ATP Estimates 585 Bcfe of New Recoverable Hydrocarbons

ATP Oil & Gas Corp.

ATP Oil & Gas Corp. said the company's management estimates that the amount of new recoverable hydrocarbons from reservoirs not included in its year-end 2005 reserve reports is 585 Bcfe. As of December 31, 2005, ATP reported 1.1 Tcfe of proved, probable and possible reserves, 758 Bcfe of proved and probable reserves, and 527 Bcfe of proved reserves, all prepared by third-party independent reservoir engineers. These amounts do not include management's estimate of recoverable hydrocarbons of 585 Bcfe.

Oil and gas reservoirs with logged hydrocarbons, including those recently acquired by ATP, have not yet been evaluated by third party independent reservoir engineers. In addition, ATP has acquired several properties without logged hydrocarbons which have demonstrated exploration opportunities that management believes are relatively low-risk and most are step-out locations to existing reserves.

Twelve ATP properties with logged hydrocarbons have been evaluated by management and it is management's estimate that they contain recoverable hydrocarbons of 360 Bcfe. Five of those properties with logged hydrocarbons plus three additional properties have identified exploration targets. It is management's estimate that these exploration opportunities contain 225 Bcfe of recoverable hydrocarbons. The following table sets forth management's estimates of the recoverable hydrocarbons for those properties acquired during 2006 and those properties owned as of December 31, 2005:

               		Logged    	Exploration    	Total
              		Hydrocarbons  	Opportunities  	Estimated
2006 Acquisitions
 Telemark, Mirage,     	190 Bcfe    	60 Bcfe    	250 Bcfe
  Oasis and Morgus
 Green Canyon 37      	45 Bcfe    	50 Bcfe     	95 Bcfe

Properties owned at
 Gomez           	30 Bcfe    	70 Bcfe    	100 Bcfe
 Other Properties      	95 Bcfe    	45 Bcfe    	140 Bcfe
Total            	360 Bcfe    	225 Bcfe    	585 Bcfe

The largest accumulation of unrecorded recoverable hydrocarbons is 250 Bcfe at the four-property group comprising Telemark (Atwater Valley 63), Mirage (Mississippi Canyon 941), Oasis (Mississippi Canyon 943) and Morgus (Mississippi Canyon 942). Previous drilling with logged hydrocarbons at Telemark, Mirage and Morgus has identified approximately 190 Bcfe of recoverable hydrocarbons at those locations. Management believes an additional 60 Bcfe may be recoverable through exploration. ATP has begun building a spar that is scheduled to be installed at the complex in early 2008. While final design parameters may change, initial design is for at least two risers, a 2,000 horsepower platform drilling rig, 20,000 to 30,000 Bbls of daily oil throughput and 60 to 100 MMcfe of daily natural gas throughput. ATP has a 100% working interest in and is operator of all four blocks at Telemark, Mirage, Oasis, and Morgus.

The next largest area of unrecorded hydrocarbons in management's opinion is 100 Bcfe at ATP's Gomez (Mississippi Canyon 711) property. Recent drilling at the #5 well and additional identified sands in the existing wells provide an estimated 30 Bcfe of logged hydrocarbons in zones that were not previously recorded in ATP's reserve reports. A location in the southern portion of the block and targets at Mississippi Canyon 667/668, immediately north of Gomez, account for an estimated 70 Bcfe of recoverable hydrocarbons from exploratory targets. Production at those locations will flow through the facility at Gomez. Current capacity of the Gomez production facility is 20,000 Bbls of oil per day and 60 MMcfe per day of natural gas. ATP has a 100% working interest in and is operator of the blocks at Gomez.

Green Canyon 37, a 2006 acquisition, accounts for the third largest area of unbooked hydrocarbons. Management's estimate of recoverable hydrocarbons is approximately 95 Bcfe and is essentially split between an exploration target and zones identified by logged hydrocarbons. Current plans are for work to begin at this location in 2007 or 2008, with first production approximately 18 months later. ATP has a 100% working interest in and is operator of Green Canyon 37.

Other operations in the Gulf of Mexico include Ladybug (Garden Banks 409), West Cameron 663, High Island A-589, Ship Shoal 351, and South Marsh Island 189/190. At Cheviot in the North Sea, ATP has identified recoverable hydrocarbons, all from logged hydrocarbons, which have not been booked. There are also exploratory targets at Cheviot and Wenlock that are still being evaluated that are not included in these estimates. Collectively, these properties account for another 140 Bcfe net to ATP (95 Bcfe from logged hydrocarbons and 45 Bcfe from exploratory targets) of recoverable hydrocarbons based on management's estimates. ATP has a 50% to 100% working interest in these blocks and is operator of all of these blocks.

ATP is currently working with its independent reservoir engineers to determine their estimates of the amount and SEC classification of these recoverable hydrocarbons. In addition, ATP will continue to evaluate these and other properties for unrecorded recoverable hydrocarbons as well as adjustments to those reserves that have been recorded.

ATP Oil & Gas is focused on development and production of natural gas and oil in the Gulf of Mexico and the North Sea.