Numerical Simulation Of Response Of Electromagnetic Logging While Drilling(LWD) By Hybrid Algorithm

In this paper,a hybrid method for calculating the response of drilling electromagnetic wave in horizontal stratified strata is studied and the corresponding calculation software is developed.The numerical simulation results show the spatial distribution of the electric field and magnetic field in the drill collar,the logging response in the layered medium and the partial results of the borehole correction library.The whole calculation process is summarized as follows:1,2 D electromagnetic field numerical simulation of axisymmetric problem,through the component variables into three ordinary differential equation,differential equation of radial and vertical differential equation and differential equation,coefficient of each layer formation in the basic solution of electromagnetic field;2.Using the Green integral formula,the internal electric field intensity of the layered formation is expressed as the integral form of the electric field intensity on the upper and lower interface;3.The boundary integral equation of electric field intensity is established by using the continuity condition of the electromagnetic field on the horizontal boundary.4.Using the partitioning feature of boundary integral equation,a fast algorithm for solving the boundary integral equation is established.5.Using the electric field intensity on the horizontal boundary of the stratum and the basic solution of the electric field intensity in the stratified layer,the electric field in the layered non-homogeneous layer is further represented as a semi-analytical form;6.According to Farady electromagnetic induction law,the semi-analytical solution of magnetic field intensity is derived by using the semi-analytical solution of electric field strength.7.According to the structure and real size of the electromagnetic logging instrument,the spatial distribution of the electric field and magnetic field around theborehole is studied in the case of high resistance and low resistance mud in the complete column medium.8.The response characteristics of the layered heterogeneous texture layer with drilling electromagnetic logging are investigated.9.The calculation method and some numerical simulation results of the borehole calibration library with drilling electromagnetic wave are studied.