个人信息Personal Information
教授
博士生导师
硕士生导师
主要任职:President of international exchange committee of the Chinese Society of Rock Mechanics and Engineering CSRME
其他任职:国际岩石力学与岩石工程学会(ISRM)中国国家小组副主席
性别:男
毕业院校:东北大学
学位:博士
所在单位:土木工程系
办公地点:综合实验四号楼330
联系方式:tca@mail.neu.edu.cn
Numerical Simulation of 3D Hydraulic Fracturing Based on an Improved Flow-Stress-Damage Model and a Parallel FEM Technique
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论文类型:期刊论文
发表时间:2021-01-12
发表刊物:ROCK MECHANICS AND ROCK ENGINEERING
卷号:45
期号:5,SI
页面范围:801-818
ISSN号:0723-2632
关键字:Coupled fluid and solid deformation; Damage mechanics; Hydraulic fracture; Numerical stimulation; Fracture process; Heterogeneity
摘要:The failure mechanism of hydraulic fractures in heterogeneous geological materials is an important topic in mining and petroleum engineering. A three-dimensional (3D) finite element model that considers the coupled effects of seepage, damage, and the stress field is introduced. This model is based on a previously developed two-dimensional (2D) version of the model (RFPA2D-Rock Failure Process Analysis). The RFPA3D-Parallel model is developed using a parallel finite element method with a message-passing interface library. The constitutive law of this model considers strength and stiffness degradation, stress-dependent permeability for the pre-peak stage, and deformation-dependent permeability for the post-peak stage. Using this model, 3D modelling of progressive failure and associated fluid flow in rock are conducted and used to investigate the hydro-mechanical response of rock samples at laboratory scale. The responses investigated are the axial stress-axial strain together with permeability evolution and fracture patterns at various stages of loading. Then, the hydraulic fracturing process inside a rock specimen is numerically simulated. Three coupled processes are considered: (1) mechanical deformation of the solid medium induced by the fluid pressure acting on the fracture surfaces and the rock skeleton, (2) fluid flow within the fracture, and (3) propagation of the fracture. The numerically simulated results show that the fractures from a vertical wellbore propagate in the maximum principal stress direction without branching, turning, and twisting in the case of a large difference in the magnitude of the far-field stresses. Otherwise, the fracture initiates in a non-preferred direction and plane then turns and twists during propagation to become aligned with the preferred direction and plane. This pattern of fracturing is common when the rock formation contains multiple layers with different material properties. In addition, local heterogeneity of the rock matrix and macro-scale stress fluctuations due to the variability of material properties can cause the branching, turning, and twisting of fractures.