Comparison of application effect of magnetotelluric sounding using different inversion methods in shale gas investigation in Wanjiang area of Anhui Province

Magnetotelluric sounding(MT)section investigation was carried out during geological survey for shale gas in Wanjiang area of Anhui Province. Based on inversion results of four different inversion methods and different polarization modes, this study analyzed their advantages and disadvantages. The results show that the four inversion methods have their own characteristics and different polarization modes also have different inversion effects. Geological and drilling data also shows that 2D conjugate gradient inversion in TM mode inversions present distinct electrical characteristics and best effect of iterative convergence. Their coupling well with geological data can successfully identify low resistivity anomaly of Permian shale. Therefore, this study preliminarily infers the spatial distribution characteristics of faults and the target strata of shale gas in Wanjiang area, which will provide thinking way for selecting inversion methods of MT exploration in other similar areas.