Application Research of Gas Drainage by Comb-like Drilling in Soft Coal Seam of Zhaozhuang Coal Mine

In order to solve the problem of poor drainage hole completion rate, short gas drainage drilling distance, we use the technology of comb-like drilling to control gas, and the main borehole is arranged in the roof or floor stratum in the soft seam to control branch boreholes to go into the coal seam and conduct gas drainage, and it can increase drilling depth. Combined with the condition of Zhaozhuang Coal Mine, we optimized the drilling forms, stratum, and construction technology of branch boreholes. The results showed that in a single borehole, the depth over 300 m, branch boreholes spacing can be controlled at 24 m; the optimized double branch holes effectively improved the effect of the drilling gas drainage.