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Exploiting the temperature effects on low frequency electrical spectra of sandstone: a comparison of effective diffusion path lengths

Research output: Contribution to journalJournal article

Published

Journal publication date20/10/2010
JournalGeophysics
Journal number6
Volume75
Number of pages4
PagesA43
Original languageEnglish

Abstract

A number of recent investigations have highlighted the potential value of using relaxation times derived from electrical spectra to infer key physical properties of permeable rocks. To date, most studies have assumed a grain size or pore throat as a measure of the length scale of the ionic diffusive process, although this has been challenged in recent experimental investigations. We compare the electrical spectra of three sandstones, adopting a new approach in which the temperature of the rock samples is perturbed and the relaxation time measured as a function of temperature. Our results suggest that, for the sandstones tested here, the effective diffusion coefficient should be considered as a function of the electrical tortuosity. These findings may help explain the apparent long relaxation times observed in low-permeability rocks in recent experimental studies. We also highlight the need to account for temperature in related studies of electrical spectra.