The Study Of 1-D Lateral Constrain Inversion Of Resistivity And Transient Electromagnetic Method

Both the resistivity method and the transient electromagnetic method are based on the differences in electrical properties-the conductivity of crustal rocks or ore bodies studied the spatial or temporal distribution of electromagnetic fields to solve various geological problems.In previous studies of the multidimensional resistivity method and transient electromagnetic method,finite difference method,finite element method,and the integral equation method are usually used for forwarding simulation calculation.Many scholars have developed different inversion algorithms,such as generalized inversion,Backus-Gilbert inversion,and non-linear inversion algorithms such as conjugate gradient,Gauss-Newton,genetic,etc.The purpose of these algorithms is to solve the non-uniqueness and stability of the solution in the interpretation of geophysical data in order to make the inversion results more credible and better guide the practical application.The resistivity method and the transient electromagnetic method are widely used in practical applications,but there are still some problems.The most typical is that in hydrogeology,the underground is often a layered stratum with complex distribution,such as encountering faults,or other two-dimensional and three-dimensional structures.The inversion results obtained by these two methods often have problems such as poor model fitting,difficult identification of layered boundaries,and low resolution of some parameters,which do not reflect the actual geological conditions well.This paper studies the two-dimensional forward modeling of the resistivity method and transient electromagnetic method and the one-dimensional inversion of lateral constraint.The two-dimensional forward modeling of two methods uses the finite element method for numerical simulation.The theory of lateral constraint inversion is described on the basis of previous studies,and a laterally constrained 1-D inversion code is completed.A reasonable two-dimensional geoelectric model designed is used to perform forward calculation to obtain synthetic data,which is used in the prepared inversion code to perform a laterally constrained one-dimensional inversion.Finally,the measured data is used to perform lateral constrained one-dimensional inversion to more accurately and reflect the actual geological conditions of the formation.The validity of lateral constraint inversion is verified by the measured data.The research results in this paper show that the one-dimensional inversion method with lateral constraint is fast,the anomaly boundary is easy to identify,and the parameter resolution is excellent.