ATP Oil & Gas Corporation (ATP) is engaged in the acquisition, development and production of oil and natural gas properties in the Gulf of Mexico and the United Kingdom and Dutch Sectors of the North Sea (the North Sea). At December 31, 2008, the Company owned leasehold and other interests in 77 offshore blocks, 41 platforms and 129 wells, including 22 subsea wells, in the Gulf of Mexico. It operates 111 (86%) of these wells, including all of the subsea wells, and 78% of offshore platforms. It also had interests in 10 blocks and two Company-operated subsea wells in the North Sea. The Company’s average working interest in these properties was approximately 76%. ATP had leasehold interests located in the Gulf of Mexico and North Sea covering approximately 412,000 gross and 307,836 net acres, of which 255,638 gross acres were developed and 158,386 net acres were developed.