Influence of existing natural fractures and beddings on the formation of fracture network during hydraulic fracturing based on the extended finite element method

Li, Zhenquan; Li, Xueli; Yu, Jia; Cao, Weidong; Liu, Zhifeng; Wang, Min; Wang, Xiaohong

doi:10.1007/s40948-020-00180-y

Cited by 20 publications

(13 citation statements)

References 38 publications

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“…This shows that HSD controls the geometry of the fractures, and when HSD is small, the angle between the fractures' morphological expansion and the maximum principal stress will increase significantly. This is because the higher HSD increases the initial shear stress in the coal seam, especially in locations with natural fractures, where hydraulic fractures are more likely to expand [36][37][38].…”

Section: Parametric Analysis On Fracture Propagationmentioning

confidence: 99%

Experimental and Numerical Simulation Study of Hydraulic Fracture Propagation during Coalbed Methane Development

et al. 2021

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The extraction of low-permeability coalbed methane (CBM) has the dual significance of energy utilization and safe mining. Understanding hydraulic fracturing mechanism is vital to successful development of CBM. Therefore, it is important to improve the law of hydraulic fracture propagation in coal and rigorously study the influencing factors. In this paper, laboratory experiments and numerical simulation methods were used to investigate the hydraulic fracture propagation law of coal in coalbed methane reservoir with natural fractures. The results show that the maximum and minimum horizontal in situ stress and the difference in stress significantly affect the direction of crack propagation. The elastic modulus of coal, the mechanical properties of natural fractures, and the injection rate can affect the fracture length, fracture width, and the amount of fracturing fluid injected. To ensure the effectiveness of hydraulic fracturing, a reservoir environment with a certain horizontal stress difference under specific reservoir conditions can ensure the increase of fractured reservoir and the controllability of fracture expansion direction. In order to increase the volume of fractured reservoir and fracture length, the pumping speed of fracturing fluid should not be too high. The existence of stress shadow effect causes the hydraulic fracture to propagate along the main fracture track, where the branch fracture cannot extend too far. Complex fractures are the main hydraulic fracture typology in coalbed methane reservoir with natural fractures. The results can provide a benchmark for optimal design of hydraulic fracturing in coalbed methane reservoirs.

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Section: Parametric Analysis On Fracture Propagationmentioning

confidence: 99%

Experimental and Numerical Simulation Study of Hydraulic Fracture Propagation during Coalbed Methane Development

et al. 2021

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“…However, the distribution of fracture network cannot describe by a simple approach, such as analytical equations (Meng et al, 2020). The complex fracture network was formed based on communicating and extending natural fractures (Li et al, 2020), so the fracture network structure is consistent with the distribution of natural fractures in the reservoir. Pfeiferper and Avnir (1983), Katz and Thompson (1985), Krohn (1988) used adsorption method, electron microscope observation and mercury intrusion method to study the microscopic pore and natural fracture structure of unconventional reservoirs.…”

Section: Introductionmentioning

confidence: 99%

Description of Fracture Network of Hydraulic Fracturing Vertical Wells in Unconventional Reservoirs

Liu

Sheng

2021

Front. Earth Sci.

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Based on the distribution of complex fractures after volume fracturing in unconventional reservoirs, the fractal theory is used to describe the distribution of volume fracture network in unconventional reservoirs. The method for calculating the fractal parameters of the fracture network is given. The box dimension method is used to analyze a fracturing core, and the fractal dimension is calculated. The fractal index of fracture network in fracturing vertical wells are also firstly calculated by introducing an analysis method. On this basis, the conventional dual-media model and the fractal dual-media model are compared, and the distribution of reservoir permeability and porosity are analyzed. The results show that the fractal porosity/permeability can be used to describe the reservoir physical properties more accurately. At the same time, the flow rate calculating by conventional dual-media model and the fractal dual-media model were calculated and compared. The comparative analysis found that the flow rate calculated by the conventional dual-media model was relatively high in the early stage, but the flow rate was not much different in the later stage. The research results provide certain guiding significance for the description of fracture network of volume fracturing vertical well in unconventional reservoirs.

