Creation of an HDR reservoir at 5000 m depth at the European HDR project

Roy Baria (1) , R. Jung (2) , T. Tishner (2) , J. Nicholls (3) , Sophie Michelet (1) , Bernard Sanjuan (4) , N. Soma (5) , H. Asanuma (6) , B. Dyer (1) , John Garnish (1)

1 GEIE Exploitation Minière de la Chaleur
2 BGR - Bundesanstalt für Geowissenschaften und Rohstoffe
3 School of Biological and Chemical Sciences
4 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
5 AIST - National Institute of Advanced Industrial Science and Technology
6 Hatakeyama Laboratory

Three 5000 m deep wells (GPK2, GPK3 and GPK4) have been drilled into the crystalline basement at the European HDR research site at Soultz in France to form a modular three well system consisting of a central injector and two producers. The system will be used to produce electricity after the creation of an HDR reservoir. The first well GPK2 was drilled in 1999 to 5000 m depth and stimulated in 2000. A second well GPK3 (the injector) was targeted using microseismic and other data and drilled in 2002. The bottom hole temperature of GPK3 was 200.6ºC and separation between GPK2 and GPK3 at the bottom is around 650 m. Similarly, GPK3 was successfully stimulated in 2003 to create a reservoir between GPK2 and GPK3 (Baria et al., 2000, Baria et al., 2004). The second producer GPK4 was targeted using the same technique as above and drilled in 2003 to a depth of 4982 m TVD. GPK4 was initially stimulated in 2004 but the injection had to be stopped towards the end of the stimulation because of collapsed casing near the wellhead. Both the microseismic and hydraulic data indicated that the required hydraulic link between GPK4 and GPK3 had not been established. GPK4 was re-stimulated in early 2005 but the hydraulic and microseismic data indicated that a hydraulic link to GPK3 had still not been achieved. Production logging in GPK4 during the stimulation of GPK4 showed that about 20 % of the injected flow were leaving around 50 m above the casing shoe. Microseismic monitoring, production logging and other diagnostic methods were used during these injections. The microseismic events from the initial stimulationof GPK4 in 2004 migrated from the bottom of the well, approximately NW and SE. The NW direction took the micoseismicity towards GPK3 but it appeared to stop migrating after around 200 m where it encountered the previous microseismic events created in 2003 during the stimulation of GPK3. A similar trend in microseismicity was observed during the second stimulation of GPK4 in 2005. There appears to be some form of a barrier that restricts the growth of micoseismicity towards GPK3. The nature of this barrier is not clear and it may also be responsible for a very poor hydraulic response in GPK3 from the injection in GPK4.

Domaines: Milieux et Changements globaux; Sciences de la Terre

Roy Baria, R. Jung, T. Tishner, J. Nicholls, Sophie Michelet, et al.. Creation of an HDR reservoir at 5000 m depth at the European HDR project. Thirty-First Workshop on Geothermal Reservoir Engineering, Stanford University, Jan 2006, Stanford, United States. 8 p. ⟨hal-00768762⟩