A first well realized in 1995 to produce water from Neocomian sand formation-lower cretaceous give clear indication of the importance of this water table on quantity and qualify as well as mineral as geothermal (150 m3/h at 38.5 deg. C at the head of the well). A second well planned in 1997 is necessary to provide process needs. The installation of a heat pump will allow to improve the utilisation of the geothermal energy. The production of both geothermal wells will represent an instantaneous thermal power of 11 MW thermic for a cold water network of 6 deg. C reference temperature. This heat pump project will allow the valorisation of a parisian basin intermediate sheet of water.