DOI: 10.1038/ngeo2879
论文题名: Potentially exploitable supercritical geothermal resources in the ductile crust
作者: Watanabe N. ; Numakura T. ; Sakaguchi K. ; Saishu H. ; Okamoto A. ; Ingebritsen S.E. ; Tsuchiya N.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2017
卷: 10, 期: 2 起始页码: 140
结束页码: 144
语种: 英语
Scopus关键词: continental crust
; crust
; deformation mechanism
; exploitation
; geothermal energy
; granite
; permeability
; rock mechanics
; temperature effect
; tensile strength
英文摘要: The hypothesis that the brittle-ductile transition (BDT) drastically reduces permeability implies that potentially exploitable geothermal resources (permeability >10 -16 m2) consisting of supercritical water could occur only in rocks with unusually high transition temperatures such as basalt. However, 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. Here we present experimental results suggesting that the BDT is not the first-order control on rock permeability, and that potentially exploitable resources may occur in rocks with much lower BDT temperatures, such as the granitic rocks that comprise the bulk of the continental crust. We find that permeability behaviour for fractured granite samples at 350-500 °C under effective confining stress is characterized by a transition from a weakly stress-dependent and reversible behaviour to a strongly stress-dependent and irreversible behaviour at a specific, temperature-dependent effective confining stress level. This transition is induced by onset of plastic normal deformation of the fracture surface (elastic-plastic transition) and, importantly, causes no jump in the permeability. Empirical equations for this permeability behaviour suggest that potentially exploitable resources exceeding 450 °C may form at depths of 2-6 km even in the nominally ductile crust. © 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/105846
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: Department of Environmental Studies for Advanced Society, Graduate School of Environmental Studies, Tohoku University, Sendai, Miyagi, Japan; Renewable Energy Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Koriyama, Fukushima, Japan; US Geological Survey, Menlo Park, CA, United States
Recommended Citation:
Watanabe N.,Numakura T.,Sakaguchi K.,et al. Potentially exploitable supercritical geothermal resources in the ductile crust[J]. Nature Geoscience,2017-01-01,10(2)