EXHIBIT 4.6.1 UNION BANK OF CALIFORNIA, N.A. 4200 LINCOLN PLAZA 500 NORTH AKARD DALLAS, TEXAS 75201 September 10, 2001 Chesapeake Energy Corporation Chesapeake Exploration Limited Partnership 6100 North Western Avenue Oklahoma City, Oklahoma 73118 Re: Second Amended and Restated Credit Agreement dated as of June 11, 2001 (as amended, supplemented or restated, the "Credit Agreement"), by and among Chesapeake Exploration Limited Partnership, an Oklahoma limited partnership ("Borrower"), Chesapeake Energy Corporation, an Oklahoma corporation ("Company"), Bear Stearns Corporate Lending Inc., as syndication agent ("Syndication Agent"), Union Bank of California, N.A., as administrative agent and collateral agent ("Administrative Agent"), and the several banks and other financial institutions or entities from time to time parties thereto ("Lenders") Ladies and Gentlemen: Reference is hereby made to the Credit Agreement. Terms which are defined in the Credit Agreement and not otherwise defined herein are used herein with the meanings given them in the Credit Agreement. Borrower and Company have requested that Administrative Agent and Lenders consent to the purchase by Company of a portion of the outstanding 11 1/2% Senior Notes due 2008 issued by RAM Energy, Inc. from the holders thereof for cash (the "Note Purchases"). In addition, Borrower and Company have requested that Administrative Agent and Lenders consent to the sale by Company of all of the outstanding capital stock of Chesapeake Canada Corporation to a Person that is not an Affiliate of Company for a sales price of approximately C $232,000,000 (the "Canadian Sale"). Subject to the terms and provisions hereof, Administrative Agent and Lenders hereby: (a) (i) consent to the Note Purchases, (ii) waive any violations of the Credit Agreement resulting therefrom, and (iii) agree that such Note Purchases shall be permitted in addition to the Investments otherwise permitted pursuant to Section 7.7 of the Credit Agreement; provided that (1) at the time of each Note Purchase, no Default or Event of Default (excluding any occurring pursuant to a Note Purchase) has occurred which is continuing, (2) the Note Purchases shall be approved by the Board of Directors of Company, (3) the aggregate cash purchase price for all Note Purchases paid to the holders thereof pursuant to this Letter Agreement shall not exceed $50,000,000, (4) the Canadian Sale shall have consummated prior to the commencement of such Note Purchases, and (5) nothing in this Letter Agreement shall allow any Person to make any other new Investments not allowed pursuant to Section 7.7 of the Credit Agreement; and (b) (i) consent to the Canadian Sale, (ii) waive any violations of the Credit Agreement resulting therefrom, and (iii) agree that the Canadian Sale shall be in addition to the asset dispositions otherwise permitted pursuant to Section 7.5 of the Credit Agreement; provided that (1) at the time of the Canadian Sale, no Default or Event of Default (excluding any occurring pursuant to the Canadian Sale) has occurred which is continuing, (2) the Canadian Sale shall be approved by the Board of Directors of Company, (3) the net cash proceeds from the Canadian Sale shall be paid to the Administrative Agent, for the benefit of the Lenders, for application to the Revolving Loans pursuant to the provisions of the Credit Agreement (and such payment shall not be deemed to constitute a reduction in the Borrowing Base or otherwise affect Borrower's ability to request Revolving Loans pursuant to the terms of the Credit Agreement), (4) the Canadian Sale shall be consummated on or before December 31, 2001, and (5) nothing in this Letter Agreement shall allow any Person to make any other asset dispositions not allowed pursuant to Section 7.5 of the Credit Agreement. The limitations set forth in clause (a) above shall not be deemed to restrict Investments otherwise allowed under clause (n) of Section 7.7 of the Credit Agreement, including without limitation, additional Note Purchases under such clause. The Credit Agreement is hereby ratified and confirmed in all respects. Except as expressly set forth above, the execution, delivery and effectiveness of this Letter Agreement shall not operate as a waiver of any right, power or remedy of Administrative Agent or 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. By its execution below, each Guarantor hereby (i) consents to the provisions of this Letter Agreement and the transactions contemplated herein, (ii) ratifies and confirms the Guarantee Agreement dated as of June 11, 2001 made by it for the benefit of Administrative Agent and Lenders and the other Loan Documents executed pursuant to the Credit Agreement, (iii) agrees that all of its respective obligations and covenants thereunder shall remain unimpaired by the execution and delivery of this Letter Agreement and the other documents and instruments executed in connection herewith, and (iv) agrees that the Guarantee Agreement and such other Loan Documents shall remain in full force and effect. This Letter Agreement is a "Loan Document" as defined and described in the Credit Agreement and all of the terms