ATP Announces Deepwater Development Update and Fourth Quarter and Annual 2009 Results

ATP Oil & Gas Corporation (NASDAQ: ATPG) today issued its annual 2009 results, a 376% reserve replacement ratio, and announced that its major deepwater Gulf of Mexico development, the Telemark Hub, is on schedule for first production later this month. At ATP’s other deepwater development, the Canyon Express Hub, the MC 217 #3 well was placed on initial production March 11, 2010 at 30 MMcf/d gross.

Telemark Hub Update
ATP’s major deepwater Gulf of Mexico development, the Telemark Hub, is on schedule to commence production during March 2010 from the Atwater Valley 63 # 4 well.

This well was tested in February at a gross rate in excess of 10,700 Boe/d from two zones. The ATP Titan, the Telemark Hub’s state-of-the-art floating production and processing facility, is in the final stages of commissioning following the installation of all major production and processing components. The sales pipelines have been hydro-tested and dewatered.

The initial sections of the Nabor’s platform rig 202 began arriving this week. Following erection of the drilling rig on the ATP Titan over the next several weeks, ATP will begin the process of re-entering and completing the Mississippi Canyon (“MC”) 941 #3 well. The MC 941 #3 well, which has been drilled and cased, is expected to commence production in the second quarter 2010. In September 2009, this well encountered 266’ of net pay, triple the amount of net pay found in the original control well.

ATP operates the Telemark Hub with a 100% working interest and owns 100% of the ATP Titan and associated pipelines and infrastructure.

Canyon Express Hub Update

At King’s Peak, the MC 217 #3 well began production through the Canyon Express pipeline on March 11, 2010 at a gross rate of 30 MMcf/d. At Aconcagua, MC 305, two additional wells, the #3 and #4, are scheduled to resume production at a rate of 30 MMcf/d gross, bringing the entire Canyon Express Hub production rate up to 60 MMcf/d gross.

ATP operates the Canyon Express Hub with a greater than 50% working interest in the wells and associated pipelines, which have a throughput capacity of approximately 500 MMcf/d.

Results of Operations

Oil revenues rose to 75% of total oil and gas revenues in 2009 compared with 56% in 2008. Oil and gas production for 2009 was 5.9 MMBoe compared to 9.6 MMBoe for 2008. In the fourth quarter 2009, ATP produced 1.3 MMBoe compared to 0.9 MMBoe in the fourth quarter 2008. With the startup of production at the Telemark Hub, ATP anticipates a further increase in its oil revenues as a percent of total revenues as well as its oil to gas production ratio during 2010.

Lease operating expense was $85.0 million for 2009 and $24.5 million for the fourth quarter 2009, compared to $91.2 million for 2008 and $18.1 million for the fourth quarter 2008. Lease operating expense for 2009 decreased compared to 2008 primarily due to the sale of 80% of the two North Sea properties mentioned above and from reduced fuel and chemical costs in the Gulf of Mexico. These cost decreases were partially offset by increases related to insurance premiums and nonrecurring workover activities at various Gulf of Mexico and North Sea properties.

General and administrative expense was $44.2 million for 2009 and $19.1 million for the fourth quarter of 2009, compared to $41.7 million for 2008 and $14.4 million for the fourth quarter of 2008. The general and administrative expense increased in 2009 compared to 2008 due primarily to the payment of third party fees related to ATP’s debt modification in the fourth quarter 2009.

Interest expense decreased to $40.9 million in 2009 compared to $100.7 million in 2008 primarily due to 2009 capitalized interest of $110.1 million compared to capitalized interest of $44.6 million in 2008. Capitalized interest in 2009 increased due to higher average construction work-in-progress balances.

ATP recorded a net loss attributable to common shareholders of $51.8 million or $1.24 per basic and diluted share for 2009, compared to net income of $121.7 million or $3.43 per basic and $3.39 per diluted share for 2008. For the fourth quarter, ATP recorded a net loss of $40.0 million or $0.80 per basic and diluted share, compared to net income of $50.2 million or $1.41 per basic and diluted share for the fourth quarter 2008. Fourth quarter results were impacted by delays related to a well recompletion at ATP’s Gomez Hub. The recompletion of the MC 711 #4 well was successful in January 2010 and, as a result, the comingled well tested at a net rate in excess of 4,600 Boe/d.

The net loss for the fourth quarter 2009 was impacted by several nonrecurring items research analysts typically exclude from their published estimates including an after-tax impairment at several Gulf of Mexico shelf properties of $24.1 million, an after-tax gain on the sale of properties of $8.5 million, an after-tax expense of $4.0 million relating to debt modification and an unrealized after-tax loss on derivatives of $10.1 million. Accordingly, net loss before these nonrecurring items, a non-GAAP measure, in the fourth quarter 2009 was $10.3 million or $0.20 per basic and diluted share. For the same metric in 2008, ATP recorded net income of $78.4 million or $2.21 per basic and $2.20 per diluted share. A reconciliation of non-GAAP net income is provided below:

ATP's selected operating statistics and financial information below contain additional information on the company’s activities for the year and fourth quarter of 2009 and the comparable periods in 2008.

