—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.

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.

Features and main conclusions of publications devoted to the study of medium transverse-isotropic geoelectric models which are characterized by inclination of the electrical anisotropy axis relative to a logging tool are reviewed in this article. Such models can be defined either by horizontal and vertical conductivities (or their reciprocals, called resistivities) with a non-zero dip of a logging tool or by the conductivity tensor with the tilt of the principal axes.

Accuracy of the horizontal well placement in the target reservoir becomes essential for efficient oilfield development. Geosteering of a well with a complex trajectory is performed using real-time geophysical data obtained while drilling. The presented work is devoted to the development of a new software for horizontal oil and gas wells geosteering. Algorithms based on logging data correlation and electromagnetic logging data numerical inversion methods are used for well placement. The developed application is based on web-technologies and has a client-server architecture. To optimize the resource-intensive calculations execution time, high-performance cloud computing is used.