Research on the joint inversion of 3D DC resistivity and polarizability based on the equivalent resistivity method

Abstract:

The induced polarization method and the DC resistivity method play an important role in the exploration of metal ore. Traditional polarizability inversion relies heavily on resistivity inversion results, and the inversion results are not ideal in areas with drastic electrical changes (Yan Zhuang, 2020). In order to obtain more accurate underground resistivity and polarizability information, the equivalent resistivity formula (Seigel, 1959) was used to conduct twice resistivity inversion to obtain the polarizability information independent of resistivity inversion results. At the same time,we generally expect to get results similar to the abnormal structure of polarizability and resistivity in practical work. The relationship between polarizability and resistivity in structure is described by cross gradient function, and the cross gradient function is introduced into the inversion target function to realize the three-dimensional joint inversion of DC resistivity/polarizability. In the process of realizing joint polarizability inversion, a method of indirect joint polarizability inversion is proposed and realized. Finally, the theoretical models of single anomalous body with the same structure and double anomalous body with different structures are designed, the results of single inversion and joint inversion with cross gradient are compared and meaningful conclusions and insights are drawn.