Abstract: Aiming at the demanding requirements of sealing performance in ultra⁃deep oil and gas wells, a double main sealing structure consisting of conical surface to conical surface and cylindrical surface to spherical surface was designed based on the special thread sealing mechanism. Using numerical simulation method, the changes of contact stress and the contact length of the sealing surface under the four conditions of tensile, compression, tension and internal pressure, tension and internal and external pressures were analyzed. The sealing performance of threaded joints under the ultimate load was studied, and the change rule of sealing capacity with different loads was obtained. The full⁃scale test results show that the sealing performance of the double main seal premium threaded joint meets the application requirements.

Key words: Premium threaded, Contact stress, Sealing structure, Sealing performance, Full?scale test

摘要： 针对超深油气井中对密封性能的严格要求，基于特殊螺纹密封机理，设计一种由锥面对锥面和柱面对球面组成的双主密封特殊螺纹接头结构。采用数值模拟方法分析接头在拉伸、压缩、拉伸和内压、拉伸和内外压4种工况下，双主密封面接触应力、接触长度的变化情况，并对螺纹接头在极限载荷下的密封性能进行研究，得到接头密封能力随不同载荷的变化规律。最后对接头试样进行全尺寸试验，结果表明该双主密封特殊螺纹接头的密封性能满足使用要求。

关键词: 特殊螺纹, 接触应力, 密封性能, 密封结构, 全尺寸试验