Existing drilling methods are only able to advance slowly though hard rock and drill bits wear out quickly. Now an alternative drilling procedure fragments rock with a high-voltage impulse. This method causes little wear to the drill bits and enables up to 30% lower drilling costs.
When drilling with the electric impulse process (EIP), two electrodes are positioned below ground on the rock layer. Through them, 400-kV impulses are shot into the rock. In the impulse’s breakdown channel, the pressure and temperature within the rock increase and the rock breaks up.
The resulting drill cuttings are removed by a non-conductive drilling fluid. The EIP drill bit has been successfully tested on a test stand under wellbore-like conditions. The aim of the ongoing follow-up project is to develop a complete drilling system and to test it in a real borehole.
Scientists at Dresden University of Technology are developing the EIP drilling system in collaboration with industrial partners. Drilling work can account for up to 90% of the investment costs in geothermal projects. Each technical improvement and cost reduction in the drilling process therefore brings new geological heat reservoirs within economic reach.