One-dimensional Occam's inversion for transient electromagnetic data excited by a loop source
XING Tao1(), YUAN Wei2, LI Jian-Hui3()
1. Beijing Exploration Resources Technology Co., Ltd., Beijing 100071, China 2. Inner Mongolia Geological Engineering Co., Ltd., Hohhot 010010, China 3. Institute of Geophysics and Geomatics, China University of Geosciences(Wuhan), Wuhan 430074, China
A 1D inversion code is developed for the loop-source transient electromagnetic method (TEM) based on the open-source code Dipole1D and Occam's algorithm. This code is tested by a four-layer stratified model. Then, the model with a tilted earth-air interface is considered, for which the synthetic data are calculated by 3D finite-element method. The inversion results show that 1D inversion can be directly used for the scenario with tilted interface. Finally, this 1D inversion code is used for a field case, in which TEM is employed to delineate the 3D distributed domains of a basalt which intruded into shale and sandstone. The inversion result shows that the thickness of the basalt coincides with the drilling data, and the shape of the basalt like a pot bottom.
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