High Pressure Pumps are mobilised for hydraulic reservoir stimulation.

For a geothermal project in Bad Urach, South Germany, 70 litres of water per second is pumped with high pressure (350 bar) to depths up to 4,700 meters. The pressure enhances the natural permeability of the fractured rock network between 4,300 to 4,700 meters. An analysis of these cracks showed the optimal location for the second well. Water compressed in the first well circulates through the fractured network to the second where it rises as it is heated. In the power station constructed at the surface, the heat is used for generation of electricity.
 

1. Hot Dry Rock

The concept of Hot Dry Rock aims to connect different drillings by hydraulic reservoir stimulation. The transmissivity of the rock can be increased by pumping water downhole with high pressure to expand cracks or create new ones. The position of the cracks is analysed to find the optimal location for the next well. After the second well is drilled water circulates through the fracture network in the hot rock and gathers heat which can be extracted at the surface to generate electricity or to be used directly.

2. Hydrothermal

For the hydrothermal concept both wells are placed directly in the ground water. The water circulates from one to the other well through the natural area of ground water.

3. Earth Thermal Probe

The concept for the earth thermal probe is a pipe in pipe system. The water is pressed through the outer pipe into the depth, is heated and rise in the inner pipe to the surface, where the heat can be used to generate energy.