井口管汇旋转接头密封性能评价及优化

Evaluation and Optimization of Sealing Performance of Wellhead Manifold Rotating Connectors

摘要: 针对井下开采中井口管汇旋转接头密封性能不足的问题，本研究以超弹性材料(氟橡胶O型密封圈)为研究对象，通过理论分析与非线性有限元仿真，系统评价了密封结构的性能并提出了优化设计策略。研究发现，初始结构下O型密封圈最大接触应力仅为3.339~3.957 MPa，远低于21 MPa的密封要求。温度升高虽对接触应力有正向促进作用(增幅 < 11%)，但不足以解决密封失效问题。通过优化密封槽几何参数(槽顶距离由7.5 mm压缩至6.63 mm，槽宽由3.2 mm压缩至2.87 mm，O型圈截面直径由2.65 mm增大至3.55 mm)，峰值接触应力提升至28.4 MPa，满足21 MPa密封要求，且密封面有效接触宽度大于整个接触宽度的1/2，无挤出现象。研究表明，密封性能不仅取决于材料特性，更与密封槽几何形状的精确控制及材料与配合表面的公差密切相关。本研究构建的多指标密封性能评价体系及优化设计方法，为提升井下旋转密封结构的可靠性提供了理论依据和实用方法，对保障超深、超高压复杂油气资源的安全高效开发具有重要工程价值。

Abstract: To address the insufficient sealing performance of wellhead manifold rotary joints in deep and ultradeep well exploitation, this study focuses on hyperelastic materials (fluororubber O-ring seals). Through theoretical analysis and nonlinear finite element simulations, the sealing structure’s performance was systematically evaluated, and optimization strategies were proposed. Results show that the initial design yields a maximum contact stress of only 3.339~3.957 MPa for the O-ring seal, far below the required 21 MPa sealing threshold. While elevated temperatures positively enhance contact stress (increase < 11%), this effect alone cannot resolve sealing failure. By optimizing geometric parameters of the sealing groove (reducing groove top distance from 7.5 mm to 6.63 mm, groove width from 3.2 mm to 2.87 mm, and increasing O-ring cross-sectional diameter from 2.65 mm to 3.55 mm), the peak contact stress is elevated to 28.4 MPa, meeting the 21 MPa sealing requirement. The effective contact width exceeds half of the total contact width, with no extrusion observed. This study reveals that sealing performance depends not only on the hyperelastic material’s constitutive properties but also on precise geometric control of the sealing groove and tolerance matching between materials and contact surfaces. The proposed multi-index sealing performance evaluation system and optimization methodology provide a theoretical foundation and practical approach for enhancing the reliability of downhole rotary sealing structures. These findings hold significant engineering value for ensuring safe and efficient development of ultradeep, ultra-high-pressure complex oil and gas resources.