Simulation of Triaxial Induction Tool Response in Biaxial Anisotropic Formation

A fast 1D electromagnetic method for simulating triaxial induction tool responses is used to model the field distribution in fractured anisotropic formations. Fractures are a specific feature of geological formations. Using the bucking coil technique, we interpreted the simulation results as apparent conductivity of the formation and modeled the practical wireline induction tool response. The method is validated versus other independent modeling software. Multiple examples are presented to compare the apparent conductivity of transversely isotropic and biaxial anisotropic formations. Sensitivity to anisotropic conductivity, bed boundaries, dip angle and layer thickness were observed, which proves that the failure to consider the biaxial anisotropy would have great impact on the interpretation of triaxial induction tool responses. We discuss particular features which enable visual log interpretation for the presence of possible fractures.