A 2D mixed fracture–pore seepage model and hydromechanical coupling for fractured porous media

• DOI: 10.1007/s11440-021-01183-z
• Publication Date: 2021-05-31T11:26:17Z
• Authors: Chengzeng Yan; Hongwei Fan; Duruo Huang; Gang Wang
• Keywords: Finite-discrete element method; Hydromechanical coupling; Fracture seepage; Fractured porous media; 0211 other engineering and technologies; 02 engineering and technology; Fluid-driven fracturing; Pore seepage

A novel two-dimensional mixed fracture–pore seepage model for fluid flow in fractured porous media is presented based on the computational framework of finite-discrete element method (FDEM). The model consists of a porous seepage model in triangular elements bonded by unbroken joint elements, as well as a fracture seepage model in broken joint elements. The principle for determining the fluid exchange coefficient of the unbroken joint element is provided to ensure numerical accuracy and efficiency. The mixed fracture–pore seepage model provides a simple but effective tool for solving fluid flow in fractured porous media. In this paper, examples of 1D and 2D seepage flow in porous media and porous media with a single fracture or multiple fractures are studied. The simulation results of the model match well with theoretical solutions or results obtained by commercial software, which verifies the correctness of the mixed fracture–pore seepage model. Furthermore, combining FDEM mechanical calculation and the mixed fracture–pore seepage model, a coupled hydromechanical model is built to simulate fluid-driven dynamic propagation of cracks in the porous media, as well as its influence on pore seepage and fracture seepage.