Study on Surface U-shaped Drilling Technology for CBM Extraction in Low-rank Thick Coal Seam

In order to solve the problem of how to realize efficient extraction of CBM in low-rank, the second panel area of Baode Coal Mine in Shendong Coal Group were taken as research area. Through the comparison and selection of technical schemes, the method of using surface U-shaped drilling to extract low-rank thick CBM reservoir resources was put forward. The results show that after nearly 2 years of joint discharge and production, the daily maximum gas production of surface U-shaped drilling is 3 133.241 m³/d, the cumulative gas production is 726 300 m³, and for 231 consecutive days, the daily production exceeds 2 400 m³/d. The successful application of surface U-shaped drilling technology in low-rank thick coal seam of Baode Coal Mine marks the leap-forward development in the extraction of low-rank CBM reservoirs in domestic coal mining areas. It is of great significance to ensure national energy security and promote social and economic development.