Experimental Study on the Relationship Between Reservoir Permeability and Its Formation Resistivity Factor

Abstract

AbstractTo improve the evaluation of low permeability reservoirs with strong heterogeneity by using electrical logging data, it is essential to correctly understand the relation of formation permeability to its resistivity factor. In this paper, a comprehensive analysis is made on the assorted experimental data obtained from the Bohai Bay Basin, including porosity, permeability, NMR T2 spectrum, rock resistivity, mercury injection, X‐ray diffraction, casting thin sections and so on. For the same group of core samples, the relation of formation resistivity factor to permeability, average pore throat radius and reservoir quality index is further studied separately. Each result is compared to the relation of formation resistivity factor to porosity. The study reveals that the relation of formation permeability to its resistivity factor is not monotonic, and core samples with similar porosity but different pore structure quality and permeability can have close electrical conductivity. The reasonability of this phenomenon is further proved with theoretical analysis. It is also found that the difference of permeability is related to the square of the ratio of average pore throat, pore tortuosity and geometry for core samples with similar porosity and electrical conductivity.