Seepage And Deformation Coupling Pore Scale Of Mesoscopic Numerical Simulation Research

In the process of oil-gas field development, the constant change of the reservoir pore structure seriously affects the oil-gas field development. Stress sensitivity (pressure sensitivity) is one of the important reasons that led to the change of the pore structure. In order to study the inflence of effective stress change on reservoir pore structure evolution, and make clear the stress sensitivity of oil reservoir, through laboratory experiment, theoretical analysis and·numerical simulation, choosing the correlation of effective stress change and pore structure evolution as breakthrough, combining scanning electron microscope technology and digital image processing, give the quantitative analysis of reservoir rock pore structure paremeters, and construct the reservoir pore structure model. Establish coupled mathematical mechanical model of fluid flow and pore structure deformation in pore scale, and give out the effective numerical solution method and simulation software. Through numerical simulation schemes, the evolution of pore structure and water flooding dynamic behaviour under different axial load, confining pressure and pore pressure will be investigated, based on the numerical simulation results, the infulence of pore structure evolution on reservoir properties (porosity, permeability, relative permeability, etc) will be analyzed. The research findings will rich and develop the reservoir fluid-solid coupling theory and has practical significance for guiding development of oil-gas field.The thesis includes the following sections:1. The mathematical model of the coupling of pore-scale percolation and the deformation of the rock matrix was established based on computational fluid dynamics which is short for CFD, mechanics of fluids in porous media and elastic theory.2. The two-dimensional pore-scale numerical model of percolation and deformation was generated by the image processing toolbox of MATLAB, derived from the digital imaging processing technology;3. The internal relation of the velocity field and pressure field was obtained by using the model as input to COMSOLMultiphysics to simulate single-phase flows based on N-S equation, aiming to show the pattern of pore fluid flow; Good agreement is obtained on both the predicted single-phase transport properties and the porosity change against benchmark data;4. Simulate the coupling pore-scale percolation and the deformation of the rock matrix to acquire the evolution of the pore structure under the stress and analyze the relation of fluid flow and porous material deformation. The macroscopic influence on the porosity by pore structure deformation was studied.