Permeability behavior in high-temperature ductile crust and prediction of spatiotemporal evolution in supercritical geothermal resource

2021 Fiscal Year Final Research Report

• Project/Area Number: 17H03504
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Earth system and resources engineering
• Research Institution: Tohoku University
• Principal Investigator: Watanabe Noriaki 東北大学, 環境科学研究科, 教授 (60466539)
• Co-Investigator(Kenkyū-buntansha): 岡本 敦 東北大学, 環境科学研究科, 教授 (40422092) ; 坂口 清敏 東北大学, 環境科学研究科, 准教授 (50261590)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Keywords: 超臨界地熱資源 / 再生可能資源・エネルギー / 延性地殻 / 浸透率

Outline of Final Research Achievements

The scale and characteristics of new geothermal resources, "supercritical geothermal resources", which consist of fractured rocks containing supercritical water, are highly dependent on the permeability of the intrusive rocks and its host rocks. On the other hand, it has been suggested that the permeability may change drastically due to changes in mechanical properties or rocks such as the brittle-ductile transition, and fast, nucleation-type precipitation associated with fluid phase changes, but the details are unknown. In this study, we derived model equations of permeability behaviors involving changes in the mechanical properties of rocks and phase changes of fluids through laboratory experiments, and clarified the possibility of a prediction method of spatio-temporal evolution of supercritical geothermal resources by conducting spatio-temporal evolution simulations.

Free Research Field

地球・資源システム工学

Academic Significance and Societal Importance of the Research Achievements

これまでの“延性岩体は不透水”という仮説が正しくないことを独自に見出し，水理地質学分野と地熱貯留層工学分野の新たな研究を展開した。本研究の成果は，地震学や鉱床学の分野でも議論が絶えない高温延性地殻の浸透性に関する知見を新たに提供し，世界的にも我が国にとってもエネルギー・環境問題の解決に重要な役割を果たすと考えられる超臨界地熱資源のより良い理解および開発・生産の実現に貢献する。