Three-dimensional Inversion Of Magnetic Data Based On Cokriging Method

The multi-solution of magnetic inversion has always been a difficult point of 3D quantitative inversion.How to reduce the multi-solution of inversion and improve the reliability of inversion results become the key problem to solve magnetic inversion.In the known magnetic inversion method,the commonly used method for reducing the multiplicity is to add the known information as a constraint to the inversion to reduce the multiplicity of the inversion.The key to this is how to effectively combine a priori information as a constraint with the inversion process.However,in practice,some prior information is difficult to integrate with the methods used in the inversion,thus limiting the role of a priori information constraints.In this paper,a highly practical cokriging method in geostatistics is applied to magnetic three-dimensional inversion,and a three-dimensional inversion method of magnetization based on cokriging method is realized.Using the logging curves of the Carboniferous igneous rocks in the Junggar Basin,the density of the drilling core and the density and magnetic susceptibility data of the outcropped rock specimens,it is determined that the Gaussian variogram is satisfied between the density and magnetization of the Carboniferous in the Junggar Basin.The 3D apparent density inversion results are used as secondary variables,and the magnetization intensification results are taken as the main variables.On this basis,the magnetization model is modified by the density model with the established cokriging system,and the 3D magnetizing intensity inversion is performed with the corrected magnetization data volume.When the calculated objective function reaches the accuracy requirement,the result is obtained.The magnetization three-dimensional data volume is the end result of the need.The design of the igneous rock mass model shows that the magnetic inversion under the cokriging method can reduce the multiplicity of the inversion results.The main performances are as follows:(1)The apparent magnetization intensity value obtained from the final inversion is more than the actual value.Close,the anomalous body position obtained by the inversion is closer to the actual model.(2)In the case where both high magnetic and low magnetic magnetic coexist,the effect of low magnetic inversion can be improved to reduce multiplicity.Finally,the method applied in this paper is applied to a certain work area in the Boer Basin for practical application.The application results show that the method can improve the reliability of igneous rock identification.