High Temperature Electrical Conductivity Of Shaly Sands

The electrical conductivity of 100% water saturated sandstones has been studied in the laboratory as a function of salinity and temperature, and results have been used to obtain shale conductivities. Data have been obtained on core samples from four different reservoirs, as well as Berea sandstone. The low frequency dielectric constants of these cores have also been measured as a function of temperature and have been correlated with the shale conductivities. The electrical conductivity due to shaliness exhibits a temperature dependence similar to that of saline solutions; i.e., shale conductivity increases linearly with temperature. However, the formation factor decreases with increasing temperature by an amount that depends on shaliness.