Fluid-flow tests and simultaneous measurements of water saturation (Sw), complex resistivity and elastic wave velocity were conducted in the laboratory to elucidate the relationship between these properties in fractured andesite. The elastic wave velocity showed almost no dependence on Sw while the resistivity decreased with increasing Sw (up to 800 Ω m for 5% < Sw < 15%). Changes in the resistivity of the rock were also detected when the salinity and fracture porosity changed (1 order of magnitude difference in resistivity with a change of ~1 order of magnitude salinity or with ~2.5 times the porosity change). Our experimental results suggest that the resistivity is a suitable parameter for monitoring the artificial recharge into a depleted reservoir in the early stages of an Enhanced Geothermal System.
|Number of pages
|journal of the geothermal research society of japan
|Published - 2019
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