Gas hydrate systems in Garden Banks, Gulf of Mexico

Natural gas hydrates exist in the shallow subsurface throughout the Gulf of Mexico, though many systems have not been discovered and described in detail. In this study, we analyze ~5000 km² of publicly available 3D multichannel seismic data and well log data from six wells to interpret the potential for gas hydrate presence in the Garden Banks protraction area of the northern Gulf of Mexico. In seismic data, bottom simulating reflectors (BSR) often indicate the occurrence of free gas below the hydrate stability zone and identify its lower boundary. Over the Garden Banks seismic datasets, root mean square amplitude analysis was used to identify zones with high amplitudes, indicating the potential presence of BSRs. In addition, salt diapirs and buried turbidite-channel systems were mapped as these features impact geothermal and porosity characteristics that control hydrate formation. Seven distinct zones containing BSRs were identified, including at least one newly discovered system in the southeastern portion of Garden Banks. This new system has an area of approximately 15 km² containing largely continuous BSRs occurring above salt and in channel levees. While no wells in this study area were directly drilled into identified BSRs, gamma ray logs that are in close proximity were tied to seismic and analyzed at the base of gas hydrate stability to confirm the presence of sand which is more conducive to hosting high saturations of hydrate.