Drilling rig at Vinzel, Switzerland (source: screenshot of live feed, EnergeO)
Non-exploitable productivity in Dogger
The plan for the geothermal well in Vinzel was to target the Dogger formation, a geological layer of naturally fractured limestone. The abundance of these fractures was confirmed by the cuttings collected during drilling. However, productivity tests measured a maximum flow rate of only 80 liters per minute – far below the expected 30 liters per second needed for commercial exploitation of this aquifer.
Cuttings from Dogger formation show fractures and quartz mineralized by calcite (source: EnergeO)
In-well geophysical measurements had also been made on the well. Geophones lowered at different depths detected waves send by vibrating trucks on the ground for this purpose.
Operations suspended to decide on Plan B
Based on the data and results obtained to date, developer EnergeÔ decided to activate “Plan B,” one of the options that had been planned since the start of the project. The possibility of exploiting geothermal water from the shallower Malm aquifer will now be explored. The high-pressure influx of water from this aquifer had already been confirmed during drilling of the second section of the well.
In order to assess this option, a decision was made to suspend operational activities on site to allow for the necessary decision-making process on how to continue with the operations. The exploration and possible exploitation of the Malm are part of the secondary hydrogeological objectives of the project. The results of this evaluation and the realization of this plan B will be communicated and detailed soon.
The decision of EnergeÔ to drill in Vinzel follows the disappointing results of a previous drilling campaign in Lavey-les-Bains, Switzerland.
