Multi-Source SATEM 1D Inversion and Its Application to the 3D Model Data

In order to avoid the volume effect of long-wire sources in semi-airborne transient electromagnetic device and leverage the advantages of high detection depth and working efficiency, numerical simulations were conducted using single and multiple field sources. The effect of source distribution on the transient fields and resolution characteristics of underground models was analyzed. The feasibility of achieving 3D complex target inversion using simple explanation techniques was discussed by applying the 1D inversion to interpret 3D geoelectric model data. First, the 3D FEM is used to realize the 3D forward modeling of multi-source semi-airborne TEM, analyze the characteristics of the multi-sources transient field, and prove that the volume effect of electrical sources can be reduced by changing the source layout. Then, the 1D inversion method is used to interpret the 3D model data to prove that the simple interpretation method of multi-source device can also improve the resolution of the result. Finally, 1D inversion interpretation of survey data from a coal mine goaf in Gansu Province is carried out. The results show that compared with the results of single-radiation source survey data, the multi-source survey data can be more accurate on the distribution of water zone. The interpretation of the synthetic model and the survey data demonstrate that the resolution of the results can be effectively improved even if simple inversion methods are used for complex excitation sources, which provides new ideas and useful explorations for improving the accuracy of TEM interpretation.