Drilling for gas treatment in soft coal seams has a series of problems such as serious hole spraying and collapse, many jamming accidents and difficulty in hole forming, which is one of the biggest obstacles to the safe and efficient production of mines. CCTEG Xi'an Coalbed Methane Research Institute adopts the technical equipment for underground pneumatic directional drilling of coal mines composed of pneumatic screw drilling tools, explosion-proof air compressors/nitrogen generators, narrow-body directional drilling rigs, pneumatic electromagnetic wave measurement while drilling system, etc., which has achieved remarkable results in the field test at Wang Pokuang. The drilling efficiency is increased from less than 35 m/d to 82.3 m/d, and the maximum footage per shift reaches 72 m. The volume fraction of gas extraction in boreholes is as high as more than 90%. The stability of borehole wall is good, and the accident rate in boreholes is significantly reduced.
Electromagnetic wave measurement while drilling system
Narrow-body directional drilling rig
