Hydraulic properties of the crystalline basement

Stober, Ingrid; Bucher, Kurt

doi:10.1007/s10040-006-0094-4

Cited by 159 publications

(163 citation statements)

References 37 publications

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“…The solutes have different origins including the reaction of recharge water with the rock matrix, fossil seawater and sedimentary waters imported from cover sequences of the basement (Frape et al 2004;Bottomley et al 1993;Edmunds et al 1987;Stober and Bucher 1999;Louvat et al 1999;Casanova et al 2001;Negrel et al 2003). In general, the permeability of fractured crystalline basement is relatively high and permits groundwater advection and large-scale fluid flow (Manning and Ingebritsen 1999;Caine and Tomusiak 2003;Stober and Bucher 2007). The information on chemical properties of groundwater in the basement comes from shallow near surface wells (Banks and Banks 1993), scientific deep drilling (Möller et al 1997), research for nuclear waste disposal (e.g., Nordstrom et al 1989), prospection for geothermal energy (e.g., Stober and Bucher 2004) and deep mines (Fritz and Frape 1987;Negrel and Casanova 2005).…”

Section: Introductionmentioning

confidence: 98%

Groundwater in fractured crystalline rocks, the Clara mine, Black Forest (Germany)

Bucher

Zhu

Stober

2008

Int J Earth Sci (Geol Rundsch)

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The chemical composition of water sampled in a 700 m deep underground barite-fluorite mine in the crystalline basement of the Black Forest area (SW Germany) varies systematically with depth and the length of flow paths trough, the fracture porosity of the gneiss matrix. Calcium and sulfate increase as a result of a combined sulfide oxidation and plagioclase alteration reaction. The gneiss contains andesine-plagioclase (An 20 -An 40 ) and is rich in primary sulfide. As an effect of Ca and SO 4 release by the prime water-rock reaction, dissolved oxygen decreases and the waters become more reduced. The waters have Cl/Br mass ratios of about 50, which is very close to that of experimentally leached gneiss powders indicating that the rock matrix is the source of the halogens. The waters are undersaturated with respect to calcite in the upper parts of the mine. With increasing reaction progress, calcite saturation is reached and carbonate forms as a reaction product of the prime reaction that also controls the partial pressure of CO 2 to progressively lower values. The chemical evolution of groundwater in fractured basement of the Clara mine suggests that the partial pressure of CO 2 is an internally buffered parameter rather than a controlling external variable.

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Section: Introductionmentioning

confidence: 98%

Groundwater in fractured crystalline rocks, the Clara mine, Black Forest (Germany)

Bucher

Zhu

Stober

2008

Int J Earth Sci (Geol Rundsch)

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“…Based on geothermal development in the URG, the permeability of the granitic reservoir appears to be controlled by fractured zones that act as preferential pathways for natural hydrothermal circulation Ledésert et al 2010Ledésert et al , 1993Rotstein et al 2006;Sausse et al 2010;Sausse and Genter 2005;Villemin and Bergerat 1987). A large number of studies have tried to characterize permeability, fracture geometry, and hydrogeological systems for geothermal applications or nuclear waste storage, whereas a few studies have addressed the hydrogeology of the deep-seated crystalline rocks (Ishibashi et al 2016;Moreno and Neretnieks 1993;Stober and Bucher 2007). In a volcanic geothermal context, fault zones are also main pathways for fluids (Gailler et al 2014;Gudmundsson et al 2002).…”

Section: Introductionmentioning

confidence: 99%

How do the geological and geophysical signatures of permeable fractures in granitic basement evolve after long periods of natural circulation? Insights from the Rittershoffen geothermal wells (France)

