The GeConnect project proposal aims at increasing the reliability of the downhole construction of geothermal wells beyond the state of the art, using new innovative technology of flexible couplings. Full scale prototypes of the flexible coupling allowing axial casing movements have already been laboratory tested in GeoWell (TRL 3-4) and in GeConnect the concept will be tested in real working environment (TRL 5-6). Together with the new flexible couplings, cement sheath integrity and the cement-metal boundary will be evaluated by simulating thermal cycling loads at moderate (<100°C) to high temperatures (~300°C). The concept of flexible couplings is to significantly lower the risk of casing failures, e.g. plastic deformation and collapse due to high axial compressive forces during well heat-up and cooling. In GeConnect, we will validate the concept in real geothermal environment (in situ), the integrity of cemented annulus and the casing using flexible couplings in a surface experiment. After successfully tested in the framework of the EC funded projects IMAGE and GeoWell, fiber optic distributed strain sensing technology together with conventional acoustic sensors will be used to validate the operation of the flexible coupling. Possible implications and risks associated with using the new flexible couplings will be assessed through structural modeling of surface test, structural modeling of a geothermal well and by performing a quantitative risk assessment analysis. Structural analysis will be used to evaluate the performance of flexible connections and demonstrate the benefits to well integrity of reducing thermal axial stress and strain in casings by introducing the new flexible coupling.