Geophysical Imaging of Subsalt Geology
Davis W. Ratcliff and David J. Weber
Exploration and production of huge subsalt hydrocarbon accumulations in the Gulf of Mexico has been an ambitious challenge for many explorationists throughout the industry. The complexities associated with the three dimensional nature of salt structures, as well as the highly deformed tops and bottoms of salt, demand 3-D Prestack Depth Migration (3-D PreSDM) technology in order to correctly stack and position reflectivity below salt. Application of "large-volume" 3-D PreSDM techniques has been, and will continue to be, instrumental in unraveling the structural and stratigraphic complexities of the subsalt environment. "Large-volume" 3-D PreSDM technology allows the explorationist to better assess subsalt exploration and development risk, as well as improve subsalt explora ion success.
In this paper, we discuss a full-volume 3-D PreSDM case study that, to our knowledge, is the largest prestack depth imaging project ever attempted, to date. The 3-D PreSDM case study is centered over the Mahogany Discovery in the Gulf of Mexico's Ship Shoal South Addition Block 349 area. Information about input and output data coverage, computer run times and 3-D depth imaging strategies will be discussed. Numerous examples of closely spaced 3-D prestack depth migrated seismic data will also be shown in order to demonstrate how "large-volume" 3-D PreSDM technology improves subsalt imaging, (both structural and stratigraphic), as well as subsalt prospecting.
AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California