中文摘要：

在高含CO2油气田作业中，橡胶O型圈的适用性对油气田的生产安全具有一定影响。以往橡胶O型圈的相关研究只是在自由状态，而在实际工况下，橡胶O型圈通常处于压应力状态。为此，自行设计了一种检测承压状态下橡胶密封件耐腐蚀和密封性能的装置，在压力为35 MPa、温度为140℃、气相组成为5%CO2和95%N2的环境中，对4种橡胶材料的O型圈进行了耐CO2腐蚀实验。通过比较它们在腐蚀前后物理性能和形貌的变化，对其在此环境中的适用性做出了评价。研究发现，腐蚀后O型圈的物理性能下降；在承压状态下的腐蚀程度比自由状态下弱，并且，在承压状态下，液相腐蚀比气相腐蚀弱，而自由状态下则相反；腐蚀后O型圈发生溶胀老化等现象，引起密封失效。此项研究为高温高压高含CO2油气田上油气井橡胶密封件的选材和使用提供了参考依据。

英文摘要：

In the high CO2 oil and gas field operations,the applicability of rubber O-ring has a certain effect on the production safety. Previous studies related to the rubber O-ring is merely in a free state,but in the actual operating condition,the rubber O-ring is mostly in a compressive stress state. Therefore,we designed a new device for corrosion resistance and sealing property test of rubber seals in a compressive stress state,in the harsh environment with pressure of 35 MPa,temperature of 140℃,gas phase composition of 5%CO2 and 95%N2,and the CO2 corrosion resistance experiments on the O-rings of four kinds of rubber materials were conducted. Through comparing the mechanical properties and morphology changes before and after corrosion, the applicability evaluation of them in the above experiment environments was made. The study found that the mechanical properties of O-rings after corrosion decreased. The corrosion extent of O-rings was weaker in the compressive stress state than in the free state,and in the compressive stress state,the liquid corrosion was weaker than the gaseous corrosion,but stronger in the free state. After corrosion the swelling and aging of O-rings occurred,which caused the seal failure. The study provided references for the selection and use of rubber seals in the high temperature and high pressure oil and gas field with high CO2 content.