Role of fracture geometry in the evolution of flow paths under stress

Gentier, Sylvie; Hopkins, Deborah; Riss, Joëlle

doi:10.1029/gm122p0169

Cited by 29 publications

(36 citation statements)

References 9 publications

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“…Nevertheless, this is not consistent with field and laboratory observations of flow channeling in single fractures [Moreno et al, 1985;Bourke, 1987;Gentier et al, 2000]. On the basis of these observations, flow channeling is mainly explained by a variation of apertures and contact areas within the fracture [Neretnieks et al, 1982;Tsang andTsang, 1987, 1989;Tsang et al, 1988;Moreno et al, 1988Moreno et al, , 1990Tsang and Neretnieks, 1998].…”

Section: Flow Pattern Within a Fracture And Consequences On Hydromechcontrasting

confidence: 40%

“…Some models accounting for the effects of contact areas on fracture flow and deformability are proposed from laboratory observations [Yang et al, 1989;Myer, 1991;Pyrak-Nolte and Morris, 2000;Detwiler et al, 2002]. Sibaï et al [1997] and Gentier et al [2000] showed through laboratory hydromechanical experiments that the spatial distribution of contact areas within the fracture varies under normal stress and induces preferential flow paths through localized channels. Recent hydromechanical simulations of flow in a rough deformable fracture confirmed observations of flow channeling, and showed that the distributions of fracture aperture during shearing change and cause significant fluid flow channeling effects [Koyama et al, 2005].…”

Section: Flow Pattern Within a Fracture And Consequences On Hydromechmentioning

confidence: 99%

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Estimation of fracture flow parameters through numerical analysis of hydromechanical pressure pulses

Cappa

Guglielmi

Rutqvist

et al. 2008

Water Resources Research

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[1] The flow parameters of a natural fracture were estimated by modeling in situ pressure pulses. The pulses were generated in two horizontal boreholes spaced 1 m apart vertically and intersecting a near-vertical highly permeable fracture located within a shallow-fractured carbonate reservoir. Fracture hydromechanical response was monitored using specialized fiber-optic borehole equipment that could simultaneously measure fluid pressure and fracture displacements. Measurements indicated a significant time lag between the pressure peak at the injection point and the one at the second measuring point, located 1 m away. The pressure pulse dilated and contracted the fracture. Field data were analyzed through hydraulic and coupled hydromechanical simulations using different governing flow laws. In matching the time lag between the pressure peaks at the two measuring points, our hydraulic models indicated that (1) flow was channeled in the fracture, (2) the hydraulic conductivity tensor was highly anisotropic, and (3) the radius of pulse influence was asymmetric in that the pulse traveled faster vertically than horizontally. Moreover, our parametric study demonstrated that the fluid pressure diffusion through the fracture was quite sensitive to the spacing and orientation of channels, hydraulic aperture, storativity, and hydraulic conductivity. Comparison between hydraulic and hydromechanical models showed that the deformation significantly affected fracture permeability and storativity and, consequently, the fluid pressure propagation, suggesting that the simultaneous measurements of pressure and mechanical displacement signals could substantially improve the interpretation of pulse tests during reservoir characterization.

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Section: Flow Pattern Within a Fracture And Consequences On Hydromechcontrasting

confidence: 40%

Section: Flow Pattern Within a Fracture And Consequences On Hydromechmentioning

confidence: 99%

Estimation of fracture flow parameters through numerical analysis of hydromechanical pressure pulses

Cappa

Guglielmi

Rutqvist

et al. 2008

Water Resources Research

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“…The hydraulic stimulation consists in injecting water with high flow rate in order to increase the pore pressure within the rock mass which promotes the shearing of existing fractures, a mechanism accompanied partly by detectable induced microseismicity. When the injection is stopped, the shearing relaxation is irreversible and the reactivated fractures do not close totally, yielding to a new and/or enhanced permeability [26].…”

Section: Introductionmentioning

confidence: 99%

Structure of the low permeable naturally fractured geothermal reservoir at Soultz

