Scientists under the ORCHYD project are developing a new drilling system to help reduce the total cost of obtaining geothermal energy from deep hard rocks.
The ORCHYD project is funded by the EU Horizon 2020 program and it includes scientists from France’s ARMINES/Mines-ParisTech, UK’s Imperial College London, Norway’s SINTEF, Greece’s University of Piraeus, China University of Petroleum, and French drilling company Drillstar.
Geothermal energy harnesses the heat of rocks, steam and water deep beneath the Earth’s surface. It is carbon neutral, widely available and, unlike wind and solar energy, can provide a stable supply 24/7.
The only drawback here is that the drilling required to reach far enough into deep hard rocks is slow and inefficient, and this makes it prohibitively expensive.
Drills currently penetrate hard rocks at rates of 1-2 metres per hour, but the researchers anticipate that the new drilling technique will work at up to 10 metres per hour – reaching geothermal reservoirs four times faster on average than what is possible today.
They also say that their system could help reduce drilling costs by up to 65%, making the use of renewable geothermal energy much more cost-effective.
This is the first time a research team is combining high-pressure water jets and downhole fluid-driven hammers to tap into geothermal reservoirs.
They say that the combined technology could pave way for further decarbonization of the energy sector.
The Imperial team is using their rock fragmenting computer simulations, combining solid and fluid dynamics, to find the optimal jetting settings to shape and groove the advancing rock face.
The simulations will also help explain the breakage process and why the hybrid drill is able to bore through rock more rapidly.
The novel down hole high-pressure intensifier system is being designed by China’s University of Petroleum and Norway’s SINTEF, and percussive drilling bits by Drillstar.
The drilling prototype – scheduled for 2024 – will be first tested in the ARMINES laboratory by drilling horizontally through great thicknesses of rock before real-world testing.
Image and content: Medford Taylor-National Geographic/ICL