Research Of The Influence Of Object Functions In 2D TDIP Inversion

Time-domain induced polarization method(TDIP),which based on the theory of IP effect and the observations of IP effect of the earth,is a kind of electrical methods to explorate subsurface geology. The method plays an important role in the field of metal mineral, energy and engineering geology, especially in the exploration of disseminated mineral resources. The domestic and foreign scholars have conducted a lot of research on two-dimensional TDIP inversion algorithm,but all of them adopt the single inversion,that is,the polarizability value is gained after the resistivity value is calculated, which results in some problems like that the polarizability value is depend on the accuracy of the calculation of the resistivity inevitably.To solve the problem, this article studyed a two-dimensional synchronous inversion algorithm of TDIP data with cross-gradient constraints on the basis of the cross-gradient theory proposed by Gallardo and Meju.The article complete the inversion algorithm of TDIP. Weerachai and Gary improved the OCCAM inversion algorithm and they transform the inversion algorithm from the spatial domain to the dataspace, which means that the method reduced the number of orders of the equations of the inversion process and we needn’t calculate the inverse matrix of covariance model. Thus the algorithm need less time and CPU and it is more efficient.We study a two-dimensional synchronous inversion algorithm of TDIP data with cross-gradient constraints. Based on well-developed two-dimensional forward and inversion algorithms for DC resistivity, a two-dimensional forward and inversion algorithms for induced polarization and synchronous inversion algorithm having common inversion grids,with cross-gradient as structural constraint,and with both resistivity and polarizability models able to be synchronously updated has been achieved. With synthetic data from a model with the same physical structure and models with different physical structure,trial computation of synchronous inversionhas been carried out,and the results indicate that,compared with single inversion,synchronous inversion has better effect in recovering both the various models’ numerical value and spatial morphology.The resistivity and polarizability value of the conductive-high polarizability models are much closer to the true model in synchronous inversion,while by the resistive-high polarizability model,synchronous inversion can not only improve the vaules of TDIP data to some extent,but also has large improvement on increasing the accuracy of spatial distribution.Moreover,synchronous inversion can improve the result of the model with different physical structure and thus has wide applicability.