摘要
近年来,连续管在油气田水平井中的应用越来越广泛,但由于连续管的挠度大、材质刚性低于常规接箍油管,在水平井筒内会形成比较严重的螺旋屈曲现象并产生自锁,无法达到作业深度。因此,通过对超长水平井连续管下入影响因素分析和筛选,利用经典管柱力学进行影响因素定量计算分析,提出相应的优化方案。分析、应用结果表明:①影响连续管下入的主要因素为连续管在入井前残余弯曲应力,在井筒的限制和轴向力的作用下,在井筒内发生屈曲变形,产生自锁;②选择相对大尺寸、小壁厚的连续管可以延长一定的下入深度,但要大幅增加连续管的下入深度还要采用增加管端牵引力以及降低摩擦系数的方法;③通过加入水力振荡器和添加金属减阻剂来降低摩擦系数,能够有效提高连续管的下放深度。
In spite of its wide application to horizontal wells in the latest years,coiled tubing suffers from serious spiral buckling and self-locking in wellbore due to its large deflection and small rigidity compared with conventional one.It cannot run the drilling depth.So,some factors affecting the running depth of coiled tubing were examined for the extremely long horizontal wells.Furthermore,a quantitative analysis on these factors using pipe string mechanics was implemented to develop an optimization scheme.Results show that(1)the running depth is mainly related to residual bending stress in the coiled tubing before running,which leads to buckling deformation and self-locking due to wellbore restriction and axial force;(2)this depth may be increased somewhat by increasing tubing size and decreasing its wall thickness,but a large improvement may be realized by increasing tractive force at pipe end and reducing frictional coefficient;and(3)the frictional coefficient may be reduced by introducing both hydraulic oscillator and metallic drag reducer so as to significantly increase this running depth.
作者
刘研言
尹俊禄
慕鑫
王宝宏
Liu Yanyan;Yin Junlu;Mu Xin;Wang Baohong(Changqing Downhole Technology Company,CNPC Chuanqing Drilling Engineering Company Limited,Xi’an,Shaanxi 710018,China)
出处
《天然气勘探与开发》
2022年第1期80-86,共7页
Natural Gas Exploration and Development
基金
中国石油集团油田技术服务有限公司科学研究与技术开发项目“3000 m超长水平段连续管作业技术与工具”(编号2020T-002-005)。
关键词
连续管下入深度
长水平段
水平井
影响因素
现场验证
Running depth of coiled tubing
Long horizontal section
Horizontal well
Affecting factor
Field test
