Permeability and Effective Stress

Permeability of the Berea Sandstone was measured as a function of both confining pressure and pore pressure. As expected, permeability decreased with increased confining pressure and increased with increasing pore pressure. However, pore pressure had a significantly larger effect on permeability than did confining pressure. This behavior can be explained if the matrix through which the pore fluid flows has a higher compressibility than the granular framework which supports externally applied stresses.