ATP Drills 10 for 10 Successful Wells.

HOUSTON -- ATP Oil & Gas Corporation (NASDAQ:ATPG) today announced a summary of its 2006 operations where it is four for four on exploratory wells and six for six on development wells. ATP also announced an update on its production and acquisitions in the Gulf of Mexico and North Sea.

Drilling Operations - Thus far in 2006, ATP has major interests in 10 wells, all of which have been successful and all of which have been or will be completed for production. Development wells, those with reserves classified at December 31, 2005 as proved undeveloped, include:

Gulf of Mexico:
        West Cameron 663 (Working Interest "WI" 100%)
        Mississippi Canyon 711 (WI 100%)
        West Cameron 237 (WI 75%)

    North Sea:
        L06-d, Dutch Sector (WI 50%)
        Tors, UK Sector Kilmar K1 (WI 85%)
        Tors, UK Sector Kilmar K2 (WI 85%)

Also of significance is ATP's success at those wells that must be classified as "exploratory", wells that did not have "proved" reserves according to the definition of proved reserves by the SEC. Thus far in 2006, ATP is four for four in the exploratory well category.

Gulf of Mexico:
        South Marsh Island 166 (WI 100%)
        High Island 74 (WI 41%)
        West Cameron 462 (WI 100%)
        South Marsh Island 233 (WI 30%)

ATP's West Cameron 663 well encountered not only larger reservoirs than expected in the proved undeveloped zone but also discovered additional sands that were not included in the December 31, 2005 reserve report. The new zone is approximately 80-90' of natural gas pay in a shallower reservoir. The jacket and deck which is being reused from High Island 354 is being installed. The four-mile pipeline to ATP's Garden Banks 142 platform is expected to be completed in the third quarter 2006. First production is expected in the fourth quarter 2006. ATP is the operator with a 100% working interest.

In the Deepwater Gulf of Mexico, the Ocean Quest drilling rig is on location at ATP's Mississippi Canyon 711 ("Gomez"). Two pay zones have been gravel packed in the #5 well and the well should be completed during the third quarter 2006. Installation of a subsea flow line will follow in the fourth quarter. As with West Cameron 663, the #5 well at Gomez was completed in the proved undeveloped zone and in a new sand which was not included in our December 31, 2005 reserve report. In March 2006, ATP placed online the first two wells at Gomez. Since then, the wells have produced at combined rates as high as 85 MMcfe/d. Facility constraints have limited production volumes due to issues with compression and separation. Work is ongoing to eliminate these bottlenecks. Early performance data indicates both of the wells are exceeding the company's expectations.

At West Cameron 237, the development well has reached total measured depth at 7,616' and is undergoing completion operations. First production is projected during the third quarter 2006.

In the North Sea, the L06-d development in the Dutch Sector was completed in the first quarter 2006 and continues to produce at high rates as expected by ATP. At Tors in the UK Sector, the Kilmar K1 well began production on April 2, 2006. During the second quarter it has produced at rates as high as 50 MMcfe/d, which is above the original expected rates for the well. Start-up operations during the second quarter included an unexpected shut-in during June for thirteen days for gas transmission system maintenance. The Ensco 70 drilling rig is on location drilling the Kilmar K2 well at Tors after which it will move to the Garrow phase of the Tors development. The platform for the Garrow field, the second phase of the development at Tors, has been installed and the pipeline was laid. When fully developed, the Kilmar and Garrow fields are expected to have at least three producing wells with net production of 50-75 MMcfe/d. ATP is the operator of the Tors with an 85% working interest.

South Marsh Island 166 (100% WI), an exploratory well, was drilled in late 2005, completed in early 2006 when the facilities were installed and placed on production in the second quarter 2006.

The exploratory well at High Island 74 was completed in the first quarter 2006. This well, north of ATP's producing well in the southern portion of the block, targeted a deeper sand at the 16,500' level. The well will be tied back to ATP's platform in the southern portion of the block with first production expected in the fourth quarter 2006.

At West Cameron 462, ATP has both a proved undeveloped location and an exploratory opportunity. The first well, the exploratory target, was drilled to total depth and encountered new natural gas pay. The second well, the development well which has already been drilled, is scheduled to be completed early 2007. The platform and pipeline installation should be completed during the first quarter 2007. The first well along with the second well will be tied back to a nearby sales pipeline with first production scheduled for the first half of 2007. There were no reserves included in the year-end 2005 reserve report for the exploratory well. ATP is the operator of West Cameron 462 with a 100% working interest.

South Marsh Island 233 was acquired as part of a package in late 2005. The exploratory well reached total depth at 7,100' and encountered the targeted sand. The pipeline is currently being completed with first production planned for the fourth quarter 2006.

Production - In addition to the new production noted above, Ship Shoal 358 resumed production on April 7 and Ship Shoal 321 on July 21 following 2005 hurricane related repairs. Production for the second quarter was impacted by the temporary circumstance of gas processing curtailment at MC 711 and the temporary pipeline maintenance shut-in at Tors. Production at Grand Isle 9A (50% WI) was shut-in beginning the early part of the third quarter. King's Peak, a producing property acquired in September 2005 which achieved payout before year end 2005, is currently off production. The undeveloped locations at King's Peak, which were primary reasons for the acquisition, are slated for development in 2007 and 2008. Helvellyn, a seasonal well in the UK Sector of the North Sea, was taken offline in May 2006. The company anticipates resuming production at Helvellyn in the fourth quarter 2006 after its planned summer shut-in.

ATP expects second quarter 2006 production of approximately 150 MMcfe/d, an increase of more than double from the first quarter 2006 rates of 66 MMcfe/d. With the new development operations noted above, ATP believes it will continue to steadily increase its production to higher levels heading into the higher price winter season. ATP continues to expect 2006 production to be within the estimated range ATP had projected for the year with additional growth coming in 2007 and 2008.

Acquisitions - Thus far in 2006, ATP has acquired five blocks, all with a 100% working interest and all operated by ATP. The blocks, Telemark (Atwater Valley 63), Mirage (Mississippi Canyon 941), Oasis (Mississippi Canyon 943), Morgus (Mississippi Canyon 942) and Green Canyon 37 are located in the Gulf of Mexico deepwater. These blocks demonstrate a continuing commitment by ATP to expand its inventory of future developments on projects where previous operations have shown the presence of hydrocarbons. Four of the five blocks have previous drilling where hydrocarbons have been discovered but have not yet been developed. In addition there are several identified exploration targets on these blocks. ATP is currently working with its independent engineers to determine their estimates of the amount and classification of the proved reserves associated with these acquisitions. ATP expects to issue before the end of the week its own estimate of the recoverable hydrocarbons associated with these acquisitions.

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 Global Select 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. More information about the risks and uncertainties relating to ATP's forward-looking statements are found in our SEC filings.