Numerical model of takenoyu-sugawara geothermal area and an interpretation of a low resistivity zone with KYU88-1, the simulator for thermal water flow

Yasuhiro Fujimitsu, Kozo Yuhara

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Abstract

A three-dimensional steady state liquid phase simulator for hydrothermal systems was developed. It is called KYU88-1. In this simulator, thermal water flow through a porous medium is assumed to obey Darcy's law. The governing equations are approximated by the finite difference equations and calculated by the successive overrelaxation method. Using this simulator, a base model of a real field (the Takenoyu-Sugawara geothermal area in the middle Kyushu, Japan) is constructed. From this model, it is inferred that the hydrothermal system of this area extends to more than -3000 m above sea level and the Takenoyu fault, along which Takenoyu and Hagenoyu hot springs appear, has high permeability at the shallower part but not so high permeability at the deeper part. Moreover, a low resistivity zone near the well DW-7 detected by ELF-MT surveys is explained by this model, and the low resistivity zone is regarded as not a well fractured high permeable zone but a low permeable alteration zone which acts as a barrier to the hot water flow from eastern side.

Original languageEnglish
Pages (from-to)285-306
Number of pages22
Journaljournal of the geothermal research society of japan
Volume11
Issue number4
DOIs
Publication statusPublished - Jan 1 1989

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thermal water
water flow
simulators
simulator
electrical resistivity
hydrothermal systems
permeability
hydrothermal system
difference equations
sea level
Darcy law
Japan
liquid phases
thermal spring
porous medium
liquid

All Science Journal Classification (ASJC) codes

  • Geophysics

Cite this

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title = "Numerical model of takenoyu-sugawara geothermal area and an interpretation of a low resistivity zone with KYU88-1, the simulator for thermal water flow",
abstract = "A three-dimensional steady state liquid phase simulator for hydrothermal systems was developed. It is called KYU88-1. In this simulator, thermal water flow through a porous medium is assumed to obey Darcy's law. The governing equations are approximated by the finite difference equations and calculated by the successive overrelaxation method. Using this simulator, a base model of a real field (the Takenoyu-Sugawara geothermal area in the middle Kyushu, Japan) is constructed. From this model, it is inferred that the hydrothermal system of this area extends to more than -3000 m above sea level and the Takenoyu fault, along which Takenoyu and Hagenoyu hot springs appear, has high permeability at the shallower part but not so high permeability at the deeper part. Moreover, a low resistivity zone near the well DW-7 detected by ELF-MT surveys is explained by this model, and the low resistivity zone is regarded as not a well fractured high permeable zone but a low permeable alteration zone which acts as a barrier to the hot water flow from eastern side.",
author = "Yasuhiro Fujimitsu and Kozo Yuhara",
year = "1989",
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AU - Fujimitsu, Yasuhiro

AU - Yuhara, Kozo

PY - 1989/1/1

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N2 - A three-dimensional steady state liquid phase simulator for hydrothermal systems was developed. It is called KYU88-1. In this simulator, thermal water flow through a porous medium is assumed to obey Darcy's law. The governing equations are approximated by the finite difference equations and calculated by the successive overrelaxation method. Using this simulator, a base model of a real field (the Takenoyu-Sugawara geothermal area in the middle Kyushu, Japan) is constructed. From this model, it is inferred that the hydrothermal system of this area extends to more than -3000 m above sea level and the Takenoyu fault, along which Takenoyu and Hagenoyu hot springs appear, has high permeability at the shallower part but not so high permeability at the deeper part. Moreover, a low resistivity zone near the well DW-7 detected by ELF-MT surveys is explained by this model, and the low resistivity zone is regarded as not a well fractured high permeable zone but a low permeable alteration zone which acts as a barrier to the hot water flow from eastern side.

AB - A three-dimensional steady state liquid phase simulator for hydrothermal systems was developed. It is called KYU88-1. In this simulator, thermal water flow through a porous medium is assumed to obey Darcy's law. The governing equations are approximated by the finite difference equations and calculated by the successive overrelaxation method. Using this simulator, a base model of a real field (the Takenoyu-Sugawara geothermal area in the middle Kyushu, Japan) is constructed. From this model, it is inferred that the hydrothermal system of this area extends to more than -3000 m above sea level and the Takenoyu fault, along which Takenoyu and Hagenoyu hot springs appear, has high permeability at the shallower part but not so high permeability at the deeper part. Moreover, a low resistivity zone near the well DW-7 detected by ELF-MT surveys is explained by this model, and the low resistivity zone is regarded as not a well fractured high permeable zone but a low permeable alteration zone which acts as a barrier to the hot water flow from eastern side.

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