期刊
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
卷 109, 期 B2, 页码 -出版社
AMER GEOPHYSICAL UNION
DOI: 10.1029/2002JB001782
关键词
crack healing; crack closure; hydrothermal
[1] Time-dependent closure of fractures in quartz was measured in situ at 22 - 530 degreesC temperature and 0.1-150 MPa water pressure. Unlike previous crack healing and rock permeability studies, in this study, fracture aperture is monitored directly and continuously using a windowed pressure vessel, a long-working- distance microscope, and reflected-light interferometry. Thus the fracture volume and geometry can be measured as a function of time, temperature, and water pressure. Relatively uniform closure occurs rapidly at temperatures and pressures where quartz becomes significantly soluble in water. During closure the aperture is reduced by as much as 80% in a few hours. We infer that this closure results from the dissolution of small particles or asperities that prop the fracture open. The driving force for closure via dissolution of the prop is the sum of three chemical potential terms: ( 1) the dissolution potential, proportional to the logarithm of the degree of undersaturation of the solution; ( 2) the coarsening potential, proportional to the radius of curvature of the prop; and ( 3) the pressure solution potential, proportional to the effective normal stress at the contact between propping particles and the fracture wall. Our observations suggest that closure is controlled by a pressure solution-like process. The aperture of dilatant fractures and microcracks in the Earth that are similar to those in our experiments, such as ones generated from thermal stressing or brittle failure during earthquake rupture and slip, will decrease rapidly with time, especially if the macroscopic stress is nonhydrostatic.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据