The effect of a variable pore radius on formation resistivity factor

摘要

Formation resistivity factor F was introduced as the ratio of the resistivity of a rock fully saturated with conductive water to the resistivity of the conductive water based on results of laboratory measurements. It was also found that the formation factor is a function of the type and character of a formation and is related to porosity by a relationship including an exponent m. For model calculations of the formation factor, capillary channel models describing a straight tube with a constant circular cross-sectional area are frequently used. However, the pore channel radius is not constant in natural rocks.