SELF-PROPPING AND FLUID-FLOW IN SLIGHTLY OFFSET JOINTS AT HIGH EFFECTIVE PRESSURES

被引:129
作者
DURHAM, WB
BONNER, BP
机构
关键词
D O I
10.1029/94JB00242
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
We have made laboratory measurements of joint closure and permeability of both well- and poorly mated, laboratory-produced joints in Westerly granite under joint normal stresses to 160 MPa, appropriate to midcrustal depths. We have also made detailed topographic measurements of the joint surfaces, both before and after pressure testing. The purpose of the study was to characterize and understand the hydraulic behavior of joints under conditions where fluid migration under natural settings is known to occur but where physical conditions, namely high lithostatic load, suggest that the presence of open, fluid-conducting joints might be improbable. Normal stress was applied by hydrostatic confinement of cylindrical samples, each containing a single axial tensile fracture. Experiments were performed at room temperature under conditions designed to minimize chemical effects of dissolution or precipitation. We found that while a mated joint can be completely closed by the application of high normal stresses, the same joint laterally offset by 0.53 mm remains open and many orders of magnitude more hydraulically conductive than the mated joint even at highest stresses. Detailed topographic observations are consistent with self-propping of the offset joint. Permanent damage to the surfaces of the offset joint is not widespread but occurs at isolated locales covering about 10% of the surface. Damage is confined to regions of negative (convex upward) curvature, such as summits and the edges of plateaus. Approximately 20% of the joint surface is in wall-to-wall contact at 160 MPa, and the flow tortuosity thus induced is probably the cause of the breakdown of the parallel plate approximation for fluid flow in the offset joint.
引用
收藏
页码:9391 / 9399
页数:9
相关论文
共 38 条
  • [1] FUNDAMENTALS OF ROCK JOINT DEFORMATION
    BANDIS, SC
    LUMSDEN, AC
    BARTON, NR
    [J]. INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES, 1983, 20 (06): : 249 - 268
  • [2] STRENGTH, DEFORMATION AND CONDUCTIVITY COUPLING OF ROCK JOINTS
    BARTON, N
    BANDIS, S
    BAKHTAR, K
    [J]. INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES, 1985, 22 (03): : 121 - 140
  • [3] PERMEABILITY OF CRYSTALLINE AND ARGILLACEOUS ROCKS
    BRACE, WF
    [J]. INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES, 1980, 17 (05): : 241 - 251
  • [4] FLUID-FLOW THROUGH ROCK JOINTS - THE EFFECT OF SURFACE-ROUGHNESS
    BROWN, SR
    [J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS, 1987, 92 (B2): : 1337 - 1347
  • [5] CLOSURE OF ROCK JOINTS
    BROWN, SR
    SCHOLZ, CH
    [J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS, 1986, 91 (B5): : 4939 - 4948
  • [6] NATURAL JOINTS IN ROCK - MECHANICAL, HYDRAULIC AND SEISMIC BEHAVIOR AND PROPERTIES UNDER NORMAL STRESS
    COOK, NGW
    [J]. INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES & GEOMECHANICS ABSTRACTS, 1992, 29 (03) : 198 - 223
  • [7] Cook NGW, 1976, FUNDAMENTALS ROCK ME, P169
  • [8] GEOLOGICAL AND INDUSTRIAL IMPLICATIONS OF EXTENSIVE-DILATANCY ANISOTROPY
    CRAMPIN, S
    [J]. NATURE, 1987, 328 (6130) : 491 - 496
  • [9] CRISS RE, 1986, REV MINERAL, V16, P373
  • [10] HYDROLOGICAL PROPERTIES OF TOPOPAH SPRING TUFF - LABORATORY MEASUREMENTS
    DAILY, W
    LIN, W
    BUSCHECK, T
    [J]. JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS, 1987, 92 (B8): : 7854 - 7864