Flow channeling in a single fracture induced by shear displacement

Auradou, Harold; Drazer, Germán; Boschan, Alejandro; Hulin, Jean-Pierre; Koplik, Joel

doi:10.1016/j.geothermics.2006.11.004

Cited by 95 publications

(65 citation statements)

References 19 publications

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“…It was found that fluid flows in rock fractures through connected and tortuous channels that bypass the contacts areas. However, the effects of contacts and the channel distribution patterns on the fluid flow and tracer transport processes in a rock fracture, and their change due to both normal stress and shear displacements, have not been fully understood, even though the effect of the mechanical processes on the fluid flow and transport phenomena has been investigated experimentally and numerically by considering normal stresses without shear [4][5][6] or shear displacement without (or very weak) normal stress [5,[7][8]. This is mainly due to the difficulties of quantitative measurements of changing fracture surface roughness and aperture during laboratory coupled stress-flow tests, especially the contact areas, as well as a number of technical difficulties in laboratory shear-flow testing, most notably the sealing of fluid during shear.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulations for the effects of normal loading on particle transport in rock fractures during shear

Koyama

Jiang

et al. 2008

International Journal of Rock Mechanics and Mining Sciences

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The fluid flow and tracer transport in a single rock fracture during shear processes has been an important issue in rock mechanics and is investigated in this paper using Finite Element Method (FEM) and streamline particle tracking method, considering evolutions of aperture and transmissivity with shear displacement histories under different normal stresses, based on laboratory tests. The distributions of fracture aperture and its evolution during shear were calculated from the initial aperture fields, based on the laser-scanned surface roughness features of replicas of rock fracture specimens, and shear dilations measured during the coupled shear-flow tests in laboratory. The coupled shear-flow tests were performed under two levels of constant normal loading (CNL). A special algorithm for treating the contact areas as zero-aperture elements was used to produce more accurate flow field simulations by using FEM. The simulation results agreed well with the flow rate data obtained from the laboratory tests, showing that complex histories of fracture aperture and tortuous flow channels with changing normal stresses and increasing shear displacements for the flow parallel with the shear direction. The flow perpendicular to the shear direction was also predicted and normalized flow rates were compared with those for the flow parallel with the shear direction. A greater increase is observed in the direction perpendicular to the shear direction due to the significant flow channels newly created by shear. This clearly shows the shortcomings of the conventional coupled shear-flow tests in a laboratory with flow in direction parallel with the shear direction. From the obtained flow velocity fields, the particle transport was predicted by using a streamline particle tracking method with calculated flow velocity fields (vectors) from the flow simulations, obtaining results such as flow velocity profiles, total flow rates, particle travel time, breakthrough curves and the Péclet number, Pe, respectively. Analyzing breakthrough curves for the unidirectional particle transport, the transport behavior in the fracture is also anisotropic and advective transport is more dominant in the direction parallel with the shear direction. The effect of normal stress on the particle transport is significant and dispersion becomes larger with increasing normal stress. The scientific findings from these studies provided new insights to the physical behavior of fluid flow and mass transport in rock fractures that is the scientific basis for many rock mechanics problems at the fundamental level, and with special importance to rock engineering problems.

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Section: Introductionmentioning

confidence: 99%

Numerical simulations for the effects of normal loading on particle transport in rock fractures during shear

Koyama

Jiang

et al. 2008

International Journal of Rock Mechanics and Mining Sciences

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“…Ainsi les écarts d'approximativement un ordre de grandeur obtenus en laboratoire par . Ces trois études révèlent un mécanisme similaire : la formation dans le plan de faille de canaux perpendiculaires au glissement favorisant significativement les écoulements dans la direction normale au jeu, soit KTN>Krr- Auradou et al (2006) montrent que cette chenalisation est générée lors du cisaillement par la rugosité paramétrée des parois de la fracture (décrites ici par une fonction auto-affine). Ce mécanisme est extensible à l'échelle des failles naturelles, les virgations décimétriques à décamétriques du plan de faille produisant par décompression une chenalisation des écoulements selon un schéma sensiblement analogue , illustré par la figure 1.4-a.…”

Section: Changements D'échelleunclassified

“…Il s'agit notamment de déterminer les mouvements réels et les vitesses de transfert d'un soluté en hydrogéologie des contaminants (e.g., Gierczak et al, 2005), d'anticiper les effets d'une exploitation à long terme d'un réservoir hydrique discontinu, de caractériser la formation et les comportements des gisements tectoniques pétroliers (Fisher et Knipe, 2001), ou encore de quantifier les surfaces d'échanges eau-roche dans le cadre de recherches sur l'extraction d'énergie géothermique (Dezayes et al, 2004;Auradou et al, 2006 .…”

