三维井眼抽油杆工作行为仿真研究

针对造成抽油杆、管偏磨的原因及目前理论研究的不足,采用计算机仿真技术,应用有限元软件ANSYS对抽油杆柱变形、接触及受力状态进行分析,找出了定向井、水平井中容易发生偏磨的部位及接触力。建模时采用Pipe16单元模拟抽油杆和活塞,采用Contac176和Target170单元来模拟柔性抽油杆与刚性油管的接触。仿真结果表明,抽油杆在上下行程中将产生很大的屈曲并和油管壁发生激烈的碰撞,下行程的屈曲状态较上行程更为严重;抽油杆底部接箍和光杆均可能与油管壁发生接触碰撞,但接箍部位的接触力更大,更易磨损,而上部的抽油杆则摆动幅度较小。

A simulation study of the operation behavior of the sucker rod in 3-D borehole

In light of the reason for the eccentric wear of the sucker rod, the position of eccentric wear and contact force in directional and horizontal wells were identified by adopting the computer simulation technology and the finite element software ANSYS to analyze the deformation, contact and force state of the sucker rod. In modeling, the Pipe16 unit was adopted to simulate the sucker rod and piston; the Contact176 and Target 170 units were adopted to simulate the contact between the flexible sucker rod and the rigid tubing. The simulation result shows that in upward and downward movements, the sucker rod will produce remarkable buckle and collide fiercely with the tubing wall. The buckling state of the downward movement is more severe than that of the upward movement. The bottom coupling of the sucker rod and the polished rod may both contact and collide with the tubing wall. But the contact force in the coupling position is larger, so wear is apt to occur there, while the upper sucker rod has a relatively small oscillation.