Geoelectric Model of the Bazhenov Formation Deposits According to Electrical and Electromagnetic Logging Sounding Data

The increased interest in the development of low-permeability and low-porosity reservoirs leads to the necessity of developing new approaches to quantitative interpretation of geophysical data, providing the acquisition of more detailed information about the structure and properties of sediments by contrast to the traditional approach. The paper proposes techniques for determining the electrical parameters of a consistent geoelectric model explaining the behavior of lateral logging sounding and high-frequency electromagnetic sounding signals measured in vertical wells at intervals of the Bazhenov formation.

The technique is based on the present-day finite element numerical simulation and inversion of electrical and electromagnetic logging signals in a two-dimensional axisymmetric model, taking into account the resistivity anisotropy, dielectric permittivity and its frequency dispersion in the 0.875–14 MHz range. The resulting models fit the measured signals of the both methods within the measurement error, and focused lateral logs, which are not involved directly.

According to the data inversion results at intervals of the Bazhenov formation from more than twenty wells from Fedorovskoe, East-Surgutskoe and Russkinskoye fields, we determined the features of the resistivity anisotropy coefficient distribution and carried out the first numerical experiments to evaluate the values of the effective dielectric permittivity.