June 17, 2008

Mariner Energy Announces Deepwater Discovery at Its Geauxpher Prospect on Garden Banks 462

HOUSTON, June 17 /PRNewswire-FirstCall/ -- Mariner Energy, Inc. today announced a deepwater discovery on its Geauxpher prospect located on Garden Banks Block 462. The well, which lies in water depths of approximately 2,700 feet, was drilled to a total depth of 23,156 feet (measured depth). Mariner estimates the field's gross proved and probable reserves on the block to be approximately 100 billion cubic feet of natural gas equivalent. Development is underway with initial production expected as soon as year-end 2008.

Mariner is the designated operator at Garden Banks 462 and holds a 60% working interest in the discovery. Apache Corporation holds the remaining 40% interest. In November 2007 Mariner farmed into Geauxpher, providing the rig to test the prospect. The drilling rig remains on location and a second well is planned to delineate the extent of the discovery. Mariner has identified additional potential on the block and expects to test these amplitudes over time.

Scott D. Josey, Chairman, Chief Executive Officer, and President of Mariner Energy said, "Our discovery at Geauxpher provides further evidence of the value potential in Mariner's deepwater prospect inventory. It is a credit to the capabilities of our commercial, exploration and development teams that identify and convert these opportunities into value for our shareholders. We appreciate the opportunity to work with Apache on this project."

Mariner also announced that it has expanded its deepwater prospect inventory, farming into the Heidelberg Miocene subsalt prospect with a 12.5% interest. Heidelberg is operated by Anadarko Petroleum Corporation on Green Canyon blocks 816, 859, 860 and 903. An exploration well is expected to spud on the acreage by year-end 2008.

About Mariner Energy, Inc.

Mariner Energy is an independent oil and gas exploration, development, and production company headquartered in Houston, Texas, with principal operations in West Texas and the Gulf of Mexico. For more information about Mariner, visit the company's website at http://www.mariner-energy.com/.

Important Information Concerning Forward-looking Statements

This press release includes 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. All statements, other than statements of historical facts, that address activities that Mariner assumes, plans, expects, believes, projects, estimates or anticipates (and other similar expressions) will, should or may occur in the future are forward-looking statements. Our forward-looking statements generally are accompanied by words such as "may", "will", "estimate", "project", "predict", "believe", "expect", "anticipate", "potential", "plan", "goal" or other words that convey the uncertainty of future events or outcomes. Forward-looking statements in this press release are based on Mariner's current belief based on currently available information as to the outcome and timing of future events and assumptions that Mariner believes are reasonable. Mariner does not undertake to update its guidance, estimates or other forward-looking statements as conditions change or additional information becomes available. Mariner cautions that its forward-looking statements are subject to all of the risks and uncertainties normally incident to the exploration for and development, production and sale of oil and natural gas. These risks include, but are not limited to, price volatility or inflation, environmental risks, drilling and other operating risks, regulatory changes, the uncertainty inherent in estimating future oil and gas production or reserves, and other risks described in the Annual Report on Form 10-K for the fiscal year ended December 31, 2007, and other documents filed by Mariner with the Securities and Exchange Commission (SEC). Any of these factors could cause Mariner's actual results and plans to differ materially from those in the forward-looking statements. Investors are urged to read the Annual Report on Form 10-K for the year ended December 31, 2007 and other documents filed by Mariner with the SEC.

The SEC generally has permitted oil and gas companies, in their filings with the SEC, to disclose only proved reserves that a company has demonstrated by actual production or conclusive formation tests to be economically and legally producible under existing economic and operating conditions. Mariner uses the terms "probable,""possible" and "non-proved" reserves, reserve "potential" or "upside" or other descriptions of volumes of reserves potentially recoverable through additional drilling or recovery techniques that the SEC's guidelines may prohibit it from including in filings with the SEC. These estimates are by their nature more speculative than estimates of proved reserves and accordingly are subject to substantially greater risk of actually being realized by Mariner.

This press release does not constitute an offer to sell or a solicitation of an offer to buy any securities of Mariner.

Mariner Energy, Inc.

CONTACT: Patrick Cassidy of Mariner Energy, Inc., office,+1-713-954-5558, or mobile, +1-713-261-2627, [email protected]

Web site: http://www.mariner-energy.com/