Journal ArticleDOI
Fluid Flow through Rough Rock Fractures: Parametric Study
Debanjan Guha Roy,Trilok Singh +1 more
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In this paper, two-dimensional fractures with different surface roughness were simulated in a finite-element modeling (FEM) program, and the fluid-flow parameters were evaluated, including fracture inflow pressure, aperture of the fracture, and shearing displacement during flow.Abstract:
The knowledge of fluid flow through rock fractures is directly related to hydrocarbon migration, waste disposal, and carbon dioxide sequestration. The hydraulic nature and response of the fractures are directly controlled by the roughness of the fracture surfaces. However, this parameter is hard to understand because it can behave differently under different ambient conditions. The prevalent controlling parameters are the fracture inflow pressure, aperture of the fracture, and shearing displacement during flow. To understand the influence of these parameters, a systematic study was carried out numerically on different fracture geometries. In this paper, two-dimensional fractures with different surface roughness were simulated in a finite-element modeling (FEM) program, and the fluid-flow parameters were evaluated. The Navier–Stokes (NS) equation was used to model the fluid flow through the roughness profiles generated using Barton’s joint roughness coefficient. By simulating the laminar fluid flow...read more
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VALIDITY OF CUBIC LAW FOR FLUID FLOW IN A DEFORMABLE ROCK FRACTURE - eScholarship
Abstract: The validity of the cubic law for laminar flow of fluids through open fractures consisting of parallel planar plates has been established by others over a wide range of conditions with apertures ranging down to a minimum of 0.2 µm. The law may be given in simplified form by Q/Δh = C(2b)3, where Q is the flow rate, Δh is the difference in hydraulic head, C is a constant that depends on the flow geometry and fluid properties, and 2b is the fracture aperture. The validity of this law for flow in a closed fracture where the surfaces are in contact and the aperture is being decreased under stress has been investigated at room temperature by using homogeneous samples of granite, basalt, and marble. Tension fractures were artificially induced, and the laboratory setup used radial as well as straight flow geometries. Apertures ranged from 250 down to 4µm, which was the minimum size that could be attained under a normal stress of 20 MPa. The cubic law was found to be valid whether the fracture surfaces were held open or were being closed under stress, and the results are not dependent on rock type. Permeability was uniquely defined by fracture aperture and was independent of the stress history used in these investigations. The effects of deviations from the ideal parallel plate concept only cause an apparent reduction in flow and may be incorporated into the cubic law by replacing C by C/ƒ. The factor ƒ varied from 1.04 to 1.65 in these investigations. The model of a fracture that is being closed under normal stress is visualized as being controlled by the strength of the asperities that are in contact. These contact areas are able to withstand significant stresses while maintaining space for fluids to continue to flow as the fracture aperture decreases. The controlling factor is the magnitude of the aperture, and since flow depends on (2b)3, a slight change in aperture evidently can easily dominate any other change in the geometry of the flow field. Thus one does not see any noticeable shift in the correlations of our experimental results in passing from a condition where the fracture surfaces were held open to one where the surfaces were being closed under stress.
Journal ArticleDOI
Review: Mathematical expressions for estimating equivalent permeability of rock fracture networks
TL;DR: A review of previous works that have focused on the estimation of equivalent permeability of two-dimensional (2D) discrete fracture networks (DFNs) considering the influences of geometric properties of fractured rock masses is provided in this article.
Chemically- and mechanically-mediated influences on the transport and mechanical characteristics of rock fractures - eScholarship
TL;DR: In this paper, a model representing pressure-dissolution-like behavior is adapted to define the threshold and resulting response in terms of fundamental thermodynamic properties of a contacting fracture.
Journal ArticleDOI
Geometrical heterogeneity of the joint roughness coefficient revealed by 3D laser scanning
TL;DR: In this paper, the joint roughness coefficient (JRC) is an important indicator that characterizes the physical and mechanical behaviors of a jointed rock mass, and the effects of sampling interval on JRC were assessed during the JRC calculation process.
Geometrical, fractal and hydraulic properties of fractured reservoirs: A mini-review
Wei Wei,Yuxuan Xia +1 more
TL;DR: Wei et al. as mentioned in this paper reviewed and summarized the geometrical, fractal and hydraulic properties of fracture networks and fracture networks in fracture porous media, including fracture length distribution, aperture distribution, boundary stress and anisotropy.
References
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Journal ArticleDOI
Validity of Cubic Law for fluid flow in a deformable rock fracture
TL;DR: The validity of the cubic law for laminar flow of fluids through open fractures consisting of parallel planar plates has been established by others over a wide range of conditions with apertures ranging down to a minimum of 0.2 µm.
VALIDITY OF CUBIC LAW FOR FLUID FLOW IN A DEFORMABLE ROCK FRACTURE - eScholarship
Abstract: The validity of the cubic law for laminar flow of fluids through open fractures consisting of parallel planar plates has been established by others over a wide range of conditions with apertures ranging down to a minimum of 0.2 µm. The law may be given in simplified form by Q/Δh = C(2b)3, where Q is the flow rate, Δh is the difference in hydraulic head, C is a constant that depends on the flow geometry and fluid properties, and 2b is the fracture aperture. The validity of this law for flow in a closed fracture where the surfaces are in contact and the aperture is being decreased under stress has been investigated at room temperature by using homogeneous samples of granite, basalt, and marble. Tension fractures were artificially induced, and the laboratory setup used radial as well as straight flow geometries. Apertures ranged from 250 down to 4µm, which was the minimum size that could be attained under a normal stress of 20 MPa. The cubic law was found to be valid whether the fracture surfaces were held open or were being closed under stress, and the results are not dependent on rock type. Permeability was uniquely defined by fracture aperture and was independent of the stress history used in these investigations. The effects of deviations from the ideal parallel plate concept only cause an apparent reduction in flow and may be incorporated into the cubic law by replacing C by C/ƒ. The factor ƒ varied from 1.04 to 1.65 in these investigations. The model of a fracture that is being closed under normal stress is visualized as being controlled by the strength of the asperities that are in contact. These contact areas are able to withstand significant stresses while maintaining space for fluids to continue to flow as the fracture aperture decreases. The controlling factor is the magnitude of the aperture, and since flow depends on (2b)3, a slight change in aperture evidently can easily dominate any other change in the geometry of the flow field. Thus one does not see any noticeable shift in the correlations of our experimental results in passing from a condition where the fracture surfaces were held open to one where the surfaces were being closed under stress.
Journal ArticleDOI
Strength, deformation and conductivity coupling of rock joints
Nick Barton,S. Bandis,K. Bakhtar +2 more
TL;DR: In this paper, the results of many years of research on joint properties are synthesized in a coupled joint behaviour model, which simulates stress and size-dependent coupling of shear stress, diplacement, dilation and conductivity.
Journal ArticleDOI
Fluid flow through rock joints: The effect of surface roughness
TL;DR: In this article, a simulation of flow between rough surfaces was done using a fractal model of surface topography and the hydraulic aperture was compared to the mean separation of the surfaces.
Journal ArticleDOI
A Criterion for Non-Darcy Flow in Porous Media
Zhengwen Zeng,Reid B. Grigg +1 more
TL;DR: In this article, the critical Forchheimer number for non-Darcy flow is defined as the ratio of pressure drop caused by liquid-solid interactions to that by viscous resistance.
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