Analysis on influence of ground transmitting electrode on bidirectional EM-MWD signal transmission based on ANSYS

The grounded emitter electrode is a necessary component of the bidirectional EM-MWD signal downlink system, and its reasonable parameter setting can improve the signal downlink effect, but at present, little is known about its influence on the downlink signal. This paper is based on the bi-directional EM-MWD working mechanism, combined with the current field theory, using ANSYS finite element software, establishes a three-dimensional simulation model of bidirectional EM-MWD signals, and analyzes the emission distance, length, diameter and resistivity of the ground transmitting electrode versus the downlink signal. The simulation results show that the downlink signal reception effect is positively correlated with the diameter and length of the ground transmitting electrode; when the grounded emitter electrode resistivity is less than 10-4 Ω·m, its resistivity change has little influence on the downlink signal transmission, the conventional metal material can meet the requirement of resistivity; as the transmission distance of the bidirectional EM-MWD increases, the received signal strength of the downlink signal increases rapidly first, after exceeding a certain distance, the signal strength tends to be fixed.