The Study Of Complex Adaptive Well Pattern Construction And Optimization

As an important energy source,petroleum plays an important role in the development of the country's economy.How to maximize oil & gas production has always been the key issue in the field of oil & gas development.The design and optimization of well pattern is an important method to solve this problem.Especially for large-scale reservoirs with complex geological conditions,reasonable and efficient well pattern arrangement can significantly improve oil & gas recovery,reduce development costs and ensure high and stable oil & gas production,conducive to the long-term development of the oil field.However,for a long time,the well pattern construction and optimization at home and abroad focus on conventional well patterns with regular shape injection-production unit,which have poor adaptability.Especially for those reservoirs with strong heterogeneity,strong anisotropy,irregular boundaries,existing faults and existing wells,the disadvantages of the conventional well pattern are increasingly obvious.Based on this situation,this paper proposes a method for constructing and optimizing complex adaptive well pattern.The unstructured meshing algorithm is introduced into the construction of well pattern.The Delaunay triangulation algorithm and Frontal-Delaunay quadrangulation algorithm are adopted to efficiently construting large-scale high-quality triangular and quadrangular well patterns.The well patterns constructed by the method can restrain the complicated boundary conditions such as irregular boundaries,faults and existing wells,and can control the arrangement and density of well patterns in different areas.By using the hybrid PSO algorithm and based on the economic net present value(NPV)to optimize the well pattern generated,a variable density adaptive well pattern different from the regular well pattern is obtained.The well pattern density is varied according to the geological parameters in different areas of the reservoir,reflecting the strong adaptability of the well pattern to the heterogeneity reservoir.In view of the anisotropy of reservoir geological parameters,this paper introduces the vector transformation method into the well pattern optimization.By doing vectorial optimization such as scaling,stretching and shearing to the entire well pattern,and doing vectorial fine adjustment of the well position within every injection-production unit,the adaptability of the well pattern to anisotropic reservoirs is realized.At the same time,this paper takes the uncertainty of reservoir geological modeling into consideration,the expected value and standard deviation of NPV are treated as the objective function,fuzzy clustering algorithm is used to filter the uncertain models and the loop optimization algorithm is used to do the optimization under uncertainty.The computational quantity is greatly reduced while ensuring the calculation accuracy,and the robust well pattern optimization based on the reservoir uncertainty is realized.Finally,an actual reservoir model is used to verify the method proposed in this paper.The results show that the well pattern generated and optimized by this method can constrain the complex boundary conditions of reservoirs,improve heterogeneity and anisotropy,enhance the oil recovery,and can greatly reduce the development risk while improving the expected benefits for the uncertainty reservoir.