微小井眼CT钻井牵引器系统结构设计

Micro-hole coiled tubing sliding drilling tractor system structure design

侯学军 高德利 沈忠厚

HOU Xuejun GAO Deli SHEN Zhonghou

中国石油大学油气资源与探测国家重点实验室，北京　102249 重庆科技学院石油与天然气工程学院，重庆　401331

State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China College of Petrol Engineering, Chongqing University of Science and Technology, Chongqing 401331, China

针对微小井眼连续油管（CT）滑动钻井技术在井眼中不旋转、井下遇阻严重、送进困难、钻压无法施加等难题，设计了一种微小井眼CT滑动钻井井下电控液压驱动牵引器。该牵引器主要包括上卡瓦支撑与牵引系统、中心滑管总成、控制系统、下卡瓦支撑系统，采用电控液压回路实现钻井液压能牵引驱动，适用于小井眼，灵活性和稳定性好，牵引过程能保证正常的钻井液循环，柔性弯曲适应能力强，能实现双向牵引和断电保护，能顺利下入和取出CT管柱，解决了因井下CT摩阻较大，下入和取出困难、钻压难施加等技术难题。

Micro-hole coiled tubing(CT) sliding drilling can improve development benefit and cost cutting for the maturing field, shale gas, coal seam gas, tight gas and other unconventional gas reservoirs. It can reduce reservoir pollution, protect the environment and have a wide application prospects in China. However its wellbore diameter is very small, the CT drill string cannot revolute in the tiny wellbore, friction resistance of CT sliding drilling is so seriously that it is difficulty to run back into the well. The drilling weight can’t apply and even happen to sticking accidents. This has directly influenced the application and popularization of micro-hole CT sliding drilling technology. According to the present research situation of tractor at home and abroad, a kind of micro-hole CT sliding drilling tractor by electronic controlled hydraulic drive is designed. The tractor mainly includes a top slips support and traction system, a central sliding tube assembly, a control system and a bottom slip support system. The drilling fluid hydraulic energy drives its tractor by electronic control. The tractor is suitable for micro-hole underground work with good flexibility, good stability and strong flexible bending ability. The tractor can provide normal drilling fluid circulation, can realize two-way traction and power-off protection and make a trip for CT string. The difficult technical problems of CT sliding resistance will be solved for tripping CT string well by the tractor, which will promote the micro-hole CT sliding drilling technology development.