Comparative analysis of rock destruction mechanisms during drilling with carbide and diamond tools

The purpose of the work is a detailed study and analysis of rock destruction processes during drilling, in particular, determining the efficiency characteristics of various drilling tools and methods. Particular attention is paid to the influence of drilling conditions, such as the type of tool and its interaction with the rock surface, on the nature of rock destruction. This allows obtaining in-depth information on the mechanisms of destruction, which will contribute to increasing the efficiency of drilling and reducing energy costs, and will also allow predicting behavior under rock displacement and compression conditions. Methodology. The study was carried out on soft sandstone with characteristics σс = 50 MPa, which is a typical representative of medium-hard rock. To conduct experimental studies, bench tests were used, which made it possible to observe the behavior under various load options and drilling methods. In addition, for a more in-depth analysis of the destruction mechanisms, a theoretical approach based on fracture mechanics was used, which allows calculating the main process parameters, such as stress, strain and movement within the destruction limits. In addition, the finite element method was used to model complex fracture processes, which allows obtaining accurate numerical results reflecting the behavior of the material when interacting with different drilling tools under different conditions. These methods provide a comprehensive understanding of the fracture processes and their impact on drilling efficiency. Results. The carbide cutter provides a larger volume of removed rock (10 cm3) at lower energy costs (120 J/cm3) and a higher penetration rate (0.8 cm3/s) due to shear cleavage. The diamond crown removes 6 cm3 at 180 J/cm3 and 0.5 cm3/s due to grinding under compression. The free surface promotes a wider distribution of stresses (55 MPa), while compression localizes them (60 MPa). The carbide tool is more effective in soft rocks, and the diamond tool is more effective in hard rocks. Scientific novelty. An updated approach to the comparative analysis of rock fracture mechanisms under free surface displacement and compression, as well as detailed modeling of stresses and fracture results when using different tools. Practical significance. Recommendations for optimizing the cutter attack angle (45°) and the crown pressure (2000 – 3000 N), as well as prospects for developing hybrid tools and studying heterogeneous rocks can significantly improve drilling efficiency and reduce energy costs. Keywords: rock fracture, carbide cutter, diamond crown, fracture mechanics, numerical modeling, well drilling efficiency