Originally Posted by layback40

The geothermal is not done in hydrocarbon containing formations.
It normally uses granite formations that contain low levels of uranium, hence the heat. The water is heated by the formation, it does not frack the formation. Well at least that is the case on this side of the pond.

Fracking is drilling into formations such as coal & fracturing the formation to allow any hydrocarbon to be released. The type that is in question at the moment is normally shallow depth and can be close to ground water.

Conventional oil/gas wells into low porosity formations are "fracked" as well. This used to be called proving the well. Often with explosive charges to help the recovery rates.