Exploration for Deepwater Natural Gas Hydrate

The potentially large volume of oceanic natural gas hydrate (NGH) resources, combined with new understanding of the NGH petroleum system and demonstrated exploration techniques, suggests that near-term extraction of natural gas from the resource is feasible. Sandy marine turbidite sediments in the Nankai (Japan) and Walker Ridge (US—Northern Gulf of Mexico) localities have been proven to host high concentrations of NGH. NGH is a stratigraphic play insofar as the present primary exploration targets are marine turbidite sands. Sediments of this type, deposited on deep continental shelves and slopes, are a primary target for NGH extraction potential. Similar, more deeply-buried turbidites are prominent first-order hosts for conventional gas and oil deposits. Concentrations of NGH cluster along the base of the GHSZ although NGH is more stable toward its top. These are proven hydrocarbon resources and amenable to extraction of gas and oil. We infer that conversion of NGH to its constituent gas and water will allow the natural gas to be recovered. Exploration tools are sufficient to identify and value NGH concentrations.