Variation of whole and fractured porous rock permeability with confining pressure

Gangi, Anthony F.

doi:10.1016/0148-9062(78)90957-9

Cited by 514 publications

(302 citation statements)

References 4 publications

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“…In the past, the stress dependency of fracture permeability and its hysteretic behavior due to stepwise loading and subsequent unloading were investigated by various authors (e.g., Gangi, 1978;Kranz et al, 1979;Snow, 1965). Various empirical models were developed that approximate stressdependent fracture permeability by adding roughness-based variables to the common cubic law approach (Bernabe, 1986;Gale, 1982;Gangi, 1978;Huo and Benson, 2015;Swan, 1983;Walsh, 1981;Witherspoon et al, 1980;Zimmerman et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

Simulating stress-dependent fluid flow in a fractured core sample using real-time X-ray CT data

et al. 2016

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Abstract. Various geoscientific applications require a fast prediction of fracture permeability for an optimal workflow. Hence, the objective of the current study is to introduce and validate a practical method to characterize and approximate single flow in fractures under different stress conditions by using a core-flooding apparatus, in situ X-ray computed tomography (CT) scans and a finite-volume method solving the Navier-Stokes-Brinkman equations. The permeability of the fractured sandstone sample was measured stepwise during a loading-unloading cycle (0.7 to 22.1 MPa and back) to validate the numerical results. Simultaneously, the pressurized core sample was imaged with a medical X-ray CT scanner with a voxel dimension of 0.5 × 0.5 × 1.0 mm 3 . Fracture geometries were obtained by CT images based on a modification of the simplified missing attenuation (MSMA) approach. Simulation results revealed both qualitative plausibility and a quantitative approximation of the experimentally derived permeabilities. The qualitative results indicate flow channeling along several preferential flow paths with less pronounced tortuosity. Significant changes in permeability can be assigned to temporal and permanent changes within the fracture due to applied stresses. The deviations of the quantitative results appear to be mainly caused by both local underestimation of hydraulic properties due to compositional matrix heterogeneities and the low CT resolution affecting the accurate capturing of sub-grid-scale features. Both affect the proper reproduction of the actual connectivity and therefore also the depiction of the expected permeability hysteresis. Furthermore, the threshold value CT mat (1862.6 HU) depicting the matrix material represents the most sensitive input parameter of the simulations. Small variations of CT mat can cause enormous changes in simulated permeability by up to a factor of 2.6 ± 0.1 and, thus, have to be defined with caution. Nevertheless, comparison with further CT-based flow simulations indicates that the proposed method represents a valuable method to approximate actual permeabilities, particularly for smooth fractures (< 35 µm). However, further systematic investigations concerning the applicability of the method are essential for future studies. Thus, some recommendations are compiled by also including suggestions of comparable studies.

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Section: Introductionmentioning

confidence: 99%

Simulating stress-dependent fluid flow in a fractured core sample using real-time X-ray CT data

et al. 2016

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“…As stress increases, the modulus increases and approaches the value of the intact rock at higher stresses. Gangi (1978) has used an asperity model to determine the stress dependence permeability in fractured rock. In Gangi's "bed of nails" model, the closure of the fracture under stress is ascribed to the elastic compression of the asperities, and the "softness" of the fracture is said to result from the small 5 number of asperities that are in contact.…”

Section: Introductionmentioning

confidence: 99%

Hydromechanical behavior of a deformable rock fracture subject to normal stress

Tsang¹,

Witherspoon²

1981

J. Geophys. Res.

365

163

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“…Statistical models are also being developed [17][18] to characterize the macro-roughness of the surfaces as well as the contact asperities. Laboratory studies on flow through fractured specimens of rock have been performed by several investigators [16,19,20] but only limited data are currently available to check the validity of numerical and statistical models.…”

Section: Flow Through Rock Fracturesmentioning

confidence: 99%

Electrical Analogy of Hydraulic Flow Through Rock Fractures

Selig¹,

Sundaram

Frink

1983

Geotechnical Testing Journal

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Electrical analogy is used to study the influence of contact areas on the hydraulic flow through rock fractures. The investigation has shown that in the case of radial flow the location of contact zones, as well as the total contact area, influences the flow rate. It is also demonstrated that when injection tests are conducted in boreholes, where the fracture close to the borehole is partially plugged by loose particles or other debris, the flow rate may be substantially underestimated.

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Variation of whole and fractured porous rock permeability with confining pressure

Cited by 514 publications

References 4 publications

Simulating stress-dependent fluid flow in a fractured core sample using real-time X-ray CT data

Simulating stress-dependent fluid flow in a fractured core sample using real-time X-ray CT data

Hydromechanical behavior of a deformable rock fracture subject to normal stress

Electrical Analogy of Hydraulic Flow Through Rock Fractures

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