ATP Achieves First Production at Tors.

HOUSTON & SURREY, England -- ATP Oil & Gas Corporation (NASDAQ:ATPG) today announced first production from its Tors development located in Block 43/22 ("Kilmar" field) of the Southern Gas Basin of the U.K. North Sea. The Company's wholly-owned subsidiary, ATP Oil & Gas (UK) Limited, is the operator and owns an 85% working interest.

The Kilmar production is the first phase of the Company's development at Tors and is from the first well of at least four wells scheduled for Tors, which is located in 180 feet of water. As of December 31, 2005, ATP's published independent reserve reports estimated Tors at approximately 73 Bcfe net proved reserves and 42 Bcfe net probable reserves. When fully developed, ATP estimates Tors will add net production of approximately 50-75 MMcf/d to its current production levels.

T. Paul Bulmahn, Chairman and President of ATP, stated, "First production at Tors significantly contributes to ATP's near-term ramp in production. Also of significance is that it is in the North Sea where developments are usually marked in terms of years and ATP brought Tors to production in less than nine months from the issuance of the field development plan approval. I commend both our U.K. team and the involvement from our U.S. operations in achieving this accomplishment."

About ATP Oil & Gas

ATP Oil & Gas is focused on development and production of natural gas and oil in the Gulf of Mexico and the North Sea. The Company trades publicly as ATPG on the NASDAQ National Market.

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" 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 reserves in this press release have been prepared by our independent third party engineers. More information about the risks and uncertainties relating to ATP's forward-looking statements are found in our SEC filings.