《连续油管疲劳寿命计算》-毕业论文.doc

PAGE 摘要 连续油管(CT)是相对于常规螺纹联接油管而言的，它又称为挠性油管、蛇形管或盘管。连续油管(CT)技术广泛应用于油气田修井、钻井、完井、测井、增产等作业，在油气田勘探与开发中发挥越来越重要的作用。研究、开发及推广应用连续油管作业技术，将会进一步提高勘探开发效益。 连续油管工作条件比较恶劣,受力状态比较复杂。失效形式可分为变形失效,断裂失效,表面损伤失效,其疲劳断裂失效占的比例较大。疲劳寿命是衡量其可靠性的关键指标。连续油管的疲劳是应力状态较复杂的多轴低周疲劳,目前该疲劳寿命预测理论还不成熟, 为此,在前人疲劳研究方法的基础上,建立了连续油管的疲劳寿命预测模型。在该模型中,将连续油管的复杂应力转化为等效的单向拉伸应力,将连续油管的低周疲劳应变-寿命关系转化为应力-寿命关系,得到了一个半经验寿命公式。用国外连续油管的部分疲劳实验数据验证，结果表明,建立的寿命预测模型计算寿命值与实验值基本接近,模型基本正确。 分析了影响连续油管寿命的因素以及提高连续油管使用寿命的方法。研究表明，内压、油管外径、油管壁厚、卷筒直径、导向拱半径、杨氏模量、抗拉强度等严重影响了连续油管的寿命。因此，可采用增大卷筒直径和导向拱半径、尽量增加大直径连续油管的壁厚以及优先选用小直径的连续油管等办法来提高连续油管的使用寿命。 关键词: 连续油管； 受力分析 ； 工作特性 ； 疲劳寿命 ABSTRACT The coiled tubing(CT) shall be defined relative to conventional thread connection tubing．coiled tubing(CT) is used extensively in well wokrover，well drilling，well completion，well logging and well stimulation in oil-gas field. It plays a more and more important part in exploration and produetion. It will improve the efficiency of exploration and exploitation，studying，developing and using CT technology. Working conditions of coiled tubing is bad, the stress state is more complex. Failure forms can be divided into distortion, fracture failure and surface damage, the failure of the proportion of the fatigue fracture failure. Fatigue life is the key indicators to measure its reliability. The fatigue of coiled tubings are more complex stress state of multiaxial fatigue, the low cycle fatigue life prediction theory still not mature, therefore, on the fatigue study method is established, on the basis of coiled tubing fatigue life prediction model. In this model, the transformation of coiled tubing complex stress the uniaxial tensile stress for the equivalent of coiled tubings, low cycle fatigue strain-life relationship into stress, and the relationship between life and life experience. With foreign coiled tubing parts fatigue test data validation, the results show that the prediction model is established with