Free Gas Exploitation Within the Northern Gulf of Mexico: A Viable Potential?

Allen Lowrie¹ and Carol Blanton Lutken^2
1238 F. Z. Goss Road, Picayune, Mississippi 39466
²Room 220, Old Chemistry Building, University of Mississippi, University, Mississippi 38677

Gas hydrates, and free gas that may be trapped beneath them, present a new area of potential hydrocarbon exploitation. Both are known to be widely distributed along both active and passive continental margins around the world.

Hydrocarbon production from the northern Gulf of Mexico is well-established, extending to depths in excess of 5-8km with source-rocks beneath those depths. Hydrates on the seafloor and free gases rising through the ocean are often reported; estimates of their volumes vary widely. An initial gas exploitation play would be to high-grade free gas accumulations including those that apparently occur beneath hydrate, drill extensive horizontal-inclined wells out to 5-10km and perhaps farther in unconsolidated sediments, then harvest the available gases.

Background regional and local analyses are needed to effect successful free gas exploitation. Existent free gases and accompanying hydrates need to be mapped. If seismic records are to be useful, surveys employing sources of varying frequencies should be used in concert with ground-truthing, to the extent that such is possible on the seafloor and in the sub-seafloor. Coring at all depths possible - both piston and foundation boring – is needed to facilitate geochemical studies of fluids migrating through the sedimentary section. The complex influences of salt deposits complicate hydrate accumulation in the Gulf by inhibiting hydrate formation and altering heat-flow in the subsurface. Details of fluid migration routes, rates and volumes, are needed. The rapidly expanding capabilities of horizontal drilling make it one of the technological keys to successful exploitation of free gas, including that associated with gas hydrates.

AAPG Search and Discovery Article #90080©2005 GCAGS 55th Annual Convention, New Orleans, Louisiana