Hydro-mechanical modeling of impermeable discontinuity inrock by extended finite element method
来源期刊：中南大学学报(英文版)2015年第11期
论文作者：ZHENG An-xing LUO Xian-qi
文章页码：4337 - 4346
Key words：extended finite element method; crack; hydraulic fracture; fluid flow; coupling model; impermeable discontinuities
Abstract: The extended finite element method (XFEM) is a numerical method for modeling discontinuities within the classical finite element framework. The computation mesh in XFEM is independent of the discontinuities, such that remeshing for moving discontinuities can be overcome. the extended finite element method is presented for hydro-mechanical modeling of impermeable discontinuities in rock. The governing equation of XFEM for hydraulic fracture modeling is derived by the virtual work principle of the fracture problem considering the water pressure on crack surface. The coupling relationship between water pressure gradient on crack surface and fracture opening width is obtained by semi-analytical and semi-numerical method. This method simplifies coupling analysis iteration and improves computational precision. Finally, the efficiency of the proposed method for modeling hydraulic fracture problems is verified by two examples and the advantages of the XFEM for hydraulic fracturing analysis are displayed.
ZHENG An-xing(郑安兴), LUO Xian-qi(罗先启)
(School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao tong University, Shanghai 200240, China)
Abstract:The extended finite element method (XFEM) is a numerical method for modeling discontinuities within the classical finite element framework. The computation mesh in XFEM is independent of the discontinuities, such that remeshing for moving discontinuities can be overcome. the extended finite element method is presented for hydro-mechanical modeling of impermeable discontinuities in rock. The governing equation of XFEM for hydraulic fracture modeling is derived by the virtual work principle of the fracture problem considering the water pressure on crack surface. The coupling relationship between water pressure gradient on crack surface and fracture opening width is obtained by semi-analytical and semi-numerical method. This method simplifies coupling analysis iteration and improves computational precision. Finally, the efficiency of the proposed method for modeling hydraulic fracture problems is verified by two examples and the advantages of the XFEM for hydraulic fracturing analysis are displayed.
Key words:extended finite element method; crack; hydraulic fracture; fluid flow; coupling model; impermeable discontinuities
