Drilling Technology for Subsurface Karst Strata of Coalbed Methane Wells in Liupanshui Area

Development of coalbed methane in Liupanshui Area has been restricted by the leakage in subsurface karst strata. Based on the analysis of the near surface karst electrical surveying technology and air drilling through karst cave containing water technique, this article explores DTH hammer back reaming technology and temporary sealing technology for surface karst cave containing water. A drilling technique for surface kast strata is proposed. It has been successfully applied in the CBM well with string-shaped water-bearing karst caves in Liupanshui Area.