Methane hydrate rock physics models for the Blake Outer Ridge: SEP–80

Seismic analyses of methane hydrate data from the Blake Outer Ridge indicate high P-wave velocity and anomalously low S-wave velocity in sediments containing methane hydrates. In an attempt to explain this observed P-wave and S-wave velocity structure at the transition from gas to hydrates, the effe...

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Bibliographic Details
Main Author: Christine Ecker
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Published: 1994
Subjects:
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.386.5063
http://sepwww.stanford.edu/data/media/public/docs/sep80/christine2.pdf
Description
Summary:Seismic analyses of methane hydrate data from the Blake Outer Ridge indicate high P-wave velocity and anomalously low S-wave velocity in sediments containing methane hydrates. In an attempt to explain this observed P-wave and S-wave velocity structure at the transition from gas to hydrates, the effect of different hydrate models on elastic moduli and velocities are explored. After construction of an initial gas model, the properties of the hydrates are estimated using the bound averaging method together with the Voigt and Reuss bounds for elastic moduli. The result suggests that the hydrates becomes part of the rock matrix and softens the pores by fracturing. The additional formation of ice is required to obtain the desired P- to S-wave velocity ratio in the hydrate bearing sediments, indicating temperature conditions around the freezing point of water.