Numerical Simulation Of Migration Rules On Two-phase Flow In Single Fracture Rock Mass

In recent years, as the engineering constructing such as oil, gas and coal seam gas and other natural energy exploitation, nuclear energy discharge wastes and underground space utilization, Water-air two-phase flow in fractured rock mass of seepage problem have an more and more attention. Based on the viscosity fluid mechanics and multiphase percolation mechanics theory, the fractured rock mass simplified as equivalent continuum, double pore and double permeability medium and pore - fissure medium, And it study the migration rule of the water-air two-phase fluid in different rock mass medium. What the work targets include two-phase flow theory analysis, rock medium model mathematical model establishment and seepage effect analysis contrast. This paper main job as follows.(1) Application of continuum mechanics theory and two phase flow seepage theory, Van-Genuchten model and Darcy law established isotropic media two-phase flow migration dynamic model. The two phase flow percolation model describes two phase flow in equivalent continuum, double pore and double permeability mediums and pore-fissure medium porous media section flow state. Meanwhile quoted Navier-Stokes equation as the pore-fissure medium of fissure medium motion equation, we have established three kinds of rock mass medium of different mathematical model.(2) Considering the application of rock real fracture, lognormal distribution function of describing a single fissure gap width change, established the two-dimensional rough fracture model.(3) According to the numerical simulation research of two phase flow of flow law in three different medium model compared and analyzed relative permeability curve and two phase flow conveyance speed vectors. We could know that the multi-gas effect of double pore and double permeability model is obviously than the continuum model, and the pore gas phase saturation of pore - fissure medium model by fissure influence. because of the fluid exchange, gas more along the fracture outflow. Double pore and double permeability medium model fluid faster than equivalent continuum model about two orders of magnitude. However, the fracture flow of pore-fissure medium model is a leading role. Therefore it is more appropriate to the actual that adopt this model simulated in rock mass flow.(4) There are parallel plate fracture model and rough fracture geometry model describes a single fracture in rock mass. And three kinds of mathematical models respectively in two kinds of geometric model cases fluid flow pattern were analyzed respectively. The parallel plate model fluid velocity is about twice that of rough fractured rock mass in double pore and double permeability medium model of low speed. Rough fracture model is farther small parallel plate geometric model when the pore-fissure medium model of fissure system of velocity is very large.