空心抽油杆热洗工艺及其风险性分析

发布时间：2018-09-17 07:14

【摘要】：我国大多数原油含蜡量比较高,一般原油含蜡量高于20%,属于开采稠油的国家之一。在生产中,为了解决油井因温度和压力的变化而导致的油管内壁结蜡问题,开始采用空心抽油杆热洗工艺技术。随着下井深度变化,空心抽油杆连接不同数量的抽油杆杆柱。由这些多个杆柱组成的系统,当有一个出现问题时,将导致整个系统不能正常工作。在热洗除蜡过程中,杆体在热应力作用下可能会发生空心抽油杆的失效。本文根据空心抽油杆系统安全生产的要求,对空心抽油杆在使用过程中安全性进行了研究,主要研究的内容包括:(1)为了保证空心抽油杆系统的使用寿命,依据空心杆的选型标准,从空心抽油杆的拉应力、变形量、螺纹连接等方面对其进行了强度计算、分析和校核,为确保所选空心抽油杆满足生产的要求奠定了基础。(2)计算了空心抽油杆式抽油机的悬点载荷和空心抽油杆杆体及其接头的应力、强度。通过ANSYS软件进行模拟和仿真,得到空心抽油杆模拟拉伸强度云图;最大应力值位于空心抽油杆的顶端位置,应力从顶端向下数值逐渐变小;得到了螺纹的等效应力云图,两端螺纹牙受到的应力最大;对空心抽油杆抗挤强度进行了分析,得出了油管磨损的偏心距对油管磨损强度的影响关系。(3)对空心抽油杆热洗工艺中的热效应进行了分析。包括空心杆热洗过程中的热变形量、热效率的分析与计算,热变形量对采油工况影响的分析与计算,提出了可采取的解决方案。应用ANSYS得到了空心抽油杆内部温度沿管径变化的曲线;得出了空心抽油杆内部径向、周向应力沿路径的分布曲线图。(4)运用事故树分析的方法对空心抽油杆系统进行了风险性分析。根据空心抽油杆系统各个部件常见的失效形式,建立了空心抽油杆系统事故树模型。对所建立的事故树进行分析,定性分析主要找出了导致顶事件发生的最小割集,定量分析结合空心抽油杆系统各个零件失效概率的统计数据,计算了系统概率重要度。通过分析可以得出的结论是:建立事故树模型中各个底事件均为最小割集,但各个底事件概率重要度有差别。其中应力集中失效、接箍处应力集中失效、偏磨失效、热应力耦合失效对空心抽油杆系统有较大影响。
[Abstract]:The wax content of most crude oils in China is higher than 20%. Generally, the wax content of crude oil is higher than 20%. It is one of the countries that exploit heavy oil. Number of sucker rod strings. A system consisting of these multiple rod strings, when a problem occurs, will cause the whole system to fail. In the process of hot washing and dewaxing, the sucker rod may fail under the action of thermal stress. In order to ensure the service life of the hollow sucker rod system, according to the selection standard of the hollow rod, the strength of the hollow sucker rod is calculated, analyzed and checked from the aspects of tensile stress, deformation and thread connection, etc. in order to ensure the hollow sucker rod system to meet the production requirements. (2) The suspension load of the hollow sucker rod pumping unit and the stress and strength of the hollow sucker rod and its joint are calculated. The simulated tensile strength nephogram of the hollow sucker rod is obtained by ANSYS software. The maximum stress is located at the top of the hollow sucker rod and the stress is calculated from the top to the bottom. The equivalent stress nephogram of the threads was obtained, and the stress on the threads at both ends was the greatest. The influence of eccentricity of tubing wear on tubing wear strength was analyzed. 3. The thermal effect in the hot washing process of the hollow sucker rod was analyzed, including the hot washing process of the hollow sucker rod. Thermal deformation, thermal efficiency analysis and calculation, thermal deformation on the analysis and calculation of the impact of oil production conditions, put forward the solution can be taken. The application of ANSYS hollow sucker rod internal temperature along the diameter of the curve; obtained hollow sucker rod internal radial, circumferential stress along the path of the distribution curve. (4) Using fault tree. The risk analysis of the hollow sucker rod system is carried out by the method of analysis.According to the common failure modes of each component of the hollow sucker rod system,the fault tree model of the hollow sucker rod system is established.The fault tree is analyzed,and the qualitative analysis mainly finds out the minimum cut set which causes the top event.The quantitative analysis is combined with the hollow sucker rod system. The statistical data of failure probability of each part of the rod system are used to calculate the probabilistic importance of the system.The conclusion can be drawn from the analysis that each bottom event in the fault tree model is the minimum cut set,but the probabilistic importance of each bottom event is different. Failure has great influence on the hollow sucker rod system.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE933.2

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