Review of Recent Drilling Projects in Unconventional Geothermal Resources at Campi Flegrei Caldera, Cornubian Batholith, and Williston Sedimentary Basin

Unconventional geothermal resource development can contribute to increase power generation from renewable energy sources in countries without conventional hydrothermal reservoirs, which are usually associated with magmatic activity and extensional faulting, as well expand the those regions where resources already used. Three recent drilling experiences focused on characterization of unconventional described compared: Campi Flegrei Deep Drilling Project (CFDDP) Italy, United Downs Geothermal Power (UDDGP) project Kingdom, DEEP Earth Energy Production Canada. The main aspects each (geology, drilling, data collection, communication strategies) compared discuss challenges encountered at tree sites considered, including a scientific two industrial ones (UDDGP DEEP). first project, stage pilot hole, although not reaching deep supercritical targets, showed extremely high, very rare thermal gradients even shallow depths. Although has its own history, social economic context, lessons learned site be used further facilitate development.