Research and Application of Directional Drilling Technology in Broken Soft Coal Seam

Aiming at the problems such as shallow depth, low construction efficiency and drilling accidents of directional drilling in broken soft coal seam, we developed the compound directional drilling technology based on mud pulse measurement while drilling system. The typical composition of the drilling equipment system is introduced, and the working principle and characteristics of mud pulse measurement while drilling system are analyzed. The directional drilling test in broken and soft coal seam has been carried out using compound directional drilling technology and wireless measurement technology. 5 directional drilling holes were completed in the coal seam, and the depth of the deepest hole came to 324 meters. Compared with the conventional sliding directional drilling technology, the comprehensive drilling efficiency is more than 50%, the hole forming rate reached 60%. It reflected the high porosity, good slag return effect and obvious advantage of comprehensive drilling efficiency. The technology can be used for gas drainage in broken soft coal seam.