Similar to the Grimsel ISC project, the Bedretto Reservoir project will perform in-situ stimulation tests while monitoring the hydro-seismo-mechanical parameters at a high spatial resolution. Based on lessons learned and findings from previous experiments, for example at Grimsel, the scientists will address the following issues:
- Appropriate stimulation concepts for permeability enhancement by orders of magnitudes while minimizing induced seismicity
- Relationships between the hydro-mechanical response, the stimulation concept, permeability creation, effective porosity and induced seismicity
- Transition zone evolution with respect to the injection volume over time
- Heat exchanger properties of the reservoir
- Identification of the source processes of seismic events and their relation to the reservoir stimulation.
The Bedretto Reservoir Project encompasses three sub-projects with complementary targets aiming at providing evidence for the development of large-scale deep reservoirs for the circulation of water and the storage and extraction of geothermal energy:
- VALTER (Validation of Technologies for Reservoir Engineering), funded by the Swiss Federal Office of Energy (SFOE) (lead ETHZ / SCCER-SoE)
- DESTRESS (Demonstration of soft stimulation treatments of geothermal reservoirs), a Horizon 2020 project funded by the EU (lead Geo-Energie Suisse)
- ZoDrEx (Zonal Isolation, Drilling and Exploitation of EGS Projects), funded by EU initiative Geothermica – Era Net (lead Geo-Energie Suisse)
VALTER and DESTRESS deal with the demonstration and optimization of large rock volume stimulation treatments related to fluid circulation in significant quantities while minimising environmental impacts such as seismic events or pollution of groundwater reservoirs. ZoDrEx focuses on the performance of zonal isolation technologies and their potential importance during stimulations as well as on the fluid driven percussion drilling method in highly deviated trajectory boreholes to enhance drilling efficiency in crystalline rock. For this purpose, sophisticated monitoring is prepared, including monitoring of induced seismicity on the pico and micro scale, strain monitoring as well as pressure, tilt and geochemical monitoring.