复杂长裸眼井段套管下放动态过程模拟研究

Simulation Study on Dynamic Process of Casing Running in Complex Long Openhole

长裸眼水平井由于复杂的空间轨迹和较高的摩阻会导致套管在下放过程中承受较大的阻力而无法到达预定位置。针对该技术问题,基于动力学理论、现场井眼轨迹、井身结构、井径和套管柱结构等数据,建立了全井段动态下放的套管柱有限元模型,对不同下放深度下全井段套管柱的力学行为进行了研究,并在此基础上对现场下套管采取上提冲放措施进行了动态过程分析。模拟结果表明:随着套管摩阻的增大,套管柱在下放5 400 m后无法继续,直井段套管发生了严重的螺旋屈曲;上提下放过程中,套管柱的受力十分复杂;通过对下套管采用动态模拟既可以得到套管在一定井深阶段能否自由下放的决定因素,还可以明确现场采取“上提冲放”优化下套管作业对套管产生的实际影响。研究结果为指导套管顺利下放提供了理论依据。

Casing running in long open-hole horizontal wells with complex well trajectory and high frictional resistance may withstand great resistance and could not reach the predetermined depth.To address the problem,based on the kinetic theory and the well trajectory,casing program,caliper data and casing string,the finite element model of the whole casing string dynamic running is established.The mechanical behaviors of the whole casing string at different running depths are studied.On this basis,the dynamic process of casing uplifting and fast running is analyzed.The simulation results show that with the increase of friction,the casing string can no longer be run at 5 400 m,and serious helical buckling is observed.During the casing lifting and running process,the casing string stress is very complicated.By dynamic simulation of the casing running,the decisive factor influencing free casing running at a certain depth could be obtained,and the actual impact of“uplifting and fast running”on the casing stress could be attained.The study results could provide technical support for guiding casing running.