Geochemical fluid characteristics and main achievements about tracer tests at Soultz-sous-Forêts (France).

Bernard Sanjuan (1) , Jean-Louis Pinault (1) , Peter Rose (2) , André Gerard (3) , Michel Brach (1) , Gilles Braibant (1) , Catherine Crouzet (1) , Jean-Claude Foucher (1) , Anne Gautier (1) , Stéphane Touzelet (1)

1 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
2 University of Utah
3 GroupeES - ESGéothermie

Three wells drilled at a depth of about 5,000 m in the granite (T close to 200°C) will constitute the heat exchanger for electricity generation in the site of Soultz-sous-Forêts. After several hydraulic stimulation operations carried out in these wells in order to improve the well injectivity and the quality of inter-well connections, a five month fluid circulation test was conducted in 2005 between the injection well GPK-3 and the production wells GPK-2 and GPK-4, in the framework of the construction of the Scientific Pilot Plant of the European HDR Program, initiated in 2001. A tracer test using fluorescein and a geochemical fluid monitoring accompanied this operation. This paper presents the major results obtained during these works and summarizes the main characteristics of the native geothermal fluids (reservoir brine and gases) which can be drawn up in 2006, in terms of geochemistry (chemical and isotopic composition, fluid origin, reservoir temperature, water-rock-gas interaction processes) and circulation (natural fluid convection flux, existence of more permeable areas and different circulation paths in the heat exchanger, fluid velocities).

Domaines: Géochimie; Milieux et Changements globaux

Bernard Sanjuan, Jean-Louis Pinault, Peter Rose, André Gerard, Michel Brach, et al.. Geochemical fluid characteristics and main achievements about tracer tests at Soultz-sous-Forêts (France).. EHDRA Scientific Conference, 2006, Soultz-sous-Forêts, France. 13 p. ⟨hal-00773150⟩