Abstract:Extended reach horizontal well is the main way of shale gas exploitation, and the reasonable prediction of its limit extension has attracted much attention. In this paper, the horizontal drilling and completion of shale gas in Fuling area is studied. With the help of the prediction model of drilling extension limit, the drilling extension limit under different working conditions is calculated, and the influence of drilling rig performance, drilling tool assembly, hole tortuosity and drilling fluid density on drilling extension limit is analyzed. The results show that sliding drilling mode is the main working condition to restrict the extension of horizontal section, and when the friction coefficient is high, the helical buckling locks up, which leads to the failure to drill to the design well depth; High hole tortuosity limits the extension length of the hole, so the times of trajectory adjustment should be reduced as much as possible in drilling operation to ensure smooth trajectory; In addition, fracturing operations in adjacent wells may lead to an increase in formation pressure while drilling, which will reduce the drilling extension limit, and it is necessary to optimize the drilling fluid density. This study has important guiding significance for the design and construction of shale gas horizontal drilling.