Potential candidates of supercritical geothermal reservoir

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

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. The critical point of multicomponent geothermal fluids is considered to be located between the critical point trajectories of H2O-NaCl and H2O-CO2 solutions, and the supercritical state divided into 'liquid-like' and 'vapor-like' regions in terms of dissolution of rocks. 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 m2) could be maintained even under supercritical conditions. The permeableimpermeable boundary of the crust and geothermal reservoirs were affected by water-rock interaction such as dissolution and precipitation of silica minerals. Geochemical processes are a significant influence on the creation of a permeable-impermeable boundary in the crust. Possible tectonic settings for supercritical geothermal resources are classified into subduction zones, ridges, rifts, and hot spots. 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, and fossil calderas in late Miocene and Pleistocene are alternative candidates for supercritical geothermal reservoirs.

Original languageEnglish
Title of host publicationGeothermal Energy
Subtitle of host publicationPower To Do More - Geothermal Resources Council 2017 Annual Meeting, GRC 2017
PublisherGeothermal Resources Council
Pages1587-1598
Number of pages12
ISBN (Electronic)0934412227
Publication statusPublished - 2017
EventGeothermal Resources Council 41st Annual Meeting - Geothermal Energy: Power To Do More, GRC 2017 - Salt Lake City, United States
Duration: 2017 Oct 12017 Oct 4

Publication series

NameTransactions - Geothermal Resources Council
Volume41
ISSN (Print)0193-5933

Other

OtherGeothermal Resources Council 41st Annual Meeting - Geothermal Energy: Power To Do More, GRC 2017
CountryUnited States
CitySalt Lake City
Period17/10/117/10/4

Keywords

  • Fossil caldera
  • Geological model
  • Supercritical geothermal resources
  • Volcanic front

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Geophysics

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