Erik P. Mason1, M.J. Bastian1, R. Detomo1, M.N. Hashem1, A.J. Hildebrandt1
(1) Shell Exploration & Production Company, New Orleans, LA
ABSTRACT: Results and Conclusions of a Horizontal Drilling Program at South Pass 62 Salt Dome Field
A horizontal 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 sands, partially depleted zones and massive sand-filled channels. Failures attempted to connect multiple fault blocks and drain low resistivity / laminated sand reservoirs. This paper reviews the field history, describes the geologic setting including a summary of significant structural features and producing-sand depositional environments, discusses the horizontal well strategy and examines successful and unsuccessful wells.
South Pass 62 Field lies 30 miles east of the Mississippi River delta in 300 feet of water. The field was discovered in 1965, developed with 61 directionally drilled wells from three platforms in the late 1960's, redeveloped in 1986-88 with 31 wells from a fourth platform and redeveloped again from 1994-present with horizontal and directionally drilled slim-hole sidetracks. A 3D seismic-based field study completed in 1994 identified reservoir targets for the horizontal drilling program.
Nearly sixty stacked, variable pay-sands combine with steep formation dips and extensive faulting to create a complex field with hundreds of reservoirs. The field lies on the north flank of a mushroom-shape, south-leaning salt dome which rises from below 25,000 feet to near the sea floor. Typical formation structural dips decrease from 70 degrees next to the salt to 10 degrees off-structure. Several generations of faults exist with throws ranging from inches to several hundred feet. Approximately 60 Pliocene and Miocene age deltaic and turbidite pay sands ranging in depth from 3,800 to 19,000 feet onlap the salt.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado