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Water
Temperature on Shallow Gas Hydrate Stability, Gulf of Mexico Continental Slope
MILKOV, ALEXEI V., ROGER SASSEN, Geochemical and Environmental Research Group, Texas A&M University, College Station, TX; IRINA NOVIKOVA, EUGENIY MIKHAILOV, Department of Physics, Texas A&M University, College Station, TX
Gas hydrate stability is a function of water depth, bottom water
temperature, pressure and thermal gradients in sediments, pore water salinity, gas
availability and composition. In the Gulf of Mexico slope, where large volumes of gas
hydrates are concentrated in sediments near the seafloor, bottom water temperature varies
because of seasonal changes, and because of the propagation of warm core Loop Current
eddies across the slope. We have modeled the influence of heat flow from seawater on gas
hydrate stability. The preliminary results of modeling indicate that both seasonal and
short-term variations of bottom water temperature may affect gas hydrate stability only in
the upper 1-2 m of sediments. However, the zone where gas hydrate formation and
decomposition occur because of bottom water temperature change is very extensive in area,
encompassing much of the Gulf slope. Gas blowouts, oil ejection into water
column,
sediment slumps, and other geohazards triggered by gas hydrate decomposition could occur
in this zone, and impact sub-sea operations.
MILKOV, ALEXEI V., ROGER SASSEN, IRINA NOVIKOVA, and EUGENIY MIKHAILOV
AAPG Search and Discovery Article #90908©2000 GCAGS, Houston, Texas