論文

2006年4月

Evolution of fracture permeability through fluid-rock reaction under hydrothermal conditions

EARTH AND PLANETARY SCIENCE LETTERS
  • H Yasuhara
  • ,
  • A Polak
  • ,
  • Y Mitani
  • ,
  • AS Grader
  • ,
  • PM Halleck
  • ,
  • D Elsworth

244
1-2
開始ページ
186
終了ページ
200
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1016/j.epsl.2006.01.046
出版者・発行元
ELSEVIER SCIENCE BV

We report flow-through experiments on a natural fracture in novaculite under moderate effective stresses (similar to 1.4 Mpa) and temperatures (20-120 degrees C) to examine the effect on flow and transport characteristics. The efflux of fluid and dissolved minerals were measured throughout the 3150-h experiment. After the experiment the fracture was imaged by X-ray CT, impregnated with Wood's metal, and a cast recovered of the Wood's metal-filled fracture. These measurements constrain the evolution of fracture structure, and the change in permeability that resulted from stress- and temperature-dependent dissolution at both propping asperities and fracture void surfaces. During the first 1500 h, the aperture of one fracture decreased from 18.5 to 7.5 mu m, when it was loaded with constant effective stress of 1.4 MPa, at room temperature, and a flow rate decreasing with time from 1 to 0.0625 mL/min. This reduction is attributed to the removal of mineral mass from bridging asperities. After 1500 h the fracture aperture increased, ultimately reaching 13 pm. Apparently the dominant dissolution process switched from prop removal to etching of the void surfaces. We used X-ray CT images, digital radiographs, and fracture casts as independent methods to constrain the resulting architecture of the evolved fracture porosity, and developed a simple process-based model to examine the relative roles of asperity removal and free-face dissolution. The comparison of the model with the measurements identifies the relative importance of mass removal at fracture faces and at propping asperities. The experiments underscore the importance of dissolution in determining the sense, the rates and the magnitude of permeability-enhancement within rock fractures stimulated by chemical permeants in geothermal and petroleum reservoirs, and to a lesser degree under natural conditions pushed far-from-equilibrium. (c) 2006 Elsevier B.V. All rights reserved.

リンク情報
DOI
https://doi.org/10.1016/j.epsl.2006.01.046
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000236991300013&DestApp=WOS_CPL
URL
http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=33645520862&origin=inward
ID情報
  • DOI : 10.1016/j.epsl.2006.01.046
  • ISSN : 0012-821X
  • SCOPUS ID : 33645520862
  • Web of Science ID : WOS:000236991300013

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