Abstract: In drilling the ERD wells, in Dagang Oilfield, many difficulties are confronted, such as the high drag and torque, difficult well trajectory control and well wall stability, running casing at long openhole section, high requirement of well cleaning, and so on. In response to this situation, a series of technologies for drilling ERD wells are researched and established. In this paper, the technologies used in the ERD wells drilling operation, including well trajectory control, steering drilling, running casing with floatation collar, high inhibitory ＆ lubricative drilling fluid, drag and torque forecasting and monitoring are discussed. Among the 3 ERD wells drilled, the ratio of horizontal displacement to TVD of each well is greater than 2, the ratio of horizontal displacement to TVD of zhuanghai 8Ng-H1 well is 2.74, and horizontal section is 732 m in lenth. The practice shows that all the technologies used in ERD well drilling operation are feasible.

Key words: ERD well, trajectory control, drag &, torque, running casing with floatation collar, Dagang Oilfield