STEPS TOWARDS A COMPREHENSIVE THERMO-HYDRAULIC ANALYSIS OF THE HDR TEST SITE SOULTZ-SOUS-FORÊTS

Abstract

During the exploration of the HDR test site Soultz-sous-Forêts (France) numerous unexpected thermal and hydraulic features have been encountered. The HDR reservoir at the Soultz-sous-Forêts site is targeted in a granitic horst zone bounded by subvertical N-S trending normal faults. The high surface heat flow at HDR test site, Soultz-sous-Forêts, being a main reason for its selection dropped from nearly 150 mW m-2 at surface to <25 mW m-2 in 2-3 km depth and recovers at greater depth to ~70 mW m-2. In the depth range between 2-3.8 km (i.e. the range with low heat flow) numerous hydraulic experiments have been performed which highlighted the importance of far field drainage systems. The analysis of these features, jointly investigated by numerical models, elucidate that the local temperature field can be