Abstract: Mahogany: Seismic Technology Leading to the First Economic Subsalt Field

Mark E. Westcott, Mark C. Leach, Paul A. Valasek, Kay D. Wyatt, Keith Branham

Phillips Petroleum has been involved in the Gulf of Mexico subsalt play since the 1989 Central Gulf lease sale. In 1990, Phillips acquired the Ship Shoal 349 and 359 leases, better known as Mahogany. At that time, the oil and gas industry lacked the 3-D seismic imaging technology required to adequately define drillable prospects below the salt. By 1992, Phillips had developed a 3-D post-stack depth migration that allowed a prospect to be defined beneath the allochthonous salt sheet on the Mahogany prospect. The potential was large enough to offset the risk of testing such a new play concept. The result was the Mahogany discovery in 1993. Continued improvements in subsalt imaging using 3-D prestack depth migration have played a key role in the further development of the Ma ogany field. With more accurate and better resolved subsalt structures, it is now possible to analyze waveform variations using techniques such as AVO and seismic inversion to help determine reservoir attributes. Prestack seismic imaging combined with advanced waveform analysis techniques provide the information necessary to success fully exploit the hydrocarbon reserves at Mahogany.

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela