Logging Components Extraction Method and Anisotropy Recognition Based on 3D Holographic LWD Instrument

Abstract Addressing the challenges of extracting all electromagnetic logging components in a self-developed 3D holographic logging while drilling (LWD) tool using existing theoretical methods, this study focuses on the following core work: starting from a three-directional electromagnetic wave instrument and combining the basic measurement principles of the logging coil system, deriving the transmission-reception response formulas for two antenna systems (Co-planar and Antiplanar antenna systems), extracting all nine logging components to form a method directly calculable and applicable to the instrument. By integrating extracting algorithms with the specific antenna configuration of the 3D holographic LWD tool, high-fidelity extraction and complete separation of all nine electromagnetic logging components are achieved. Based on the theoretical support of this method, a new anisotropy signal is constructed for research. Through analysis, it is found that the anisotropy signal constructed by the extraction method can produce a significant distinguishing response to formation resistivity anisotropy and possesses excellent azimuthal characteristics. It can also clearly express anisotropy and instrument azimuth in azimuthal imaging. By employing the same inversion method, the anisotropy coefficients calculated from the new signal will be more accurate than those derived from traditional signals, with the developed signal inversion average error controllable within 0.01.