Permeability of illite-bearing shale: 1. Anisotropy and effects of clay content and loading Academic Article uri icon

abstract

  • Permeability of illiterich shale recovered from the Wilcox formation and saturated with 1 M NaCl solution varies from 3 1022 to 3 1019 m2, depending on flow direction relative to bedding, clay content (4065%), and effective pressure Pe (212 MPa). Permeability k is anisotropic at low Pe; measured k values for flow parallel to bedding at Pe = 3 MPa exceed those for flow perpendicular to bedding by a factor of 10, both for low clay content (LC) and high clay content (HC) samples. With increasing Pe, k becomes increasingly isotropic, showing little directional dependence at 1012 MPa. Permeability depends on clay content; k measured for LC samples exceed those of HC samples by a factor of 5. Permeability decreases irreversibly with the application of Pe, following a cubic law of the form k = k0 [1 (Pe/P1)m]3, where k0 varies over 3 orders of magnitude, depending on orientation and clay content, m is dependent only on orientation (equal to 0.166 for beddingparallel flow and 0.52 for flow across bedding), and P1 (1827 MPa) appears to be similar for all orientations and clay contents. Anisotropy and reductions in permeability with Pe are attributed to the presence of cracklike voids parallel to bedding and their closure upon loading, respectively.

published proceedings

  • JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH

author list (cited authors)

  • Kwon, O., Kronenberg, A. K., Gangi, A. F., Johnson, B., & Herbert, B. E.

citation count

  • 204

complete list of authors

  • Kwon, O||Kronenberg, AK||Gangi, AF||Johnson, B||Herbert, BE

publication date

  • October 2004