--  Year-over-year net production increased 18% to 118.4 billion cubic       feet equivalent (Bcfe)   --  217% reserve replacement rate from all sources   --  Year-end estimated proved reserves up 17% to 973.9 Bcfe   --  Net loss for the year of $388.7 million ($4.44 per share).  Adjusted       net income, which excludes a non-recurring, non-cash gain and non-cash       charges, was $284.1 million or $3.25 per share (see reconciliation of       this non-GAAP measure below).   --  Operating cash flow was $885.9 million for the full 2008 fiscal year,       an increase of 42% from 2007 (see reconciliation of this non-GAAP       measure below).   

Commenting on Mariner's 2008 results, Scott D. Josey, Mariner's Chairman, Chief Executive Officer and President, said: "Despite plummeting commodity prices, hurricanes, and the turmoil in the financial markets, Mariner posted another record year. Our capital program was very successful in 2008, with quality acquisitions, an 80% success rate offshore, and 100% success onshore. While non-cash impairments necessitated by low year-end commodity and stock prices negatively affected our earnings, our fundamentals are good.

"Economic circumstances continue to present challenges in the year ahead, but we are off to a good start in 2009. Our capital program should not only allow us to live within our cash flows, but also to increase production and pay down debt while exposing our shareholders to upside potential. We intend to carefully monitor changing industry and general economic conditions and can quickly adjust our capital program as circumstances warrant."

NON-CASH GAIN AND CHARGES

The company's results for 2008 reflect a non-recurring, non-cash gain of $46.5 million for the release as of year-end of suspended revenue associated with a disputed MMS royalty liability. Based on low commodity prices at year-end, Mariner recorded a full cost ceiling test impairment of its proved oil and gas properties in the amount of $575.6 million. The company also recorded other impairments, including goodwill, of $310.9 million for the year. Additionally, Mariner recognized a non-cash charge of $36.0 million for a contingent insurance premium. These items are detailed below in the reconciliation of adjusted net income, a non-GAAP measure.

FOURTH QUARTER 2008 RESULTS

For the three-month period ended December 31, 2008, Mariner reported a net loss of $648.9 million, or $7.41 per basic and fully-diluted share, which reflects the non-cash gain and charges cited above. This compares with net income of $50.2 million and basic and fully-diluted earnings per share of $0.59 and $0.58, respectively, for the same three-month period in the prior year. Adjusted net income, which excludes the non-cash gain and charges, was $14.5 million for fourth quarter 2008, or $0.17 per basic and fully-diluted share (see reconciliation of this non-GAAP measure below). The lower year-over-year results are due primarily to decreased production volumes as a result of Hurricanes Ike and Gustav and lower commodity prices.

Net production for fourth quarter 2008 was 23.5 Bcfe, compared with 27.1 Bcfe for fourth quarter 2007. Total natural gas net production for fourth quarter 2008 was 16.1 billion cubic feet (Bcf), compared with 18.4 Bcf for the same period in the prior year. Total net oil production for fourth quarter 2008 was 1.0 million barrels (MMBbls), compared with 1.1 MMBbls for the same period in 2007. Natural gas liquids (NGL) net production for fourth quarter 2008 was 0.3 MMBbls, compared with 0.3 MMBbls for fourth quarter 2007.

For fourth quarter 2008, Mariner's average realized natural gas price was $7.44 per thousand cubic feet (Mcf) compared with $8.07 per Mcf for the same period in 2007. Mariner's average realized oil price was $65.29 per barrel (Bbl) for fourth quarter 2008, compared with $79.64 per Bbl for fourth quarter 2007. The average realized NGL price was $26.63 per Bbl for fourth quarter 2008, compared with $55.32 per Bbl for the same period in 2007. Average realized prices reflect settlements during the period under Mariner's hedging program.

FULL-YEAR 2008 RESULTS

For the 12-month period ended December 31, 2008, Mariner reported a net loss of $388.7 million, which equates to a loss of $4.44 per basic and fully-diluted share. For the same period in the prior year, Mariner reported net income of $143.9 million, or $1.68 per basic share/$1.67 per fully-diluted share. Adjusted net income, which excludes the non-cash gain and charges noted above, was $284.1 million or $3.25 per share (see reconciliation of this non-GAAP measure below).

