Research On The Generation Of Facture Networks And Fluid Flow Simulation In Fractured Reservoir

The geological reserve of fractured reservoir is abundant,which has a broad prospect for development.However,the research of fractured reservoir faces with many difficulties because of the complexity of fractures' spatial distribution and the specificity of the seepage mechanism.One of the research difficulties is the generation of the fracture networks.The conventional generation methods include the Monte Carlo simulation,which is based on the object,and the multipoint geostatistics simulation,which is based on the pixel.The fracture networks generated by former have clear geometry and are well connected.But this method ignores the spatial correlation of the fractures.Moreover,this method is difficult to match the conditional data provided by geological data.the latter develops relatively late,whose theory is still not perfect.Although the fracture networks generated by this method considers the spatial correlation,the connectivity of the factures is unsatisfactory.Another research difficult is the numerical simulation of the fractured reservoir.According to the numerical simulation,there are two models,the equivalent continuous media model and the discrete fracture network model in wide use.Because the equivalent continuous media model over simplifies the heterogeneity of the fractures,it is not applicable for the strong heterogeneity and multi-scale fractured reservoir.The discrete fracture network model highlights the heterogeneity of the reservoir.Therefore,it better depicts the seepage mechanism of the fractured reservoir than the equivalent continuous media model.But this model is attached to the finite element method or the finite volume method,which can only deal with dozens of fractures.Therefore,for large scale fracture networks,the numerical simulation fails to be implemented.To solve above problems,this paper proposes an integrated method from fracture networks generation to numerical simulation.The specific works can be list as follows:(1)For fracture network generation,this paper abandons the traditional Monte Carlo simulation,and adopts the multipoint geostatistics method instead.The continuity of the generated fractures is well improved by combining the FILTERSIM with binary image connected component labeling algorithm.By this way,the fracture networks generated have the spatial correlation,and also have good connectivity.(2)For the numerical simulation,because the fractures and matrix generated are composed by pixels,the finite element method and the finite volume method fail to implement,so this paper adopts the lattice Boltzmann method to carry out numerical simulation.Through the image processing,the fracture networks are converted to the original condition that lattice Boltzmann method can deal with.Then the REV scale lattice Boltzmann method is used to simulate the fluid flow process.(3)The fracture generation algorithm and numerical simulation algorithm are applied to the field test to simulate the fluid flow,which verifies the feasibility of the algorithm presented by this paper.The example indicates that in fractured reservoirs,the fluid mainly flows through the fracture networks.But there also exists slowly velocity in matrix.However,compared with the velocity in the fracture networks,the velocity in the matrix is quite small.This paper provides mew methods for fracture networks generation and numerical simulation,and a new viewpoint for the research of fractured reservoir.