Rock Drillability Evaluation Based On Drilling Process Monitoring (DPM)

Rock drillability evaluation is an important research content in the field of geological engineering.In the context of the development and utilization of underground space and the drilling of new energy sources such as shale gas,oil shale and geothermal energy,improving drilling efficiency and improving drilling technology are inseparable from the accurate evaluation of rock drillability.In order to comprehensively and accurately evaluate the drillability of the subterranean formation in real time,the borehole was monitored by the DPM system in the Yanan area,and the uniaxial resistance of different depth cores was determined by the indoor physical mechanics test method.The compressive strength,longitudinal wave velocity,abrasiveness and mineral composition are evaluated by correlation analysis and regression methods.It is found that there is a high correlation between the DPM drilling speed V₀ and the uniaxial compressive strength UCS and the drillability level value K_d.The regression equations were K_d = 0.565ln?V₀?+ 2.7957?R² = 0.6910?and K_d =-0.0183 UCS + 2.4979?R² = 0.8151?,respectively.The results show that DPM drilling speed can be used to evaluate the drillability of rock.