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Velocities and Attenuations of Gas Hydrate-Bearing Sediments

Scientific Investigations Report 2007-5264

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Abstract

Monopole and dipole logging data at the Mallik 5L-38, Mackenzie Delta, Canada, provide a challenge for sonic velocity and attenuation models used to remotely estimate pore-space gas hydrate content. Velocity and attenuation are linked, with velocity dispersion causing increased attenuation. Sonic waveforms for Mallik 5L-38, however, show no velocity dispersion in gas hydrate-bearing layers, yet are highly attenuated. Attenuation models applied to Mallik 5L-38 data are shown to be inconsistent with the observed velocity measurements, and therefore are suspect in their ability to predict gas hydrate content. A model explicitly linking velocity and attenuation data is presented, accurately predicting gas hydrate content from velocity data alone while demonstrating that the attenuation mechanisms at the Mallik 5L-38 site have not yet been identified.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Velocities and Attenuations of Gas Hydrate-Bearing Sediments
Series title:
Scientific Investigations Report
Series number:
2007-5264
Edition:
Version 1.0
Year Published:
2007
Language:
ENGLISH
Publisher:
Geological Survey (U.S.)
Contributing office(s):
U.S. Geological Survey
Description:
iv, 11 p.
Online Only (Y/N):
Y