Deflection and propagation of fluid-driven fractures at frictional bedding interfaces: A numerical investigation

Zhang, Xi; Jeffrey, Robert G.; Thiercelin, M.

doi:10.1016/j.jsg.2006.09.013

Cited by 252 publications

(121 citation statements)

References 31 publications

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“…Factors such as pre-existing cracks, bedding planes, frictional effect, crustal stresses, and liquid-solid interaction may collectively influence the propagation of a hydraulic crack ( Warpinski and Teufel, 1987;Zhang and Jeffrey, 2006;Bunger and Detournay, 2008;Chuprakov et al, 2014 ). Such complexity renders it difficult to carry out theoretical analysis, and numerical methods were broadly employed to examine the hydraulic fracture: Zhang et al (2007), Olson (2011, 2014 ), Weng et al (2011), Kresse et al (2013), Guo et al (2015) and Zou et al (2016) simulated the interaction between a hydraulic fracture and frictional or sealed natural cracks. A coupled, implicit time-stepping numerical model was developed by Bunger et al (2013) to capture the hydraulic fracture that grows near a free surface and curves towards the surface.…”

Section: Introductionmentioning

confidence: 99%

Crack deflection in brittle media with heterogeneous interfaces and its application in shale fracking

Zeng

Wei

2017

Journal of the Mechanics and Physics of Solids

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a b s t r a c tDriven by the rapid progress in exploiting unconventional energy resources such as shale gas, there is growing interest in hydraulic fracture of brittle yet heterogeneous shales. In particular, how hydraulic cracks interact with natural weak zones in sedimentary rocks to form permeable cracking networks is of significance in engineering practice. Such a process is typically influenced by crack deflection, material anisotropy, crack-surface friction, crustal stresses, and so on. In this work, we extend the He-Hutchinson theory (He and Hutchinson, 1989) to give the closed-form formulae of the strain energy release rate of a hydraulic crack with arbitrary angles with respect to the crustal stress. The critical conditions in which the hydraulic crack deflects into weak interfaces and exhibits a dependence on crack-surface friction and crustal stress anisotropy are given in explicit formulae. We reveal analytically that, with increasing pressure, hydraulic fracture in shales may sequentially undergo friction locking, mode II fracture, and mixed mode fracture. Mode II fracture dominates the hydraulic fracturing process and the impinging angle between the hydraulic crack and the weak interface is the determining factor that accounts for crack deflection; the lower friction coefficient between cracked planes and the greater crustal stress difference favor hydraulic fracturing. In addition to shale fracking, the analytical solution of crack deflection could be used in failure analysis of other brittle media.

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Section: Introductionmentioning

confidence: 99%

Crack deflection in brittle media with heterogeneous interfaces and its application in shale fracking

Zeng

Wei

2017

Journal of the Mechanics and Physics of Solids

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“…In recent years, different techniques have been used to incorporate heterogeneity into numerical models, such as FEM (Wang 2013), RFPA (Tang et al 2002;Yang et al 2004;Li et al 2013;Wang et al 2013), and PFC (Al-Busaidi et al 2005;Hiyama et al 2013;Shimizu et al 2011Shimizu et al , 2014 methods. In addition, there are other methods, such as unconventional fracture models (UFM) (Kresse et al 2011, BEM (Zhang et al 2007), XFEM (Wang et al 2015), DDM (Gu et al 2008). These numerical studies are useful for understanding and characterizing the initiation and propagation of hydrofracturing cracks.…”

Section: Introductionmentioning

confidence: 99%

Visual representation and characterization of three-dimensional hydrofracturing cracks within heterogeneous rock through 3D printing and transparent models

Liu

Ranjith

et al. 2016

Int J Coal Sci Technol

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The heterogeneity of unconventional reservoir rock tremendously affects its hydrofracturing behavior. A visual representation and accurate characterization of the three-dimensional (3D) growth and distribution of hydrofracturing cracks within heterogeneous rocks is of particular use to the design and implementation of hydrofracturing stimulation of unconventional reservoirs. However, because of the difficulties involved in visually representing and quantitatively characterizing a 3D hydrofracturing crack-network, this issue remains a challenge. In this paper, a novel method is proposed for physically visualizing and quantitatively characterizing the 3D hydrofracturing crack-network distributed through a heterogeneous structure based on a natural glutenite sample. This method incorporates X-ray microfocus computed tomography (lCT), 3D printing models and hydrofracturing triaxial tests to represent visually the heterogeneous structure, and the 3D crack growth and distribution within a transparent rock model during hydrofracturing. The coupled effects of material heterogeneity and confining geostress on the 3D crack initiation and propagation were analyzed. The results indicate that the breakdown pressure of a heterogeneous rock model is significantly affected by material heterogeneity and confining geostress. The measured breakdown pressures of heterogeneous models are apparently different from those predicted by traditional theories. This study helps to elucidate the quantitative visualization and characterization of the mechanism and influencing factors that determine the hydrofracturing crack initiation and propagation in heterogeneous reservoir rocks.

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“…Using two-dimensional particle flow code-PFC 2D , Wang et al investigated relevant parameters and analyzed the correlation between macroscopic and mesoscopic mechanical parameters [14]. Zhang et al established a two-dimensional numerical fracture model to analyze the coupled rock deformation and fluid flow in such fractures, and the results show that fracture escape from the interface is likely under the conditions of fracture growth from stiff to soft rocks, small layer-to-layer far-field stress contrasts, and moderately low fluid viscosity, and small parent fracture lengths and offset distances [15,16].…”

Section: Introductionmentioning

confidence: 99%

Analysis on the Initial Cracking Parameters of Cross-Measure Hydraulic Fracture in Underground Coal Mines

Cheng

et al. 2015

Energies

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Initial cracking pressure and locations are important parameters in conducting cross-measure hydraulic fracturing to enhance coal seam permeability in underground coalmines, which are significantly influenced by in-situ stress and occurrence of coal seam. In this study, stress state around cross-measure fracturing boreholes was analyzed using in-situ stress coordinate transformation, then a mathematical model was developed to evaluate initial cracking parameters of borehole assuming the maximum tensile stress criterion. Subsequently, the influences of in-situ stress and occurrence of coal seams on initial cracking pressure and locations in underground coalmines were analyzed using the proposed model. Finally, the proposed model was verified with field test data. The results suggest that the initial cracking pressure increases with the depth cover and coal seam dip angle. However, it decreases with the increase in azimuth of major principle stress. The results also indicate that the initial cracking locations concentrated in the second and fourth quadrant in polar coordinate, and shifted direction to the strike of coal seam as coal seam dip angle and azimuth of maximum principle stress increase. Field investigation revealed consistent rule with the developed model that the initial cracking pressure increases with the coal seam dip angle. Therefore, the proposed

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Deflection and propagation of fluid-driven fractures at frictional bedding interfaces: A numerical investigation

Cited by 252 publications

References 31 publications

Crack deflection in brittle media with heterogeneous interfaces and its application in shale fracking

Crack deflection in brittle media with heterogeneous interfaces and its application in shale fracking

Visual representation and characterization of three-dimensional hydrofracturing cracks within heterogeneous rock through 3D printing and transparent models

Analysis on the Initial Cracking Parameters of Cross-Measure Hydraulic Fracture in Underground Coal Mines

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