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

Petroleum, natural gas, geothermal energy exploitation engineering and underground fluid system of environmental protection can be seen in both the multiphase fluid flow phenomena in a crack. Cracks in the multiphase flow in petroleum migration, mineral deposition and water heat exchange system plays an important role in evolution, the seepage problem of gas-liquid two-phase flow in fractured rock masses has attracted more and more attention. In this paper, based on the viscous fluid mechanics and multiphase percolation mechanics theory the jointed rock mass simplified as equivalent continuum and fracture pore dual medium, systematic study the migration law of two-phase fluid in fractured rock mass, including the analysis of seepage theory, two-phase medium model mathematical model is established and the seepage effect the content of the three part, the main work in this paper are as follows:(1) Applying continuum mechanics theory, two-phase flow seepage theory, and combined with Darcy’s law established a two-phase flow model of transport capacity and the equivalent isotropic continuum model and fracture pore dual medium model;(2) The model of rock mass fracture network is established based on Monte Carlo method. According to the fracture geometric parameters of rock mass (attitude, spacing or density, length and Zhang Kaidu) random distribution in the rock mass fracture simulation based on the basic assumptions, Monte Carlo method in MATLAB to construct the structural plane in the two-dimensional plane the combination of based form, form two dimensional fracture network model;(3) According to the numerical simulation study of two kinds of flow law of two-phase flow model in different medium, respectively on the relative permeability curve and two-phase flow migration velocity vector changes are described and analyzed, obtain fracture pore dual medium model with the continuous medium model of equivalent displacement effect;(4) Fracture network model considered the rock mass as a single according to geometry distribution consists of fractured media, so the permeability of fractured rock mass with different geometric parameters on the fracture network model established will have effect, the results showed that:the effect of density on permeability is relatively-Ⅱ- large, along with the increase of the density, the increase of the density effect the permeability of the smaller. Trace length have influence on permeability, with trace length increases, trace length increased effect on permeability is more and more small. With the aperture increases, the permeability increasing. Fracture orientation angle is discrete, the gap between the minimum and maximum permeability model smaller; fracture direction angle is concentrated, between the maximum and minimum coefficient of permeability model of the greater the gap.