ATP Provides Operations Update

ATP Oil & Gas Corporation (NASDAQ: ATPG) today announced an operations update:

• Drilling operations at the fourth Telemark Hub well at Mississippi Canyon (MC) Block 942 #2 are complete. ATP encountered 167 feet of new net pay sands above pre-drill estimates. These sands are in addition to the 72 feet of logged net oil pay seen in the original target sand. With this additional pay sand, ATP is modifying completion plans for MC 942 #2 and now expects to complete both hydrocarbon sands and establish production in late January 2012. ATP believes that these new pay sands will have a positive effect on production by extending the production life and third-party reserve estimates associated with MC 942.
• Operations continue at the second Clipper well at Green Canyon (GC) Block 300 #4, where ATP has encountered oil pay sands. The well encountered 56 feet of logged net oil pay confirming reserves already booked. Completion operations are underway. Production at Clipper is still scheduled to begin in the third quarter of 2012 upon the completion of a pipeline, which is already under contract.
• Third quarter production was 24,200 barrels of oil equivalent (BOE) per day, representing an increase of 14.7% over the same period a year ago.

ATP Chairman and CEO T. Paul Bulmahn stated, "ATP is excited with the drilling results from both the fourth Telemark Hub well, where we have encountered additional net pay sands above our projections, and the second Clipper well, which has now reached its total depth with completion operations underway. This development success demonstrates ATP’s commitment to advancing the company’s production growth, cash flow and asset base. ATP expects to begin production from the fourth Telemark well in the beginning of 2012, followed by additional planned production at Clipper and Gomez projects later in 2012, Entrada in 2013/2014 and Cheviot in 2014. We also look forward to drilling our first deepwater well at Shimshon in offshore Israel in 2012.”

Telemark Update

ATP encountered 167 feet of additional net pay sands above pre-drill estimates. These sands are in addition to the 72 feet of logged net oil pay seen in the original target sand at the Morgus well located at MC 942 #2.

Because of the considerable additional hydrocarbon-bearing sands, ATP is adjusting its completion plan to include two new gravel packs which will extend the projected completion time to late January 2012, and ATP expects a positive effect on production by extending the production life and third-party reserve estimates associated with MC 942.

The MC Block 942 #2 well, located in approximately 4,000 feet of water, was completed at a measured depth of 21,400 feet in the Miocene S sand at ATP’s deepwater Telemark Hub in the Gulf of Mexico. It is the fourth well that will be tied back to the ATP Titan floating drilling and production platform located at MC Block 941. ATP operates the deepwater Telemark Hub with a 100% working interest and owns 100% of the subsidiary that owns the ATP Titan and associated pipelines and infrastructure.

Clipper Update

ATP has encountered oil pay sands at the second Clipper well located at GC 300 in the deepwater Gulf of Mexico. The GC 300 #4 well, located in approximately 3,450 feet of water, encountered 56 feet of logged net oil pay confirming reserves previously booked. The 9-5/8 inch casing has been set at 15,778 feet measured depth through the pay intervals. The well will now be completed and tested. In July 2011, ATP successfully completed and flow tested the first Clipper well, GC 300 #2 ST #1, at a rate of 45.6 MMcf per day and 4,656 Bbls per day. The pipeline lay barge for the Clipper wells is contracted for third quarter 2012 and will tie in both the GC 300 #4 and #2 wells to the Murphy Oil operated Front Runner production facility. ATP operates Clipper and presently owns a 100% working interest.

Third Quarter 2011 Conference Call

ATP Oil & Gas Corporation (NASDAQ: ATPG) will host a conference call on Wednesday, November 9^th at 10:00 am CST to discuss the company’s third quarter results followed by a Q&A session.

3rd Quarter Results Conference Call

Date: Wednesday, November 9, 2011
Time: 11:00 am EST; 10:00 am CST; 9:00 am MST and 8:00 am PST

ATP invites interested persons to listen to the live webcast on the company’s website at www.atpog.com. Phone participants should dial 888-334-3020. A digital replay of the conference call will be available at 888-203-1112, ID# 7348227, for a period of 24 hours beginning at 1:00 pm CST.

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, Mediterranean Sea 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 oil and natural gas 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 ability to access them, and uncertainties regarding environmental regulations or litigation and other legal or regulatory developments affecting its business. While ATP does not file reports with the SEC containing probable and possible reserve quantities, ATP occasionally will include them in presentations and discuss such reserves publicly. ATP and its 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. Any 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 the company's SEC filings.