Dezayes

Genter²,

Valley

2009

Comptes Rendus. Géoscience

126

105

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The permeability of the granite geothermal reservoir of Soultz is primarily related to major fracture zones, which, in turn, are connected to dense networks of small-scale fractures.The small-scale fractures are nearly vertical and the major direction is about N0°E. This direction differs from that of the Rhine graben, which is about N20°E to N45E in northern Alsace.A total of 39 fracture zones, with a general strike of N160°E, have been identified in six wells between 1400 and 5000 m depth. These fracture zones are spatially concentrated in three clusters. The upper cluster at 1800-2000m TVD (True Vertical Depth) is highly permeable. At 3000-3400m TVD, the intermediate cluster in composed of a dense network developed in an altered matrix and forms the upper reservoir. In the lower part of the wells, the deeper cluster appears as a fractured reservoir developed within a low permeable matrix.Fracture zones represent a key element to take into account for modeling of geothermal reservoir life time submitted to various thermo-hydro-mechanical and chemical processes generated by hydraulic or chemical stimulations and hydraulic circulations. RésuméLe réservoir géothermique de Soultz est constitué par des zones de fracture majeures connectées à un réseau dense de fractures secondaires.Les méso-fractures sont pratiquement verticales et la direction majeure est à peu près N-S. Cette direction diffère de la direction régionale du fossé rhénan qui est localement à dominante N20°E à N45°E dans le Nord.Un total de 39 zones de fracture a été identifiées et caractérisées dans six puits entre 1400 et 5000 m de profondeur. Ces structures sont réparties en trois clusters suivant la profondeur. Le premier cluster à 1800-2000m TVD (profondeur verticale) est très perméable. A 3000-3400m TVD, le cluster intermédiaire apparaît comme un réseau plus dense dans un milieu plus altéré et constitue le réservoir supérieur. Dans la partie inférieure des puits, le cluster profond apparaît comme un réservoir fracturé développé dans une matrice très peu perméable. 2La caractérisation des zones de fracture représente un élément important à prendre en compte dans la modélisation de la durée de vie du réservoir géothermique soumis à des processus thermo-hydromécaniques et chimiques engendrés par les stimulations hydrauliques et chimiques et les circulations de fluide. Key words: Rhine graben, fractures, fracture zones, cores, borehole images, Enhanced GeothermalSystem. Mots-clés : Fossé rhénan, fractures, zones de fractures, carottes, image de paroi, Système GéothermalAmélioré. IntroductionSince 1980 [27; 28], the EGS project at Soultz (France) goals to experiment and develop a new geothermal technology. After an initial Hot Dry Rock (HDR) concept of artificial fractures creation in a homogeneous rock by hydraulic fracturing, the concept at Soultz has progressively evolved to an Enhanced Geothermal System (EGS) where reservoir development involved the reactivation of the preexisting fractures in the granite [16; 29]. Thus, a good knowledge...

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“…Depending on the atti tude and intensity of the principal component of the imposed stress, hydraulic properties of the fracture system can change consistently, affecting the per meability of the media (Aydin, 2000;Baghbanan and Jing, 2008;Tondi et al, 2016). This is valid at the scale of microfractures (Gentier et al, 2000;Simpson et al, 2001) and at regional scales (Bell and Babcock, 1986;Mandl and Hark ness, 1987;Storti et al, 1997;Morin and Savage, 2003;Tondi et al, 2016). In re sponse to the direction of the crustal stress field, fractures can be kept open or undergo closure (Gale et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Lineament domain analysis to infer groundwater flow paths: Clues from the Pale di San Martino fractured aquifer, Eastern Italian Alps

2017

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An automatic lineament extraction was carried out on a processed digi tal elevation model of a highaltitude Alpine fractured reservoir, the Pale di San Martino area (Dolomites) located in the southern sector of the Eastern Italian Alps. The strike of the main lineament domain indicates the direction of the principal crustal stress. This direction was compared with earthquake focal mechanisms to confirm the orientation of the regional crustal stress. The two data sets provide similar results and show a NNWSSE maximum horizontal crustal stress orientation, compatible with the direction of the last Alpine compression reported by previous studies in the investigated region. The orientation of the maximum horizontal compressive stress was then used to explore the ability of specific fracture and fault sets to enhance ground water flow. Subvertical strikeslip faults and joints oriented NWSE to north south provide the greater contribution to the groundwater flow. The location of the main springs and evidence from a dye tracer test conducted in the area confirm this main drainage direction. This study demonstrates that automatic lineament analysis is an efficient and inexpensive method to identify the tra jectories of groundwater flow in fractured aquifers.

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Role of fracture geometry in the evolution of flow paths under stress

Cited by 29 publications

References 9 publications

Estimation of fracture flow parameters through numerical analysis of hydromechanical pressure pulses

Estimation of fracture flow parameters through numerical analysis of hydromechanical pressure pulses

Structure of the low permeable naturally fractured geothermal reservoir at Soultz

Lineament domain analysis to infer groundwater flow paths: Clues from the Pale di San Martino fractured aquifer, Eastern Italian Alps

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