| Project/Area Number |
18K19039
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 31:Nuclear engineering, earth resources engineering, energy engineering, and related fields
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| Research Institution | Tohoku University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
坂口 清敏 東北大学, 環境科学研究科, 准教授 (50261590)
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| Project Period (FY) |
2018-06-29 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000)
Fiscal Year 2020: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2019: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2018: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
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| Keywords | 超臨界地熱資源 / 水圧破砕 / 延性地殻 / 透水性 / 貯留層 |
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| Outline of Final Research Achievements |
We aimed to create a new scientific field for hydraulic fracturing of subsurface rocks based on results from a set of the first-ever hydraulic fracturing experiments on granite under true triaxial stress state at supercritical temperatures of water, with consideration for the formation environments of supercritical geothermal resources. We systematically and quantitatively investigated influences of various factors (temperature, stress state, fluid injection rate and so on) on fracture pattern and permeability enhancement for granite, and developed a fundamental theory of supercritical hydraulic fracturing which can be applied to a new method to create high-permeability cloud-fracture networks.
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| Academic Significance and Societal Importance of the Research Achievements |
超臨界地熱資源が形成されうる地殻環境で生じる超臨界水圧破砕現象は，従来の水圧破砕とは全く異なる新しいタイプの水圧破砕現象である。したがって，この新発見の現象を地熱発電等において工学的に利用するためには，既存の水圧破砕に関する学術体系を大きく変革させる必要があった。そこで本研究では，超臨界地熱資源の形成条件を考慮した温度や真三軸応力条件で花崗岩の水圧破砕実験を実施し，超臨界水圧破砕の基礎理論を構築した。本研究の成果は，超臨界地熱資源の開発・生産において常に懸念事項となる不十分な透水性への遭遇による経済的リスクの大幅な低減を通じて，超臨界地熱発電の実現，低炭素化社会の構築に貢献すると期待できる。
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