Using Variscan Metasediments as an EGS Reservoir on a European Scale – Preliminary Stages of Outcrop Analogue Characterisation

The MEET (Multidisciplinary and multi-context demonstration of Enhanced Geothermal Systems exploration and Exploitation Techniques and potentials) aims to explore and bring about this potential in Variscan crystalline and metasedimentary reservoirs. This project will focus on the conversion of the University of Göttingen’s natural gas power plant, into a geothermal power plant to supply the district heating, focusing on the structural model of the reservoir.
Through investigative surveys, the target horizon has been identified as Variscan metasediments (meta-greywackes, slates and quartzites) contained in the Variscan fold and thrust belt. which has been locally overprinted by younger tectonics related to the Leinetal Graben system. Suitable outcrop analogues can be found in from the Rhenish Massif to the Harz Mountains (explain harz was chosen). Through intensive field campaigns and photogrammetry sessions the potential reservoir rocks will be characterised to eventually create a 3D structural model of the reservoir beneath Göttingen campus. From this structural model, general conceptual reservoir models will be created.
The preliminary research presented shows the first stages of the characterisation of one of the chosen outcrop areas located in the Western Harz and the planned future work flow for the building of the structural model. Due to the complexity of the deformation, a heavy focus has been put on the fold and thrust structures and how these affect fracture network characteristics such as density and topology. This includes the initial structural field data and preliminary interpretations of the fold structures of the outcrop through digital methods. Throughout this presented work I aim to address the next steps in creating a detailed structural model of the Variscan metasediments as seen in the Harz Mountains.