【摘要】 钻铤螺纹连接失效是钻铤失效的主要形式,在整个钻具失效事故中占很大比重。从分析螺纹载荷分布和螺纹应力分布入手,得出造成钻铤螺纹连接疲劳失效的原因是螺纹连接载荷分布极不均匀和应力局部集中,并据此提出了通过降低啮合区螺纹牙高度和采用不同摩擦系数的螺纹脂使载荷分布更合理、加工应力减轻槽改善应力分布和对螺纹表面进行处理预防钻铤连接疲劳失效的工艺技术措施。更多还原

【Abstract】 Thread failure is the main factor for the drill collar broken, which account for a large proportion of downhole accidents about drilling tools. On the basis of force and stress analysis exerted on threads, this paper draws a conclusion that the fatigue failure of drill collar screws is mainly caused by unsymmetric loads and strvss concentration to local area, based on which a preventive technique for drill collar threads failure has been developed. This technique is carried out by decreasing thread height of engaging area, employing various thread grease with unique friction coefficient to rearrange load distribution, using machine-stress alleviation slot to improve stress field, and treating thread face, etc.更多还原