The Effects of Pore Pressure and Confining Pressure on Pore and Bulk Volume Compressibilities of Consolidated Sandstones

Abstract

A computer-controlled system has been devised that allows measurement of pore and bulk compressibilities of porous rocks over a full range of pore and confining pressures. Pore compressibilities have been measured for Bandera, Boise, and Berea sandstones. It is shown from these data that the pore compressibilities of these sandstones are functions of the difference between the confining pressure and the pore pressure. A simple physical explanation for this behavior is then given in terms of the closure of very fine microcracks in the rock.