Research on drilling process technology and parameter optimization in soft coal seam

Due to the low firmness coefficient of soft coal seam and the influence of formation pressure and in-situ stress, it is easy to cause hole collapse in bedding drilling, resulting in low hole forming rate and insufficient hole forming depth, so the drilling technology needs to be improved. This paper focuses on the study of hole forming technology and parameters of bedding drilling in soft coal seam. The research results show that: the key to improve the construction efficiency of bedding drilling in soft coal seam is to improve the slag removal ability of drilling engineering, and the drilling technology of spiral drilling and pressure air slag removal is conducive to improve the drilling depth and drilling effect. The hole forming process and parameters of spiral drilling and pressure air slag removal are systematically described. The drill pipe speed, the coal conveying capacity in the hole, the minimum wind speed of pressure air slag removal and the air supply pressure of slag removal are determined. It is of great practical significance to develop and improve the drilling technology of bedding hole drilling in soft coal seam to improve the gas drainage capacity of coal mine and the drilling depth and rate of bedding hole drilling in soft coal seam.