A standard geothermal system is made of two wells, a production well and an injection well. This is called a Geothermal Doublet. The fluid will enter the production well from the rock formation in the open hole section and travel upwards to the surface within the cased sections of the well. Once the fluid has been used at the surface, it will then be reinjected through the injection well.
A geothermal well is very similar to an oil and gas well in construction, containing layers of casing and cement around open hole through which geothermal fluid will flow. As the wells are targeting hot water and not flammable gas or oil, there is far less danger of blowout or gas pockets.
However, geothermal wells are regulated in exactly the same way as oil and gas wells by the Oil & Gas Authority (OGA) and the Health & Safety Executive (HSE). We must also work closely with the Environment Agency (EA) to ensure there is no risk of pollution to the surrounding environment. This regulation ensures the safety and effective operation of all drilling and well activity at geothermal developments in the UK.