Alexei V. Milkov¹, Roger Sassen¹

(1) Texas A&M University, College Station, TX

ABSTRACT: Structurally-Focused Gas Hydrate Accumulations in the Gulf of Mexico: Economically Viable Exploration Target

New improved estimates of gas hydrate resource in the Gulf of Mexico (GOM) indicate that gas hydrate on the continental slope contain 30-40 times more hydrocarbon gas than conventional subsurface reservoirs. Gas hydrate could be a future energy source in the GOM, but the gas hydrate resource volumetrically is less significant than previously suggested. The geological estimation of gas hydrate resource is further constrained by economical considerations to assess the importance of gas hydrate as a future energy source. Bacterial methane gas hydrate in minibasins is too widely disseminated to represent a viable exploration target. In contrast, thermogenic and bacterial gas hydrates focused between minibasins along structures formed by ongoing salt deformation and active faulting contain significant amount of methane and heavy hydrocarbon gases. Structurally-focused accumulations (such as in GC 184/185 and MC 852/853) often outcrop at the seafloor, are characterized by relatively thick stability zone, and contain as much as ~100% of gas hydrate in sediments. From the perspective of economic geology, a concentrated deposit in the deep sea is more likely to be economical than a thinly disseminated deposit. Successful exploitation of gas hydrate accumulations in the future will, most likely, take place where geologic data are utilized to objectively constrain plans for development. We propose that shallow gas hydrate "elephants" in the GOM may be economically viable for exploration even in the near future since they could be developed with existing technology.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado