Research On 3D Inversion Of Resistivity Method

Resistivity method is an important branch of electrical prospecting.In recent years,resistivity method has been widely used in oil and gas exploration,mining,hydrology,archaeology and other fields,and has developed rapidly.Both the resistivity profile method,resistivity sounding method,high density resistivity method and ground potential method,their basic principles are based on the difference of the conductivity of rocks and minerals in the earth's crust,established and studied the electric field in the earth's electric field to find the mineral resources or to solve the geological problems.The effective interpretation of the potential data obtained by resistivity method is an important part of the exploration process.Therefore,it plays an important role in the exploration data processing.Due to that geological bodies showed three-dimensional electrical structure,only a two-dimensional data inversion is inevitably affected by effects of three dimensional structure.Therefore,the study of 3D DC resistivity forward and inversion has important practical significance.In addition,with the rapid development of computer technology,the study of three-dimensional inversion of resistivity and even four-dimensional inversion is irresistible.The basic principle of resistivity prospecting is introduced firstly,and then introduced the basic method for solving three dimensional resistivity forward problem of point source by using the finite volume method.In the forward modeling,the finite volume method has the advantages of finite difference method and finite element method and in the whole calculation region the discrete equations derived from the finite volume method are integral conserved,and the physical meaning is clear.In terms of inversion,on the basis of the least square resistivity inversion,the mixed regularization constraint is introduced,which greatly improves the accuracy of the edge shape of the abnormal body.In the algorithm,the iterative reweighted method is introduced to solve the problem that TV regularization constraint cannot derivative directly.The calculation results show that the hybrid regularization method can better reflect the edge shape of the anomaly body compared with the smooth constrained least square inversion.Finally,simulate the well ground cross hole data acquisition and high density data acquisition,and the data of the two kinds of acquisition methods are combined to use in inversion,and get a better result.