【摘要】 随着油气井钻井深度不断增加，钻杆承受较大轴向力和扭矩作用，而钻杆螺纹作为薄弱结构，需要进行力学强度分析及结构优化，为此针对现场使用的普通美国石油学会(American Petroleum Institute, API)螺纹接头与结构优化后的非标新型螺纹接头，建立了多工况下螺纹接头力学及裂纹扩展有限元分析模型。有限元计算结果表明：非标新型接头具有更高力学强度，更容易上扣且速度快，还具有3扣非工作螺纹，降低了螺纹接头大端刚度，改善了应力集中问题，具体的非标新型接头抗扭强度比普通接头的抗扭强度高23.86%,增加了扣根的截面刚度，且优化螺纹接头在内台肩第三扣和外台肩第三扣处的裂纹扩展长度明显减小，有效抑制了裂纹扩展，断裂壁厚比有效减少40%以上。特别的在四川开发的万米超深川科1井钻探过程中将采用该非标新型螺纹接头，文中研究方法和成果对超深井非标新型钻杆螺纹设计提供了理论依据。更多还原

【Abstract】 With the continuous increase in the drilling depth of oil and gas wells, drill pipes are subjected to greater axial forces and torques. As a relatively weak structural component, drill pipe threads require mechanical strength analysis and structural optimization. Finite element analysis(FEA) models was established for the mechanical behavior and crack propagation of standard API(American Petroleum Institute) threaded joints and structurally optimized non-standard new threaded joints under multiple working conditions. The FEA results show that the non-standard new joint has higher mechanical strength, it is easier and faster to make up, and features three non-working threads, which reduce the stiffness at the large end of the threaded joint and alleviate stress concentration problems. Specifically, the torsional strength of the non-standard joint is 23.86% higher than that of the standard joint, the cross-sectional stiffness at the thread root is increased, and the crack propagation lengths at the third internal and external shoulder threads are significantly reduced. This effectively suppresses crack propagation, with fracture wall thickness reduced by more than 40%. During the drilling process of the 10 000 meter ultra deep Chuanke 1 well developed in Sichuan, the non-standard new type of threaded joint will be used. The research methods and results in this article provide a theoretical basis for the design of non-standard new drill pipe threads in ultra deep wells.更多还原