尾管固井用牵制短节的研制与应用

深井、超深井和大斜度井起下管柱摩阻大,短尾管固井时因尾管短、重量轻易导致丢手不易判断及丢手困难等问题,为此研制了尾管固井用牵制短节.牵制短节设计有锁定机构和解锁机构,在尾管悬挂器坐挂后,采用液压方式实现牵制短节的锁定功能,将尾管串锁定在上层套管上,给尾管串施加一个向下的牵制力,可以通过指重表明确判断丢手是否成功.利用有限元分析校核了牵制短节的强度,结果表明,其强度满足设计要求.地面试验和现场应用表明,牵制短节的锁定功能和解锁功能均能顺利实现,各项技术指标均达到设计要求,能够解决短尾管固井丢手不易判断及大斜度井固井丢手困难的问题. 

Development and Application of a Holddown Sub for Liner Cementing

To address the liner cementing issues such as unsure or difficult release due to short liner length,light liner weight and high friction in deep,ultra-deep and highly deviated wells,the holddown sub was developed for liner cementing.The holddown sub was designed with locking and unlocking mechanisms.After the liner hanger was set and positioned,the holddown sub could be hydraulic locked to hold the liner on upper casing and provide downward force for determining the release through a weight indicator.The strength of the holddown sub was verified by finite element analysis and the results met the design requirements.The ground test and field application results showed that the holddown sub had successfully achieve the function of locking and unlocking and each technical index had met the design requirements.Thus,the holddown sub could solve the problem of unsure releasing in liner cementing and difficult release in highly deviated wells.