Modeling Research On Transient Electromagnetic 3D Forward Modeling Of Complex Geoelectric Model

In reality,the spatial distribution of geological anomalies is extremely complex.In the process of transient electromagnetic numerical simulation,limited to the level of modeling,simple physical models such as spheres,cylinders,and cubes are often used instead of complex physical geoelectric models.This results in a large deviation between the numerical simulation results and the actual transient electromagnetic field response characteristics of the actual geoelectric model,which affects the reliability of data interpretation.In order to solve the problem of complex electromagnetic model transient electromagnetic numerical simulation,this paper builds complex geophysical models based on various modeling platforms,and in order to avoid cumbersome manual processing of large amounts of spatial data,this paper defines a series of transient electromagnetic observation system files.And through the program development,the spatial combination information of points,lines and planes of the geoelectric model is quickly obtained,and the spatial information of the observation system is merged,and the merged model is segmented according to the Delaunay tetrahedral principle to obtain unstructured In the grid discrete space,the vector finite element method is used to realize the three-dimensional forward modeling of the complex geoelectric model by transient electromagnetic method.In this paper,we set the different meshing parameters to explore the influence of meshing quality on the transient accuracy of transient electromagnetic threedimensional forward modeling.Ways to optimize mesh quality include setting a reasonable tetrahedral minimum dihedral angle,maximum radius-edge ratio,and volume constraint for a particular area.The results show that all of the above factors will have a certain impact on the accuracy of forward modeling.At the same time,considering the increase of computational load caused by grid quality optimization,how to balance the calculation accuracy and computational efficiency is a very important part of the complex model transient electromagnetic three-dimensional forward modeling process.Finally,various complex geoelectric models such as collapse column,karst development zone,fault fracture zone,double thrust structure,three-dimensional roadway goaf,metal deposit,etc.are established,and three-dimensional forward modeling of transient electromagnetic based on vector finite element is carried out.Study its response characteristics.It is proved by examples that the establishment and forward modeling of complex geoelectric models can be realized,and the application of transient electromagnetic three-dimensional forward modeling in production practice can be promoted.