Numerical Modeling of the Induction Logging Signal in Anisotropic Oil and Gas Reservoirs with a Layered Structure

The aim of this work is to analyze the effect of the anisotropic nature of the electricconductivity in an oil-bearing formation on the induction logging signal. The numerical modelingof the logging signal from a device consisting of an alternating current excitation coil and tworeceiving coils moved along the wellbore is carried out. The electromotive force induced in thereceiving coils is investigated. The electric conductivity of the oil-bearing formation ischaracterized by either a diagonal tensor with dominant \(\sigma _{xx}\) , \(\sigma _{yy}\) components or a dense tensor obtained by rotation to a specified zenithangle. Numerical modeling is performed with the vector finite element method on an adaptiveunstructured tetrahedral grid taking into account the geometry of the logging device, vertical well,and layered host medium. The tensor electric conductivity is plugged into the variationalformulation. Dependences of the apparent electric conductivity of the depth are obtained based onthe electromotive force induced in the receiving coils.