Offshore Technology Research Center

 

OTRC Project Summary

Project Title:

In Situ Detection of Natural Gas Hydrates Using Electrical and Thermal Properties

Prinicipal Investigators:

Wayne Dunlap

Sponsor:

National Science Foundation

Completion Date:

June, 1992

Final Report ID#

A28(Click to view final report abstract)

Within the scope of this research is the development of methods for the in situ detection of natural gas hydrates in ocean sediments.  Since a great deal of uncertainty exists as to the form in which natural gas hydrated occur in deep sea sediments a combination of detection methods that utilize different properties may be necessary.

The first objective was to experimentally determine the electrical resistivity and thermal conductivity of the (THF) hydrates, used as a substitute for natural gas hydrates.  Tetrahydrofuran (THF) has been used by many researchers studying the properties of natural gas hydrates because THF can form hydrates under atmospheric pressure and at a temperature of approximately +4 °C.  The specimens to be tested would include massive hydrates and hydrates contained in porous media.  In the case of hydrates in sand it would be useful to examine if there is any relation between the electrical resistivity and thermal conductivity as in the case of water saturated sands.

The second objective was to study and suggest methods for hydrate detection in ocean sediments based on borehole electrical resistivity measurements including numerical model studies.

The third objective was to evaluate the effect of the in situ hydrate formation on the thermal regime of the sediments.  It has been suggested that hydrate formation may alter the geothermal gradient and if this is the case in situ temperature measurements may be useful for detecting hydrates.

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