ATP Increases Gulf of Mexico Reserves by 32%

ATP Oil & Gas says that progress on its Gulf of Mexico development program by the end of the first quarter increased proved developed producing reserves 32% compared to year-end 2002. The Company completed two developments, Eugene Island 71 and West Cameron 101, and placed them on production during the latter part of March. The combined production from these two fields led to an exit production rate on March 31, 2003 of 70 MMcfe per day, compared to first quarter average production of 56 MMcfe per day.

The company's third Gulf of Mexico development in 2003, West Cameron 284, is underway and on schedule for first production near the end of the second quarter. The Company developed this field by installing a caisson and drilling and completing a horizontal and a vertical well. With first production from West Cameron 284 in the second quarter and successful execution of our Gulf of Mexico developments in the second half of this year, the Company anticipates continued growth in proved developed producing reserves throughout the remainder of the year.