Theoretical And Numerical Study On Multi-field Coupling Behavior Of Inhomogeneous Model

Fractures and vugs occur extensively in many application fields of porous media,such as geophysics, biophysics, chemical engineering and so on. Research model hassevere heterogeneous due to fractures and vugs. Based on the fractured and vuggyinhomogeneous model, the multi-field coupling problems are studied to discuss theinfluence of fractures and vugs. The main works of the thesis and achievement aresummed up as follows:(1) Boundary layer effect of permeability properties is discussed based on themodel of single-fractured porous medium. The large-scale finite element analysissoftware COMSOL Multiphysics are used to study the permeability properties of thecoupling model of Brinkman-Stokes and Darcy-Stokes. The coupling results ofBrinkman-Stokes are compared with the theoretical solution and the equivalentpermeability is proposed by considering the boundary layer effect.(2) Based on the equivalent permeability properties of single-fractured porousmedia, the equivalent permeability tensor of fractured medium is determinated byusing the calculation methods of inhomogeneity reservoir permeability. Thecontinuous media is characterized by replacing each fracture with the surroundingporous media. The equivalent permeability, equivalent elastiv matrix and equivalentheat transfer coefficient are deduced to form new continuous media.(3) Numerical examples of seepage simulation and fluid-solid couplingsimulation are presented to demonstrate the validity and efficiency of the equivalentmethod. The influence of fractures is discussed by combining the fluid-solid-heatcoupling problem in the fractured reservoir.(4) The method of coupling boundary is given based on the model ofDarcy-Stokes for vuggy medium. The multi-field coupling influence of vug isdiscussed by combining the fluid-solid-heat coupling problem.