Analysis on Running Ability of Coiled Tubing Based on Axial Load Discrete Model
Coiled tubing is prone to buckling deformation during operation in horizontal wells,which restricts its setting depth.In this paper,a study was conducted on the influence of axial load of coiled tubing on its setting depth in different hole sections.First,by analyzing the key parameters in the well track,a full angle plane of curved section was constructed.Second,based on the soft rod model and the constructed full angle plane,and considering the rigidity of coiled tubing,fluid friction,wall contact friction and additional contact friction after buckling,an axial load calculation model of coiled tubing was built.Finally,with the help of iterative method and combined with buckling state analysis,a case analysis was conducted on an well.The analysis results show that coiled tubing is more prone to spiral buckling in the vertical and slant sections.As the friction factor increases from 0.10 to 0.35,the spiral buckling length increases to 1 189.19 m,and the setting depth decreases from 4 370.00 m to 3 905.41 m.When the friction factor is 0.25,the active weight on bit(WOB)increases to 2.5 kN,and the setting depth decreases from 4 370.00 m to 4 148.48 m.Obviously,under axial pressure,the spiral buckling length of coiledtubing is directly proportional to the friction factor,and the setting depth is inversely proportional to both the friction factor and the active WOB.The conclusions provide reference for research on the running ability and operation parameters of coiled tubing.
horizontal wellrunning ability of coiled tubingaxial loadthread bucklingsetting depthfriction factor
万方数据
维普
