The Valter project comprises two large scale in-situ experiment at different scales: Grimsel and Bedretto tunnels. Both will address questions associated with the validation of stimulation procedures and sustainable utilization of heat exchangers in the deep underground. Stimulation concepts will be tested in-situ while hydro-seismo-mechanical key parameters will be monitored at a high spatial resolution. The addressed questions are:
- Which stimulation concepts are appropriate for enhancing the permeability by orders of magnitudes while minimizing induced seismicity?
- What are the relationships between the hydro-mechanical response, the stimulation concept, permeability creation, effective porosity and induced seismicity?
- How can micro-seismicity be minimized?
- What are the heat exchanger properties of the reservoir?