Geometrical model of conductive and dielectric properties of partially saturated rocks

Dielectric constant and conductivity of three‐component porous media are calculated using a geometrical model. Applications are made to experiments on clay‐free sedimentary rocks partially saturated with hydrocarbon and water, and air and water. A good agreement with experimental data at high frequency (GHz) is obtained using only a spherical grain shape. The low‐frequency (MHz) data cannot be explained by the spherical grain alone, but a bimodal distribution of spherical and platey grains gives a fair agreement. The low‐frequency dielectric constant is very sensitive to the grain‐shape distribution, but at high frequency is not.