Section: Introduction Generaleunclassified

Comportement hydraulique des milieux faillés /

Rafini¹

2008

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UIUQAC Mise en garde/AdviceAfin de rendre accessible au plus grand nombre le résultat des travaux de recherche menés par ses étudiants gradués et dans l'esprit des règles qui régissent le dépôt et la diffusion des mémoires et thèses produits dans cette Institution, l'Université du Québec à Chicoutimi (UQAC) est fière de rendre accessible une version complète et gratuite de cette oeuvre.Motivated by a desire to make the results of its graduate students' research accessible to all, and in accordance with the rules governing the acceptation and diffusion of dissertations and theses in this Institution, the Université du Québec à Chicoutimi (UQAC) is proud to make a complete version of this work available at no cost to the reader.L'auteur conserve néanmoins la propriété du droit d'auteur qui protège ce mémoire ou cette thèse. Ni le mémoire ou la thèse ni des extraits substantiels de ceux-ci ne peuvent être imprimés ou autrement reproduits sans son autorisation.The author retains ownership of the copyright of this dissertation or thesis. Neither the dissertation or thesis, nor substantial extracts from it, may be printed or otherwise reproduced without the author's permission. LISTE DES TABLEAUX Ce modèle reproduit efficacement les signaux transmis par les milieux discontinus, toutefois sa signification physique est incertaine et les conditions hydrodynamiques associées au développement de dimensions non-radiales demeurent énigmatiques. Il en résulte une très faible applicabilité du modèle GRF malgré le très fort potentiel diagnostique renfermé par le paramètre n. On montre que ce paramètre décrit l'évolution géométrique de l'équipotentielle frontale au cours du test hydraulique transitoire. Le comportement non-radial serait donc produit par tout système dont la géométrie -ou les propriétés hydrauliques -produisent une évolution transitoire de cette surface admettant des modifications de forme progressives et régulières. On peut s'attendre à ce que ce phénomène soit engendré par les interactions transitoires entre une faille et sa matrice.Le premier volet de cette thèse se consacre à la vérification de cette hypothèse. La production de comportements non-radiaux n = 1,5 par le discontinuum faille verticale-matrice est démontrée par la modélisation numérique tridimensionnelle aux éléments finis. L'outil numérique a permis de contraindre quantitativement les conditions hydrodynamiques associées à ce comportement.

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“…Whereas, natural fractures usually display a strong hydraulic complexity coming from the aperture anisotropy induced by the roughness of two fracture walls (Isakov et al, 2001;Auradou et al, 2006;Huang et al, 2017aHuang et al, , 2017b. The hydraulic properties of natural fractures depend on the factors such as surface roughness, aperture distribution and the contact areas between the two opposing faces of the fracture (Baghbanan and Jing, 2008;Rasouli and Hosseinian, 2011;Jafari and Babadagli, 2013).…”

Section: Introductionmentioning

confidence: 99%

Hydraulic properties of 3D crossed rock fractures by considering anisotropic aperture distributions

Liu

Jiang²,

Huang³

et al. 2018

Adv. Geo-Energy Res.

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Abstract:This study presents a numerical study on the geometrical and hydraulic properties of a three-dimensional intersected fracture model that is a fundamental element involved in complex fracture networks. A series of rough fracture surfaces were generated using the modified successive random additions (SRA) algorithm. Different shear displacements were applied to the fracture to obtain the anisotropic aperture fields that will be further assigned to the two fractures in the intersected fracture model. The flow was calculated using the Reynolds equation with the continuity conditions addressed at intersection part between the two fracture planes. The evolutions of the aperture distributions, flow channels and equivalent permeability were estimated. The simulation results reveal that as the shear displacement and joint roughness coefficient (JRC) increase, the aperture increases anisotropically, which causes significant fluid flow channeling effects. The main flow channels change from being concentrated in one fracture to the other fracture during the shear, accompanied by the change of the flow rate ratios between two flow planes at the inlet/outlet boundary. During the shear the average contact area accounts for approximately 4% to 15% of the fracture planes, and the actual calculated flow area is about 35% to 42% of the fracture planes, which is smaller than the noncontact area. As the shear displacement and JRC increase, the equivalent permeability of the intersected fracture increases. Therefore, the channeling flow should be considered to interpret the fluid flow through the rough fractures even in the simplest fracture networks.

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Flow channeling in a single fracture induced by shear displacement

Cited by 95 publications

References 19 publications

Numerical simulations for the effects of normal loading on particle transport in rock fractures during shear

Numerical simulations for the effects of normal loading on particle transport in rock fractures during shear

Comportement hydraulique des milieux faillés /

Hydraulic properties of 3D crossed rock fractures by considering anisotropic aperture distributions

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