Study On Tetrahedron Division And Optimization Of Three-Dimensional Geological Model

Three-dimensional geological model plays an important role in petroleum exploration and development,mineral resources exploitation and other fields.In recent years,with the continuous development of computer technology and the urgent need of exploration and development of underground resources,the three-dimensional geological model is divided into scientific and fine tetrahedral mesh model by computer,and then the tetrahedral mesh model is used in discontinuous finite element numerical simulation algorithm,so as to understand the propagation law of seismic wave field in various complex geological conditions,and to find out more effective.Geological exploration methods to guide exploration and development have become one of the hot topics in the field of geoscience.Three-dimensional geological tetrahedron mesh model is a necessary condition for the application of discontinuous finite element numerical simulation algorithm.The discontinuous finite element numerical simulation algorithm requires high quality of tetrahedron mesh.The shape and size of each tetrahedron must meet the quality requirements during the implementation of the simulation algorithm,otherwise the calculation will fail.However,compared with the building or mechanical model,the three-dimensional geological model has larger volume,more complex surface,larger undulation of model surface,and geological phenomena such as fracture,pinch-out,lens and intrusive body,so it is more difficult to divide the three-dimensional geological model into tetrahedrons.Aiming at the problem that there is no other mature research on the optimization of tetrahedron subdivision of three-dimensional geological model at home and abroad,and no commercial software for tetrahedron subdivision of three-dimensional geological model,Delaunay insertion optimization and particle swarm optimization are innovatively proposed to optimize the quality of tetrahedron,so as to obtain high-quality tetrahedron mesh model.Firstly,the three-dimensional geological model is subdivided into Delaunay tetrahedral meshes,and then the constraint surface of the model is restored on the basis of the limited conditions.In order to solve this problem,Delaunay insertion optimization is used to refine the larger mesh in the model by inserting additional vertices,eliminating the tetrahedron whose radius-to-side ratio of outer sphere does not meet the requirement.Because of the limitation of tetrahedron size in discontinuous finite element numerical simulation algorithm,Delaunay can not be used to insert the optimized mesh indefinitely.In this paper,particle swarm optimization algorithm is innovatively used to optimize the quality of the mesh,and the final tetrahedron mesh model is obtained through experimental analysis,and the quality of each tetrahedron meets the requirements.Finally,according to the requirements of forward simulation algorithm of XXX Institute of Geophysics,the Seam Foot Hills model is divided into tetrahedrons and optimized.When more than 200 million tetrahedron grids are generated,the quality of each tetrahedron unit is still guaranteed to meet the requirements.The tetrahedron model is submitted to XXX Institute of Geophysics for forward simulation calculation,and a good plan is obtained.The computational results show that the tetrahedral mesh generation and optimization technology of the three-dimensional geological model studied in this paper has high availability and effectiveness.