Simulation of hydraulic fracturing using particle flow method and application in a coal mine

Wang, Tao; Zhou, Wenyi; Chen, Jinhua; Xiong, Xiao; Li, Yang; Zhao, Xianyu

doi:10.1016/j.coal.2013.10.012

Cited by 209 publications

(110 citation statements)

References 33 publications

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“…A number of numerical models for hydrofracture formation exist already [30,31] while new models are continuously developed [e.g., [32][33][34][35][36]. The current interest in these models is mainly triggered by the enormous economic importance of artificial hydraulic (aka "fracking") as a means of oil and gas extraction.…”

Section: Introductionmentioning

confidence: 99%

Transport efficiency and dynamics of hydraulic fracture networks

2015

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Intermittent fluid pulses in the Earth's crust can explain a variety of geological phenomena, for instance the occurrence of hydraulic breccia. Fluid transport in the crust is usually modeled as continuous Darcian flow, ignoring that sufficient fluid overpressure can cause hydraulic fractures as fluid pathways with very dynamic behavior. Resulting hydraulic fracture networks are largely self-organized: opening and healing of hydraulic fractures depends on local fluid pressure, which is, in turn, largely controlled by the fracture network. We develop a crustal-scale 2D computer model designed to simulate this process. To focus on the dynamics of the process we chose a setup as simple as possible. Control factors are constant overpressure at a basal fluid source and a constant "viscous" parameter controlling fracture-healing. Our results indicate that at large healing rates hydraulic fractures are mobile, transporting fluid in intermittent pulses to the surface and displaying a 1/f α behavior. Low healing rates result in stable networks and constant flow. The efficiency of the fluid transport is independent from the closure dynamics of veins or fractures. More important than preexisting fracture networks is the distribution of fluid pressure. A key requirement for dynamic fracture networks is the presence of a fluid pressure gradient.

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Section: Introductionmentioning

confidence: 99%

Transport efficiency and dynamics of hydraulic fracture networks

2015

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“…ese native defects play an important role in the mechanical properties of the rock mass, further influencing the stability of underground engineering [1][2][3]. Among them, the joint is a common native defect.…”

Section: Introductionmentioning

confidence: 99%

Simulation Study on Strength and Failure Characteristics for Granite with a Set of Cross‐Joints of Different Lengths

Yin

Chen

Liu

et al. 2018

Advances in Civil Engineering

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e strength and failure characteristics for granite specimen with a set of cross-joints of different lengths were studied using PFC 2D software. e results show that when the included angle of α between the main joint and loading direction is 30°or 45°, no matter what the included angle of β between main and secondary joints is, the main joint controls crack propagation and failure of granite specimen, which occurs the shear failure propagating from main joint tips, and the corresponding uniaxial compressive strength is low. Meanwhile, the secondary joint is the key joint for crack propagation and failure at α of 0°and 90°except when β is 90°. e granite specimen occurs the shear failure propagating from secondary joint tips. And, the shear failure crossing upper tips of main and secondary joints is found at α of 0°or 90°and β of 90°. eir uniaxial compressive strengths are large. Also, the combined actions of main and secondary joints determine crack propagation and failure at α of 60°except when β is 90°. e granite specimen occurs the hybrid failure, including shear failure propagating from main joint tips and tensile failure propagating from main and secondary joints center or secondary joint tips. And, when α is 60°and β is 90°, the granite specimen occurs the shear failure along secondary joint plane direction, and its uniaxial compressive strength is small. Generally, when α or β is a fixed value, the uniaxial compressive strength firstly decreases and then increases with the increase of β or α. Additionally, when α is 60°and β > 45°, the uniaxial compressive strength represents a decreasing trend. e uniaxial compressive strength at α and β between 30°a nd 60°is generally small. Finally, the microdisplacement field distributions of granite specimen were discussed.

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“…As a reliable and economic formation stimulation technology, it has been successfully used in shale gas reservoirs. Due to low matrix porosity and low permeability of shale gas reservoirs, to make long well lengths for effective drainage areas in traditional designs, it is not practical for tight shales (Zhou et al 2010;Zeng et al 2010;Wu et al 2011Wu et al , 2012Wang et al 2014a). In order to create complex fractures in shale reservoirs through multi-stage hydraulic fracturing in horizontal wells, analysis of stage spacing and stress interference among fractures needs to be done.…”

Section: Introductionmentioning

confidence: 99%

Stress redistribution in multi-stage hydraulic fracturing of horizontal wells in shales

Zeng

Zhang

2015

Pet. Sci.

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Multi-stage hydraulic fracturing of horizontal wells is the main stimulation method in recovering gas from tight shale gas reservoirs, and stage spacing determination is one of the key issues in fracturing design. The initiation and propagation of hydraulic fractures will cause stress redistribution and may activate natural fractures in the reservoir. Due to the limitation of the analytical method in calculation of induced stresses, we propose a numerical method, which incorporates the interaction of hydraulic fractures and the wellbore, and analyzes the stress distribution in the reservoir under different stage spacing. Simulation results indicate the following: (1) The induced stress was overestimated from the analytical method because it did not take into account the interaction between hydraulic fractures and the horizontal wellbore. (2) The hydraulic fracture had a considerable effect on the redistribution of stresses in the direction of the horizontal wellbore in the reservoir. The stress in the direction perpendicular to the horizontal wellbore after hydraulic fracturing had a minor change compared with the original in situ stress. (3) Stress interferences among fractures were greatly connected with the stage spacing and the distance from the wellbore. When the fracture length was 200 m, and the stage spacing was 50 m, the stress redistribution due to stage fracturing may divert the original stress pattern, which might activate natural fractures so as to generate a complex fracture network.

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Simulation of hydraulic fracturing using particle flow method and application in a coal mine

Cited by 209 publications

References 33 publications

Transport efficiency and dynamics of hydraulic fracture networks

Transport efficiency and dynamics of hydraulic fracture networks

Simulation Study on Strength and Failure Characteristics for Granite with a Set of Cross‐Joints of Different Lengths

Stress redistribution in multi-stage hydraulic fracturing of horizontal wells in shales

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