4 Results and Conclusions of a Horizontal-drilling

Ahorizontal-well redevelopment drilling program around the flanks of the South Pass 62 salt-dome field resulted in significant successes and costly failures. Successful wells exploited thin, oil-filled shoreface sandstones; partially depleted zones; and massive, sand-filled channels. Failures were those wells that attempted to connect multiple fault blocks and drain low-resistivity/laminated-sandstone reservoirs. This paper reviews the field history; describes the geologic setting, including a summary of significant structural features and producing-sandstone depositional environments; discusses the horizontal-well strategy; and examines successful and unsuccessful wells. South Pass 62 field lies 50 km (30 mi) east of the Mississippi River delta in 104 m (300 ft) of water. The field was discovered in 1965, developed with 61 directionally drilled wells from three platforms in the late 1960s, redeveloped from 1986 to 1988 with 31 wells from a fourth platform, and redeveloped again from 1994 to the present with horizontal and directionally drilled slim-hole sidetracks. A 3-D seismic-based field study completed in 1994 identified reservoir targets for the horizontal-drilling program.