and provisions of the Credit Agreement relating to Loan Documents shall apply hereto. This Letter Agreement may be executed in multiple counterparts, all of which shall constitute one Letter Agreement. This Letter Agreement may be validly executed by facsimile or other electronic transmission. [THE REMAINDER OF THIS PAGE IS INTENTIONALLY LEFT BLANK.] Please execute a copy of this Letter Agreement in the space provided below to evidence your agreement to and acknowledgment of the foregoing. Very truly yours, UNION BANK OF CALIFORNIA, N.A. Administrative Agent, Collateral Agent and Lender By: /s/ RANDALL OSTERBERG ------------------------------------------ Name: Randall Osterberg ---------------------------------------- Title: Senior Vice President --------------------------------------- By: /s/ SEAN MURPHY ------------------------------------------ Name: Sean Murphy ---------------------------------------- Title: Assistant Vice President --------------------------------------- ACKNOWLEDGED AND AGREED to as of the date first written above: By: Chesapeake Operating, Inc., its general partner By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: GUARANTORS: CHESAPEAKE ENERGY CORPORATION By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: THE AMES COMPANY, INC. By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: ARKOMA PITTSBURG HOLDING CORPORATION By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: CHESAPEAKE ACQUISITION CORPORATION By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: CHESAPEAKE ENERGY LOUISIANA CORPORATION By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: CHESAPEAKE OPERATING, INC. By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: CHESAPEAKE OPERATING, INC., as General Partner of Chesapeake Panhandle Limited Partnership By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: CHESAPEAKE ROYALTY COMPANY By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: CHESAPEAKE OPERATING, INC., as General Partner of Chesapeake-Staghorn Acquisition L.P. By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: CHESAPEAKE OPERATING, INC., as General Partner of Chesapeake Louisiana, L.P. By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: CHESAPEAKE OPERATING, INC., as General Partner of Chesapeake Exploration Limited Partnership By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: GOTHIC ENERGY CORPORATION By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: GOTHIC PRODUCTION CORPORATION By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: NOMAC DRILLING CORPORATION By: /s/ MARTHA A. BURGER -------------------------------------- Name: Title: LENDERS: BANK OF OKLAHOMA. N.A. By: /s/ JOHN N. HUFF ------------------------------------------ Name: John N. Huff Title: Vice President BANK OF SCOTLAND By: /s/ JOSEPH FRATUS ------------------------------------------ Name: Joseph Fratus Title: Vice President BEAR STEARNS CORPORATE LENDING INC. By: /s/ VICTOR F. BULZACCHELLI ------------------------------------------ Name: Victor F. Bulzacchelli Managing Director Title: BNP PARIBAS By: /s/ A. DAVID DODD /s/ LARRY ROBINSON ------------------------------------------ Name: A. David Dodd Larry Robinson Title: Vice President Vice President COMERICA BANK - TEXAS By: /s/ PETER L. SEFZIK ------------------------------------------ Name: Peter L. Sefzik Title: Corporate Banking Officer COMPASS BANK By: /s/ KATHLEEN J. BOWEN ------------------------------------------ Name: Kathleen J. Bowen Title: Vice President CREDIT AGRICOLE INDOSUEZ /s/ PATRICK COCQUEREL By: /s/ BRIAN D. KNEZEAL --------------------------- ------------------------------------------ Patrick Cocquerel Name: Brian D. Knezeal FVP, Managing Director Title: First Vice President NATEXIS BANQUES POPULAIRES /s/ LOUIS P. LAVILLE, III By: /s/ DONOVAN C. BROUSSARD --------------------------- ------------------------------------------ Louis P. Laville, III Name: Donovan C. Broussard Vice President and Title: Vice President Group Manager NATIONAL BANK OF CANADA, NEW YORK BRANCH By: /s/ RANDALL K. WILHOIT ------------------------------------------ Name: Randall K. Wilhoit Title: Vice President By: /s/ DOUG CLARK ------------------------------------------ Name: Doug Clark Title: Vice President RZB FINANCE LLC By: /s/ DIETER BEINTREXLER ------------------------------------------ Name: Dieter Beintrexler Title: President By: /s/ FRANK J. YAUTZ ------------------------------------------ Name: Frank J. Yautz Title: First Vice President SUMITOMO MITSUI BANKING CORPORATION By: /s/ DAVID A. BUCK ------------------------------------------ Name: David A. Buck Title: Senior Vice President TORONTO DOMINION (TEXAS), INC. By: /s/ JIM BRIDWELL ------------------------------------------ Name: Jim Bridwell Title: Vice President UNION BANK OF CALIFORNIA, N.A. By: /s/ SEAN MURPHY ------------------------------------------ Name: Sean Murphy Title: Assistant Vice President U.S. BANK NATIONAL ASSOCIATION By: /s/ M. WARD POLZIN ------------------------------------------ Name: M. Ward Polzin Title: Vice President WASHINGTON MUTUAL BANK, FA By: /s/ MARK M. ISENSEE ------------------------------------------ Name: Mark M. Isensee Title: Manager