Interpretation of limestone drilling results using E - S diagrams

The article deals with the possibility of evaluating the drilling process in the effective area using E-S diagrams. Experiments were carried out on a laboratory drilling rig when drilling limestone with surface-set diamond core drill bits of two types. The measured data were processed by numerical methods and compared with theoretical models, confirming a high agreement between calculations and experiment. The results showed that the efficient drilling area consists of two phases with different specific energy and drilling strength. Comparison of both drill bits indicated comparable efficiency of the limestone disintegration. Statistical analysis also confirmed the usefulness of the cutting coefficient as an indicator of drilling mode optimization. The proposed methodology has the potential for wider application in other types of rocks and can contribute to the optimization of drilling technologies in geothermal wells, mining or engineering geology.