Currently, the greatest potential for gas hydrate production is in units of sand lithol­ogy with high intrinsic permeability [10], a condition that (a) enables the fluid and gas migration necessary for gas hydrate has to accumulate to SH of 60% or more of pore volume, (b) allows easier transmission of destabilizing pressure and tempera­ture pulses from wellbores, and (c) provides the pathways by which dissociated gas can be produced. It is currently not well known how large the resource of gas hydrate that exists in sand reservoirs is, but it is clearly sizeable. Current best estimates are that the in-place resources within sand reservoirs in the GOM alone likely exceed 6,000 tcf of gas. Given expected recovery efficiencies, a technically recoverable resource exceeding 1,000 tcf or more is reasonable.

However, this sand-based resource is just the tip of the hydrate resource pyramid

[9] . Large volumes of in-place methane are known to exist within fine-grained sedi­ments in locations such as the Blake Ridge [148], offshore India [27], Malaysia [57], and Korea [176, 147]. Such occurrences may be relatively common, and may occur more widely than the sand-hosted variety. Economic and environmentally sound production from such deposits clearly faces enormous technical challenges, not only because of the leanness of the resource but also because of their adverse flow and geomechanical properties. While gas production from sandy HBS is con­ceivable using largely existing processes, it is clear that much more needs to be known, and perhaps fundamentally new approaches developed, to further the pros­pects of production from elements lower in the gas hydrates resource pyramid.