Temperature dependence of electrical resistivity of water-saturated rocks

Francisco J. Llera, Motoyuki Sato, Katsuto Nakatsuka, Hidekichi Yokoyama

Research output: Contribution to conferencePaperpeer-review

Abstract

The electrical resistivity of several rocks saturated with an aqueous solution has been determined experimentally in the range from room temperature to 250 °C. Of particular interest are the data for temperatures above 200 °C, scarcely documented in the literature. All the rock samples used in the present study experience a quasiexponential decay of resistivity with temperature up to 200 °C. The same temperature dependence is found for the resistivity of the saturating solution, thus confirming that conduction in watersaturated rocks is essentially electrolytic. At temperatures above 200°C, some specimens of highly porous dacitic tuff still follow closely the saturating solution in the pattern of resistivity variation with temperature, exhibiting a minimum around 220 °C. However, the behaviour of other types of rock, notably low-porosity crystalline rocks, where a steady decay of resistivity is maintained up to 250 °C, departs from that of the saturating solution. Resistivity hysteresis phenomena are observed in most rock samples. This experimental evidence points out that mechanisms different from water characteristics, such as growth of microcracks or chemical reactions, contribute to electrical conduction at high temperature. The electrical signature of the thermally induced growth of microcracks (thermal cracking) is made clear for welded tuff and granite, and the possibility of using electrical measurements to monitor hydraulic fractures in Hot Dry Rock is suggested.

Original languageEnglish
Pages43-46
Number of pages4
DOIs
Publication statusPublished - 1987
Event1987 Society of Exploration Geophysicists Annual Meeting, SEG 1987 - New Orleans, United States
Duration: 1987 Oct 111987 Oct 15

Other

Other1987 Society of Exploration Geophysicists Annual Meeting, SEG 1987
CountryUnited States
CityNew Orleans
Period87/10/1187/10/15

ASJC Scopus subject areas

  • Geophysics

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