| Title | Low to Medium Temperature Geothermal Resources in the Limagne Basins (France) |
|---|---|
| Authors | Genter A., Giot D., Guillou-Frottier L., Bertin C., Bitri A., Calcagno P., Courrioux G., Courtois N., Giraud-Petellet E., Goyeneche O., Martelet G., Negrel P., Nehlig P., Perrin J., Rocher P., Serra H., Serrano O., Laplaige Ph. |
| Year | 2005 |
| Conference | World Geothermal Congress |
| Keywords | Low enthalpy, geothermal resources, Limagne, France |
| Abstract | As most of the French geothermal potential inventories are more than 25 years old, an updated project has been launched in 2002, jointly funded by Ademe and BRGM, based on a geoscientific synthesis. The main goal of this geothermal compilation is focused on the low to medium temperature resources encountered in some French Tertiary basins, namely the Limagne system, surrounding the northern part of the French Massif Central. Those basins correspond to a graben system that was developed at the Oligocene time. They are filled by tertiary sediments of 2-km thick that overlain Palaeozoic basement. The maximum temperature measured in an old well, at 1500 m is about 100?C and the flow rate of the geothermal fluid is about 20 m3/h. The geology of several hundred of old wells was revisited in terms of potential reservoirs or non-reservoirs. The main potential reservoir corresponds to clastic rocks (sand, feldspathic sandstone, conglomerate), overlying the pre-Tertiary basement. 26 old seismic lines were also reinterpreted in order to built a 3D model of these deep-seated reservoir rocks. Those seismic lines underline a high fault system indicating that those reservoirs are fractured. The combination of the potential reservoir location with those of the socio-economic needs of this region allows prioritising some promising zones in terms of geothermal developments. |