Abstract In view of the fatigue failure of tubing string caused by fluid-induced vibration (FIV) in high-yield curved well, a nonlinear vibration model of tubing string is established using energy method and Hamilton principle, which considers the longitudinal/lateral coupling effect of tubing string and the nonlinear contact collision effect of tubing-casing and verified by a similar experiment of tubing vibration. The cumulative damage theory (Miner's Law) is used to establish the fatigue life prediction method of the tubing string in high-yield curved well combined with the stress response which was determined by the proposed vibration model and the S-N curve of the tubing material (13Cr-L80) which was measured by fatigue experiment. Based on that, the fatigue life of the tubing in two typical horizontal well and directional well was analyzed under different production rate (0.4-1.6 million square/day) and different tubing diameter (3.5-in and 4.5-in). The result shows that the most dangerous position of the tubing string appears between 3/4 position of the tubing string and the packer. The critical production rate of 4.5-in tubing string in horizontal well is 1.08 million square/day to satisfy the life requirements of gas reservoir tubing (20 years), and which is 0.45 million square/day in directional well. The fatigue life of 4.5-in tubing string is higher than that of 3.5-in tubing string in both horizontal and directional wells. The research results provide a theoretically sound guidance for designing and practically sound approach for effectively improving the service life of tubing string in high-yield curved wells.

中文翻译：

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高产弯井油管柱疲劳研究

摘要 针对高产弯井流体激振（FIV）引起的管柱疲劳失效问题，利用能量法和哈密顿原理，建立了考虑纵向/横向耦合效应的管柱非线性振动模型。管柱的非线性接触碰撞效应和油管-套管的非线性接触碰撞效应，并通过类似的油管振动实验验证。利用累积损伤理论（Miner's Law），结合所提出的振动模型和油管材料（13Cr）SN曲线确定的应力响应，建立了高产弯井油管柱疲劳寿命预测方法。 -L80)，这是通过疲劳实验测量的。基于此，分析了两种典型水平井和定向井在不同产量（0.4-160万方/天）和不同油管直径（3.5-in和4.5-in）下的油管疲劳寿命。结果表明，油管柱最危险的位置出现在油管柱与封隔器的3/4位置之间。水平井4.5英寸管柱临界产量108万平方/天，满足气藏油管寿命要求（20年），定向井45万平方/天。4.5 英寸油管柱的疲劳寿命在水平井和定向井中均高于 3.5 英寸油管柱。