--> ABSTRACT: A Subsalt Prospect in Offshore Louisiana - Evolution of a Prospect from Lease Sale to Present, by Alan D. Zick, Daniel J. Addis, and Andy W. Pieprzak; #91019 (1996)

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A Subsalt Prospect in Offshore Louisiana - Evolution of a Prospect from Lease Sale to Present

Alan D. Zick, Daniel J. Addis, and Andy W. Pieprzak

The Garnet subsalt prospect in the East Cameron, South Addition area of offshore Louisiana was acquired by Anadarko Petroleum Corporation in the 1994 offshore Louisiana federal lease sale. The prospect is a structural closure beneath a rugose and highly deformed allochthonous salt sheet. This salt geometry has distorted the seismic image below it making necessary the use of more elaborate and costly seismic depth imaging techniques. The prospect is further complicated by the lack of proximate deep well control to aid in predicting stratigraphy below salt

In this paper, we present the progressive stages of prospect evaluation leading to the current interpretation, beginning first with the initial lease sale identification of the prospect. Through the various stages of evaluation, geophysical efforts have reflected an attempt to balance time and costs with the anticipated benefits. Seismic evaluation has progressed from various 2D methods through 3D time migration, 3D post-stack depth migration and ultimately to 3D pre-stack depth migration. The primary goal of the 3D pre-stack depth migration was to image below salt and considerable effort has been expended in deriving an accurate velocity model for the final depth migration.

The improved imaging of the various salt bodies has produced a more accurate picture of the salt geometries and subsalt structures. From this, we have reconstructed the salt movement within the prospect area and have inferred salt tectonic and sedimentation interrelationships.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California