Drilling Technologies for Shale Gas Horizontal Well Dingye 2HF

Well Dingye 2HF is a horizontal well with the designed depth 5 655 m drilled for shale gas in Silurian Formation in Dingshan Structure,southeastern Sichuan.There were several drilling challenges,such as extremely thick terrestrial formation,water production in upper formation,limited sections for gas drilling, poor drillability of formation,difficult in selecting bit type,not easy for putting weight on bit in long horizontal section,and poor stability of wellbore in deviated mud-shale section.Therefore,after investigating geological conditions of Dingshan Structure,and considering the drilling data of adjacent areas,Well Dingye 2HF was drilled by integrating several techniques,including gas drilling,efficient drill bit selection,PDC bit with PDM drilling,oil-based drilling fluids with plugging material,floated casing running, and 3-stage cementing slurry system.Practical operations proved good effects of such techniques,which allowed Well Dingye 2HF to penetrate successfully into the target layer,with total depth of 5 700 m,recording the deepest shale gas well in China.The drilling techniques,processes and results of Well Dingye 2HF was reviewed,and suggested that they could be valuable references for drilling other shale gas horizontal wells in Dingshan Structure.