Abstract
Permeability measurement of Kimachi sandstone was carried out to obtain the permeability and specific storage under effective confining pressure and axial differential stress conditions. The Kimachi sandstone has a not clear bedding plane and cross lamina in cm size specimen, which is mainly caused by grain orientation and pore distribution in microscopic scale. We confirmed that P wave velocity show isotropic in parallel to bedding plane and vertically anisotropic in normal to bedding plane, and that major axis of grain plane assumed as an ellipsoidal shape distribute dominantly to horizontal east-west direction from microscopic observation of the thin section. Permeability for vertical direction show larger value than those for horizontal two directions. Permeability reduction with increasing effective confining pressure and axial differential stress are almost same manner for mutually perpendicular three directions, which consist of two horizontal directions parallel to bedding plane and vertical direction normal to bedding plane. Specific storage for three directions decreased with increasing effective confining pressure, and showed dominant reduction around the maximum strength. Using the data related to the connecting path and tortuosity of the Kimachi sandstone, anisotropic phenomenon for different three perpendicular directions on permeability and specific storage under various stress conditions are discussed consistently. However, it is well known that fluid flow of composite materials are rather complex, only the simple quantification of the number of connecting path or tortuosity in a limited small range could not descide systematically anisotropic transport parameter of the whole and large specimen.
