Application of simultaneous casing drilling to large bore shale gas well drilling in shallow complex formation: A case of conductor drilling for the Qianshuidi-1 well

Abstract:

There are a lot of fractures， karst caves and fractures in the shallow strata in the Guizhong-Nanpanjiang region， thus causing serious lost circulation and borehole wall collapse. It was difficult for hole drilling with conventional mud protection. The simultaneous casing drilling process has been applied to large diameter shale gas well drilling for the first time， which effectively solved the drilling problem with the conductor hole. The practical application of the process in the Qianshuidi-1 well is systematically summarized and can serve as valuable reference for similar projects in the future．

Key words:simultaneous casing drilling; pneumatic DTH hammer; large bore shale gas well; complex formation; Guizhong-Nanpanjiang region; well completion rate