--> Abstract: Subsalt Exploration In The Deepwater Foldbelts Of The Gulf Of Mexico: Regional Analysis Of A Giant Petroleum System, by M. J. Roberts and T. W. Hall; #90928 (1999).

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ROBERTS, MICHAEL J., and THOMAS W. HALL
Chevron North America Exploration and Production Company, New Orleans, LA

Abstract: Subsalt Exploration In The Deepwater Foldbelts Of The Gulf Of Mexico: Regional Analysis Of A Giant Petroleum System

The geologic setting of the distal U.S. waters is characterized by a complex assemblage of salt related contractional features. In the U.S. western Gulf, the Perdido Foldbelt involves Mesozoic through Miocene strata covering an area of 20,000 square kilometers. In the deep east central U.S. Gulf, the Mississippi Fan Foldbelt is an arcuate trend of Mesozoic through Pliocene strata encompassing 25,000 square kilometers. Approximately 80% of both trends are in the subsalt environment.

Pre-existing basement conditions and sediment loading history control the location, distribution and character of the foldbelts. Contraction in both areas has lifted objective intervals up to 4km above regional elevation. The folding accommodates only a small portion of the total extension however, with the emplacement of the vast Sigsbee Salt Canopy serving as the primary balancing mechanism. Both Foldbelts are sourced by rich Jurassic Petroleum Systems that charge Tertiary age turbidite reservoirs.

Understanding the linkage between contraction of the objective intervals and the overlying salt canopy is the key to successful exploration in these trends. An integrated approach utilizing regional structural cross sections, base of salt maps, potential field methods and prestack depth migrated seismic images can best define prospects in the subsalt Foldbelts.

The combination of rich source intervals, favorable timing, large structural traps, potentially excellent reservoirs and a regional top seal place the subsalt Foldbelts in the forefront of future Gulf of Mexico exploration.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas