摘要
套管下入水平井弯曲段时,套管螺纹是否已发生屈服对于随后的钻进和油气井生产有至关重要的影响,而目前国内外对于井眼曲率(弯矩)对套管螺纹连接强度和密封性能影响的研究极少。笔者基于虚功原理、接触非线性理论及von Mises屈服准则,建立了API短圆套管螺纹连接的三维计算模型,研究了拉弯复合载荷下连接螺纹的应力分布规律,指出井眼曲率(弯矩)对套管的连接强度和密封性能影响极大,并通过大量计算绘制了给定井眼曲率时的最大许用套管悬重图,综合考虑连接强度和密封能力推荐了API短圆套管螺纹标准所列锥度、螺距、螺纹长度、牙高参数系列中的最优值。
While casing goes down into the curved section of a horizontal well, whether casing threads have been yielded has a great in- fluence on following drilling and oil-gas production. However, there have been very few researches on mechanical behaviors of casing threads while casing goes down through the curved portion of a horizontal well, such as connection strength and sealing ability of the casing. Based on the principle of virtual work, nonlinear contact theory and yon Mises yield criterion, we established a 3-D calcula- tion model for the API short-round casing thread connection, examined the stress distribution of short-round casing threads under combined load of stretching and bending moment, and figured out that hole curvature （bending moment） would significantly influence the connection strength and sealing ability of easing. In addition, a maximum allowance hanging load for various given hole curvature was worked out through a large number of calculations. Based on synthetic considerations of thread connection performance and seal- ing ability,we recommended the optimized parameters of the API short-round casing thread criteria, including thread taper, thread pitch, thread length and thread ridge thickness. This research has an important engineering reference value for reducing casing thread failure and selecting the casing thread type for the curved section of a horizontal well.
出处
《石油学报》
EI
CAS
CSCD
北大核心
2013年第1期157-163,共7页
Acta Petrolei Sinica
基金
国家自然科学基金项目(No.51004082
No.51222406)
四川省杰出青年学术技术带头人项目(2011JQ0020)
四川省高等学校科技创新团队项目"油气井管柱力学与井下工具"(12TD007)资助
关键词
套管
圆螺纹
井眼曲率
复合载荷
连接强度
密封能力
casing
round thread
hole curvature
combined load
connection strength~ sealing ability
