PXP Plains Exploration & Production Company

Anadarko Petroleum Corporation (NYSE: APC) today announced the finalization of a unitization agreement with Exxon Mobil Corporation and co-owners to develop the Lucius field. The unitization includes portions of Keathley Canyon blocks 874, 875, 918 and 919 in the deepwater Gulf of Mexico. Anadarko will operate the unit with a 35-percent working interest. Following the unitization agreement, the Lucius interest owners entered into an agreement with the Hadrian South co-venturers whereby natural gas produced from the Hadrian South field will be processed through the Lucius facility in return for a production-handling fee and reimbursement for any required facility upgrades.

"As a result of these agreements, we expect Lucius to be among the most economically efficient projects in our portfolio, while providing important infrastructure in an emerging area of the Gulf of Mexico," said Al Walker, Anadarko President and Chief Operating Officer. "We've already placed orders for the long-lead items, including the truss spar floating production facility, which will have a capacity of more than 80,000 barrels of oil per day (BOPD) and 450 million cubic feet of natural gas per day. We look forward to working with our new co-owners and anticipate sanctioning the project later this year, with first production expected in 2014."

Anadarko and the co-owners also recently completed an extended well test at the Lucius discovery that provided assurance regarding the flow rates and excellent reservoir characteristics of the field. With equipment-constrained rates in excess of 15,000 BOPD of high-quality oil (29° API gravity), the test provided additional confidence in Anadarko's previous resource estimates and indicated that Lucius can be developed with a minimal number of wells.

Co-owners in the Lucius unit include Plains Exploration & Production Company (NYSE: PXP) with a 23.3-percent working interest; Exxon Mobil Corporation (NYSE: XOM) with a 15-percent working interest; Apache Deepwater LLC, a subsidiary of Apache Corporation (NYSE: APA) (NASDAQ: APA) with an 11.7-percent working interest; Petrobras with a 9.6-percent working interest; and Eni Petroleum with a 5.4-percent working interest.

A map of Lucius will be available under the "Media Center/Anadarko News" tab at www.anadarko.com.

Anadarko Petroleum Corporation's mission is to deliver a competitive and sustainable rate of return to shareholders by exploring for, acquiring and developing oil and natural gas resources vital to the world's health and welfare. As of year-end 2010, the company had approximately 2.42 billion barrels-equivalent of proved reserves, making it one of the world's largest independent exploration and production companies. For more information about Anadarko, please visit www.anadarko.com.

This news release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Anadarko believes that its expectations are based on reasonable assumptions. No assurance, however, can be given that such expectations will prove to have been correct. A number of factors could cause actual results to differ materially from the projections, anticipated results or other expectations expressed in this news release, including Anadarko's ability to successfully sanction the Lucius project, achieve first production and receive the necessary permits in the Gulf of Mexico to successfully drill, complete, test and produce the wells and prospects identified in this news release. See "Risk Factors" in the company's 2010 Annual Report on Form 10-K and other public filings and press releases. Readers are cautioned not to place undue reliance on forward-looking statements, which speak only as of the date hereof. Anadarko undertakes no obligation to publicly update or revise any forward-looking statements.

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Anadarko Contacts Media: John Christiansen Email Contact 832.636.8736 Brian Cain Email Contact 832.636.3404 Investors: John Colglazier Email Contact 832.636.2306 Clay Gaspar Email Contact 832.636.2541 Wayne Rodrigs Email Contact 832.636.2305