关键词: 定向钻头, 扩孔钻头, 定向长钻孔

Abstract: Aiming at the short life and low efficiency of conventional single-tooth PDC directional drill bits and conventional reamer bits used in the drilling of medium-hard strata in coal mines, as well as conventional reamer drill bits were difficult to drill along the original hole trajectory. In view of the demands for the three kinds of drill bits in the directional long drilling hole, two new PDC bits were developed. The PDC directional drill bit were designed with scraper flat structure, the cutting teeth arrangement was optimizing, the reaming drill bit with circular arc profile, and the cutting teeth was arranging along the bit profile, these two kinds of PDC bits carried out on-site applications. Field application shows that, the new PDC directional drill bit control is good, drilling stability. In the mid-hard ground drilling efficiency and life significantly improved, is the ordinary single-tooth drill bit 2 times, the new reaming drill can be drilled through the pilot hole trajectory, drill life is more than 3 times the normal reaming drill bit.