The Implementation Of Time-domain Electromagnetic Simulation Of Axisymmetric Formation

In the oil industry,electromagnetic well logging methods play an indispensable role for formation evaluation.To study the response of the electromagnetil logging tool,frequency domain numerical simulation in the axisymmetric formation is frequently used.In recently,the study of electromagnetic methods in the time-domain becomes a hot topic.Therefore,developing and implementing software platforms that can simulate the time-domain electromagnetic response of axisymmetric formations accurately and quickly with actual-sized logging instruments has important value for the research of time-domain electromagnetic methods.This paper uses the client/server(C/S)software architecture of front-end and backend separation.Based on the modularized concept,the entire software implementation is divided into three parts: the electromagnetic simulation calculation module on the serverside,the C/S network communication module,and the client-side interface module.These three parts are implemented in three chapters of the paper,and the programming implementation of the C++ server-side and Python client-side is completed.The paper first implements the electromagnetic simulation calculation process in the C++ server-side,outlines the basic principles and implementation methods of timedomain electromagnetic simulation for axisymmetric formations,derives the control partial differential equation of the axisymmetric formation model,and realizes the frequency-domain electromagnetic response calculation tool in the finite element method to obtain the frequency-domain electromagnetic response of a specified measurement point in the grid.Then,four types of excitation waveforms,including step waveform,onoff waveform,Gaussian pulse waveform,and custom half-sine waveform,are studied and implemented.The time-domain electromagnetic field response is obtained through cubic spline interpolation and Fourier frequency-time transformation.The parallel computing technology is used to improve the time-domain electromagnetic simulation calculation speed of axisymmetric formations.Experimental tests show that using the method proposed in this paper can greatly improve the calculation speed of electromagnetic simulation while ensuring computational accuracy.In addition,this paper also implements the C/S architecture of the software platform,uses the g RPC framework to implement the network communication of C/S,and uses the C++ server-side to ensure both calculation speed,accuracy,and code security.The Python client-side is used to realize the visualization interface interaction and result graph drawing,which meets the cross-platform usage needs of users and provides a reference for the design and implementation of time-domain electromagnetic simulation software platforms for axisymmetric formations both domestically and internationally.