--> Abstract: Structural Setting And Geochemistry Of Gas Hydrates, Gulf Of Mexico Continental Slope, by R. Sassen, J. S. Watkins, C. L. Decker, D. A. Defreitas, and A. Milkov; #90928 (1999).

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ROGER SASSEN1, JOEL S. WATKINS2, CARRIE L. DECKER2, DEBRA A. DEFREITAS1, and ALEXEI MILKOV1
1Geochemical and Environmental Research Group, Texas A&M University, College Station, TX 77845, USA
2Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA

Abstract: Structural Setting and Geochemistry of Gas Hydrates, Gulf of Mexico Continental Slope

The Gulf of Mexico slope is unique because all three major hydrate types occur. Thermogenic gas hydrates (structure 11 and H) and bacterial methane hydrates (structure 1) occur within a province that extends across much of the continental slope from 425 to >2,000 meters water depth. The slope is characterized by a prolific Mesozoic (mainly Upper Jurassic) hydrocarbon source system that charges subsurface oil and gas accumulations. Efficient salt and fault conduits for fluid flow permit rapid vertical migration in an evolving basin with poor trapping efficiency. Thermogenic gas at or near the sea-floor undergoes a rapid phase change at ambient temperatures and pressures to crystallize in hemipelagic muds as gas hydrate. Major salt-related structural features focus gas hydrate accumulation along the rims of intrasalt basins, over salt ridges, and at the edge of the Sigsbee Escarpment. Gas hydrates are often found near oil and gas fields. Bacterial methane hydrates are also widely distributed, and most form by bacterial reduction of carbon dioxide at low temperatures in sediment. Unlike other gas hydrate provinces, the resource is not thinly dispersed. Because of the structural focusing of a substantial gas hydrate resource in restricted areas, future economic production of hydrate energy could occur first in the Gulf of Mexico.

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