Electrical and Petrophysical Properties of Carbonate Rocks

Electrical and other petrophysical properties were measured in the laboratory versus pressure in 54 carbonate core samples from 11 oil-producing reservoirs. The measured electrical and petrophysical properties include formation factor F, cementation exponent m, and saturation exponent n, porosity φ, permeability K, grain density p_s, capillary pressure P_c, residual (irreducible) water saturation S_wr, and sonic velocities. In the measured cores, systematic relationships exist between formation factor and porosity, permeability and porosity, permeability and residual water saturation, saturation exponent and residual water saturation, and formation factor and sonic velocities, although the data are significantly scattered. The formation factors were best-fit to Archie’s equation so that the coefficient a and cementation exponent m were obtained. The empirical equations allow for calculation of porosity from formation factor, permeability from porosity and residual water saturation, and saturation exponent from residual water saturation, or vise versa.