Natural Gas Hydrate (NGH) Arctic Ocean Potential Prospects and Resource Base

The compact Arctic Ocean region is the last major hydrocarbon frontier areain the Northern Hemisphere and may possibly be the single richest natural gashydrate (NGH) province on Earth. Because of the extreme weathering and erosionconditions associated with the alternating glacial and interglacial conditions, much of the sediment in accessible gas hydrate stability zones (GHSZ) may havethe same well bed-differentiated, coarse grained character of excellent NGHreservoir hosts. These reservoirs are of the same type that may hostconventional hydrocarbon deposits in more deeply buried sediments. Existingindustry exploration techniques have been used to identify potential NGHdrilling targets, and drilling in the northern Gulf of Mexico has validated theexploration technique. The Nankai deposits off SE Japan and the depositsdrilled in the northern Gulf of Mexico are excellent examples of thesand-turbidite continental margin paratype. It is estimated from examples andapplication of NGH petroleum system analysis that over 6,000 Tcf of natural gasin place may be present in NGH-enriched deepwater turbidite sands within deepcontinental shelf and slope sediments of the Arctic Ocean. In addition todeepwater turbidites, which are well known from other continental margin areas, such as the Gulf of Mexico, two other prospective zones may exist in the ArcticOcean. Troughs, which are glacially excavated depressions that generally deepentoward the shelf margins, may host NGH in sediments that are transitionalbetween the deepwater turbidites and continental shelf sedimentation. Concentrations of NGH may also be accessible from isolated outliers, which areupstanding continental crust fragments that are present within the Amerasia andEurasia Basins.