Isotope Behavior During Circulation Test at the Hijiori EGS Site, Japan
- Key words
- Stable isotope ratio; ? D; ? 18O; EGS; HDR; circular test; geochemistry
- Location
- Hijiori, Japan
- Conference
- Geothermal Resources Council Transactions
- Year
- 2014
- Session
- HDR/EGS; Well testing; Circulation testing; Isotopes
- Language
- English
Abstract
A long-term circulation test was conducted between November 2000 and August 2002 at the hot dry rock (HDR) test site in Hijiori, Japan. During this test, hydrogen and oxygen isotope composition of production wells (HDR-2 and HDR-3), injection well, river water and hot springs were analyzed. The isotope ratio of the river water and hot springs plot along the meteoric water line. The isotope ratio of hydrogen and oxygen ratio of HDR-2 increased with circulation and reached value of -45? of ?D and -4.6? of ?18O at end of May 2001, respectively. However?D and ?18O rapidly decreased to -54.4? and -8.6? respectively from May to June and came close to meteoric line. The isotope ratio of HDR-3 plot at higher?18O than that of HDR- 2 and the change of the isotope ratio of HDR-3 is similar as that of HDR-2. The change of ?18O value of HDR-2 is corresponds with Cl concentration change during the circulation progress.
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