石油学报 ›› 2019, Vol. 40 ›› Issue (12): 1531-1541.DOI: 10.7623/syxb201912012

• 石油工程 • 上一篇    下一篇

碳纤维抽油杆采油系统柱塞超冲程产生机理

王旱祥, 吕孝孝, 刘延鑫, 陈升山, 兰文剑   

  1. 中国石油大学(华东)机电工程学院 山东青岛 266580
  • 收稿日期:2019-03-16 修回日期:2019-09-16 出版日期:2019-12-25 发布日期:2020-01-04
  • 通讯作者: 吕孝孝,男,1993年3月生,2015年获中国石油大学(华东)学士学位,现为中国石油大学(华东)博士研究生,主要从事油气井杆管柱力学研究。Email:lvxx2014@163.com
  • 作者简介:王旱祥,男,1967年10月生,1990年获石油大学(华东)学士学位,2007年获北京工业大学博士学位,现为中国石油大学(华东)研究生院副院长、教授,主要从事油气井杆管柱力学和井筒完整性研究工作。Email:wanghx@upc.edu.cn
  • 基金资助:

    中央高校基本科研业务费专项资金(18CX06055A、17CX02022A)、中国石油大学(华东)研究生创新工程资助项目(YCX2017051)。

Mechanism of plunger overstroke in oil production system using carbon fiber sucker rod

Wang Hanxiang, Hanxiang Lü, Xiaoxiao Liu, Yanxin Chen, Shengshan Lan   

  1. College of Electrical and Mechanical Engineering, China University of Petroleum, Shandong Qingdao 266580, China
  • Received:2019-03-16 Revised:2019-09-16 Online:2019-12-25 Published:2020-01-04

摘要:

碳纤维抽油杆由于其本身的优势在油田得到推广;但在使用时存在柱塞超冲程现象,导致碳纤维连续抽油杆的设计使用缺少理论依据。采用运动分解的方法将抽油杆运动分解为由悬点位移激励和泵载荷激励的两个子运动,并建立相应数学模型,采用有限差分法求解,与现场数据对比,验证了模型的准确性。同时,建立了柱塞超冲程的仿真模型,分析了柱塞超冲程的产生机理及冲数、悬点冲程、泵径、泵挂和碳杆占比对柱塞超冲程的影响。仿真和分析结果表明:①柱塞相对超冲程由悬点位移激励的同频超冲程和泵载激励的谐振超冲程组成;②加载完成时悬点的速度、杆柱的谐振性能参数越大,谐振截止相位越接近3π/2,柱塞谐振超冲程越大;阀二次动作会削弱柱塞谐振超冲程;同频超冲程随抽油杆柱的固有频率增加而下降,随冲数和悬点冲程增加而上升;③柱塞相对超冲程随冲数的增加波动上升,随悬点冲程的增加先下降、后上升,随泵径的增加先上升、后下降,随泵挂的增加单调上升;④在极值冲数或较高冲数、极值碳杆占比(杆柱固有频率最低时的碳杆占比),高泵挂时,柱塞超冲程现象明显。

关键词: 碳纤维抽油杆, 超冲程, 柱塞冲程, 谐振, 数学模型

Abstract:

Carbon fiber sucker rod has been applying in oil fields because of its own advantages. However, the occurrence of plunger overstroke during application and the absence of corresponding theoretical support lead to the fact that there is no theoretical basis for designing and using the carbon fiber continuous sucker rod. Aiming at this problem and utilizing the motion decomposition method, the motion of sucker rod is decomposed into two sub-motions stimulated by suspension center displacement and pump load. Further, the corresponding mathematical model is established and solved by finite difference method, and the accuracy of the model is verified by comparing with field data. Meanwhile, the simulation model of plunger overstroke is also established. On this basis, this paper analyzes the production mechanism of plunger overtravel, and the influence of stroke frequency, suspension center stroke, pump diameter, pump depth and the proportion of carbon rod on plunger overstroke. The simulation and analysis results show that:(1)the relative overstroke of plunger is composed of the same-frequency overstroke stimulated by suspension center displacement and the resonance overstroke stimulated by pump load; (2)when the loading is finished, the higher the suspension center velocity and the resonance performance parameter of rod string are, the closer the resonance cut-off phase is to 3π/2, and the larger the overstroke of plunger under resonance is; the secondary action of valve will weaken the overstroke of plunger under resonance; the same-frequency overstroke decreases with the increasing inherent frequency of sucker rod string, and increases with the increasing stroke frequency and suspension center stroke; (3)The relative overstroke of plunger fluctuates with the increase of stroke frequency, rises after an initial decrease with the increasing of suspension center stroke, and decreases after an initial rise with the increasing of pump diameter, and then monotonously increases with the increasing of pump depth; (4)Plunger overstroke is obvious in case of high pump depth, extremely high or high stroke frequency and extremely high proportion of carbon rod (the proportion of carbon rod at the lowest inherent frequency of rod string).

Key words: carbon fiber sucker rod, overstroke, piston stroke, resonance, mathematical model

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