Modelling an ATES geothermal exploitation - From fracture network and aquifer static modelling to hydrothermal simulation of the geothermal doublet

Conférence Chapitre d'actes Modelling an ATES geothermal exploitation - From fracture network and aquifer static modelling to hydrothermal simulation of the geothermal doublet eng 2025-10 author Polasek David 804246 author Damy Pierre-Clément author Rusillon Elme 655620 author Barrois Aurélien author Rouvroy Patrick author Quiquerez Loic 645337 https://europeangeothermalcongress.eu/wp-content/uploads/2025/11/David-et-al.pdf ATES (Aquifer Thermal Energy Storage) medium-depth geothermal technology uses aquifers to store and extract thermal energy. It allows regulating seasonal temperatures by means of hot and cold wells. This technology principally uses matrix aquifers, due to their good thermal conductivity and ability to effectively store and release heat. This process is being considered by Services Industriels de Genève (SIG) in the fractured and karstified limestones of the Upper Mesozoic series in the Satigny area (Geneva, Switzerland). By planning a new geothermal doublet, SIG would like to store the residual heat of a heating network in summer and use it in winter. The GEo-01 exploration borehole drilled in 2018, located close to the study area, indicated favorable characteristics for the implementation of such a system, such as high permeabilities and low hydraulic flow. However, the heterogeneity and complexity of fractured aquifers, as well as the presence of preferential conduits in this geological context can complicate the implementation of this technology. To assess its feasibility, a DFN (Discrete Fracture Network) model was built using offset well data (including GEo-01), 2D seismic data and outcrop analog (Jura mountains) data. This model needed to mitigate hydrogeological uncertainty in the project area by integrating spatial, field, geophysical and well data to assess the equivalent parameters of the dual environment present in the targeted geological formations. The hydrogeological parameters were dynamically calibrated. An uncertainty analysis was run to determine which of the geological, hydrogeological or operational parameters could have the major influence on the pressure and temperature conditions to be expected, with a view to optimize the energy efficiency of the exploitation. The main outcomes of this analysis are as follows: Fracture permeability and production rate essentially control pressure differentials across wells; Block size and production rate mainly influence production temperature evolution; Sustainable and even enhanced production parameters are found in both wells of the doublet over 30 years, with limited impact on GEo-01. These promising results allowed the launch of the execution phase of this ATES project. Additional drilling data from the doublet boreholes, as well as the integration of 3D seismic interpretation data in the Satigny area will help updating the simulation of this reversible exploitation and specifying the production. ATES Geothermal doublet Dual porosity model Discrete fracture network Geological static modelling Hydrothermal simulation Dewey 550 Dewey 333.7-333.9 18 Institut des sciences de l'environnement 0DB 41 Département F.-A. Forel des sciences de l'environnement et de l'eau 153 false 938 ISE Pôle Sciences 945 ISE Energie 659 Systèmes énergétiques European Geothermal Congress 7-9 Octobre 2025 Zürich (Switzerland) eba86a46-416e-4f0f-ba60-674bf7492dec Proceedings chapter (Published version) Public Papers-EGC-2025_ATES_modelisation_S.pdf 1581955 application/pdf 8c017cf2aade0e49dde799bf7af548f9e0f1c07c6b90a2beee24785e67380bfe openAccess Centres et instituts / Institut des sciences de l'environnement Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département F.-A. Forel des sciences de l'environnement et de l'eau

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Modelling an ATES geothermal exploitation - From fracture network and aquifer static modelling to hydrothermal simulation of the geothermal doublet	European Geothermal Congress			2025	53	156

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Polasek, David