Composite directional drilling technology in underground coal mine

Aiming at the problems in directional drilling of over 1 000 m long distance by traditional sliding drilling, composite directional drilling technology was put forward, and its efficient drilling mechanism and trajectory control principle were analyzed. In view of the technology requirement of composite directional drilling, mud pulse measurement while drilling system was applied for long distance directional drilling in coal mine for the first time, and the composite directional drilling technology and its matching equipment were perfected. A long directional drilling hole of 1 566 m in coal seam was completed in field industrial test. Compared with traditional sliding drilling technology, drilling efficiency has increased based on significant improvement in drilling safety, and achieved safe and efficient drilling for directional drilling in this coal seam.