Numerical Simulation Of One-phase Fluid Flow In Fractured-Vuggy Media Under Electric Field

The electric field enhance displacement is an effective exploitation technique in the past years. Due to the difference among rock, oil and brine, the physics field affects media, which is saturated liquid. The electrochemistry and electromotion phenomena such as electroosmosis and electrophoresis will change oil-water flowing in reservoir pore under electric field.Based on the formulation of fluid kinematics, mathematical models to described one-phase fluid flow in fractured-vuggy media under electric field are established and the finite element equation of numerical models are derived. Numerical calculations of the one-phase flow in fracture network and the electroosmotic flow in curve pipe are obtained through COMSOL Multiphysics software. The relative error between the result of numerical simulation in this paper and that in literatures is less than 1.27%. It is shown that the present mathematical models are correct.Mechanism of fluid flow in fractured-vuggy media under electric fields was systematically investigated by finite element method (FEM). The distributions of velocity, pressure and potential in the fracture and vug is studied. The results show that the fluid flow can be effectively increased under electric fields. The distributions of isobar and equipotential line could be effected by the fracture and vug.Sixteen with three models of fractured-vuggy media are designed, which are different in the ratio between vug diameter and fracture aperture, vuggy density and vug porosity. The effect of electric field on one-phase flow (water) in fractured-vuggy media is systematically studied. The results show that fluid flow in fractured-vuggy media can be effectively increased under electric fields. When the electric-field ranging from 0 to 5V/cm was applied, the velocity ratio of one-phase flow with electric field and without electric field in fractured-vuggy media models is 1 to 10.2 for the ratio between vug diameter and fracture aperture, 1 to 5.8 for vuggy density and 1 to 4.5 for vug porosity. On the condition of the same pressure gradient and electric-field, the influence of electric field on one-phase fluid flow in fractured-vuggy media models is more remarkable if the permeability of this fractured-vuggy media model is smaller.Nonlinear percolation feature in various fractured-vuggy medium is studied. The results show that the higher permeability the models have, the easier the nonlinear flow occurs. In three present fractured-vuggy models, nonlinear flow is easy to occur in the vug porosity models.The achievements in this paper are very important to enhance oil recovery of fractured -vuggy media by electric field. And it is very important to direct the enhancing oil recovery of fractured-vuggy reservoir by electric fields.