摘要
It is very important to understand correctly the relation of formation permeability with the resistivity factor in order to improve the evaluation of low permeability reservoirs with strong heterogeneity by using electrical logging data. This paper made a comprehensive analysis of the assorted experimental data obtained from the Bohai Bay basin including porosity, permeability, NMR T2 spectrum, rock resistivity, mercury injection, X-ray, 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. It is found that the relation of formation permeability to its resistivity factor is not monotonic and that 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 theoretically. It is also pointed out that the difference of permeability is related to square ratio of average pore throat, pore tortuosity and geometry for core samples with similar porosity and electrical conductivity.