深井钻具稳定器失效分析及设计研究

【作者】 贺林；

【导师】 吕瑞典； 杨启明；

【作者基本信息】 西南石油学院 ， 机械制造及其自动化， 2003， 硕士

【摘要】 现场钻具失效资料的统计分析表明，在钻具失效事故中稳定器失效占有很大一部分。为了提高在深井和超深井井底钻具组合中稳定器的使用寿命，根据收集的国内外和现场的关于稳定器的资料，对稳定器作失效分析，得出现场使用中稳定器失效的主要机理；然后就稳定器的工作段、螺纹联接区和本体三部分的结构进行设计研究，提出相应的改进措施。 通过对稳定器进行失效分析，找出现场使用中稳定器的主要失效类型和失效机理：螺纹接头发生粘扣或刺扣；螺纹接头发生疲劳断裂；工作段基体材料因磨料磨损和冲蚀磨损而凹陷，凸出基体表面的硬质合金块折断或因失去基体支撑而脱落，工作段因无法保持工作直径而失效。 基体材料的抗磨损性能是工作段寿命的关键，为此采用在硬质合金块之间的基体上堆焊一层抗磨料磨损的材料，增加基体的抗磨损性能。选择了几种抗磨料磨损性能好的焊接材料，与基体材料进行了抗磨损性能对比实验，优选出在基体表面堆焊铸造WC能够大大的提高工作段的抗磨损性能。对试件的表面进行电镜分析，验证了失效分析得出的结果和机理的正确性。 螺纹联接区是另一个稳定器失效的常见区域，对螺纹接头在预紧力和轴向力作用下进行了受力分析，得出了螺纹各牙的载荷百分比。计算出在横向力作用下螺纹的周向应力。对接头进行疲劳计算，得出螺纹根底是一个高的应力集中源。螺纹部位承受高的交变应力，是导致螺纹联接螺纹失效的主要原因。针对螺纹联接区的设计，综述了一系列改进措施。 提出在稳定器的本体上加工应力分散区，既有利于降低本体段的应力峰值，同时可降低螺纹接头的应力峰值，提高螺纹联接的可靠性。针对应力分散区不同的深度、宽度和位置建立了相关的有限元模型，分析出应力分散区深度、宽度和位置的不同对螺纹接头应力峰值的影响程度。更多还原

【Abstract】 The statistics of drill tool failures from the oil field shows that failures of the stabilizer are large part of failures of drill tool failures. According to the domestic and overseas datum of the stabilizer, after analyzing failure of the stabilizer, Primary failure mechanism has been found. Research and design will be carried out in three aspects that are the wall contact, the thread joint and the fishing neck of the stabilizer. The measures that improve the stabilizer will be put forward, for extending used life of the stabilizer.Through failure analysis of stabilizer, there are three main types in failure form of the stabilizer: First, the threads are adhered or pierced. Second, the thread joint fractured in fatigue. At last, the face of wall contact sunk below the tungsten carbide slugs for abrasion and erosion, whereas because the tungsten carbide slug extend out of the face of body, that will be prone to snap and come off. Then the failure that is reduction of diameter of wall contact occurs. As concerning the key of wall contact life is wear resistance character of body materials. It is recommended that cast tungsten carbide is applied by oxygenacetylene flame on the wear face of body among the tungsten carbide slugs, for improving wear resistance character of body materials. Through the contrast experiences of selected wear resistance materials, the cast tungsten carbide is used as wear resistance materials to improve wear resistance character of body. By means of Transmission Electron Microscope analysis to the surface of specimen, the result of failure analysis has got corroboration. Other frequent failure region is in the thread joint. Thus the force of stabilizer is calculated under the action of pretightening force and axial force. According to the result of fatigue count, it was one high stress raiser for thread root. That the thread endures high alternate stress is the first cause of failure of thread joint. As concerning the design of thread joint, a great deal of improvement is brought forward.It is recommended that the stress relief groove is in the body of stabilizer. This will decrease not only the stress maximum of body but also that of thread joint. As concerning slug depth, width and distance to thread joint, FEA model is erected and the incidence to the stress maximum is analyzed.更多还原