Integrated 2D 4-C OBC analysis for estimating hydrate concentrations, Green Canyon, Gulf of Mexico

DeAngelo, M.V., Sava, D.C., Hardage, B.A. and Murray, P.E., 2010. Integrated 2D 4-C OBC analysis for estimating hydrate concentrations, Green Canyon, Gulf of Mexico. Journal of Seismic Exploration, 19: 263-278. A 2D four-component ocean-bottom-cable seismic survey, originally acquired for the exploration of deeper hydrocarbon targets, was used to estimate near-seafloor hydrate concentrations in the Genesis Field, Green Canyon area of the Gulf of Mexico. The high-resolution properties of the P-P and P-SV processed as common-receiver gathers were utilized to image subtle features of near-seafloor geology. Interpretation of depth equivalent events on P-P and P-SV near-offset images constrained Vp/Vs ratios and zero-offset reflection times. These events were used as inputs to create near-seafloor (<600 m below seafloor) compressional-wave and shear-wave interval velocity models. These interval velocities were used with local resistivity logs to estimate hydrate concentration using a statistical joint inversion procedure. This joint inversion method is especially critical for estimating hydrate concentration in deep-water near-seafloor strata because of the lack of sonic log measurements across the hydrate stability zone.
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