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“…Previous studies have examined the frictional problem of proppant-rock systems (Xiao et al 2016;Zhang et al 2019aZhang et al , 2019b, proppant damage and embedment (Ahamed et al 2019;Bandara et al 2018Bandara et al , 2020aBandara et al , 2020b as well as dynamic phenomena involved in rocks during the hydraulic fracturing process (Naghi Dehghan et al 2014;Hadei and Veiskarami 2020;Li et al 2021;Xu et al 2021;Wang et al 2021). As the analyses of proppant-rock (and proppant-fluid-rock) systems involve very complex mechanisms, researchers have attempted to examine the problem by means of discrete-based numerical simulations (DEM), coupled DEM with computational fluid dynamics (PFC-CFD) and finite element methods (PFC-FEM) as well as other numerical techniques (Zeng et al 2016;Zhang et al 2017Zhang et al , 2018Zhang et al , 2019cZheng and Tannant 2019;Hu et al 2020;Li et al 2020;Yang et al 2020;Duan et al 2018aDuan et al , 2021. DEM (as well as DEM coupled with computational fluid dynamics codes) have also received a significant amount of research in the study of rock mechanics and fracture propagation problems (Duan and Kwok 2015;Duan et al 2018b;Le et al 2021;Peng et al 2018Peng et al , 2021.…”

Section: Introductionmentioning

confidence: 99%

“…The study of problems in hydraulic fracturing stimulation necessitates an understanding of the influence of preexisting or newly developed fractures within the rock mass as well as other types of geological structures such as faults (Westwood et al 2017;Ranjith 2019a, 2019b;Ahamed et al 2019;Duan and Kwok 2020;Li et al 2020;Yang et al 2020). Despite the significant amount of research on proppant-rock interactions, less attention has been given to the analysis of the influence of pre-existing fractures (or newly formed fractures) on the behaviour of the fundamental analogue system of single impactor colliding on rock base block, which may be additionally influenced by the velocity at collision (e.g.…”

Section: Introductionmentioning

confidence: 99%

3D DEM analysis of analogue proppant–fractured rock system interaction

Kasyap

Senetakis

2021

Bull Eng Geol Environ

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We investigated the interaction of proppant simulant (impactor) colliding on the surface of a fractured rock by performing 3-dimensional discrete-based numerical simulations. The fractured rock represented a medium-strength clastic material, and the linear parallel bond contact model was implemented to simulate the bonding properties. The ratio of the impactor to rock particle size was equal to 30, which represents, based on the relative dimensions of the problem, typical proppants of 40/70 mesh colliding on fine-grained siltstone. A parametric study was conducted, taking into account the influence of existing fractures within the rock mass as well as their aperture and distance from the impact zone. Significant differences were observed based on the collision velocity (with a distinction in low-and high-velocity impacts), even for intact rock simulations, while, because of the second-order roughness of the rock due to its clastic nature, the impacts were oblique, resulting in the partition of the total kinetic energy. Energy losses, penetration depth, stress transmission through the rock mass, and the influence of the structural characteristics of the analogue rock were systematically investigated to provide some insights into the fundamental contributing mechanisms of impactor-fracture rock interactions.

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Influence of existing natural fractures and beddings on the formation of fracture network during hydraulic fracturing based on the extended finite element method

Cited by 20 publications

References 38 publications

Experimental and Numerical Simulation Study of Hydraulic Fracture Propagation during Coalbed Methane Development

Experimental and Numerical Simulation Study of Hydraulic Fracture Propagation during Coalbed Methane Development

Description of Fracture Network of Hydraulic Fracturing Vertical Wells in Unconventional Reservoirs

3D DEM analysis of analogue proppant–fractured rock system interaction

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