For the full-year 2008, Mariner reported net production of 118.4 Bcfe, up from 100.3 Bcfe reported in 2007. Total natural gas net production during 2008 was 79.8 Bcf at an averaged realized price of $9.31 per Mcf, compared with 67.8 Bcf for 2007 at an average realized price of $7.88 per Mcf. Total net oil production for 2008 was 4.9 MMBbls at an average realized price of $86.02 per Bbl, compared to 4.2 MMBbls during 2007 at an average realized price of $67.50 per Bbl. Total NGL net production during 2008 was 1.6 MMBbls at an average realized price of $55.02, compared to 1.2 MMBbls at an average realized price of $45.16 per Bbl for the prior year. Average realized prices reflect settlements during the period under Mariner's hedging program.

Operating cash flow was $885.9 million for the full 2008 fiscal year, an increase of 42% from $622.6 million in 2007. (See reconciliation of this non-GAAP measure below.)

Mariner's capital expenditures for the fourth quarter and full-year 2008 are summarized in the table below.

                                                      Fourth      Full-                                                      Quarter     Year                                                       2008       2008                                                       ----       ----                                                        (In Millions)    Exploration                                        $43.8     $423.3    Development     Gulf of Mexico - Deepwater                       $97.5     $280.8     Gulf of Mexico - Shelf                            42.6      198.8     Permian Basin                                     30.3      108.8                                                       ----      -----    Acquisitions                                       $48.2     $302.6    Corporate expenditures and other                   $14.7      $66.7          Total Capital Expenditures                  $277.1   $1,381.0     YEAR-END 2008 ESTIMATED RESERVES   

Mariner today also announced results of an independent, fully-engineered analysis of the company's proved and probable reserves prepared by the Ryder Scott Company, L.P. The report utilizes hydrocarbon prices in effect at December 31, 2008 of $44.61 per barrel for oil and $5.71 per million British Thermal Units for gas in accordance with Securities & Exchange Commission (SEC) requirements.

   Highlights from the report and year-end operations review include:    --  Estimated proved reserves increased 17% to a record 973.9 Bcfe.   --  Mariner achieved a reserve replacement rate of 217% from all sources       at an all-in reserve replacement cost, net of hurricane expenditures,       of $4.96 per thousand cubic feet equivalent (Mcfe), excluding probable       and possible reserves.   --  Including probable reserves estimated by Ryder Scott at 285 Bcfe,       Mariner's estimated proved and probable reserve base exceeds 1.25       trillion cubic feet of natural gas equivalent.   --  70% of Mariner's estimated proved reserves are proved developed.   

Commenting on Mariner's year-end reserves, Mr. Josey said: "Mariner's proved reserves increased across each of its core areas during 2008. Although we achieved significant reserve growth, delays in the completion of several offshore projects due to the effects of Hurricanes Ike and Gustav reduced our reserve growth. As a result, we booked a relatively small amount of proved reserves on these projects despite substantial capital outlays for them. In 2009, we expect to add significant incremental proved reserves attributable to these projects when they are completed or come online. The company wrote down 29 Bcfe of proved reserves due to low year-end commodity prices, but we expect these reserves to be restored if drilling and completion costs adjust to the current commodity price environment."

The following table sets forth certain information with respect to our estimated proved reserves by geographic area as of December 31, 2008. Reserve volumes and values were determined under the method prescribed by the SEC, which requires the application of period-end prices and costs held constant throughout the projected reserve life. Proved reserve estimates do not include any value for probable or possible reserves, nor do they include any value for undeveloped acreage. The proved reserve estimates represent Mariner's net revenue interest in its properties.

                                 Estimated Proved Reserve                                         Quantities                                Natural      Oil     NGLs   Total  % of Total                                  Gas     (MMBbls) (MMBbls) (Bcfe) Estimated                                 (Bcf)                              Proved                                                                   Reserves   Geographic Area   ---------------   Permian Basin                 136.2      27.3     22.7    436.6   44.8   Gulf of Mexico - Deepwater *  165.9       5.4      0.1    198.7   20.4   Gulf of Mexico - Shelf        255.9      11.1      2.7    338.6   34.8         Total                   558.0      43.8     25.5    973.9  100.0   Proved developed reserves     420.9      25.9     16.9    677.7   69.6    * Depths greater than 1,300 feet (the approximate depth of deepwater   designation by the Minerals Management Service of the United States   Department of the Interior)     OPERATIONAL UPDATE    Offshore   

Mariner was successful in 20 of its 25 offshore wells drilled in 2008.