Apparatus for measuring radial resistivities in cylindrical core samples of porous rock

摘要

A cylindrical core sample of a subterranean formation is place into a sleeve under confining pressure. At least one electrode array extends through the sleeve and makes contact with the core sample. The array is in a plane normal to the core sample and has an even number of electrodes equally spaced about the sleeve. A current is passed through the core sample and voltages are measured across each pair of electrodes that are spaced 180 DEG apart around the sleeve. Such measurements are utilized to identify the radial direction of any electrical anisotropy in the core sample, particularly under differing fluid saturation conditions.