Abstract:
In view of the difficult problems of drilling and discharging slag and low hole forming rate in complex weak coal seam of Wangpo Coal Mine, the high speed spiral compound drilling technology is studied, and the performance characteristics of ZDY6000LR high speed tunnel drilling rig selected are combined. Three different specifications of screw drill pipe (?准110/63.5 mm, ?准95/60.3 mm and ?准88/50 mm) and matching three-wing conical scraper PDC bit were designed respectively. The key parameters such as feed speed, drill pipe rotation speed and air volume of high speed spiral compound drilling under different bottom hole assembly conditions are studied, and the parameter range in the drilling process is defined. The field industrial test in the 3206 working face of Wangpo Coal Mine shows that the three kinds of combined drilling tools designed have high strength, good rigidity, good borehole integrity, high slag discharge efficiency and long service life of drill pipe and drill bit. High-speed spiral composite drilling technology and supporting machines and tools can effectively solve the problems existing in the construction process, such as difficult slag discharge, drilling hole top drilling, improve the deep hole drilling rate, more than 100 meters of drilling hole formation rate of more than 70%, for the mine coal seam gas extraction provides an important support; using ?准95/60.3 mm spiral drill pipe and matching drill bit has the best hole forming effect, the average hole depth is 111.2 m, and the hole forming rate is 90.9%.