Start of stimulation experiments of the VALTER project
On Wednesday, 17 November 2021, we will start the stimulations for the VALTER project. We will inject a few cubic meters of water using different injection procedures and following a multi-stage stimulation approach that isolates parts of the injection boreholes to maximise the control on the reservoir creation. Using a high-resolution observational network, it is our goal to monitor stimulation related processes in unprecedent detail at a realistic scale, with the ultimate aim to create a commercially viable underground heat exchanger while minimising the risk of felt earthquakes.
We choose a stepwise approach with different experimental phases, interrupted by periods of data analyses, to establish such a geothermal test reservoir at the BedrettoLab. The first stimulations, taking place on Wednesday, will mainly examine if the monitoring system and stimulation procedures work as foreseen. To this end, we will start small and only stimulate one interval of the injection borehole at a depth of around 220 meters from the cavern. Then, we will pause the stimulation activities, assess the data, and if required, we will improve our systems and procedures.
As for all activities in the BedrettoLab, safety is the top priority, and this also applies to the upcoming stimulations. We have deployed several safety layers to ensure that the seismicity does not reach damaging levels. Since we closely monitor the stimulations with our exceptionally dense and highly sensitive measuring system, we can identify in near real-time changes within the rock volume of interest. This enables continuously updated hazard re-evaluations. The chances are very small that these stimulations will cause damage to the tunnel (a probability of less than 1 in 10’000) and even smaller that they will cause earthquakes large enough to be felt or cause damage in nearby villages (a probability of less than 1 in 10 million).
Read more about the media event we recently had portraying the VALTER project and the project itself here. 15 November 2021