Abstract
The success of the Soultz-sous-Forêts Hot-Dry-Rock project depends on the ability to maintain fluid circulation in a fractured granite. Fractures represent the main fluid pathways. To understand the behavior of this granite in respect to thermal fluid-rock interaction the important aspects are (1) the porous network around these fractures and (2) the thermal conductivity of the rock. This granite is altered and composed of different weathered facies. Variations of porosity and thermal conductivity take place in regard to the alteration and fracturing of the granite. Two types of porosity measurements were performed, mercury injection and water porosity on two samples sizes. The two methods give similar porosity values between 0.3% and 10%. Thermal conductivity measurements were performed in two perpendicular directions to look at anisotropy with two methods at different scale and value ranges from 2.3 to 3.9 W.m-’.K“’. Optical scanning provides us with a good knowledge of local increase of thermal conductivity due to sealed fracture or quartz-cemented matrix
The relationship between porosity and thermal conductivity is not obvious and has to be studied in details, and results show three cases:
-
1
a relationship between conductivity and porosity (increase of conductivity with a decrease of porosity)
-
2
a relationship between conductivity and sealed fractures (increase of conductivity related to an increase of fracture density)
-
3
and a combination of the two previous ones
The results are carefully compared for different types of granite: alterated, fractured or both. These first results indicate that parameters such as thermal conductivity are linked to the porous medium, the structure and the mineralogy of the rock
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Carslaw, H. and Jaeger, J. C., Conduction of Heat in Solids (Clarendon, Oxford 1947).
Clauser, C. and Huenges, E. (1995), Thermal conductivity of rocks and mineral. In AGU Handbook of Physical Constants (ed. Ahrens T. J.), pp. 105–126.
Genter, A. (1990), Géothermie roches chaudes sèches: le granite de Soultz-Sous-Forêts (Bas-Rhin, France). Thesis of the University of Orléans, 201 pp.
Genter, A. and Traineau, H. (1992), Borehole EPS1, Alsace, France: Preliminary Results from Granite Core Analysis for Hot Dry Rock Research., Scientific Drilling 3, 205–214.
Gerard, A., Jung, R., Baumgärtner, J., Baria, R., Gandy, T., and Tran-Viet, T. (1998), Essais decirculation moyenne durée conduits à Soultz-sous-Foréts en 1997, Socomine Internal Report, 20 pp.
Gueguen, Y. and Palciauskas, V., Introduction à la physique des roches (Hermann, Paris 1992).
Huenges, E., Burkhardt, H., Erbas, K. (1990), Thermal Conductivity Profile of the KTB Pilote Corehole,Scientific Drilling 1, 224–230.
Ledesert, B., Dubois, J., Genter, A., and Meunier, A. (1993), Fractal analysis of Fractures Applied to Soultz-sous-Forêts Hot Dry Rock Geothermal Program, J. Volcanology and Geothermal Res. 57, 1–17.
Mertz, J. D. (1991), Structures de porosité et propriétés de transport dans les grès, Sciences Géologiques Strasbourg, Mem., 149 pp.
Pellerin, F. M. (1981), La porosité mercure appliquée à l’étude géotechnique des sols et des roches, Bull. Liaison Lab. Ponts et Chaussées 106, 106–116.
Popov, Y. A., Pribnow, D., Sass, J. H., Williams, C., and Burkhardt, H. (1999), Characterisation of Rock Thermal Conductivity by High-resolution Optical Scanning, Geothermics 28, 253–276.
Pribnow, D. and Sass, J. H. (1995), Determination of Thermal Conductivity for Deep Boreholes, J.Geophys. Res. 100, B6, 9981–9994.
Prinow, D., Williams, C., Sass, J. H., and Keating, R. (1996), Thermal Conductivity of Water-saturated Rocks from KTB Pilot Hole at Temperatures of 25 to 300°C, Geophys. Res. Lett., 23, 4, 391–394.
Sausse, J., Genter, A., Leroy, J., and Lespinasse, M. (1998), Description et quantification des altérations filoniennes. paléoécoulementsfluides dans les granites de Soultz-sous-Foréts (Bas-Rhin, France). Bull. Soc.Géol. France. 169, 5, 655–664.
Sizun, J. P. (1995), Modification des structures de porosité dans les grès lors de transformations pétrographiques dans la diagenése et l’hydrothermalisme: application au Trias de la marge ardéchoise et au fossé rhénan, Thesis of the University of Strasbourg I, 256 pp.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2003 Springer Basel AG
About this chapter
Cite this chapter
Surma, F., Geraud, Y. (2003). Porosity and Thermal Conductivity of the Soultz-sous-Forêts Granite. In: Kümpel, HJ. (eds) Thermo-Hydro-Mechanical Coupling in Fractured Rock. Pageoph Topical Volumes. Birkhäuser, Basel. https://doi.org/10.1007/978-3-0348-8083-1_20
Download citation
DOI: https://doi.org/10.1007/978-3-0348-8083-1_20
Publisher Name: Birkhäuser, Basel
Print ISBN: 978-3-7643-0253-5
Online ISBN: 978-3-0348-8083-1
eBook Packages: Springer Book Archive