Numerical Simulation of Thermo-Hydro-Mechanical Coupling in the Drilling Process of Diamond-Impregnated Bits and Optimization of Waterway Design.

In deep and ultradeep well drilling operations, the coolant flow of the drill bit directly impacts bit life and drilling efficiency. To improve the service life of impregnated diamond drill bits and reduce abnormal wear, this study employs numerical simulations of the drilling process, incorporating thermal-fluid-mechanical coupling, to analyze the flow field, pressure, and temperature distribution on the bit lip and body. By optimizing the design of the drill bit's waterway using different materials, the influence of the waterway offset angle on drilling efficiency and cooling performance is validated through field drilling tests. Simulation and field test results reveal that, during drilling, temperature and pressure are primarily concentrated along the spout wall in the drilling direction. Adjusting the waterway angle reduces lateral pressure on the waterway wall within the flow field and increases the overwater area, thereby enhancing the coolant's powder-carrying capacity, improving cooling efficiency, and effectively preventing bit overheating. A 10° offset in the waterway, opposite to the drilling direction, results in the longest service life, while a 10° offset in the drilling direction leads to the shortest service life.