On surveying depth by transient electromagnetic sounding method
Xue Guo-qiang
Teaching and Research Section of Electro-Vacuum,Electronic Department, College of Electronic and Communication, Xi’an Jiaotong University, Xi’an City, Shanxi Province, 710049, China
Abstract:The temporal procedure of equivalent circuit of transient electromagnetic transmitter loop is analyzed in the paper,the theoretical expressions of amplitude of loop self-induction signal is deduced,which considered that the attenuation of loop self-induction signal is not only relative to time,but also to the material of equivalent loops;the amplitude and time-decay scope of self-induction signals with different loop sizes are computed,which obtained the conclusion that there is the minimum depth when using transient electromagnetic method for sounding survey.The transient electromagnetic method has a maximum depth because of continuous attenuation by transmission of electromagnetic signal in underground.The paper gave the method and evaluation results for evaluated min and max sounding depths by using transient electromagnetic sounding in the conditions of common equipments (different coil sizes and different medium resistivity) and typical geoelectric scenario.The resulted transient electromagnetic sounding depths played a guide role in field production.