If the target area is not hit exactly with deep drillings or if the driller hits irregular fault zones in the stone, the vibrations in the drill pipes can damage the drill systems or even jam them. Not only does this slow down drilling progress, it also shortens the lifespan of the chisel, both of which result in high costs for the operator.

The research project OBS “Optimising drilling operations in deep geothermal drillings with the help of a systematic analysis of underground vibrations in lab experiments”, funded by the Federal Ministry for Economic Affairs and Energy (BMWi), is therefore taking a closer look at the kind of vibrations involved and their causes. Based on these lab experiments, the project partners from Clausthal University of Technology and the University of Braunschweig – Institute of Technology will then provide recommendations for action for industry. This is to prepare the ground for, as far as possible, a vibration-free drilling process.

Comprehensive analyses of the vibrations of the last 20 metres of drill string can be carried out on the unique, horizontal, full-scale drilling test rig, the Drilling Simulator Celle, thanks to real-life drilling processes. In addition to this, the behaviour of a 4000-metre-long drill string will be simulated through a virtual drill string model.

The first trial drillings in sandstone were already carried out with a polycrystalline diamond compact (PDC) chisel in February 2018.