Comparative Analysis of Contact Stress Models for Optimizing Rock-Destroying Elements in Drilling Operations

This research evaluates analytical, semi-empirical, and numerical models for predicting contact stresses in the interaction between rock-destroying elements and rock formations, a critical factor influencing wear, cutting efficiency, and energy consumption in drilling operations. The Hertzian analytical model, semi-empirical model with experimental calibration, and a Finite Element Method model incorporating plastic deformation via the Drucker-Prager criterion are compared for accuracy and applicability. Mock experimental data, based on rock mechanics literature, validates the models, revealing average prediction errors of 28%, 12%, and 4% for the Hertzian, semi-empirical, and Finite Element Method models, respectively. The Hertzian model is computationally efficient but inaccurate in nonlinear conditions, the semi-empirical model balances accuracy and practicality in calibrated scenarios, and the Finite Element Method model excels in complex formations despite high computational demands. Graphical comparisons within the contact radius highlight the Finite Element Method model’s ability to capture plastic effects, making it ideal for optimizing rock-destroying elements design in challenging geological environments. The findings underscore the importance of selecting models based on operational requirements, with the Finite Element Method model recommended for high-precision applications in deep or unconventional drilling.