| Title | Natural fractures and permeability at the geothermal site Rittershoffen, France |
|---|---|
| Authors | Vidal, J; Genter, A; Chopin, F; Dalmais, E |
| Year | 2016 |
| Conference | European Geothermal Congress |
| Keywords | Natural fractures and faults, permeability, downhole logging methods, acoustic image logs, Enhanced Geothermal System, Rhine Graben, Rittershoffen. |
| Abstract | A geothermal doublet was drilled at Rittershoffen (Alsace, France) in order to exploit the local geothermal anomaly. Geothermal resource is trapped into fracture network at the sediments-basement interface. Acoustic image logs were analyzed in openhole section of the wells GRT-1 and GRT-2 and correlated with permeability indication such as temperature anomalies and/or mud losses during drilling operations. The main fracture orientation in GRT-1 is N10°E to N20°E dipping westward. In GRT-2, the main fracture orientation is N160°E to NS dipping eastward or westward. Less than 5% of fractures present natural permeable indication at borehole scale. Permeable fracture zones present complex cluster indication with major permeable drains surrounded by damage zone. |