SUSTAINABLE QUALITY DRILLING

Important results from the project

The purpose is to understand the connection between borehole deviation and the properties and structures of the rock material and the applied drilling forces (feed, impact energy, etc.). The goal of study is to investigate whether it is possible to reduce the borehole deviation by controlling the drilling, depending on the rock properties and measured response parameters (MWD). The results show that MWD data together with analysis of vibration give good indications of where deviations occur. This open interesting possibilities for drill control towards decreasing deviations.

Expected long term effects

This study included test drilling through artificial rock materials and measurement of drilling parameters and vibrations. These controlled trials provide a unique opportunity to understand the connection between applied forces (MWD parameters), vibrations, the angle of attack between rock and drill bit, the properties of the rock material and resulting borehole deviations. The results will be further developed through a new project application or alternatively through a industrial project, where the knowledge will be applied to production drilling in a mining environment.

Approach and implementation

The tests have been done at Epiroc´s drilling laboratory in Fagersta. Circular specimens with different materials and with different angles have been manufactured and cast into rock blocks. Drilling through the blocks has been done with different feed forces, percussion pressure and rotation speeds. During the tests, MWD data was recorded together with measured vibrations, to be compared with measured deviations. This controlled lab tests provides a unique opportunity to understand the causes of deviation and in the next step, control the drilling towards smaller deviations.