Experimental study on directional drilling with high pressure nitrogen in soft-fragmentized coal seam of Wangpo Coal Mine

Abstract

Aiming at the characteristics of poor cementation and broken seam in Wangpo Coal Mine, the pneumatic directional drilling test of soft-fragmentized coal seam with high-pressure nitrogen slag discharge was carried out. Drilling equipment selection, pneumatic directional technology, deep hole and high wind pressure drilling parameters are studied. In the 3306 working face test of Wangpo Coal Mine, four directional drilling holes of broken soft coal seam were completed, in which the pneumatic directional branch was successfully tested for two times. The average daily footage reached 82.3 m, the maximum single shift footage was 72 m, and the maximum hole depth was 437 m, creating the record of hole depth for soft gas dynamic directional construction. The test results show that the pneumatic directional drilling technology meets the requirements of directional construction along the broken soft coal seam in Wangpo Mine, and the drilling trajectory is accurate and controllable. The coal seam drilling rate is high, the drilling depth is large, the drilling performance is good, and the drilling efficiency is high.

Keywords

• soft-fragmentized coal seam
• high pressure nitrogen
• pneumatic screw drill
• layered drilling
• directional drilling