抽油杆经济使用年限的可靠性分析

发布时间：2018-11-18 13:17

【摘要】：抽油杆是油井工作中的重要零部件,它负责将抽油机的动力传给抽油泵。不仅如此,抽油杆的使用寿命对抽油设备的最大泵深度以及排量有着重要的影响。在工作过程中,抽油杆的受力状态较复杂,并且直接与多种腐蚀性介质接触,受到强烈的腐蚀。因此,疲劳断裂与腐蚀疲劳断裂是抽油杆的两种主要失效形式。抽油杆一旦出现故障,就会影响原油产量,增大修井费用,从而增加原油成本。所以,在调查分析抽油机井杆系统的故障情况之后,深入研究抽油杆柱疲劳寿命可靠性具有重大的意义。首先,调查油井的现有故障,建立了抽油杆系统故障树。从抽油杆系统故障树定性、定量两个方面入手,对其进行研究分析,找出抽油杆系统中需要改进的环节;其次,针对这些待改进的环节,给出应力强度因子的计算方法,并探究抽油杆疲劳裂纹扩展的一般规律,从而在理论上便于列出抽油杆剩余寿命的表达式;再次,研究抽油杆柱轴向载荷的分布规律,运用有限元软件,研究已经出现裂纹和腐蚀等情况的抽油杆,计算最大等效应力及应力集中系数,考虑应力计算的误差以及杆柱缺陷尺寸的不确定性,列出整体杆柱的失效率和可靠度;最后,建立抽油杆经济使用年限的可靠性评价方法,并分析裂纹、使用年限和斑坑等因素对抽油杆系统可靠性的影响。本文深入探究评价抽油杆系统疲劳寿命和系统经济使用年限可靠性方法。这使得深入研究抽油杆可靠性优化方法和抽油杆评价技术有了坚实的理论基础,有助于减少系统运作成本,也有助于增加油田的经济收益。
[Abstract]:Sucker rod is an important part in oil well work, it is responsible for transferring the power of pumping unit to sucker pump. Moreover, the service life of sucker rod has an important influence on the maximum pump depth and displacement of pumping equipment. In the working process, the sucker rod is subjected to severe corrosion due to its complex stress state and direct contact with various corrosive media. Therefore, fatigue fracture and corrosion fatigue fracture are two main failure modes of sucker rod. Once the sucker rod breaks down, the crude oil production will be affected and the workover cost will be increased, thus increasing the crude oil cost. Therefore, it is of great significance to study the fatigue life reliability of sucker rod string after investigating and analyzing the fault of rod system of pumping unit. Firstly, the fault tree of sucker rod system is established by investigating the existing faults of oil well. From the qualitative and quantitative aspects of sucker rod system fault tree, this paper studies and analyzes it, and finds out the links that need to be improved in sucker rod system. Secondly, the calculation method of stress intensity factor is given, and the general law of fatigue crack propagation of sucker rod is explored, so it is convenient to list the expression of residual life of sucker rod in theory. Thirdly, the distribution law of axial load of sucker rod string is studied. By using finite element software, the sucker rod with cracks and corrosion is studied, and the maximum equivalent stress and stress concentration factor are calculated. Considering the error of stress calculation and the uncertainty of defect size, the failure rate and reliability of the whole column are listed. Finally, the reliability evaluation method of sucker rod economic service life is established, and the effects of cracks, service life and spot pit on the reliability of sucker rod system are analyzed. In this paper, the reliability method of evaluating fatigue life and economic service life of sucker rod system is studied. This makes it possible to study the optimization method of sucker rod reliability and the evaluation technology of sucker rod on a solid theoretical basis, which is helpful to reduce the operating cost of the system and to increase the economic benefits of the oil field.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE933.2

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