Effects of water saturation, fracture and salinity on electric and elastic properties of fractured geothermal rocks

Kazuki Sawayama; Keigo Kitamura; Yasuhiro Fujimitsu

doi:10.11367/grsj.41.53

Effects of water saturation, fracture and salinity on electric and elastic properties of fractured geothermal rocks

Kazuki Sawayama, Keigo Kitamura, Yasuhiro Fujimitsu

Earth Science and Technology

Research output: Contribution to journal › Article › peer-review

1 Citation (Scopus)

Abstract

Fluid-flow tests and simultaneous measurements of water saturation (S_w), 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 S_w while the resistivity decreased with increasing S_w (up to 800 Ω m for 5% < S_w < 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.

Original language	English
Pages (from-to)	53-59
Number of pages	7
Journal	journal of the geothermal research society of japan
Volume	41
Issue number	2
DOIs	https://doi.org/10.11367/grsj.41.53
Publication status	Published - 2019

All Science Journal Classification (ASJC) codes

Geophysics

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title = "Effects of water saturation, fracture and salinity on electric and elastic properties of fractured geothermal rocks",

abstract = "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.",

author = "Kazuki Sawayama and Keigo Kitamura and Yasuhiro Fujimitsu",

note = "Funding Information: We acknowledge the anonymous reviewers for their many constructive suggestions that greatly improved this manuscript. We also thank Dalia Lahav-Jones, from Liwen Bianji, Edanz Group China (www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript. Publisher Copyright: {\textcopyright} The Geothermal Research Society of Japan, 2019. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.",

year = "2019",

doi = "10.11367/grsj.41.53",

language = "English",

volume = "41",

pages = "53--59",

journal = "Journal of the Geothermal Research Society of Japan",

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publisher = "The Geothermal Research Society of Japan",

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T1 - Effects of water saturation, fracture and salinity on electric and elastic properties of fractured geothermal rocks

AU - Sawayama, Kazuki

AU - Kitamura, Keigo

AU - Fujimitsu, Yasuhiro

N1 - Funding Information: We acknowledge the anonymous reviewers for their many constructive suggestions that greatly improved this manuscript. We also thank Dalia Lahav-Jones, from Liwen Bianji, Edanz Group China (www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript. Publisher Copyright: © The Geothermal Research Society of Japan, 2019. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2019

Y1 - 2019

N2 - 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.

AB - 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.

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JF - Journal of the Geothermal Research Society of Japan

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ER -

Effects of water saturation, fracture and salinity on electric and elastic properties of fractured geothermal rocks

Abstract

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