Multi-component induction logging response simulation and environmental factors analysis in complicated anisotropic formations
摘要
In practical applications, conventional electrical anisotropy has certain limitations because it solely takes into account the resistivities along and perpendicular to the layering plane. To address more complicated electrical anisotropy issues, two parameters are used, namely anisotropic dip and anisotropic azimuth, to additionally capture the anisotropic properties in different sedimentary environments. Then the corresponding solution is proposed based on the dyadic Green function. Additionally taken into account are multilayer anisotropic issues. Using this proposed approach, the influence of various anisotropic dips and azimuths, as well as borehole dips and azimuths, is studied. Two angles are shown to exist by the Results: the critical anisotropy dip ψc and the critical borehole dip θc. Before and after these two angles, the axial components Hxx, Hyy, and Hzz show clear monotonic changes with variations in the borehole dip and anisotropy dip, respectively. The results also show that cross components (Hxy, Hyx, Hyz, Hzy, Hxz and Hzx) contain both borehole orientation and anisotropy orientation information. In layered geological models, triaxial induction responses are examined to further illustrate the correctness and robustness of the suggested approach.