Letter Agreement for Termination of Omnibus Agreement among Occidental Petroleum, Western Midstream Operating GP, Western Midstream Operating LP, and Anadarko Petroleum

Re: Omnibus Agreement

Reference is made to that certain Omnibus Agreement, dated as of May 14, 2008, by and among Western Midstream Operating, LP (formerly known as Western Gas Partners, LP), a Delaware limited partnership (the “OLP”), Western Midstream Operating GP, LLC (formerly known as Western Gas Holdings, LLC), a Delaware limited liability company (the “General Partner”) and Anadarko Petroleum Corporation, (“Anadarko”), a Delaware corporation (as amended to date by Amendment No. 1 thereto, dated December 19, 2008, Amendment No. 2 thereto, dated July 22, 2009, Amendment No. 3 thereto, dated December 31, 2009, Amendment No. 4 thereto, dated January 29, 2010 and Amendment No. 5 thereto, dated August 2, 2010, the “Omnibus Agreement”). The OLP, the General Partner and Anadarko are each herein referred to as a “Party” and together, the “Parties.” Unless otherwise noted, capitalized terms not defined herein will have the meaning set forth in the Omnibus Agreement.

The Omnibus Agreement governs certain indemnity and expense reimbursement obligations among the General Partner, the OLP and certain of their subsidiaries and Anadarko. The purpose of this letter is to memorialize the agreement among the Parties to terminate the Omnibus Agreement and release the Parties’ respective obligations under the Omnibus Agreement. Therefore, in consideration of the mutual benefits to be hereinafter derived, you agree that you hereby consent to the termination of the Omnibus Agreement and release each Party’s obligations under the Omnibus Agreement.

Please indicate your agreement to the foregoing by signing this letter in the space provided on the following page and returning to our attention. This consent may be executed and delivered in any number of counterparts and by electronic transmission, each of which will be deemed an original instrument and together will constitute for all purposes one agreement.