Key Techniques of Rotating Liners Running in High Angle Wells

Rotating liner running in high angle wells is often dragged or not efficient. To reduce the rotational friction and to improve the torsional capacity and passing through ability of pipe strings, some key tools were developed, including recessed slips, a high torsional hydraulic releasing tool, a snap ring for improving the torsional capacity of threads, low friction resin stabilizer, and eccentric guide shoe with high pass-through capacity. In addition, some key techniques were developed in field applications, which include the maximum safe torque setting and torque prediction, and rotated running operation methods. Finally, the complete tool system and application techniques suitable for rotating liner running in high angle wells were formed. According to the results of laboratory analysis, the torsional capacity of hydraulic releasing tool reached 40 kN·m, the torsional capacity of API threads was doubled by using the snap ring, and the dynamic friction coefficient of low-friction stabilizer was reduced to 0.17. Those techniques were applied successfully in five high angle wells in the South China Sea WZ6-12 Oilfield, the φ177.8 mm liners (the longest one up to 1 290 m) were run into the correct position with the maximum inclination of 68.4°. The research results indicated that those techniques of running rotating liner were significant in solving the problems in running liner in high angle wells.