Design and Application of PDC Drill Bit for Gas Drainage Drilling in Hard and Soft Water Sensitive Multi-interbedded Formation

Abstract:

Because of the serious gas outburst disasters in coal resources of Guizhou area, the gas drainage quantity is very large before mining. In the drainage process, due to the unskilled operation and the blind choice of the bits, a lot of bits were used without good effects. According to the special geological conditions, the improvement was made on the drill bits and good results were obtained. The service life of the drill bit is prolonged from 166.5 m to 399 m and the drilling efficiency is increased from 8 m/h to about 12.4 m/h.