A Model for Water Flow Through Rock Fractures Based on Friction Factor

Zhang, Zhenyu; Nemcik, Jan; Qiao, Qiuqiu; Geng, Xueyu

doi:10.1007/s00603-014-0562-4

Cited by 43 publications

(14 citation statements)

References 24 publications

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“…Furthermore, according to the analysis about the wall friction coefficient f , another formula describing the wall friction coefficient can be obtained by Equations (19) and (20) based on the Darcy-Weisbach equation and Forchheimer formula, and it can be seen that the wall friction coefficient f is closely related to the Reynolds number, fracture aperture, and roughness.…”

Section: Triggering Mechanism Of the Nonlinear Flowmentioning

confidence: 99%

“…However, rougher fracture surfaces may influence on the friction loss, inertial forces, and seepage behavior, while the fluid flowing through rough fractures. Nazridoust et al [18], Yang et al [19], Zhang et al [20], Zhou et al [21], and Xiaopeng et al [22] have conducted experiments and theories to propose the seepage model considering wall friction effect and reveal the evolution mechanism of the fluid flow in rough fractures considering the wall friction effect, which deeply explains that the seepage mechanism of the flow through rough fractures especially represents the transformation of the seepage behavior from the linearity to the nonlinearity while the fracture roughness and flow velocity change suddenly. However, above investigations are focused on flow behavior through the 2-dimensional fractures; advanced research on the flow characteristics in 3dimensional fractures should be deeply conducted.…”

Section: Introductionmentioning

confidence: 99%

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Investigation on Nonlinear Flow Behavior through Rock Rough Fractures Based on Experiments and Proposed 3-Dimensional Numerical Simulation

Liu

Zeng

et al. 2020

Geofluids

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Rock fractures as the main flow channels, their morphological features, and spatial characteristics deeply influence the seepage behavior. Reservoir sandstones as a case study, four splitting groups of fractures with different roughness were scanned to get the geometric features, and then the seepage experiments were taken to analyze the relationship of the pressure gradient ∇ P and flow rate Q , and the critical Reynolds number( Re c ) and wall friction factor ( f ) were determined to explain the translation of linear seepage to nonlinear seepage condition. Based on the scanning cloud data of different rough fractures, the fractures were reconstructed and introduced into the COMSOL Multiphysics software; a 3-dimensional seepage model for rough fractures was calibrated and simulated the seepage process and corresponding pressure distribution, and explained the asymmetry of flow velocity. And also, the seepage characteristics were researched considering aperture variation of different sample fractures; the results indicated that increasing aperture for same fracture decreased the relative roughness, the fitting coefficients by Forchheimer formula based on the data ∇ P ~ Q decreased, and the figures about the coefficients and corresponding aperture described nonlinear condition of the above rough fractures. In addition, the expression of wall friction factor was derived, and relationship of f , Re , and relative roughness indicated that f increased with increasing fracture roughness considering the same aperture, resulting in nonlinear flow more easily, otherwise is not, showing that f could be used to describe the seepage condition and corresponding turning point. Finally, it can be seen from the numerical results that the nonlinearity of fluid flow is mainly caused by the formation of eddies at fracture intersections and the critical pressure gradient decreases with increasing angle. And also, analysis about the coefficient B in the Forchheimer law corresponding to fracture intersections considering the intersecting angle and surface roughness is proposed to reveal the flow nonlinearity. The above investigations give the theoretical support to understand and reveal the seepage mechanism of the rock rough fractures.

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Section: Triggering Mechanism Of the Nonlinear Flowmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation on Nonlinear Flow Behavior through Rock Rough Fractures Based on Experiments and Proposed 3-Dimensional Numerical Simulation

Liu

Zeng

et al. 2020

Geofluids

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“…Two positive creep curves were obtained in the test. Because each curve presented a relation as in Equation (4), the values of K and G 1 were calculated by combining Equation (4) and Equation (1). The creep curves of the same object were identical when isotropic homogeneous viscoelastic solid was taken into account.…”

Section: Improved Burgers Modelmentioning

confidence: 99%

Effect of Saturation-Dehydration on the Parameters of Burgers Creep Model

Qin¹,

Fu²,

Weimin³

et al. 2017

JRST

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in the background of an open-pit slope at warehouse gold mine, the beresitization fractured granite (SγJh) was selected to conduct rock tri-axial creep test subject to different saturation-dehydration cycles. it is found that the creep characteristics conform to Burgers model without considering the change of the creep failure stage. The creep parameters, the principal stress difference and its deviation are analyzed for saturation-dehydration cycles of N = 0, 1, 5, 10, respectively. results show that the parameters of Burgers model are substantially influenced by the load level. G1 and G2 increase with the increase of axial loading. η1 and η2 decrease with the increase of axial loading. The relationship between the four parameters and the stress difference follows exponential trend. an exponential relation is found between the creep parameters and the principal stress difference for constant saturation-dehydration circles. The creep parameters are approximately exponential functions of the cycle number n for the same principal stress difference. Through curve fitting of the test data, the values of the parameters in Burgers model for the beresitization fractured granite (SγJh) are obtained by considering the water-rock interaction and principal stress difference.

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“…As a porous medium, coal acts as a tunnel for methane transition because of the presence of numerous pores and fractures on its structure (Meyers, 2012;Zhang et al, 2014;Zhang and Nemcik, 2013;Zhang et al, 2015). Therefore, studying structural changes in the coal pore structure aids in better understanding of the "methane seepage" process.…”

Section: Introductionmentioning

confidence: 97%