2017 Fiscal Year Final Research Report

Science and Technology of Geothermal Energy Frontier

Research Project

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Project/Area Number	25000009
Research Category	Grant-in-Aid for Specially Promoted Research
Allocation Type	Single-year Grants
Review Section	Science and Engineering Engineering
Research Institution	Tohoku University
Principal Investigator	TSUCHIYA Noriyoshi 東北大学, 大学院環境科学研究科, 教授 (40207410)
Co-Investigator(Kenkyū-buntansha)	ASANUMA Hiroshi 国立研究開発法人産業技術総合研究所, 再生可能エネルギー研究センター, 地熱チーム長 (50250717) OKMOTO Atsushi 東北大学, 大学院環境科学研究科, 准教授 (40422092) SAKAGUCHI Kiyotoshi 東北大学, 大学院環境科学研究科, 准教授 (50261590) WATANABE Noriaki 東北大学, 大学院環境科学研究科, 准教授 (60466539) HIRANO Nobuo 東北大学, 大学院環境科学研究科, 助教 (80344688) KIZAKI Akihisa 秋田大学, 国際資源学研究科, 准教授 (60344686) MORIYA Hirokazu 東北大学, 大学院工学研究科, 教授 (60261591)
Project Period (FY)	2013 – 2017
Keywords	地殻エネルギー / 再生可能エネルギー / 超臨界流体 / 脆性破壊 / 脆性延性遷移領域 / 地熱貯留層 / 岩石-水相互作用 / 貯留層シミュレーター
Outline of Final Research Achievements	Geological models and the properties of supercritical geothermal reservoirs are described with respect to supercritical geofluids, mechanical behaviors of reservoir rocks, crustal permeability and tectonic settings. Mechanical conditions at the elastic-plastic boundaries of granitic rocks indicate potentially exploitable supercritical geothermal resources. Tensile fracturing is possible even in ductile rocks, and some permeability-depth relations proposed for the continental crust show no drastic permeability reduction at the BDT (Brittle-Ductile Transition). The reservoir permeability (>10^[-16] m^2) could be maintained even under supercritical conditions. The permeable-impermeable boundary of the crust and geothermal reservoirs were affected by water-rock interaction such as dissolution and precipitation of silica minerals. NE Japan is representative of an Island-Arc setting in a subduction system, and it is highly possible that exploitable supercritical geothermal resources may be located on and around the present volcanic front.
Free Research Field	地熱エネルギー工学ならびに地殻流体科学