Gas production from a cold, stratigraphically-bounded gas hydrate deposit at the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Implications of uncertainties

Marine and Petroleum Geology
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Abstract

As part of an effort to identify suitable targets for a planned long-term field test, we investigate by means of numerical simulation the gas production potential from unit D, a stratigraphically bounded (Class 3) permafrost-associated hydrate occurrence penetrated in the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well on North Slope, Alaska. This shallow, low-pressure deposit has high porosities (?? = 0.4), high intrinsic permeabilities (k = 10-12 m2) and high hydrate saturations (SH = 0.65). It has a low temperature (T = 2.3-2.6 ??C) because of its proximity to the overlying permafrost. The simulation results indicate that vertical wells operating at a constant bottomhole pressure would produce at very low rates for a very long period. Horizontal wells increase gas production by almost two orders of magnitude, but production remains low. Sensitivity analysis indicates that the initial deposit temperature is by the far the most important factor determining production performance (and the most effective criterion for target selection) because it controls the sensible heat available to fuel dissociation. Thus, a 1 ??C increase in temperature is sufficient to increase the production rate by a factor of almost 8. Production also increases with a decreasing hydrate saturation (because of a larger effective permeability for a given k), and is favored (to a lesser extent) by anisotropy. ?? 2010.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Gas production from a cold, stratigraphically-bounded gas hydrate deposit at the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Implications of uncertainties
Series title Marine and Petroleum Geology
DOI 10.1016/j.marpetgeo.2010.01.005
Volume 28
Issue 2
Year Published 2011
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Marine and Petroleum Geology
First page 517
Last page 534