School of Mechanical Engineering and Automation, Northeastern University, Shenyang, Liaoning Province, China.
PLoS One. 2024 May 14;19(5):e0301610. doi: 10.1371/journal.pone.0301610. eCollection 2024.
In the process of horizontal well construction, the working environment in the well is very complicated. It is difficult to determine the actual deformation and force of the coiled tubing in the wellbore from the load change at the wellhead along. In addition, the coiled tubing wrapped around the reel and entering the wellbore through the injection head may cause an initial residual bending. In this paper, the mathematical model of the coiled tubing under axial load during buckling deformation is established, and the analytical solution with the time term is derived by reasonable simplification of the model. The effect of residual bending on the post-sinusoidal buckling of the coiled tubing in the horizontal well was investigated using the separation variable method. The effect of residual bending variations on the well wall contact forces is analyzed. The research shows that the initial parameter Г is the main factor influencing the post-sinusoidal buckling of the coiled tubing with residual bending. The larger the parameter value Г, the greater the effect of the residual bending on the post-sinusoidal buckling deformation of the coiled tubing, and the earlier the critical point of the mixed sinusoidal-helical buckling of the coiled tubing appears. The compression velocity of the coiled tubing has a significant effect on the well wall contact force. The faster the compression, the greater the contact force. By introducing the time term and the separation variable, this paper provides a new method and theoretical basis for further study of the process of entering sinusoidal-helical buckling of the coiled tubing with initial residual bending.
在水平井施工过程中，井内的工作环境非常复杂。由于无法从井口的载荷变化直接确定油管在井筒内的实际变形和受力情况，此外，缠绕在卷筒上并通过注入头进入井筒的油管可能会产生初始残余弯曲。本文建立了轴向载荷作用下的油管屈曲变形的数学模型，并通过对模型的合理简化，推导出了带有时间项的解析解。利用分离变量法研究了残余弯曲对水平井中油管正弦后屈曲的影响，分析了残余弯曲变化对井壁接触力的影响。研究表明，初始参数Г是影响具有残余弯曲的油管正弦后屈曲的主要因素。Г值越大，残余弯曲对油管正弦后屈曲变形的影响越大，油管混合正弦-螺旋屈曲的临界点出现得越早。油管的压缩速度对井壁接触力有显著影响，压缩速度越快，接触力越大。通过引入时间项和分离变量，本文为进一步研究具有初始残余弯曲的油管正弦-螺旋屈曲过程提供了一种新的方法和理论依据。
