Evidence for Natural Gas Hydrate Occurrences in Colombia Basin

Patrick D. Finley, Jan Krason, Kathryn Dominic

Multichannel and selected single-channel seismic lines of the continental margin sediments of the Colombia basin display compelling evidence for large accumulations of natural gas hydrate. Seismic bottom simulating reflectors (BSRs), interpreted to mark the base of the hydrate stability zone, are pronounced and very widespread along the entire Panama-Colombia lower continental slope. BSRs have also been identified at two locations on the abyssal plain. Water depths for these suspected hydrate occurrences range from 900 to 4,000 m.

Although no gas hydrate samples have been recovered from this area, biogenic methane is abundant in Pliocene turbidites underlying the abyssal plain. More deeply buried rocks beneath the abyssal plain are thermally mature. Thermogenic gas from these rocks may migrate upward along structural pathways into the hydrate stability zone and form hydrate. Impermeable hydrate layers may form caps over large accumulations of free gas, accounting for the very well-defined BSRs in the area.

The abyssal plain and the deformed continental margin hold the highest potential for major economic accumulations of gas hydrate in the basin. The extensive continuity of BSRs, relatively shallow water depths, and proximity to onshore production facilities render the marginal deformed belt sediments the most favorable target for future economic development of the gas hydrate resource within the Colombia basin. The widespread evidence of gas hydrates in the Colombia basin suggests a high potential for conventional hydrocarbon deposits offshore of Panama and Colombia.

AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.