Glaas

Genter²,

Girard

et al. 2018

Geotherm Energy

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Two deep wells were drilled at Rittershoffen (Alsace, France) to produce high-temperature fluids to supply heat to a biorefinery. The GRT-2 production well was drilled to a depth of 3196 m MD and was deviated to target a permeable local fault in the granitic basement buried beneath a thick sedimentary cover. The objective of this study is to better understand the permeability of fractured reservoirs within crystalline rocks, focusing on the production well GRT-2. Based on a petrographic and mineralogical analysis of cutting samples, several granitic facies associated with hydrothermal alteration were identified on the basis of the amounts of illite, chlorite, anhydrite, secondary geodic quartz, and oxides. These observations were correlated with various geological and geophysical datasets (gamma ray, porosity, density, electrical resistivity, caliper, borehole image logs, temperature, rate of penetration, and mud losses) to localize and identify permeable fracture zones. In sections where acoustic image logs were not available, such as in the deepest part of the well, the geometries of the fracture zones were interpreted from an oriented caliper log. The caliper log interpretation detected one-third of the fractures detected by acoustic image logs. However, two major fracture sets striking N-S and dipping eastward or westward were observed. Furthermore, a synthetic resistivity log that fits the measured resistivity log relatively well was built using the Archie and Waxman and Smits models. This approach is a proxy for estimating the porosity and the mineralogical changes based on the cation exchange capacity, which is controlled by the chlorite/illite ratio, derived from electrical logs in granitic formations. The correlation of all these results allowed the identification of a resistivity signature of a permeable fracture zone that spatially fits with the temperature signature. The major contribution of this study is the identification of a hierarchy of permeable fractures based on petrophysical signatures. The geophysical signature of fracture zones with low residual permeability exhibits a broad depth extent, whereas the geophysical signature of a highly permeable fracture zone is more localized. Past hydrothermal circulation has enlarged the altered and porous zones around open Open Access© The Author(s) 2018. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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“…The main groundwater flow in crystalline rock aquifers is considered to be localized in superficial formations resulting mainly from rock weathering, and below in fracture and major geologic discontinuity networks (Larsson, 1987;Stober and Bucher, 2007;Wyns et al, 2004). The compartmentalized structure includes various reservoir scales and characteristic physical parameters (permeability, porosity, etc.)…”

Section: Hydrogeological Settingmentioning

confidence: 99%

“…These recharge values are not small enough to explain the 2.3 Myr residence time observed for chlorides, which could mean either that the first model is inconsistent with data, or that the assumption of Goderniaux et al (2013) is unrealistic. A permeability decrease with depth may be observed in the continental crust with a likely factor of 100 within the first kilometer (Ingebritsen and Manning, 1999;Saar and Manga, 2004;Stober and Bucher, 2007). Such a decrease could account for a much smaller recharge of the deep groundwater system and thereby a less efficient flushing process.…”

Section: First Conceptual Model: Perfectly Mixed Aquifermentioning

confidence: 99%

Timescales of regional circulation of saline fluids in continental crystalline rock aquifers (Armorican Massif, western France)

Landes

Aquilina

Davy

et al. 2015

Hydrol. Earth Syst. Sci.

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Abstract. In recent decades, saline fluids have been sampled worldwide at great depths in continental basements. Although some of them have been attributed to marine transgressions, the mechanisms allowing their circulation are not understood. In this paper, we describe the horizontal and vertical distributions of moderately saline fluids (60 to 1400 mg L −1 ) sampled at depths ranging from 41 to 200 m in crystalline rock aquifers on the regional scale of the Armorican Massif (northwestern France). The horizontal and vertical distributions of high chloride concentrations are in good agreement with both the altitudinal and vertical limits and the succession of the three major transgressions between the Mio-Pliocene and Pleistocene ages. The mean chloride concentration for each transgression area is exponentially related to the time spanned until the present. It defines the potential laws of leaching (displacement) of marine waters by fresh meteoric waters. The results of the Armorican aquifers provide the first observed constraints for the timescales of seawater circulation in the continental crystalline basement and the subsequent leaching by fresh meteoric waters. The general trend of increasing chloride concentration with depth and the time frame for the flushing process provide useful information to develop conceptual models of the paleofunctioning of Armorican aquifers.

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Hydraulic properties of the crystalline basement

Cited by 159 publications

References 37 publications

Groundwater in fractured crystalline rocks, the Clara mine, Black Forest (Germany)

Groundwater in fractured crystalline rocks, the Clara mine, Black Forest (Germany)

How do the geological and geophysical signatures of permeable fractures in granitic basement evolve after long periods of natural circulation? Insights from the Rittershoffen geothermal wells (France)

Timescales of regional circulation of saline fluids in continental crystalline rock aquifers (Armorican Massif, western France)

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