Glass casts of rock fracture surfaces: A new tool for studying flow and transport

Wan, Jiamin; Tokunaga, Tetsu K.; Orr, Thomas R.; O'Neill, J. P.; Connors, Robert W.

doi:10.1029/1999wr900289

Cited by 33 publications

(15 citation statements)

References 14 publications

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“…In the case study, an important feature that merits additional analysis is the fundamental difference between the carried out studies on single fractures (Kumar et al, 1995;Yeo et al, 1998;Wan et al, 2000) in which Taylor dispersion was found to occur and the dominance of geometric dispersion in our complex fracture network.…”

Section: Discussionmentioning

confidence: 99%

“…In the case study, due to the complex, tortuous topology of the fracture network there may not be an opportunity for Aris-Taylor dispersion to develop. The obtained results need to be compared with previous studies carried out in limestone, granite and welded tuff fractures (Kumar et al, 1995;Yeo et al, 1998;Wan et al, 2000) that found the dominance of Aris-Taylor dispersion. The previously reported experiments (Detwiler et al, 2000) regard a single fracture in which the fraction of contact area between the fracture surfaces was relatively small.…”

Section: Solute Transportmentioning

confidence: 99%

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Evidence of non-Darcy flow and non-Fickian transport in fractured media at laboratory scale

Cherubini

Giasi

Pastore

2013

Hydrol. Earth Syst. Sci.

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Abstract.During a risk assessment procedure as well as when dealing with cleanup and monitoring strategies, accurate predictions of solute propagation in fractured rocks are of particular importance when assessing exposure pathways through which contaminants reach receptors.Experimental data obtained under controlled conditions such as in a laboratory allow to increase the understanding of the fundamental physics of fluid flow and solute transport in fractures.In this study, laboratory hydraulic and tracer tests have been carried out on an artificially created fractured rock sample. The tests regard the analysis of the hydraulic loss and the measurement of breakthrough curves for saline tracer pulse inside a rock sample of parallelepiped shape (0.60 × 0.40 × 0.08 m). The convolution theory has been applied in order to remove the effect of the acquisition apparatus on tracer experiments.The experimental results have shown evidence of a nonDarcy relationship between flow rate and hydraulic loss that is best described by Forchheimer's law. Furthermore, in the flow experiments both inertial and viscous flow terms are not negligible.The observed experimental breakthrough curves of solute transport have been modeled by the classical onedimensional analytical solution for the advection-dispersion equation (ADE) and the single rate mobile-immobile model (MIM). The former model does not properly fit the first arrival and the tail while the latter, which recognizes the existence of mobile and immobile domains for transport, provides a very decent fit.The carried out experiments show that there exists a pronounced mobile-immobile zone interaction that cannot be neglected and that leads to a non-equilibrium behavior of solute transport. The existence of a non-Darcian flow regime has showed to influence the velocity field in that it gives rise to a delay in solute migration with respect to the predicted value assuming linear flow. Furthermore, the presence of inertial effects enhance non-equilibrium behavior. Instead, the presence of a transitional flow regime seems not to exert influence on the behavior of dispersion. The linear-type relationship found between velocity and dispersion demonstrates that for the range of imposed flow rates and for the selected path the geometrical dispersion dominates the mixing processes along the fracture network.

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Section: Discussionmentioning

confidence: 99%

Section: Solute Transportmentioning

confidence: 99%

Evidence of non-Darcy flow and non-Fickian transport in fractured media at laboratory scale

Cherubini

Giasi

Pastore

2013

Hydrol. Earth Syst. Sci.

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“…1). The transparent glass casts are particularly useful for a visual and quantitative study of multiphase flow in rock fractures (Wan et al, 2000). The mean aperture of the fracture was 760 mm, and one fracture pore volume (PV) was estimated from the product of the mean aperture and the projected fracture area, leading to a 1 PV of 19.136 ml (Fig.…”

Section: Fracture and Remedial Fluidsmentioning

confidence: 99%

A capillary number for physical displacement of TCE-DNAPL trapped in a rough-walled fracture

Lee

Yeo

et al. 2011

Geosci J

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A heterogeneous nature of rough-walled rock fractures complicates a recovery of DNAPL trapped in fractured rock aquifers, which forms a persistent plume within the fractured rocks and present a long-term source of contamination. Experimental studies were conducted to suggest a criterion for the physical displacement of DNAPL from rough-walled fractures in the context of capillary number (N ca ), a dimensionless number representing the ratio of the viscous to capillary forces. A series of experiments using water, surfactant solution and dense fluid were conducted in the range of capillary number from 2.29 × 10 -4 to 3.41 × 10 -2 . The experimental results suggested that a higher capillary number than 1 × 10 -2 be required for a near complete DNAPL removal (more than 95% of initial saturation) from rough-walled fractures. For capillary number on the order of 10 -3 , DNAPL can be mobilized or recovered to some degree. For the capillary number below 1 × 10 -3 , any kind of remedial fluids would have no effect on physical displacement. It is suggested that remedial fluid utilizing physical displacement be formulated to comply with N ca > 1 × 10 -2 to maximize a complete physical removal and the fluid utilizing chemical solubilization or reaction do with N ca < 1 × 10 -3 to minimize unwanted migration.

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“…They are often associated with unpredictability and variability 2 . Decades of studies, ranging from single narrow fractures dominating flow 3 , to wells or drawdowns in a fractured formation (4)(5) revealed many fundamental features of structural geology, and hydrogeology. Emphasis has been given to understanding of fracture geometry 1 , new techniques for conductive fracture detection (6)(7) , and new tools for computer simulation 8 .…”

Section: Introductionmentioning

confidence: 99%

Rigorous Modelling of Fractures in a Porous Medium

Saghir¹,

Islam²

2000

Canadian International Petroleum Conference

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While fractured formations are possibly the most important contributors to the oil production world-wide, modelling fractured formations with rigorous treatments has eluded reservoir engineers in the past. To-date, one of the most commonly used fractured reservoir model remains the one that was suggested by Warren and Root more than three decades ago. In this paper, a new model for fractures embedded in a porous medium is proposed. The model considers the Navier Stokes equation in the fracture (channel flow) while using Brinkman equation for the porous medium. Unlike the previous approach, the proposed model does not require the assumption of orthogonality of the fractures (sugar cube assumption) nor does it impose incorrect boundary conditions for the interface between the fracture and the porous medium. The proposed model is derived through a series of finite element modelling runs for various cases using Navier Stokes equation in the channel while maintaining Brinkman equation in the porous medium. Various cases studied include different fracture orientations, fracture frequencies, fracture width, and the permeability of the porous medium. Finally, a series of numerical runs also provided validity of the proposed model for the cases for which thermal and solutal effects are important. Such a study of double diffusive phenomena in the context of fractured formations has not been reported before.

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Glass casts of rock fracture surfaces: A new tool for studying flow and transport

Cited by 33 publications

References 14 publications

Evidence of non-Darcy flow and non-Fickian transport in fractured media at laboratory scale

Evidence of non-Darcy flow and non-Fickian transport in fractured media at laboratory scale

A capillary number for physical displacement of TCE-DNAPL trapped in a rough-walled fracture

Rigorous Modelling of Fractures in a Porous Medium

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