Key Technology Research Of Block Modeling In Seismic Imaging System

The great progress of "Seismic imaging" is the predominant impetus which improving the development of oil exploration industry. Seismic Imaging System display the result of seismic exploration to help the seismic data interpreters and geological engineers analyze and process the geological structure and stratum layer information, which provide important foundation on deciding the location of Oil-Gas wells. Seismic Imaging System realizes the imaging of seismic data mainly by offset. The velocity model of exploration zone is the foundation of offset technology. The velocity model depends on the 3-dimensional geological structure model and interpolation technology, which has important status in Seismic Imaging System.The present researches show that the results of layered velocity modeling can't satisfy the requirement of high accuracy migration before stack offset imaging in Seismic Imaging System. However, block velocity modeling can reveal the underground construction accurately, and describe the geological block completely and accurately. This can help the geological analysis,3-dimensional display and velocity model building, which satisfy the requirement of high accuracy migration before stack offset imaging in Seismic Imaging System. Therefore, block velocity modeling technology becomes a hotspot of the research on Seismic Imaging System.3 key technologies of block velocity modeling in Seismic Imaging System are studied on the basis of the main process of block velocity modeling put forward in this paper. The main work and innovation are provided as follows:(1)Study and realize 2-dimensional and 3-dimensional Delaunay triangulation algorithms. Improve the key process of Bowyer-Watson algorithm ("Delaunay hole algorithm"), which decreases the deciding errors and improving the precision of the results of 2-dimensional and 3-dimensional Delaunay triangulation.(2) Put forward a geological surface intersection algorithm based on Delaunay triangulation. "Intersection test of triangle pair" is adopted to decide the line of intersection between two geological surfaces. "Surrounding box decision" is used to do the preprocessing, in order to improving the test efficiency. A weighted geological extending method based on Delaunay triangulation is put forward in this paper, which solute the problem that the inconsistency between the results of geological surface intersection process and geological analysis. A weighted surface extending method is put forward to force the two endpoints of the line of intersection locate on the surface boundary, which provide a basement of the following constrained Delaunay triangulation, surface partitioning, surface clipping, and then complete the surface boundary modeling.(3) An improved algorithm of 3-dimensional restricted Delaunay triangulation is put forward in this paper. In the process of "recover the boundary firstly, then the surface", the space topology information of triangles and tetrahedrons are fully used. A fractional steps method is put forward to simplify the analysis of adding the new point of intersection into the present net of tetrahedrons, which lower the difficulty complexity of analysis.Experiment results and real data testing results prove the practicability and validity of the block modeling flow and all of the improved algorithms put forward in this thesis. The main goal in the future is to bring forward quality standards of triangle/tetrahedron that meet the need of velocity interpolation and improve the quality of triangle/tetrahedron in tessellation.