Abstract: Basin Evolution and Trap Development Associated with Salt Movement in the Gulf of Mexico: Lessons for Exploration in Other Mobile Salt Systems

Handschy, J. W.; Diegel, F. A.; Karlo, J. F.; Ge, H.; Maler, M. O. - Shell Exploration and Production Company

The interaction of sediment influx and salt movement controls the formation of sedimentary accommodation space and development of hydrocarbon traps in the Gulf of Mexico (GOM). Within the overall GOM basin the distribution and style of sub-basin formation is the product of: 1) the initial volume, thickness and distribution of salt (either autochthonous salt or allochthonous salt), and 2) the volume, facies and depositional rate of sediment. Although there have been various debates in the past about the driving mechanism for salt movement, we find that the relationship between salt movement and sedimentation is rate dependent. In areas where sedimentation cannot keep up with salt movement, salt flow is the primary control on sub-basin geometry, structural style and sedimentary fill patterns. In other areas, where sedimentation can keep up with salt movement, sediment deposition has a stronger control on basin geometry and sedimentary fill patterns. Since these relative rates change both spatially and temporally, the evolution of any individual sub-basin can be very complex. The relative timing of salt evacuation and the interaction of allochthonous salt associated with adjacent sub-basins further complicate sub-basin evolution. Based on differences in salt distribution, structural style and depositional patterns the GOM can be subdivided into at least six salt related tectono-stratigraphic provinces. We feel that integration of province specific observations about sub-basin geometry, history and sediment distribution patterns with regional, basin wide GOM sedimentation patterns is an efficient way to focus exploration efforts.

AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil