Lessons Learnt from the Deep Heat Mining EGS Project in Basel, Switzerland

Abstract

The Kanton of Basel-Stadt in partnership with a number of Swiss utility companies is endeavouring to develop a geothermal co-generation plant from an enhanced geothermal system. The project is developed and operated by Geothermal Explorers Ltd. Prior to drilling the 5009 m deep Basel-1 well, a reconnaissance well was drilled to 2,755 m and a refined microseismic monitoring system with five additional shallower wells was set up. The monitoring array was not only for visualising microseismic activity during hydraulic stimulation, but also to observe the natural seismicity in this area, which is characterised by sparse, sometimes destructive seismicity, as shown by the historic Basel earthquake in 1356 with an estimated MW of 6.9.