A 2D continuous-discontinuous unified pore-fracture seepage model for hydro-mechanical coupling in the combined finite-discrete element method (FDEM) using node binding scheme

Cai，Weibing1; Gao，Ke1,2; Qiao，Yan3; Ai，Shu Gang1; Feng，Yu4

2024-09-01

10.1016/j.compgeo.2024.106517

Computers and Geotechnics   影响因子和分区

0266-352X

1873-7633

The combined finite-discrete element method (FDEM) has been widely used to simulate the dynamic propagation of hydraulic fractures. In the conventional FDEM, a fictitious fluid exchange coefficient between adjacent finite element pairs needs to be specified to alleviate the discontinuous pore seepage in the continuous rock matrix domain. This commonly employed approach inevitably increases computational cost and introduces additional numerical parameters (e.g., fluid exchange coefficient). To circumvent these limitations, we propose a node binding scheme that not only ensures continuous pore seepage simulations in the intact/continuous rock matrix domain, but also allows discontinuous pore pressures on the two sides of a fracture. The computational efficiency of pore seepage simulation using the proposed approach is increased by ∼120 times for a model with ∼6000 triangle elements, and fictitious numerical parameters are not required. A suite of numerical benchmarks is conducted to verify the effectiveness and robustness of the proposed pore-fracture seepage model, and its capability of capturing the dynamic propagation process of fluid-driven fractures is also demonstrated. As an application, a typical example is employed to explore the mechanism of multiple hydraulic fracturing. The proposed hydro-mechanical coupling model may help enhance the applicability and accuracy of FDEM for unconventional energy exploitation.

Combined finite-discrete element method (FDEM) Fluid-driven fracture Fracture seepage Hydraulic fracturing Node binding scheme Pore seepage

EI

英语

第一 ; 通讯

20242516290402

Binding energy ; Computational efficiency ; Dynamics ; Fracture ; Seepage

Petroleum Deposits : Development Operations:512.1.2 ; Physical Chemistry:801.4 ; Materials Science:951

COMPUTER SCIENCE

2-s2.0-85196264067

Scopus

1.Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen,Guangdong,China
2.Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology,Southern University of Science and Technology,Shenzhen,Guangdong,China
3.CNPC Engineering Technology R&D Company Limited,Beijing,China
4.School of Civil Engineering,Sun Yat-sen University,Zhuhai,519082,China

Cai，Weibing,Gao，Ke,Qiao，Yan,et al. A 2D continuous-discontinuous unified pore-fracture seepage model for hydro-mechanical coupling in the combined finite-discrete element method (FDEM) using node binding scheme[J]. Computers and Geotechnics,2024,173.

Cai，Weibing,Gao，Ke,Qiao，Yan,Ai，Shu Gang,&Feng，Yu.(2024).A 2D continuous-discontinuous unified pore-fracture seepage model for hydro-mechanical coupling in the combined finite-discrete element method (FDEM) using node binding scheme.Computers and Geotechnics,173.

Cai，Weibing,et al."A 2D continuous-discontinuous unified pore-fracture seepage model for hydro-mechanical coupling in the combined finite-discrete element method (FDEM) using node binding scheme".Computers and Geotechnics 173(2024).