scholarly journals Application of Symmetry Law in Numerical Modeling of Hydraulic Fracturing by Finite Element Method

Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1122 ◽  
Author(s):  
Shanhui Sun ◽  
Meihua Zhou ◽  
Wei Lu ◽  
Afshin Davarpanah

In this paper, influential parameters on the hydraulic fracturing processes in porous media were investigated. Besides, the simultaneous stimulation of solids, fluids and fractures geomechanical equations were numerically analyzed as a developed 3D model. To do this, the Abacus software was used as a multi-objective program to solve the physical-mechanical symmetry law governing equations, according to the finite element method. Two different layers, A (3104–2984 m) and B (4216–4326 m), are considered in the model. According to the result of this study, the maximum fracture opening length in the connection of the wall surface is 10 and 9 mm for layer B and layer A, respectively. Moreover, the internal fracture fluid pressure for layer B and layer A is 65 and 53 Mpa. It is indicated that fracture fluid pressure reduced with the increase in fracture propagation length. Consequently, the results of this study would be of benefit for petroleum industries to consider several crucial geomechanical characteristics in hydraulic fractures simultaneously as a developed numerical model for different formation layers to compare a comprehensive analysis between each layer.

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Peilun Li ◽  
Yan Dong ◽  
Sheng Wang ◽  
Peichao Li

Natural fractures usually develop in shale reservoirs. Thereby, in the process of hydraulic fracturing, it is inevitable that hydraulic fractures will intersect with natural fractures. In order to reveal the interaction mechanism between hydraulic-induced fractures and natural fractures, a two-dimensional fracture intersection model based on the extended finite element method (XFEM) is proposed, and the different types of intersecting criteria reported in the literature are compared. Then, the effects of natural fracture azimuth, fluid pressure in hydraulic fracture, and in situ principal stress difference on hydraulic fracturing are studied in detail. The results show that the fracture morphology is different under different criteria and working conditions. And the stress concentration phenomenon mainly concentrates on the tip in the obtuse angle side of natural fracture. Meanwhile, different fluid pressures in hydraulic fracture can also induce different intersection patterns. The obtained results in this work are of great benefit to understand the intersection mechanism between hydraulic fractures and natural fractures.


Author(s):  
Pei-xin Gao ◽  
Jing-yu Zhai ◽  
Qing-kai Han

The pressure fluctuation excited by the hydraulic pump can cause serious vibration in aero hydraulic pipeline system, which poses a serious threat to the safety of the aircraft. Therefore, an effective method for predicting the fluid pressure fluctuation and dynamic response of pipeline is strongly recommended. In this paper, a comprehensive model for predicting the dynamic response of pipeline, which includes the Poisson coupling, friction coupling, the vibration damping, Coriolis, and centrifugal forces is proposed. A numerical code is presented to solve the hydraulic pipeline equations. In this code, the hydraulic equations are solved by the method of characteristics and the dynamic equations of pipeline are solved by the finite element method combined with the Newmark algorithm. The numerical code is validated through the comparison of the dynamic response for a typical hydraulic pipeline with experiment. The obtained results indicate that the current combining method of characteristics and finite element method approach can predict the dynamic response of hydraulic pipeline with sufficient accuracy, which can serve as an efficient tool in the design and maintenance of aero hydraulic pipeline.


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