Seismic Modeling With Morphology Constraint:Method And Implementation

Conventional stratigraphic sequence models based on faults and horizons cannot accurately characterize lateral changes in geological structure,and plane-phased modeling for this problem uses only vertical boundary to approximate lateral changes.The accuracy of modeling can be improved to a certain extent.However,with the continuous depletion of oil and gas resources,the prediction difficulty of oil and gas is also increasing.The geological modeling technology based on planar phase can not satisfy the demand of fine reservoir modeling more and more.On the basis of fully researching the existing three-dimensional geological modeling technology,this paper proposes a three-dimensional geological body model construction algorithm under the constraints of the geological polygon sequence which can characterize the local morphology of geological body.The algorithm is universal for different types of geological units and can be competent the surface reconstruction tasks of any complex geological body.The main work and achievement in this paper are as follows:(1)The common theories and algorithms in 3D geological modeling are studied.Some geospatial spatial interpolation algorithms such as B-spline interpolation and inverse distance weighted interpolation,discrete data point management techniques represented by octree,and isosurface extraction techniques like Marching Cubes algorithm are mainly studied.The general form of the Poisson equation and the iterative solution method are also introduced.(2)Aiming at the characteristics of polygonal data in GeoScope software,a simple but efficient polygonal vertex normal estimation algorithm was proposed based on the best projection plane fitting by least square method.By this algorithm,a reasonable and consistent vertex normal can be obtained.(3)Based on the Poisson surface reconstruction algorithm,a surface reconstruction algorithm with the constraint of a set of geological polygon data is proposed,involving the upsampling of polygon vertex using b-spline interpolation,normal estimation of polygon vertex based on projection plane,poisson surface reconstruction and mesh subdivision.The actual geological data tests show that the construction algorithm of geological body with closed surface implemented in this paper can perform high precision for geological objects such as single sand bodies,lens bodies,sedimentary rivers and salt domes with closed boundary surfaces.(4)The algorithm of strata and fault construction based on linear interpolation is studied.Based on this,the method of structural modeling with horizon,fault and geological body with closed boundary is implemented.(5)With the GeoScope software platform,the earthquake morphology constraints modeling software module is developed using C++ language.The software module is then integrated into the GeoScope software platform in the form of a plug-in.Together with the existing 2D seismic data interpretation function,it constitutes a complete set of 3D geological body construction and visualization processes.(6)A lot of data tests were performed on the software modules implemented in this paper,and the influence of related parameters on the model construction results was analyzed.