| Abstract |
The Upper Rhine Graben is an approximately 300 km long, 30–40 km wide active Cenozoic rift system located in the south-west of Germany. It hosts siliciclastic and carbonate reservoirs with sedimentary layers up to 4.5 km thick overlying a crystalline basement. Large fault zones facilitate the movement of hot fluids, resulting in a geothermal gradient of up to 42°C/km. It is one of Germany’s most significant geothermal play types, with several successful deep geothermal projects and ongoing investigations for lithium production. However, the geothermal potential of medium-deep reservoirs (400 to 1500 meters) has not yet been thoroughly assessed, even though they could play a crucial role in supporting Germany’s heat supply. To address this, a 3D structural geological model was developed in Petrel using data from seismic surveys, well logs, and published sources to estimate the regional heat potential using the Heat-in-Place method. This structural model then served as the basis for creating several localized numerical models in COMSOL Multiphysics, representing different geological settings within the Upper Rhine Graben, to evaluate the heat potential and performance of hydrothermal doublets, borehole heat exchangers, and ATES systems. To provide both worst- and best-case estimates for each site, depth, reservoir properties, and operational parameters (e.g., well spacing, pumping rate, injection temperature) were systematically varied. The results indicate good geothermal potential and the feasibility of different geothermal systems. They will be integrated into the German Geothermal Information System (GeotIS), which is intended to attract and support future geothermal development in the study area. |