Abstract: The closed-loop control of the well trajectory at downhole is the most advanced technology in domestic and overseas'drilling engineering.The technology of extended-reach well has become a main focus in the drilling technology of the petroleum industry in the world.It is necessary to depend on the control technology of borehole trajectory to drill the extended-reach well successfully.A closed-loop adjustable stabilizer at downhole is developed. The structure and principle of operation of the stabilizer,and method for controlling borehole trajectory with the close-loop adjustable stabilizer at downhole are described in detail.The close-loop adjustable stabilizer at downhole has been used in oilfield.It may provide an effective way for drilling of the extended-reach well,especially for the offshore-drilling,enhancing the rate of penetration and reducing the drilling cost.

Key words: adjustable stabilizer, extended-reach well, drilling technology, downhole closed-loop, borehole trajectory, control technique

摘要： 井眼轨迹井下闭环控制技术是当前国内外石油钻井的前沿技术,将该技术与随钻测井技术结合,能实现地质导向技术.钻成大位移井必须依靠井眼轨迹控制技术,研制的井下闭环可变径稳定器是实现该项技术的关键.本文着重论述了井下闭环可变径稳定器的结构、工作原理及其控制井眼轨迹的方法.井下闭环可变径稳定器的研制及现场的初步试验成功,为解决我国大位移井问题,特别是为滩海油气勘探、提高钻井机械钻速、降低钻井成本提供了一条有效的途径.

关键词: 可变径稳定器, 大位移井, 钻井技术, 井下闭环, 井眼轨迹, 控制技术