Unique problems associated with seismic analysis of partially gas-saturated unconsolidated sediments

Marine and Petroleum Geology
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Abstract

Gas hydrate stability conditions restrict the occurrence of gas hydrate to unconsolidated and high water-content sediments at shallow depths. Because of these host sediments properties, seismic and well log data acquired for the detection of free gas and associated gas hydrate-bearing sediments often require nonconventional analysis. For example, a conventional method of identifying free gas using the compressional/shear-wave velocity (Vp/Vs) ratio at the logging frequency will not work, unless the free-gas saturations are more than about 40%. The P-wave velocity dispersion of partially gas-saturated sediments causes a problem in interpreting well log velocities and seismic data. Using the White, J.E. [1975. Computed seismic speeds and attenuation in rocks with partial gas saturation. Geophysics 40, 224-232] model for partially gas-saturated sediments, the difference between well log and seismic velocities can be reconciled. The inclusion of P-wave velocity dispersion in interpreting well log data is, therefore, essential to identify free gas and to tie surface seismic data to synthetic seismograms.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Unique problems associated with seismic analysis of partially gas-saturated unconsolidated sediments
Series title Marine and Petroleum Geology
DOI 10.1016/j.marpetgeo.2008.07.009
Volume 26
Issue 6
Year Published 2009
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Marine and Petroleum Geology
First page 775
Last page 781
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