Numerical modeling of fluid flowing properties through porous media with single rough fractures

Abstract

Due to the existence of pores in the fracture surface, the permeability of pore-fracture media is more complicated, and its permeability law and mechanism are worthy of an in-depth study. The rough fracture surface of this paper is obtained by 3D laser scanning technology, taken a small part of the middle area to carry out the finite element simulation of single fracture seepage, and studied the distribution of flow velocity fields and the nonlinear characteristics by changing the inlet flow rate, fracture thickness, and size of fracture surface. Given that for the same fracture opening, the flow velocity decreases from the middle position to both sides. When the roughness increases locally, the flow velocity suddenly increases. The nonlinear coefficient decreases as the fracture thickness increases. A dual-media model which consists of porous matrix and a single rough surface was established to study the seepage characteristics through two media. Given that it takes less time to reach a steady state when the permeability coefficient of the matrix is greater than that of the fracture. After reaching the steady state, the flow direction of the fluid in the matrix is consistent with the fluid direction in the fracture, and both are perpendicular to the isosurface of pore water pressure.