Numerical modeling on destress blasting in coal seam for enhancing gas drainage

Zhu, Wancheng; Wei, Chenhui; Li, S.; Wei, Jiong; Zhang, M.S.

doi:10.1016/j.ijrmms.2012.11.004

Cited by 154 publications

(58 citation statements)

References 23 publications

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“…During rock failure, heterogeneity has a considerable effect on evolution of the fracture network [52,53]. In order to describe the rock heterogeneity, the domain is discretized into finite nodes.…”

Section: Damage Variables and Their Evolutionmentioning

confidence: 99%

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Numerical Study of Fracture Network Evolution during Nitrogen Fracturing Processes in Shale Reservoirs

et al. 2018

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This paper develops a numerical model to study fracture network evolution during the nitrogen fracturing process in shale reservoirs. This model considers the differences of incompressible and compressible fluids, shear and tensile failure modes, shale heterogeneity, and the strength and permeability of both shale matrix and bedding planes through the coupling of mechanical-seepage-damage during fracturing fluid injection. The results show that nitrogen fracturing has a lower breakdown pressure and larger seepage zone than hydraulic fracturing under the same injection pressure. Tensile failure was identified as the major reason for the initiation and propagation of fractures. Ignoring the effect of bedding planes, the fracture initiation pressure, breakdown pressure, and fracturing effectiveness reached their maxima when the stress ratio is 1. Under the same strength ratio, the propagation path of the fractures was controlled by the stronger effect that was casused by the bedding angle and stress ratio. With increasing the strength ratio, the fracture number and shearing of the bedding plane increased significantly and the failure pattern changed from tensile-only mode to tensile-shear mode. These analyses indicated that the fracture network of bedding shale was typically induced by the combined impacts of stress ratio, bedding angle and strength ratio.Energies 2018, 11, 2503 2 of 22 more effective if N 2 is applied for the hydraulic fracturing [22,23]. Different fracturing fluids lead to the different pore pressure distributions during fluid flow due to the various properties such as viscosity and compressibility. According to the principle of effective stress, the difference in pore pressure distribution induces the difference in the stress distribution in rocks, which plays an important role in fracturing behavior during the fracturing process [24][25][26][27]. Lower breakdown pressure, larger seepage zone and more complex fracture network were observed during nitrogen fracturing [24][25][26][27]. However, these studies were performed on simple rock samples and the influence of other factors during nitrogen fracturing has not been well evaluated. It is essential to investigate fracture network evolution during the nitrogen fracturing process.Several numerical models have been developed to investigate fracture behaviors during the hydraulic fracturing process. These models include the boundary element method [28], finite element method [29][30][31], and discrete element method [32,33]. Wang et al. [29] applied a new mathematical model to investigate fracture network evolution of multi-stranded fractures with pre-existing natural fractures. Shalev and Lyakhovsky [31] studied the damage evolution and seismicity phenomenon in hydraulic fracturing using an improved damage model based on the finite element method. However, there are still only a few studies on a numerical model for nitrogen fracturing and the comparison between water fracturing and nitrogen fracturing. On the other hand, shale reservoirs occur at di...

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Section: Damage Variables and Their Evolutionmentioning

confidence: 99%

“…Also, the permeability increases significantly with damage evolution. Because of the complex relationship between damage and permeability, an amplification factor is used to characterize the impact of the damage on permeability [53]. Therefore, Equation (9) is revised as:…”

Section: Relationship Between Damage and Permeabilitymentioning

confidence: 99%

Numerical Study of Fracture Network Evolution during Nitrogen Fracturing Processes in Shale Reservoirs

et al. 2018

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“…Effects of rock heterogeneity on fracture propagation was also studied by Gironacci et al using a nonlocal stochastic method . Zhu et al developed a coupled multiphysical model to simulate single‐borehole blasting, and recently, they developed a damage‐based model to simulate stress relaxation of weak sandstone. In addition, Riera et al evaluated concrete behavior under static 3D compression using discrete element method, and Haeri et al investigated model scale and particle size effects of concrete using particle flow method.…”

Section: Introductionmentioning

confidence: 99%

Modelling of crack propagation in rocks under SHPB impacts using a damage method

Wang

Zhu

et al. 2019

Fatigue Fract Eng Mat Struct

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Rock dynamic fracture is a complex problem and has received considerable attention during the last few decades. In this paper, tensile crack softening failure criterion is used to study impact‐induced crack initiation and propagation in rocks. In order to examine applicability of the criterion, under realistic loading and boundary conditions, three boundary conditions were analyzed in details and an impacting experiment using single cleavage semicircle compression (SCSC) specimens had been successfully simulated. A good agreement was achieved between the simulation and experimental results. It was concluded that the boundary conditions play an important role in rock dynamic fracturing. When a stress wave propagates from a material with low wave impedance to a material of high wave impedance, the compression wave is partially reflected back and the process of fast cracking is suppressed. In addition, with the change of the tensile strength and the fracture energy, the crack initiation modes can be divided into four types.

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“…Along with the rapid economic development, rock blasting technology has found extensive applications in water conservancy, hydropower, mines, and transport and has generated huge social and economic benefits [4][5][6]. However, its application to complex environment of coal mines has been restricted [1,7]. Existing studies have shown that the wave impedance matching between explosives in the blast hole and the surrounding rock of hole wall is conducive to the utilization of the explosion energy and thus to a good rock-breaking effect [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study and Engineering Practice of Pressured Water Coupling Blasting

Yang

2017

Shock and Vibration

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Overburden strata movement in large space stope is the major reason that induces the appearance of strong mining pressure. Presplitting blasting for hard coal rocks is crucial for the prevention and control of strong pressure in stope. In this study, pressured water coupling blasting technique was proposed. The process and effect of blasting were analyzed by orthogonal test and field practice. Results showed that the presence of pressure-bearing water and explosive cartridges in the drill are the main influence factors of the blasting effect of cement test block. The high load-transmitting performance of pore water and energy accumulation in explosive cartridges were analyzed. Noxious substances produced during the blasting process were properly controlled because of the moistening, cooling, and diluting effect of pore water. Not only the goal of safe and static rock fragmentation by high-explosive detonation but also a combination of superdynamic blast loading and static loading effect of the pressured water was achieved. Then the practice of blasting control of hard coal rocks in Datong coal mine was analyzed to determine reasonable parameters of pressured water coupling blasting. A good presplitting blasting control effect was achieved for the hard coal rocks.

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Numerical modeling on destress blasting in coal seam for enhancing gas drainage

Cited by 154 publications

References 23 publications

Numerical Study of Fracture Network Evolution during Nitrogen Fracturing Processes in Shale Reservoirs

Numerical Study of Fracture Network Evolution during Nitrogen Fracturing Processes in Shale Reservoirs

Modelling of crack propagation in rocks under SHPB impacts using a damage method

Experimental Study and Engineering Practice of Pressured Water Coupling Blasting

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