Proved Reserves

ATP reported independent third-party proved reserves at year-end 2009 of 135.2 MMBoe. ATP’s proved reserves are located 62% in the deep waters of the Gulf of Mexico, 6% on the Gulf of Mexico shelf and 32% in the North Sea. The December 31, 2009 pre-tax PV-10 was determined using SEC pricing. All of the proved reserves shown below were prepared by independent reservoir engineers whose certification letters are available on ATP’s web site.

ATP achieved a 376% reserve replacement ratio from all sources in 2009, based on net additions of 22.0 MMBoe. A reconciliation of ATP’s reserve replacement ratio and the changes in proved reserves from December 31, 2008 to December 31, 2009 is provided below.

Transactions

During 2009, ATP closed a series of capital market, asset monetization, and financing transactions, a summary of which is provided below:

First Quarter

• Raised $149 million from the sale of a redeemable noncontrolling interest in ATP-IP. ATP continues to hold a 51% interest in ATP-IP, the entity that owns the ATP Innovator;

Second Quarter

• Completed a $68 million common stock issuance, net of fees and expenses;
• Conveyed limited-term net profits interests (“NPIs”) to three vendors in exchange for their services for a total expected value of approximately $200 million;

Third Quarter

• Executed an agreement with the contractor to defer approximately $99 million of Octabuoy hull construction costs without delaying the construction schedule;
• Realized $75 million, net of fees and expenses, from monetizing both the oil and natural gas pipelines that service ATP’s Gomez Hub;
• Raised $93 million by selling common stock and $136 million by selling convertible perpetual preferred stock, net of fees and expenses;

Fourth Quarter

• Conveyed a limited-term dollar denominated overriding royalty interest for $15 million;
• Sold a 25% working interest in the deep operating rights in one of our properties for $13 million.

ATP has continued this monetization program in 2010. On January 6, 2010, ATP completed a $140 million limited-term overriding royalty interest transaction. ATP intends to monetize other assets, primarily the ATP Titan or other Telemark Hub infrastructure, and potentially other overriding royalty and net profits interests in 2010.

As a result of the above transactions, ATP reduced its Term Loans from $1.4 billion at December 31, 2008 to $1.2 billion at December 31, 2009. Substantially all of this reduction related to the Asset Sale Facility tranche of our Term Loan Facility falling from $326.7 million at year-end 2008 to $160.7 million at year-end 2009. Additional reductions in 2010 have decreased the outstanding balance to $146.0 million as of March 11, 2010. ATP was in compliance with the covenants of its Term Loans and expects to remain in compliance throughout 2010.

Hedging and Derivative Update

Since ATP announced third quarter earnings on November 5, 2009, ATP has been active in the U.S. derivatives market, hedging 3.1 million Bbls of crude oil at prices ranging from $73.15 per Bbl to $81.00 per Bbl and 3.7 Bcf of natural gas at $5.42 per MMBtu. ATP plans to add additional hedges throughout 2010 to coincide with the ramp-up in production at the Telemark Hub.

In addition, ATP unwound 2.1 MMMBtu of natural gas collars in the U.K. and replaced them with 1.8 Bcf of natural gas swaps at an average price of $5.45 per MMBtu. A detailed hedge and derivative schedule is provided near the end of this press release.

4^th Quarter and Year-End 2009 Conference Call

ATP management will host a conference call on Friday, March 12th at 10:00 am CT to discuss the company's year-end 2009 results followed by a Q&A session.

Date: Friday, March 12, 2010

Time: 11:00 am ET; 10:00 am CT; 9:00 am MT and 8:00am PT

ATP invites interested persons to listen to the live webcast on the company's website at www.atpog.com. Phone participants should dial 877-675-4757. A digital replay of the conference call will be available at 888-203-1112, ID# 9413300, for a period of 24 hours beginning at 1:00 pm CT, and the webcast will be archived for 30 business days at www.atpog.com.

About ATP Oil & Gas Corporation

ATP Oil & Gas is focused on development and production of oil and natural gas 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. During December 2008, the SEC issued the final rule, “Modernization of Oil and Gas Reporting” and we have adopted it as of December 31, 2009. Those new regulations allow, among other things, disclosure of probable and possible reserve quantities in reports filed with the SEC. While we do not include such reserves in our filings with the SEC, our publicly available independent third party reservoir engineering reports set forth probable and possible reserve quantities. We and our independent third party reservoir engineers use the term “probable” to describe volumes of reserves potentially recoverable through additional drilling or recovery techniques that, by their nature, are more speculative than estimates of proved reserves. All estimates of reserves in this news release have been prepared by our independent third party engineers. More information about the risks and uncertainties relating to ATP's forward-looking statements is found in our SEC filings.

ATP Oil & Gas Corporation, Houston
Chairman and CEO
T. Paul Bulmahn, 713-622-3311
or
Chief Financial Officer
Albert L. Reese Jr., 713-622-3311
www.atpog.com