VELOCITY AND RESISTIVITY CHANGES DURING FREEZE-THAW CYCLES IN BEREA SANDSTONE

Abstract

We report on simultaneous measurements of resistivity, compressional (V-p), and shear (V-s) velocities made during the temperature cycling of Berea sandstone while at elevated pressure. Temperatures were cycled through the freezing point of the saturating brine. The responses of resistivity and velocities are in phase but are asymmetrical as the brine freezes and thaws. Limited freezing causes no discernible damage to the core. Free water is present below the nominal freezing point of the brine. V, V,, and resistivity change by 16%, 24%, and 500%, respectively, over the temperature range of -4 degrees C to +6 degrees C at 6.9 MPa confining pressure.