Study of water saturation in electrically anisotropic media based on conductivity tensor

Abstract

The formation electrical anisotropy means that the formation apparent resistivity changes with the direction of measurement when the formation apparent resistivity is measured. Because the electrical conductivity tensor measured by the well logging instrument coincides with the component measured in the core analysis, other tensor components are often ignored in formation evaluation. The electrical anisotropy of the laboratory core is indicated by the conductivity tensor scale. It is difficult to obtain the nine components of the conductivity tensor completely in one experiment with the conductivity tensor measuring instrument. The water saturation can be calculated according to the resistivity measured by the Archie formula logging instrument. The common method is to establish the relation of the main axis components of the conductivity tensor on water saturation respectively according to the scalar Archie formula, so as to derive the tensor expression of water saturation. In this paper, based on the literature research results, the conductivity tensor measuring instrument is used to measure the square core, and the 9 components of the conductivity tensor of the core are measured, and the expression of Archie tensor which can be applied to the laboratory is discussed. The unknown coefficients of Archie formula are determined by laboratory data.