Development of Alternative Drilling Concepts for Deep Drill Hammers - Phase 3

It is known from flat drilling technology that crystalline hard rock can be destroyed much more effectively with percussion drill hammers than with PDC or roller bits. In granite, for example, up to 10 times higher drilling speeds can be achieved with hammer drills than with roller bits. In addition, the fact that only little pressure force is required for percussion drilling means that the directional stability of the drill hole is much better. However, up to now, the use of hammer drills in deep drilling technology has failed, because the available drive system (generation of the percussive impulse by alternately accelerating and stopping the column of mud) becomes more and more energy-intensive with increasing depth and thus ultimately uneconomical.
The idea of the project is therefore to develop a percussion drilling method for deep drilling, that generates the necessary impact energy for the hammer drill directly on site in the borehole and works with conventional drilling mud.

After a prototype for an electromagnetic hammer drill has been manufactured and tested in project phase 2, a hydraulic hammer drill is to be built and tested in the laboratory as well as downhole in phase 3.

The project has been completed.

Conference Papers