Gas Pre-Drainage Technology of Ground Multi- Branch Horizontal Well Connected with Underground Mine Borehole

According to the problem of time and space limitations when gas pre-drainage through underground mine borehole and ground multi-branch horizontal w ell, the gas pre-drainage technology of ground multi-branch horizontal well connected with underground mine borehole was put forward, and it was used in multi-branch horizontal connection well engineering of No. 24307 working face Shaqu Mine. After connection, the gas production rate of gas drainage borehole XC01 was 6 000 ~ 7 000 m3/d and the average gas concentration was 95%; the gas production rate of gas drainage borehole XC02 was around 12 000 m3/d and the average gas concentra tion was 91.05%. The gas production of single well and gas drainage ratio grew significantly.