Hydraulic properties of 3D rough-walled fractures during shearing: An experimental study

Yin, Qian; Ma, Guowei; Jing, Hongwen; Wang, Huidong; Su, Haijian; Wang, Yingchao; Liu, Richeng

doi:10.1016/j.jhydrol.2017.10.019

Cited by 120 publications

(86 citation statements)

References 46 publications

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“…Granite specimens (495 × 495 × 17 mm in size) containing artificial fracture networks were established by using a high-pressure water jet cutting system [25]. The granites were taken from Linyi city in Shandong Province of China.…”

Section: Rock Fracture Specimen Preparationmentioning

confidence: 99%

“…Based on the model specimen size, a 3 mm thick rubber jacket was produced using the ethylene propylene diene monomer (EPDM) waterproof rubber [25]. Then, a rock fracture specimen was placed in the jacket, with the extra rubber seamlessly glued to the rock surface.…”

Section: Experimental Setup and Procedurementioning

confidence: 99%

“…The stress-dependent flow tests of the fracture networks were conducted by using a self-developed flow test apparatus [25], as shown in Figure 3. It mainly consists of three units: (i) a platform for fluid flow in fracture networks; (ii) a water supply and measurement unit; (iii) a pneumatic-hydraulic cylinder unit.…”

Section: Experimental Setup and Procedurementioning

confidence: 99%

“…(c) Relationships between / 0 and (after [14]). (d) Relationships between and Re (after [25]). nonlinear flow properties within fracture networks is of great significance to ensure performance and safety of engineering activities.…”

Section: Introductionmentioning

confidence: 99%

“…When > 10 2 , / 0 is sufficiently small and approaches 0; fluid flow enters a complete nonlinear regime (see Figure 1(c)). Yin et al [25] estimated the relationships between and Re for rough-walled fractures during shearing and subjected to various normal loads from 7 to 35 kN. As an example, for one of their samples with the shear displacement of 9 mm, exhibits a decreasing trend with Re and the rate of its decrease diminishes.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study on Stress-Dependent Nonlinear Flow Behavior and Normalized Transmissivity of Real Rock Fracture Networks

et al. 2018

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The mechanism and quantitative descriptions of nonlinear fluid flow through rock fractures are difficult issues of high concern in underground engineering fields. In order to study the effects of fracture geometry and loading conditions on nonlinear flow properties and normalized transmissivity through fracture networks, stress-dependent fluid flow tests were conducted on real rock fracture networks with different number of intersections (1, 4, 7, and 12) and subjected to various applied boundary loads (7, 14, 21, 28, and 35 kN). For all cases, the inlet hydraulic pressures ranged from 0 to 0.6 MPa. The test results show that Forchheimer's law provides an excellent description of the nonlinear fluid flow in fracture networks. The linear coefficient and nonlinear coefficient in Forchheimer's law = + 2 generally decrease with the number of intersections but increase with the boundary load. The relationships between and can be well fitted with a power function. A nonlinear effect factor = 2 /( + 2 ) was used to quantitatively characterize the nonlinear behaviors of fluid flow through fracture networks. By defining a critical value of = 10%, the critical hydraulic gradient was calculated. The critical hydraulic gradient decreases with the number of intersections due to richer flowing paths but increases with the boundary load due to fracture closure. The transmissivity of fracture networks decreases with the hydraulic gradient, and the variation process can be estimated using an exponential function. A mathematical expression / 0 = 1 − exp(− −0.45 ) for decreased normalized transmissivity / 0 against the hydraulic gradient was established. When the hydraulic gradient is small, / 0 holds a constant value of 1.0. With increasing hydraulic gradient, the reduction rate of / 0 first increases and then decreases. The equivalent permeability of fracture networks decreases with the applied boundary load, and permeability changes at low load levels are more sensitive.

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Section: Rock Fracture Specimen Preparationmentioning

confidence: 99%

Section: Experimental Setup and Procedurementioning

confidence: 99%

Section: Experimental Setup and Procedurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Study on Stress-Dependent Nonlinear Flow Behavior and Normalized Transmissivity of Real Rock Fracture Networks

et al. 2018

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Effect of shearing on hydraulic properties of rough‐walled fractures under different boundary conditions

Wang

Jiang

Luan

et al. 2019

Energy Science & Engineering

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This study experimentally investigated nonlinear flow characteristics of rough‐walled fractures during shear process under different boundary conditions, using the servo‐controlled shear‐flow apparatus. A series of shear‐flow tests were conducted on two types of rough fractures with different shear displacements under various boundary conditions. The effects of shear process, fracture surface roughness, boundary normal stiffness, and initial normal stress on nonlinear flow behaviors are analyzed. The results show that Forchheimer equation provides a good description of the nonlinear relationship between flow rate and pressure gradient in rough‐walled fractures. The linear and nonlinear coefficients decrease by 1‐2 and 2‐3 orders of magnitude during shear, respectively. Both the mechanical aperture and the hydraulic aperture increase with increasing shear displacement. The mechanical aperture is always larger than the hydraulic aperture, and their difference gradually increases with the increment of shear displacement. The contact area ratio exhibits a fast decrease as shear displacement ranges between 1 and 3 mm and then decreases gradually with the decreasing rate generally diminishes. With the increase in shear displacement, the critical Reynolds number shows an increasing trend. The critical Reynolds number is in range 3.22‐35.41 for fracture G1 and 1.23‐12.35 for fracture G3. As the boundary normal stiffness and initial normal stress increase, the critical Reynolds number decreases.

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An experimental investigation of the nonlinear gas flow and stress‐dependent permeability of shale fractures

Shen

Zhou

et al. 2020

Energy Science & Engineering

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The fluid flow characteristics in shale fractures are of great significance for shale gas reservoir evaluation and exploitation. In this study, artificial tension fractures in shale were used to simulate the hydraulic fractures formed by fracturing, and a gas flow test under different pressure gradients was conducted. The nonlinear gas flow and stress‐dependent permeability characteristics were analyzed. The experimental results show the following: (a) CO2 flow in shale fractures exhibits strong nonlinearity. Forchheimer's law, which considers gas compressibility, satisfactorily describes the nonlinear relationship between the flow rate and the pressure gradients in shale fractures. (b) The permeability sensitivity of shale fractures under stress is very strong, and the exponential relationship better describes the pressure dependency of the permeability for the tested shale samples. The permeability of the shale fractures is similar when measured parallel or perpendicular to bedding. Furthermore, the pressure dependence of fractures in shale obeys the Walsh permeability model. (c) As the effective stress increases, the nonlinear flow behavior appears earlier. Based on the Reynolds number and the nonlinear coefficient, a friction factor model is proposed. (d) The normalized transmissivity exhibits a strong correlation with the Reynolds number. CO2 flow through shale fractures is generally dominated by transitional flow. The critical Reynolds number ranges from 1.8 to 102.88 and decreases with increasing effective stress.

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Hydraulic properties of 3D rough-walled fractures during shearing: An experimental study

Cited by 120 publications

References 46 publications

Experimental Study on Stress-Dependent Nonlinear Flow Behavior and Normalized Transmissivity of Real Rock Fracture Networks

Experimental Study on Stress-Dependent Nonlinear Flow Behavior and Normalized Transmissivity of Real Rock Fracture Networks

Effect of shearing on hydraulic properties of rough‐walled fractures under different boundary conditions

An experimental investigation of the nonlinear gas flow and stress‐dependent permeability of shale fractures

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