Technology of Φ200 mm high-level and large-diameter directional drilling one-time hole formation

Aiming at the objective need of improving the quality and efficiency of gas drainage through high-level directional drilling in the roof during gas control in the upper corner of coal mine underground mining faces, a one-time hole formation technology for Φ200 mm high-level and large-diameter directional drilling in the roof is proposed. The drilling parameters required for the drilling tool assembly of the Φ200 mm high-level directional drilling one-time hole formation technology are analyzed. A high-efficiency composite directional drilling technology for large-diameter and one-time hole formation technology for complex strata are proposed, and the supporting equipment and technical parameters are introduced. An engineering demonstration is carried out in Zhangji Coal Mine. A total of 10 Φ200 mm high-level directional boreholes in the roof are completed, with the maximum hole depth reaching 701 m, the maximum hole diameter reaching Φ300 mm, and the total footage reaching 6 051 m. The test results show that the Φ200 mm high-level and large-diameter directional drilling in the roof can reduce the number of boreholes while increasing the borehole diameter, and the gas drainage effect is improved. This technology and its supporting equipment can meet the construction requirements of replacing roadways with boreholes in Huainan Mining Area.