AAPG ANNUAL MEETING
New Orleans, Louisiana
April 25-28, 1993

Despite extensive development of fields which may have over 1000 penetrations, significant opportunities still exist that can be exploited using 3D seismic data integrated with existing well data.

South Pass Block 27 field is a giant, mature (88% depleted) oil field with an ultimate recovery of approximately 520 MMBOE. Since discovery in 1954, over 780 wells have been drilled in the field with the deepest penetration being 13,846' (upper Miocene). A 3D seismic survey was acquired over the field in 1987, and reprocessed in 1991. A detailed study was then conducted to predict the geology and hydrocarbon occurrence in several field pay levels, and define the field's untested deep potential.

Seismic mapping revealed a significant, amplitude-supported opportunity consisting of three untested fault blocks with a total potential of approximately 15 million barrels of recoverable oil. Trap failure was indicated because the minimum offset along the bounding faults is 75' to 100', whereas the gross thickness of the objective sand package isapproximately 200'. Net-sand isopach maps of genetic units, based on well control, show that pay zones represent a series of stacked delta lobes that are dominated by river-mouth bars. Resulting sand trends demonstrate that a low risk of sand-on-sand contacts exist at the bounding faults.

Although the shelf has been extensively explored, there exists a great opportunity to find additional hydrocarbons if sequence-stratigraphic techniques, which fully employ both well and seismic data, are applied at the field scale.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.