Modeling and experimental research on temperature field of full-sized PDC bits in rock drilling and coring

Abstract

To study the effect of drilling rig working parameters and rock type on the temperature of the polycrystalline diamond composite (PDC) bit, an analytical temperature calculation model was established, and the correctness of the analytical model was verified by numerical simulation analysis. Combined with an infrared thermal imager, the temperature of PDC cutting teeth under different parameter combinations was qualitatively analyzed, and the sensitivity of cutting teeth temperature to different parameters was discussed through an orthogonal test. The research results show that increasing the rotational speed and rate of penetration (ROP) value causes more severe shearing and friction of the bit, thereby increasing the temperature of the cutting teeth. The experimental results are consistent with the simulation results. Under the same working parameters, the maximum temperature of the bit when drilling granite is about 1.5 times that of curbs and 2 times that of artificial rocks. Finally, the orthogonal test analysis found that the cutting teeth temperature has a high sensitivity to rock type and ROP value, with a weight of 48% and 32.9%, respectively; also, the index has a general sensitivity to the rotation speed, with a weight of 19.1%. The research results provide a certain reference value for the reasonable selection of the working parameters of the drilling rig.