Abstract: Salt Morphology and Hydrocarbon Trapping at Eugene Island 188 Field: Detailed Salt Surface Mapping Yields New Opportunities in an Old Field

Erik P. Mason, S. M. Weaver, M. D. French

An integrated study of Eugene Island 188 (El 188) field incorporated 175 wells, 40 salt penetrations, time and depth migrated versions of a 3-D seismic survey, salt proximity surveys, gravity data, and 3-D rendering. Results have yielded an accurate, clear picture of the El 188 salt dome surface which has lead to new drilling locations, additional reserves, an increase in production rates, and a more efficient field depletion.

The gross salt morphology of El 188 is a north dipping, "tear-drop" shape rising to within 700 feet of the sea floor. The salt body is severely overhung to the south and east. Radial and tangential faults cut into, offset, and extend out from the salt creating a very irregular, rugose surface. Numerous sills and salt intrusions have been defined and mapped by closely tying the well and seismic data.

The dome is part of a counterregional fault/salt withdrawal basin complex which began forming in the Miocene. Dome growth, continuous since the middle Miocene, reached a maximum growth rate during the late Miocene.

Sixty different deltaic sands range in depth from 5000 to 16,000 feet and from Miocene to Pleistocene in age. Hydrocarbon bearing sands are trapped within recesses in the salt surface and beneath salt overhangs. Ultimate recoverable reserves are roughly 50 MMBO and 200 BCFG.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994