The paper is devoted to the interpretation of data acquired with the complex of electrologging tools for studying electrophysical properties of geologic sections penetrated by deviated and sub-horizontal boreholes. Currently, target formations are characterized by high vertical heterogeneity, which includes thin bedding of resistivity-contrast interbeds. The application of traditional approaches to evaluate such objects results in unreliable estimates of the reservoir's resistivity and net thickness, and, consequently, the hydrocarbon saturation index. For studying electrophysical properties of rocks exposed by sub-vertical and sub-horizontal wells, we have developed an algorithm for numerical inversion of induction and galvanic soundings data. To enhance the reliability of the interpretation results in highly deviated boreholes, we utilize a horizontally layered interpretation model taking into account thin resistivity-contrast layers, as well as integrate data of induction and galvanic soundings. We have done numerical inversion of the practical data, including joint one, in the intervals of deviated and sub-horizontal wells of Western Siberia. It is shown that an increase or decrease in apparent resistivity owing to the presence of thin clayey or high-resistivity interbeds may significantly understate or overstate oil content.