ATP Secures Drilling Rigs for 2008 and 2009 Developments

ATP Oil & Gas Corporation (NASDAQ:ATPG) today announced that it has recently secured four more drilling rigs for 2008 and 2009 in addition to two rigs, the Nabors 202 and Diamond Ocean Confidence, which were previously committed. The additional rigs are the Seadrill Americas West Sirius, the Hercules Rig 211, the Ensco 72 and the Diamond Ocean Victory. George Morris, ATP’s Chief Operating Officer said, "These recent and existing commitments allow us to maintain our schedule for developing our key properties. We now have secured rigs for our entire 2008 scheduled drilling program and for all but one well of our 2009 drilling program. Our development capital budget includes the cost of all of the 18 well operations to be commenced in 2008 and 2009. These rigs will be used to drill proved and probable undeveloped reserve locations that were on our books in the beginning of 2008, plus additional logged hydrocarbons and significant upside potential not yet on our books at several of our key properties including Clipper, which was acquired earlier this year.” Gulf of Mexico Deepwater Telemark Hub – The Seadrill West Sirius, a dynamically positioned rig, is expected to be on location over the Telemark Hub for a 90-day period commencing before the end of July 2008. The West Sirius will drill and run casing on the upper sections of two wells at Mirage (Mississippi Canyon Block 941) and, if time permits, take a third well to completion at Morgus (Mississippi Canyon Block 942). The bottom section of the remaining wells will be drilled and completed with the Nabors 202 platform rig, to be installed on the ATP MinDOC I, a floating drilling and production facility that will be moored at Mirage/Morgus early in 2009. ATP has recently entered into a letter of intent with contract signing anticipated for the semi-submersible Diamond Ocean Victory to drill and run casing in four wells at Telemark (Atwater Valley Block 63) beginning in mid-2009. Similar to the operation at Mirage/Morgus, after the pre-drilling is complete, ATP will move on location its second MinDOC, the MinDOC II. The Nabors 202 platform rig will then be transferred to the MinDOC II where it will be used to finalize drilling and complete the four wells. ATP has a 100% working interest in and operates the Telemark Hub, which is in 4000’ to 4500’ of water. Clipper (Green Canyon Block 299 and Block 300) – ATP acquired Clipper in June 2008. The Diamond Ocean Victory, a moored rig, is scheduled to sidetrack and complete one well and complete a second well on the property during the first half of 2009 after the rig concludes its current assignment. Previous drilling at Clipper has identified logged hydrocarbons at the targeted sands and these reserves are not included in ATP’s 2007 year-end reserve report. ATP expects to add the undeveloped reserves at Clipper to its proved and probable reserves during 2008. Clipper is in 3,400’ of water and ATP has a 55% working interest in and operates Clipper. Canyon Express Hub – The Diamond Ocean Confidence, a dynamically positioned rig, is scheduled to arrive in the second quarter of 2009. During a 150-day period, ATP expects to sidetrack/drill and complete two development wells, one at King’s Peak (Mississippi Canyon Block 217) and one at Aconcagua (Mississippi Canyon Block 305). After completing these two wells the Ocean Confidence will depart for another job and return after approximately one year to sidetrack/drill and complete two additional wells, one each at Aconcagua and De Soto Canyon Block 133. The Canyon Express Hub is in water depths of 6,400’ to 7,000’. ATP has working interests ranging from 50% to 66.67% on the various properties comprising the Canyon Express Hub and operates the wells and the Canyon Express Pipeline System. Gulf of Mexico Shelf West Cameron Block 462 – After installation of a tripod platform, the Hercules 211, a shallow-water jack-up rig, is scheduled to be on location at West Cameron Block 462 during August 2008. It is scheduled to complete two previously drilled wells and prepare them to commence production during the third quarter 2008. West Cameron 462 is located in 125’ of water. ATP has a 100% working interest in and operates West Cameron 462. U.K. North Sea Wenlock and Tors (U.K. North Sea) – The Ensco 72, a mid-sized jack-up, is scheduled to arrive at Wenlock during the fourth quarter of 2008. In December 2007, ATP completed and placed on production its first well in the Rotliegend formation at Wenlock. The Ensco 72 is scheduled to drill a second development well into the Rotliegend reservoir as well as a new appraisal/development well in another section of the block. ATP holds an option for a third well to be drilled with the Ensco 72. If exercised, the third well could be drilled at ATP’s developments at Tors or Wenlock, both of which are operated by ATP in the Southern Gas Basin in the U.K. North Sea. About ATP Oil & Gas Corporation ATP Oil & Gas is an international offshore oil and gas development and production company with operations in the Gulf of Mexico and the North Sea. The company trades publicly as ATPG on the Nasdaq Global Select Market. For more information about ATP Oil & Gas Corporation, visit www.atpog.com. Forward-looking Statements Certain statements included in this news release are "forward-looking statements” under the Private Securities Litigation Reform Act of 1995. ATP cautions that assumptions, expectations, projections, intentions, or beliefs about future events may, and often do, vary from actual results and the differences can be material. Some of the key factors which could cause actual results to vary from those ATP expects include changes in natural gas and oil prices, the timing of planned capital expenditures, availability of acquisitions, uncertainties in estimating proved reserves and forecasting production results, operational factors affecting the commencement or maintenance of producing wells, the condition of the capital markets generally, as well as our ability to access them, and uncertainties regarding environmental regulations or litigation and other legal or regulatory developments affecting our business. The SEC has generally permitted oil and gas companies, in filings made 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. We and our independent third party reservoir engineers use the terms "probable" and "possible” and we use the term "recoverable hydrocarbons” to describe volumes of reserves potentially recoverable through additional drilling or recovery techniques that the SEC's guidelines may prohibit us from including in filings with the SEC. These estimates are by their nature more speculative than estimates of proved reserves. All estimates of probable and possible reserves in this news release have been prepared by our independent third party engineers and all estimates of recoverable hydrocarbons have been prepared by management. More information about the risks and uncertainties relating to ATP's forward-looking statements are found in our SEC filings.