Flagship stimulation experiment in the deep underground laboratory
The medium-scale experiments were carried out at the Grimsel Test Site. The project was divided into three main phases, namely a characterization phase, a stimulation phase and a circulation phase. The characterization phase included geophysical and geological imaging of faults and fractures, and determination of the actual stress field by means of small hydro-fracturing experiments. During the stimulation phase, fault zone were pressurized until slip occurred, and the associated permeability creation, pore pressure propagation, deformations and seismicity were monitored. In a second step of the stimulation phase the massive rock mass between the faults was hydro-fractured, which allowed the circulation experiments to be conducted. The characterization phase was completed in 2015, and the stimulation experiments were finished by the end of 2016. The entire medium-scale experiment was finished by the end of 2017. On the basis of the results, the large-scale "Bedretto Project" is established.
The total budget of the experiment is in the order of 6.5 Mio CHF, whereby 1.8 Mio CHF were contributed by Shell donation to ETHZ and a grant by EKZ. The remaining costs are covered through the SCCER-SoE, ETHZ and UniNe.