The Eugene Island Block 330 field is currently the largest oil-producing field in federally owned waters of the U.S. outer continental shelf. Located about 170 mi (272 km) southwest of New Orleans, the field was discovered by the Pennzoil 1 OCS G-2115 well in March 1971, after leasing on December 15, 1970. The field includes parts of blocks 313, 314, 330, 331, 332, 337, and 338, Eugene Island Area, South Addition, offshore Lousiana.

The field is an anticlinal structure on the downthrown side of a large northwest-trending growth fault. Production is from more than 25 Pliocene-Pleistocene delta-front sandstone reservoirs ranging from Lenticulina to Trimosina "A" zones and located at depths of 4,300 to 12,000 ft (1,290 to 3,600 m). The reservoir energy results from a combination water-drive and gas-expansion system. Recoverable reserves are estimated to be greater than 225 million bbl of liquid hydrocarbons and 950 Bcf of gas.

Considerable subsurface data provided by 220 exploration and development wells and several seismic grids form the basis for interpretation of the geology and geophysics of the Block 330 field and its producing zones.