Study on Magnetic Analogy Fitting Inversion of Two-dimensional IP Data Using Central Gradient Array

In this paper, the dual-frequency IP response of underground polarized ellipsoids with central gradient array on the surface is studied through Cole-Cole model, so as to learn about the characteristics of polarizability engendered by polarized bodies with different parameters, which is convenient for the construction of interactive modeling later. According to the theoretical derivation, the induced polarization anomaly generated by any geological body with induced polarization characteristics on the surface can be approximated as a three-dimensional spatial integral of an underground electric dipole. This integral form is consistent with the forward calculation formula of the magnetic field, which means that we can interpret the induced polarization anomaly by the same method applied in interpreting the magnetic anomaly; it is called Pseudo-Magnetic Interpretation Method (PMIM). As long as the model changes in real time according to the prior information, which will make the curve obtained by IP forward modeling approximate to the measured IP curve, when the fitting difference is less than the mean square error, we regard the last approximate model as the real model, so as to obtain the spatial parameters such as top buried depth, dip angle and geometric size of the underground polarizer. The test of field data shows that human-computer interaction method which merges with some prior information holds more rationality than automatic inversion.