Xue Guoqiang

Detecting shallow caverns in China using TEM

To detect shallow anomalies under certain conditions, electromagnetic methods can be more effective in reconnaissance surveying than high-resolution surface seismic. This case study describes the results of the transient electromagnetic method (TEM) in an environment where initial field trials showed that surface seismic was difficult to employ effectively and expensive to implement.

瞬变电磁探测系统(CASTEM)试验对比——安徽颖上大王庄铁矿

为推进国产电磁勘探设备的高端化进程，自主研发了CASTEM瞬变电磁系统.在前期系统开发、测试及集成基础上，开展野外试验研究，以检验CASTEM系统的稳定性及探测能力.选择已取得显著勘探成果的安徽颖上县大王庄铁矿进行试验，试验内容包括大功率发射机性能、接收系统噪声性能、实测响应曲线和反演效果，并与国际高端瞬变电磁仪在上述几方面进行了对比.试验结果表明CASTEM系统的各项指标性能稳定、可靠，已达到国际先进水平；探测成果与高端瞬变电磁仪器探测成果以及钻孔资料相吻合，表明CASTEM系统可以用于深部勘探.

Understanding of Grounded-Wire TEM Sounding with Near-Source Configuration

In order to understand the near-source TEM sounding method, the topic on the time domain electromagnetic exploration of deep targets is addressed using a grounded dipole source. At first, the development of the near source TEM is reviewed in this paper, then a new kind of technique capable of detecting geological targets located at deeper levels in the subsurface is proposed using the short-offset transient electromagnetic method (hereafter referred to as SOTEM). The detection abilities of this system, such as the feasibility of near-source detection for SOTEM, the investigation depth of SOTEM and the sensitivity of SOTEM, have been analyzed. The conclusion has been achieved that the proposed method is more applicable and convenient for exploration and could be used to obtain a greater detection depth with higher detection accuracy.

Inversion of TEM Conductive Thin Layer Based on Genetic Algorithm

Using the adaptive shrinkage genetic algorithm in the feasible region to operate the inversion of TEM (transient electromagnetic method) conductive thin layer with the apparent vertical conductance differential imaging. In contrast, this inversion method accelerates the calculation speed and improves the calculation precision. Meanwhile, we utilize the genetic algorithm to derive the conductive imaging parameter and realize the global non-linear inversion compared to traditional method in local scope.Using the adaptive shrinkage genetic algorithm in the feasible region to operate the inversion of TEM (transient electromagnetic method) conductive thin layer with the apparent vertical conductance differential imaging. In contrast, this inversion method accelerates the calculation speed and improves the calculation precision. Meanwhile, we utilize the genetic algorithm to derive the conductive imaging parameter and realize the global non-linear inversion compared to traditional method in local scope.