Gas hydrates mapped using marine CSEM methods

摘要

Marine CSEM surveys could offer a solution to the problem of quantitatively mapping gas hydrate. Methane hydrate is an ice/gas mixture stable at low temperatures and high pressures. Such conditions are found worldwide on continental shelves in water depths greater than approximately 300 m (1,000 ft), and wherever there is a source of methane, either from microbial activity or from leakage of deeper hydrocarbon reservoirs, hydrate is likely to form. Hydrate is stable in seafloor sediment until the geothermal gradient makes temperatures too high, at which point a potent seismic reflector called the bottom-simulating reflector (BSR) is often observed, associated with the small amount of free gas that can accumulate at the bottom of the hydrate stability zone.