HOUSTON, February 16, 2010 /PRNewswire/ -- Endeavour International Corporation today announced a 49 percent increase in proved and probable reserves as of December 31, 2009 resulting in a record reserve replacement rate of 980 percent of 2009 production, based on 2P reserves.

This increase is attributable to the success of our North Sea exploration and appraisal programs and demonstrates our ability to grow the company through the drill bit, said William L. Transier, chairman, chief executive officer and president. We now have four field developments underway in the United Kingdom. These longer-cycle projects complement our expanded U.S. onshore initiative that we expect to contribute significantly to reserve growth in 2010.

Proved and probable reserves at year-end 2009 increased to 38.9 million barrels of oil equivalent (mmboe) compared to 26.1 mmboe a year ago. Extensions, discoveries and upward revisions to prior estimates and purchases added 13.7 mmboe during 2009. Production for the year was 1.4 mmboe.

The upward revisions in 2P reserves were a result of the drilling of two wells in Cygnus Fault Blocks 2b and 3, the 2007 Bacchus discovery maturing to development status and better-than-expected performance from several producing assets.

Net Reserves at December 31, ---------------------------- 2009 ---- Audited by: Netherland, Sewell and Associates, Inc. Oil NGL Gas Equivalents (mbbl) (mbbl) (mmcf) (mboe) ------ ------ ------ ------ Proved Developed Producing 1,212 26 4,458 1,981 Non-Producing 150 - 4,578 913 Proved Undeveloped 1,973 5 80,064 15,322 ----- --- ------ ------ Proved (1P) 3,335 31 89,100 18,216 Probable 7,352 20 79,919 20,692 ----- --- ------ ------ Proved + Probable (2P) 10,687 51 169,019 38,908 Possible 7,859 34 89,478 22,806 ----- --- ------ ------ Proved + Probable + Possible (3P) 18,546 85 258,497 61,714 2008* ----- Prepared by: Netherland, Sewell and Associates, Inc. Oil NGL Gas Equivalents (mbbl) (mbbl) (mmcf) (mboe) ------ ------ ------ ------ Proved Developed Producing 989 - 6,657 2,099 Non-Producing 466 19 338 542 Proved Undeveloped 675 - 20,825 4,146 --- --- ------ ----- Proved (1P) 2,130 19 27,820 6,787 Probable 5,777 7 81,375 19,347 ----- --- ------ ------ Proved + Probable (2P) 7,907 26 109,195 26,134 Possible 11,034 6 107,090 28,889 ------ --- ------- ------ Proved + Probable + Possible (3P) 18,941 32 216,285 55,023

*Reserve information has been restated for the disposition of

its Norwegian operations in May 2009 (5.6 mmboe).

Endeavour International Corporation is an international oil and gas exploration and production company focused on the acquisition, exploration and development of energy reserves in the North Sea and United States. For more information, visit http://www.endeavourcorp.com.

Source: Netherland, Sewell and Associates, Inc

Certain statements in this news release should be regarded as forward-looking statements within the meaning of the securities laws. These statements speak only of as of the date made. Such statements are subject to assumptions, risk and uncertainty. Actual results or events may vary materially.

As of January 1, 2010, the Securities and Exchange Commission (SEC) changed its rules to permit oil and gas companies, in their filings with the SEC, to disclose not only proved reserves, but also probable reserves and possible reserves. Proved oil and gas reserves are those quantities of oil and gas, which, by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be economically producible - from a given date forward, from known reservoirs, and under existing economic conditions, operating methods, and government regulations - prior to the time at which contracts providing the right to operate expire. Probable reserves include those additional reserves that a company believes are as likely as not to be recovered and possible reserves include those additional reserves that are less certain to be recovered than probable reserves. We use may use certain terms in our news releases, such as reserve potential, that the SEC's guidelines strictly prohibit us from including in filings with the SEC. In addition, we do not represent that the probable or possible reserves described herein meet the recoverability thresholds established by the SEC in its new definitions. Investors are urged to also consider closely the disclosure in our filings with the SEC, available from our website at http://www.endeavourcorp.com. Endeavour is also subject to the requirements of the London Stock Exchange and considers the disclosures in this release to be appropriate and/or required under the guidelines of that exchange.

SOURCE: Endeavour International Corporation

CONTACT: Investor Relations, Mike Kirksey of Endeavour,+44-(0)-207-451-2364, or +1-713-307-8788; or United Kingdom Broker, JeffreyAuld of Canaccord Adams, +44-(0)-207-050-6500, for Endeavour; or UK Media,Philip Dennis, +44-(0)-207-743-6363, or Henry Lerwill,+44-(0)-203-178-6242, both of Pelham Public Relations, for Endeavour