Analysis and Design of the Coils System for Electromagnetic Propagation Resistivity Logging Tools by Numerical Simulations

摘要

The coils systems of electromagnetic propagation resistivity logging (EPRL) tools use coils as transmitting and receiving antennas for a fixed frequency. The Numerical Mode Matching (NMM) method is applied in the simulation of electromagnetic fields with multi-layer structure domains to study the key design parameters of logging tools, which contain the source frequency, the transmitter-receiver spacing, and the receiver interval. A critical requirement in the design of the coils system is to produce different desired signals for different typical ground model. In this paper, the three key design parameters are analyzed, and the principles and steps of coils system design are given. The parameters must be reasonable values to achieve the desired effect. The simulation results also show that depth of investigating is related with the source frequency, the transmitter-receiver spacing, and the receiver interval.