Research On Mthod About Tetrahedron Tessellation Based On Borehole Data

The generation of grid is research on how a given space to be separated as a series of simplegeometric units. Triangulation and tetrahedron are simplexes in2D and3D, which have theexcellent properties that other geometric units lack of. Delaunay Triangulation is one of the mostcommon methods in gird generation, which has been proved by mathematics perfectly and hasthe good quality of divided cells. Moreover, it’s very suitable to express the surface and complexgeometric.The paper discusses two methods of how to generate tetrahedron by using the borehole datain geological modeling. One method is to achieve the tetrahedron tessellation, charting andvisualization via the open source and tetrahedron generation tool called TetGen in "3D Assistant”geological modeling platform developed by our project group. Besides, it has also studied thedata structures, triangulation algorithms and quality evaluation of TetGen. Thus, it proposed themethod of expressing geologic body by constructing tetrahedron in TetGen that supportconstrained edge and face in the "3D Geological engineer Assistant” platform. The other one isto construct the triangulation of each formation first, then generate the triangular prism accordingto the designed algorithm, and proceed the tetrahedron division based on prism finally.Additionally, it achieved the drawing and visualization in "3D Assistant” platform.The results of tetrahedron tessellation by the TetGen method in the "3D Geological engineerAssistant” platform indicate that this algorithm has efficient tetrahedron tessellation, andgenerates high-quality tetrahedron. Thus, it can meet the basic requirements in geologicalmodeling software. It hopes to solve the problem of geological modeling under the circumstanceof constrained edge and face and the expression of fault in tetrahedron by using the requirementsof generated constrained tetrahedron. It is able to complete the tetrahedron tessellation by prismin the condition of drill points strata inconsistent with corresponding formations, however, it maycause overlaps and cavities during the tetrahedrons. Therefore, some detecting and strippingmethods must be processed in order to satisfy the precision requirements.