I. A. Moskaev

—To study the effect of tilted uniaxial electrical anisotropy parameters on electric and electromagnetic logging signals, their numerical simulation and comparative analysis in homogeneous and layered models have been performed. An algorithm for three-dimensional numerical simulation of resistivity logging signals in spatially heterogeneous models with tilted principal axes of the electrical conductivity tensor, based on the finite-element method, was used in the calculations. The obtained results indicate the potential for a more accurate estimation of electrophysical properties of fractured carbonate reservoirs of the pre-Jurassic basement of West Siberia, which are characterized by the tilt of the electrical conductivity tensor principal axes.

Important stages in the development of electromagnetic logging tools based on national and foreign literature are considered: adaptation of traditional tools to logging while drilling and modification of tools for logging while drilling in order to provide the possibility of carrying out deeper and azimuthal measurements. Applied algorithms for modeling and interpreting data are briefly described, examples of tools which are used while drilling oil wells, including the national tool, are given.

Рассмотрены особенности и основные выводы публикаций, посвященных исследованию трансверсально-изотропных геоэлектрических моделей среды, характеризующихся наклоном оси электрической анизотропии относительно скважинного прибора. Такие модели могут описываться как горизонтальным и вертикальным удельными электропроводностями (либо обратными им величинами – удельными сопротивлениями) с ненулевым зенитным углом наклона каротажного прибора, так и тензором удельной электропроводности с наклоном главных осей.

In this article, we are the first to formulate the direct and inverse problems of resistivity logging on determining the components of the electrical resistivity tensor of rocks from a set of high-frequency induction and lateral logging sounding measurements. Using a finite element approximation, high-order hierarchical basis functions, computationally efficient multilevel methods and a multistart algorithm with the DFO-LS local optimization method, we investigate the capability of reconstructing the horizontal and vertical resistivity components, as well as the tilt of the resistivity tensor principal axes with regard to the study of complex geological objects. A separate consideration is given to a realistic generalized geoelectric model of the unique hydrocarbon source with hard-to-recover reserves, the Bazhenov Formation.