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Models for Gas Hydrate-Bearing Sediments Inferred from Hydraulic Permeability and Elastic Velocities

Scientific Investigations Report 2008-5219

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Abstract

Elastic velocities and hydraulic permeability of gas hydrate-bearing sediments strongly depend on how gas hydrate accumulates in pore spaces and various gas hydrate accumulation models are proposed to predict physical property changes due to gas hydrate concentrations. Elastic velocities and permeability predicted from a cementation model differ noticeably from those from a pore-filling model. A nuclear magnetic resonance (NMR) log provides in-situ water-filled porosity and hydraulic permeability of gas hydrate-bearing sediments. To test the two competing models, the NMR log along with conventional logs such as velocity and resistivity logs acquired at the Mallik 5L-38 well, Mackenzie Delta, Canada, were analyzed. When the clay content is less than about 12 percent, the NMR porosity is 'accurate' and the gas hydrate concentrations from the NMR log are comparable to those estimated from an electrical resistivity log. The variation of elastic velocities and relative permeability with respect to the gas hydrate concentration indicates that the dominant effect of gas hydrate in the pore space is the pore-filling characteristic.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Models for Gas Hydrate-Bearing Sediments Inferred from Hydraulic Permeability and Elastic Velocities
Series title:
Scientific Investigations Report
Series number:
2008-5219
Edition:
Version 1.0
Year Published:
2008
Language:
ENGLISH
Publisher:
U.S. Geological Survey
Contributing office(s):
Central Energy Resources Team
Description:
iii, 15 p.
Online Only (Y/N):
Y
Additional Online Files(Y/N):
N