Exhibit 5.1

VINSON & ELKINS L.L.P. 2300 FIRST CITY TOWER 1001 FANNIN STREET HOUSTON, TEXAS 77002-6760 TELEPHONE (713) 758-2222 FAX (713) 758-2346 www.velaw.com

March 28, 2005

Chesapeake Energy Corporation

6100 North Western Avenue

Oklahoma City, Oklahoma 73118

Ladies and Gentlemen:

We have acted as counsel for Chesapeake Energy Corporation, an Oklahoma corporation (the “Company”) and certain of its subsidiaries with respect to with the preparation of the Registration Statement on Form S-4 (the “Registration Statement”) filed with the Securities and Exchange Commission (the “Commission”) in connection with the registration by the Company under the Securities Act of 1933, as amended (the “Securities Act”) of (i) the offer and exchange by the Company (the “Exchange Offer”) of $600,000,000 aggregate principal amount of its 6.375% Senior Notes due 2015 (the “Initial Notes”), for a new series of notes bearing substantially identical terms and in like principal amount (the “Exchange Notes”) and (ii) the guarantees (the “Guarantees”) of certain subsidiaries of the Company listed in the Registration Statement as guarantors (the “Subsidiary Guarantors”) of the Initial Notes and the Exchange Notes. The Initial Notes were issued, and the Exchange Notes will be issued, under an Indenture dated as of December 8, 2005, among the Company, the Subsidiary Guarantors and The Bank of New York Trust Company, N.A., as Trustee, as supplemented by the First Supplemental Indenture, dated as of January 31, 2005 (the “Indenture”). The Exchange Offer will be conducted on such terms and conditions as are set forth in the prospectus contained in the Registration Statement to which this opinion is an exhibit.

We have examined originals or copies, certified or otherwise identified to our satisfaction, of (i) the Registration Statement, (ii) the Indenture and (iii) such other certificates, statutes and other instruments and documents as we considered appropriate for purposes of the opinions hereafter expressed. In connection with this opinion, we have assumed that the Registration Statement, and any amendments thereto (including post-effective amendments), will have become effective and the Exchange Notes will be issued and sold in compliance with applicable federal and state securities laws and in the manner described in the Registration Statement.

Based on the foregoing, we are of the opinion that when the Exchange Notes have been duly executed, authenticated, issued and delivered in accordance with the provisions of the Indenture, (i) such Exchange Notes will be legally issued and will constitute valid and binding obligations of the Company enforceable against the Company in accordance with their terms, and (ii) the Guarantees of the Subsidiary Guarantors remain valid and binding obligations of such subsidiaries, enforceable against the Company and each such Subsidiary Guarantor in accordance with their terms, except in each case as such enforcement is subject to any applicable bankruptcy, insolvency, reorganization or other law relating to or affecting creditors’ rights generally and general principles of equity.

We express no opinions concerning (a) the validity or enforceability of any provisions contained in the Indenture that purport to waive or not give effect to rights to notices, defenses, subrogation or other rights or benefits that cannot be effectively waived under applicable law; or (b) the enforceability of indemnification provisions to the extent they purport to relate to liabilities resulting from or based upon negligence or any violation of federal or state securities or blue sky laws.

We are members of the bar of the State of Texas. We have relied as to matters of Oklahoma law on the opinion of Commercial Law Group, P.C., which opinion is also filed as an exhibit to the Registration Statement. The opinions expressed herein are limited exclusively to the laws of the State of New York and, in reliance on the opinion of Commercial Law Group, P.C., the laws of the State of Oklahoma, and we are expressing no opinion as to the effect of the laws of any other jurisdiction, domestic or foreign.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the use of our firm name in the prospectus forming a part of the Registration Statement under the caption “Legal Matters.” By giving such consent, we do not admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission issued thereunder.

Very truly yours,

/s/ Vinson & Elkins L.L.P.

Vinson & Elkins L.L.P.