Detection capability of grounded electric source TEM for thin layer
CHEN Wei-Ying1,2, XUE Guo-Qiang1,2
1. Key Laboratory of Mineral Resources, Institute of Geology and Geophysics Chinese Academy of Sciences, Beijing 100029, China;
2. Institute of Geology and Geophysics Chinese Academy of Sciences, Beijing 100029, China
Nowadays, the short-offset grounded electric source transient electromagnetic method (SOTEM) is a hot research topic. In this paper, based on the 1-D forward calculation algorithm and using relative anomalies between vertical magnetic field responses generated by a thin layer and homogeneous half space, the authors investigated the detection capability of SOTEM for thin layered models with different resistivities, different thicknesses and different buried depths as well as the impact of different offsets. In addition, the difference between electric source TEM and loop source TEM as well as CSAMT was comparatively studied. It is concluded by analysis that low resistance, greater thickness, smaller buried depth and smaller transmitter-receiver offset will be favorable for increasing the sensitivity to the earth. On the other hand, the time domain electromagnetic method is more sensitive to low resistance layer than the frequency domain electromagnetic method, and the SOTEM and the loop source TEM almost have an equal detection capability when the offset is small. What we have done in this paper has important reference value for the field production.
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