| Abstract |
Experiences from the petroleum and geothermal energy industry indicated, that reinjection of the cooled geothermal water into a sandstone aquifer often leads to a reduction of the permeability of the formation .The reinjection pressure has to be increased in order to maintain the injection rate. The phenomenon can be attributed to various reasons: microbiological effects, water sensitivity of sandstones, suspended solids, fine migration in the reservoir, trapped gases, air contamination… Numerous geothermal doublets in Europe faced this type of problems and consequently have been abandoned in France, Hungary, Germany and Romania. Two recent operations in the Paris area have proved that in non-saline environment this type of geothermal doublet should be a success using simple methods. |