Permeability and thermal cracking at pressure in Sioux Quartzite

Author:

Siddiqi Gunter12,Evans Brian1

Affiliation:

1. Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

2. Present Address: Swiss Federal Office of Energy, 3003 Berne, Switzerland

Abstract

AbstractWe heated specimens of Sioux Quartzite to 683, 783 and 830 K at confining pressures (Pc) of 0.1, 100 and 200 MPa. Following the heat treatments, we measured the permeability under confining pressures that varied from 170 MPa to 60 MPa, with pore-fluid pressures of 10, 16 or 22 MPa, resulting in tests having effective pressures ranging from 36 to 160 MPa. When measured under those effective pressures, the permeability of samples with microstructures formed by cracking at 683–830 K and atmospheric pressure increased by a factor of 3–4. Scanning electron microscopy (SEM) shows that thermal cracking increases the number of long, narrow cracks, qualitatively explaining the increased sensitivity of permeability to low effective pressure. Fracture mechanics models suggest that confining pressures lower the stress intensity factors to well below the critical value for crack propagation, and the absence of many long cracks is consistent with that prediction. At Pc=200 MPa, thermal cracking during the heat treatment is suppressed. Although the heating experiments were performed on nominally dry samples, in samples heated at the highest temperatures SEM revealed microstructural features that are similar to those seen in crack healing experiments.

Publisher

Geological Society of London

Subject

Geology,Ocean Engineering,Water Science and Technology

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3