The Study Of 1D Forward And Inverse To Spectrum Induced Polarization Including Electromagnetic Coupling

Spectral induced polarization(SIP, also called complex resistivity method) is a method in frequency domain in geophysical exploration. SIP method is based on the different IP effect of different rocks and ore. We make a multi frequency complex resistivity measurement in low frequency, and then we solve the geological problems by analyzing spectrum characteristics of complex resistivity. SIP method has become one of the most effective methods for metallic ore resources exploration. But due to the electromagnetic coupling(EM) interference exists, and because we can't remove electromagnetic coupling removing completely, we can not extract spectral IP parameter accurately from the SIP data. It will seriously affect the spectral induced polarization effect. Therefore, in this paper, the study of 1D Forward and Inverse to Spectrum Induced Polarization Including electromagnetic coupling, we summarize the characteristic of various devices with electromagnetic coupling effect and can directly inverse 1D spectral induced polarization with electromagnetic coupling. It can provide the reference for the spectral induced polarization data processing interpretation and application.In the forward aspect, the paper from the COLE-COLE complex resistivity model beginning, and then in the horizontal homogeneous bedded media field, we deduce electromagnetic formula of transmitter and receiver wires, and last we achieve 1D numerical simulation of SIP by using the Fast Hankel transform. Based on this theory, under half space and layered medium model, we simulate the SIP response characteristics of dipole-dipole array, axial central gradient array and equatorial array. The results showed that: in the homogeneous half space medium, central gradient array has the greatest effect of electromagnetic coupling, and dipole-dipole array is the least. In the layered medium, when the high resistivity layer appears on the polarization layer, the initial amplitude will increase and phase value will decrease; when the high resistivity layer appears under the polarization layer, phase negative extreme value will decrease.In the inversion, this paper starts from the basic theory of homotopy algorithm, and infers 1D homotopy inversion formula of SIP data, so we achieve the 1D homotopy inversion with electromagnetic coupling in programming. First in the assumption of homogeneous half space, we can extract the SIP parameters with electromagnetic coupling effect in dipole- dipole array?central gradient array and equatorial array. Calculation results show that the algorithm can fast accurately extract SIP parameters of different arrays without getting rid of electromagnetic coupling, and have strong anti disturbance ability. And then we invert 1D theoretical data of dipole-dipole array and equatorial array with multi arrays. The results show that: in the situation of given initial resistivity model, the algorithm can effectively inverse SIP parameters of each layer.