水下采油树油管悬挂器K形金属密封环密封性能模拟分析

摘要

The sealing performance of the K-type metal sealing ring on subsea christmas tree tubing hanger has great implications to the reliability of subsea christmas trees.Failures of the ring will lead to the leakage of the crude oil in the production stream and the injected chemical reagents,causing environmental pollution.A finite element model for the performance of K-type metal sealing rings on subsea christmas tree tubing hanger under the practical working conditions (maximum water depth of 1 500 m,pressure grade of 69 MPa,temperature grade of 180 ℃) was developed with the software ABAQUS.Different initial interferences,working pressures and working temperatures are compared to analyze their influences on the maximum Mises stress and maximum contact stress of the ring.The results show that the maximum Mises stress and maximum contact stresses on both the outer and inner sides increases with the increase in the working pressure;but only the maximum contact stress on the inner side increases with the increase in the amount of interference,with the other two parameters decreases with it.The influence of working temperature on the stresses is insignificant.Under various working temperatures and a fixed amount of interference,when the working pressure is lower than 40 MPa,the maximum contact stress on both sides of the ring is about two to three times of the medium pressure;when the working pressure is higher than 40 MPa,the maximum contact stress on the outer side of the ring is ten times of the medium pressure.Consequently the K-type metal sealing ring can meet the sealing requirements under different working conditions.The research result provides theoretical foundation for designing and fabricating K-type metal sealing rings on subsea christmas tree tubing hanger.%水下采油树油管悬挂器的密封性能直接关系到水下采油树工作的可靠性,密封一旦失效,将会导致生产通道中的原油及生产过程中注入的化学试剂发生泄漏,造成环境污染.本文利用ABAQUS软件建立了真实工况下(最大水深1 500m,压力等级69 MPa,温度等级180℃)水下采油树油管悬挂器K形金属密封环的有限元模型,分析了不同初始过盈量、工作压力和工作温度对金属密封环最大Mises应力和最大接触应力的影响.分析结果表明,K形金属密封环的最大Mises应力和两侧的最大接触应力随着工作压力的增加而增加,最大Mises应力和外侧的最大接触应力随着过盈量的增大而减小,内侧的最大接触应力则随着过盈量的增大而增大,而工作温度对其影响不大.在不同工作温度和过盈量一定的条件下,当工作压强小于40 MPa时,K形金属密封环两侧的最大接触应力均超过介质压力的2～3倍,而当工作压强大于40 MPa时,K形金属密封环外侧的最大接触应力超过介质压力的10倍,因此K形金属密封环在各种工况下均能满足密封准则,能对油管挂形成良好的密封.本文研究结果对水下采油树油管悬挂器的密封设计有一定的指导意义.