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Laboratory Electrical Conductivity of Marine Gas Hydrate
Author(s) -
Constable Steven,
Lu Ryan,
Stern Laura A.,
Du Frane Wyatt L.,
Roberts Jeffery J.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl087645
Subject(s) - hydrate , clathrate hydrate , silt , conductivity , brine , pore water pressure , seawater , mineralogy , electrical resistivity and conductivity , geology , permafrost , sediment , materials science , analytical chemistry (journal) , chemistry , environmental chemistry , geotechnical engineering , geomorphology , oceanography , organic chemistry , engineering , electrical engineering
Methane hydrate was synthesized from pure water ice and flash frozen seawater, with varying amounts of sand or silt added. Electrical conductivity was determined by impedance spectroscopy, using equivalent circuit modeling to separate the effects of electrodes and to gain insight into conduction mechanisms. Silt and sand increase the conductivity of pure hydrate; we infer by contaminant NaCl contributing to conduction in hydrate, to values in agreement with resistivities observed in well logs through hydrate‐saturated sediment. The addition of silt and sand lowers the conductivity of hydrate synthesized from seawater by an amount consistent with Archie's law. All samples were characterized using cryogenic scanning electron microscopy and energy dispersive spectroscopy, which show good connectivity of salt and brine phases. Electrical conductivity measurements of pure hydrate and hydrate mixed with silt during pressure‐induced dissociation support previous conclusions that sediment increases dissociation rate.