螺旋屈曲状态下连续管冲蚀因素分析

Erosion Factor Analysis of Coiled Tubing with Helical Buckling

针对连续管作业过程中连续管与套管之间形成较大环空间隙时,容易发生螺旋屈曲,以及连续管内壁冲蚀严重的问题,采用试验和数值模拟方法,对螺旋屈曲连续管的内壁冲蚀进行研究,并对试验和数值分析结果进行非线性拟合,以获得不同颗粒粒径、流量、屈曲螺距等因素对连续管内壁冲蚀的影响规律;同时通过试验获得相应的参数为仿真提供依据,提高模拟仿真的准确性,并利用灰色关联分析法(GRA)对连续管冲蚀模拟仿真数据进行分析。分析与试验结果表明,随着流量的增大,连续管的冲蚀速率呈线性增加;随着颗粒粒径以及屈曲螺距的增加,连续管的冲蚀速率逐渐减小。其中,当颗粒粒径增大时,颗粒的数目为主要影响因素;当屈曲螺距越小时,冲蚀分布越均匀。所得结论可为连续管作业过程中的冲蚀防护提供理论支持。

During coiled tubing(CT)operations,a wide annulus between CT and casing may lead to helical buckling and serious erosion of the CT inner wall.The inner wall erosion of CT with helical buckling was investigated through physical experiment and numerical simulation.Through nonlinear fitting of experimental and simulation results,the effects of particle size,flow rate and buckling pitch on the CT inner wall erosion were clarified.Moreover,corresponding parameters were obtained from the experimental data to provide references for accurate simulation.The grey relational analysis(GRA)was made on the CT erosion simulation data.It is found that the CT erosion rate increases linearly with the increasing flow rate,and gradually decreases with the growing particle size and buckling pitch.Especially,in case of larger particle sizes,the number of particles is the main influential factor.A smaller buckling pitch is associated with a more uniform erosion distribution.The conclusions provide some theoretical sapport for erosion in CT operations.