井下封堵球密封副接触应力建模与分析

Contact Stress Modeling and Analysis of Downhole Ball Sealer Seal Pair

封堵球密封副的密封性能是井下作业成败的关键,密封副接触应力的大小反映其密封能力。针对井下封堵球密封副的密封原理,分别建立了密封副接触应力的物理模型和有限元模型,通过实例模拟对比了二者的计算结果,分析了密封副几何结构和密封副材料特性对接触应力的影响规律。分析结果表明,封堵球密封副的接触应力可通过物理模型法或有限元法计算,二者模拟结果近似程度高,偏差较小;物理模型法可以反映模拟参数对最大接触应力的连续影响关系,有限元法可以模拟接触应力在密封副上的分布;在相同工况下采用小半锥角设计或选用较高弹性模量的封堵球材料均可增大密封副的接触应力,从而提高密封性能。

The sealability of ball sealer seal pair is the key to determining the success of downhole opera- tion. The contact stress of seal pair reflects its sealing capacity. In light of the sealing principle of downhole ball sealer seal pair, the physical model and the finite element model of the seal pair contact stress were established re- spectively. The calculation results of both models were compared through example simulation. The law of the effects of the seal pair＇ s geometric structure and material property on contact stress was analyzed. The analysis shows that the contact stress can be calculated by the physical model method or finite element method. Both simulation results are of high approximation and small deviation. The physical model method can reflect the continuous influencing re- lation of simulation parameters on the maximum contact stress. The finite element method can simulate the distribu- tion of contact stress in seal pair. In similar operating conditions adoption of semi-coning design or selection of ball sealer material of high elastic model can increase the sealing capacity of seal pair and improve the sealability.