Difficulties and Countermeasures in Horizontal Well Drilling for Shale Gas in Southern Sichuan

Shale gas drilling in southern Sichuan has been challenged by complex geological conditions, frequent lost circulation, stuck pipe and buried rotary steering tools and long drilling cycle, which severely hinder the penetration rate and efficiency enhancement. In order to solve these problems, the difficulties in drilling shale gas horizontal wells were analyzed according to reservoir characteristics and rock mechanical properties, which then formed the technical countermeasures by using “damping + centralizing” to increase drilling rate in big size holes, sand removal and anti-sticking while drilling at long horizontal section, parameter enhancement to increase drilling rate, solidification plugging, as well as simply managed pressure drilling. After the application of these technical measures, the ROP was increased, the drilling cycle was shortened, with remarkable comprehensive results. The research results can provide a reference for drilling shale gas horizontal wells in this area or other areas with similar reservoir conditions.