Electrical properties of polycrystalline methane hydrate

Geophysical Research Letters
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Abstract

Electromagnetic (EM) remote-sensing techniques are demonstrated to be sensitive to gas hydrate concentration and distribution and complement other resource assessment techniques, particularly seismic methods. To fully utilize EM results requires knowledge of the electrical properties of individual phases and mixing relations, yet little is known about the electrical properties of gas hydrates. We developed a pressure cell to synthesize gas hydrate while simultaneously measuring in situ frequency-dependent electrical conductivity (σ). Synthesis of methane (CH4) hydrate was verified by thermal monitoring and by post run cryogenic scanning electron microscope imaging. Impedance spectra (20 Hz to 2 MHz) were collected before and after synthesis of polycrystalline CH4 hydrate from polycrystalline ice and used to calculate σ. We determined the σ of CH4 hydrate to be 5 × 10−5 S/m at 0°C with activation energy (Ea) of 30.6 kJ/mol (−15 to 15°C). After dissociation back into ice, σ measurements of samples increased by a factor of ~4 and Ea increased by ~50%, similar to the starting ice samples.
Publication type Article
Publication Subtype Journal Article
Title Electrical properties of polycrystalline methane hydrate
Series title Geophysical Research Letters
DOI 10.1029/2011GL047243
Volume 38
Issue 9
Year Published 2011
Language English
Publisher AGU
Publisher location Washington, D.C.
Description L09313
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Geophysical Research Letters
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