Characterization and Quantification of Gas Hydrates in the California Borderlands
P. K. Kannberg, Steven Constable
Abstract
Abstract Electromagnetic methods are directly sensitive to electrically resistive gas hydrates and can be used to characterize and quantify hydrate deposits. Using a 1 km long deep‐towed marine electromagnetic system, six survey lines were acquired coincident with legacy seismic reflection data in the Santa Cruz Basin in the Outer California Borderlands. While the strongest seismic indicators place hydrate in the central basin, resistors inferred to be hydrate are located predominantly on the flanks of the basin, coincident with gas migration pathways such as faults and steeply dipping strata. Two features consistent with the resistivity profile from previously imaged seafloor methane seeps were also found. Resistivity is related to hydrate saturation through Archie's law, and total hydrate volume of the Santa Cruz Basin is estimated to be 980 × 10 9 m 3 of gas in place.