Amendment shall not, except as expressly provided herein, operate as a
waiver of any right, power or remedy of Lenders under the Credit Agreement, the Notes, or any other Loan Document nor constitute a waiver of any provision of the Credit Agreement, the Notes, or any
other Loan Document.

Section
5.2.Survival of Agreements. All representations, warranties, covenants and agreements of Borrower herein shall survive the
execution and delivery of this Amendment and the performance hereof, including without limitation the making or granting of the Loans, and shall further survive until all of the Obligations are paid
in full. All statements and agreements contained in any certificate or instrument delivered by Borrower hereunder or under the Credit Agreement to any Lender shall be deemed to constitute
representations and warranties by, and/or agreements and covenants of, Borrower under this Amendment and under the Credit Agreement.

Section
5.3.Loan Documents. This Amendment is a Loan Document, and all provisions in the Credit Agreement pertaining to Loan Documents
apply hereto.

Section
5.4.Governing Law. This Amendment shall be governed by and construed in accordance the laws of the State of Texas and any
applicable laws of the United States of America in all respects, including construction, validity and performance.

Section
5.5.Counterparts. This Amendment may be separately executed in counterparts and by the different parties hereto in separate
counterparts, each of which when so executed shall be deemed to constitute one and the same Amendment.

THIS AMENDMENT 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 OF THE PARTIES.

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remainder of this page is intentionally left blank.]

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IN
WITNESS WHEREOF, this Amendment is executed as of the date first above written.

| |  | KEY PRODUCTION COMPANY, INC.                
| |  | --------------------------------------------
| |  | By:                                         
| |  | BANK OF AMERICA, N.A., as Agent and Lender  
| |  | By:                                         
| |  | U.S. BANK NATIONAL ASSOCIATION, a Lender    
| |  | By:                                         
| |  | BANK ONE, NA (Main OfficeChicago), a Lender
| |  | By:                                         
| |  | CIBC INC., a Lender                         
| |  | By:                                         
| |  | BANK OF OKLAHOMA, N.A., a Lender            
| |  | By:                                         

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| |  | UNION BANK OF CALIFORNIA, N.A., a Lender
| |  | ----------------------------------------
| |  | By:                                     
| |  | By:                                     
| |  | BNP PARIBAS, a Lender                   
| |  | By:                                     
| |  | By:                                     

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CONSENT AND AGREEMENT

The undersigned hereby (i) consents to the provisions of this Amendment and the transactions contemplated herein, and (ii) ratifies and confirms its
Guaranty dated as of November 12, 1999 made by it in favor of Agent for the benefit of each Lender, and agrees that its obligations and covenants thereunder are unimpaired hereby and shall
remain in full force and effect.

Date:
May 31, 2002

| |  | BROCK GAS SYSTEMS & EQUIPMENT, INC.
| |  | -----------------------------------
| |  | By:                                

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