Fractal Behavior And Its Control Mechanism On Fluid Flow Through Bed-Packing Porous Media

The microstructures of porous media directly affect the reserves of resources and the degree of difficulty in exploitation.To accurately describe the microstructures of porous media is the key to realize resource exploration and quantitative productivity evaluation.At present,the limitation of the application scope of porous media model restricts the application and development of reservoir structure model in the occurrence and exploitation of oil and gas resources.At present,fractal porous media constructed with coal reservoir as the research object is difficult to uniquely determine the fractal behavior of its structure,so it is impossible to explain the scale-invariant property of pore structure in essence,which limits the study of related physical parameters and understanding of physical process.The newly emerged fractal topology theory gives the definition of fractal behavior from the mathematical level,and explains the fractal dimension essentially according to the fractal behavior,which provides a powerful theoretical basis for the reconstruction of reservoir porous media.In this paper,the difference and relationship between fractal topology theory and quartet structure generation set?QSGS?four-parameter stochastic growth algorithm are compared and analyzed.The physical meaning of QSGS parameters is analyzed from the perspective of fractal topology,and a generalized stochastic self-affine porous medium characterization algorithm is proposed.The algorithm realizes self-similarity and self-affine,random and deterministic characterization of porous media,thus simplifying the process of model building.At the same time,combining the relationship between fractal topological parameters and fractal dimension and porosity,the validity of the characterization algorithm is verified.This characterization algorithm can reflect the fractal characteristics of micro reservoir structure from the nature of fractal behavior,and make the structure of the model closer to reality.In this paper,the complexity of porous media is quantitatively studied by fractal topological parameters.In order to study the effect ofH_xy on the anisotropy of porous media,the structure changes of porous media under differentH_xy values are analyzed.The results show that the model is isotropic whenH_xy=1,and anisotropic when H_xy?1.At the same time,the relationship between behavior complexity and fractal dimension is analyzed by combining fractal topological parameters.The results show that the algorithm takes full account of the influence of fractal topological parameters P,F and QSGS model parameters on the structure of porous media,and can effectively describe the anisotropy,behavior complexity and original complexity of porous media.Based on the above research content,combined with LBM method,the flow field of the model is simulated,and the trend change of permeability,curvature and other physical parameters is analyzed according to fractal topological parameters.The results show that the physical parameters of the models with different fractal topological parameters change differently,and the pore-permeability relationship changes exponentially with the change of P and F.On the basis of the above model,the adsorption of fractal porous media is discussed.The gas adsorption map of generalized random fractal porous media is obtained by introducing the probability density of QSGS method,which provides a starting point for the subsequent study of adsorption and desorption.Therefore,based on Fractal topology theory,this paper focuses on the physical significance of QSGS parameters in fractal topology space,and improves the QSGS algorithm to realize the construction of generalized random fractal porous media model.Based on the definition of fractal behavior,the influence of fractal topological parameters on the complex characteristics of reservoir pore structure is analyzed,and the physical parameters such as porosity,permeability and curvature are correlated.At the same time,the adsorption mechanism in fractal porous media is preliminarily explored.