Marathon Signs Agreement to Sell Interest in Heimdal Area Offshore Norway for $416 Million

HOUSTON, July 9 /PRNewswire-FirstCall/ -- Marathon Oil Corporation (NYSE: MRO) announced today that it has entered into a definitive agreement with Centrica plc, the parent company of British Gas, under which Centrica will purchase Marathon's non-operated interests in the Heimdal infrastructure, related producing fields and associated undeveloped acreage offshore Norway. The transaction, which has a total value of $416 million and an effective date of January 1, 2008, includes a $375 million purchase price plus $41 million in associated Norwegian asset tax pools, but excludes any purchase price adjustments due at closing. The companies anticipate closing the transaction, which is subject to Norwegian regulatory approval, during the late third quarter or early fourth quarter of 2008.

Under the terms of the agreement, Centrica will acquire Marathon's 23.8 percent interest in the Heimdal field, as well as its 46.9 percent interest in the Vale field; a 20 percent interest in the Byggve field; a 20 percent interest in the Skirne field; and a 50 and 20 percent interest in the Peik and Heimdal East discoveries, respectively. Marathon's net proved reserves associated with these assets as of year end 2007 were 4.8 million barrels of oil equivalent (mmboe), and total net risked resources of approximately 17.5 mmboe. Current net production from these operations averages approximately 7,000 barrels of oil equivalent per day. None of the assets involved in this agreement are associated with Marathon's Alvheim/Vilje development or related operations on the Norwegian Continental Shelf.

"Marathon's decision to sell its interest in Heimdal and related assets is part of our ongoing efforts to actively manage the Company's global asset portfolio to ensure alignment with our business strategy and to generate sustainable value growth," said David E. Roberts, Jr., Marathon executive vice president, Upstream. "This business approach demands that we continually evaluate the value of existing operations against the value of new or emerging opportunities."

Marathon is an integrated international energy company engaged in exploration and production; oil sands mining; integrated gas; and refining, marketing and transportation operations. Marathon, which is based in Houston, has principal operations in the United States, Angola, Canada, Equatorial Guinea, Gabon, Indonesia, Ireland, Libya, Norway and the United Kingdom. Marathon is the fourth largest United States-based integrated oil company and the nation's fifth largest refiner.

This release contains forward-looking statements with respect to the anticipated disposition of interests in the Heimdal area and related assets. Some factors that could adversely affect the anticipated disposition of these interests and related assets include the inability or delay in obtaining necessary government and third party approvals and other customary closing conditions. In accordance with the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995, Marathon Oil Corporation has included in its Annual Report on Form 10-K for the year ended December 31, 2007, and subsequent Forms 10-Q and 8-K, cautionary language identifying other important factors, though not necessarily all such factors, that could cause future outcomes to differ materially from those set forth in the forward- looking statements.

Cautionary Note to U.S. Investors - The United States Securities and Exchange Commission (SEC) permits oil and gas companies, in their filings with the SEC, to disclose only proved oil and gas reserves that have demonstrated by actual production or conclusive formation tests to be economically and legally producible under existing economic and operating conditions. Marathon Oil Corporation uses certain terms in this press release, such as total net risked resources that the SEC's guidelines strictly prohibit us from including in filings with the SEC. U.S. Investors are urged to consider closely the disclosures in Marathon's periodic filings with the SEC, available from us at 5555 San Felipe, Houston, Texas 77056 and the Company's Web site at http://www.Marathon.com . You can also obtain this information from the SEC by calling 1-800-SEC-0330.

Media Relations Contacts: Lee Warren 713-296-4103
Paul Weeditz 713-296-3910

Investor Relations Contacts: Howard Thill 713-296-4140
Chris Phillips 713-296-3213
Michol Ecklund 713-296-3919

SOURCE Marathon Oil Corporation

CONTACT: Media Relations Contacts: Lee Warren, +1-713-296-4103, Paul
Weeditz, +1-713-296-3910, Investor Relations Contacts: Howard Thill,
+1-713-296-4140, Chris Phillips, +1-713-296-3213, Michol Ecklund,
+1-713-296-3919, all of Marathon Oil Corporation