Study on joint inversion of TEM and CSAMT based on one-dimensional Occam algorithm

Ground electromagnetic method is an effective geophysical method to explore the water abundance of coal mine aquifer. The multi-solution of geophysical prospecting method greatly increases the difficulty of data interpretation, which makes it difficult to effectively detect the hidden danger of coal mine water disaster by single method. In order to realize the fine exploration of water abundance in coal mine aquifer, the one-dimensional joint inversion objective function of transient electromagnetic method (TEM) and controlled source audio magnetotelluric method (CSAMT) is established, and the joint inversion of the two methods is studied by using Occam algorithm. On the basis of TEM, CSAMT and joint inversion of the data processing by different methods, combined with known geological data, the inversion results of each method are compared and analyzed. It is verified by underground drilling that the stable water inflow of underground coal seam roof drainage borehole is about 80m³/h, and it is found that the joint inversion results are most consistent with the actual situation. The research shows that the joint inversion method can effectively reduce the multi-solution interference of electromagnetic inversion, greatly improve the accuracy of ground electromagnetic method to detect the water-richness of rock strata, and provide safe geological guarantee for coal mine production.