油田在用封隔器胶筒密封材料的老化行为

Aging behavior of sealing material for in-use packer in oil field

选择在用的丁腈橡胶(NBR)、氢化丁腈橡胶(HNBR)以及HNBR/氟橡胶(FKM)5种封隔器胶筒的橡胶材料作为研究对象,分别研究了其热稳定性、玻璃化转变温度以及在热空气介质和矿化水介质中的耐老化行为。结果表明,受FKM的作用,HNBR/FKM共混胶试样D表现出最好的热稳定性,同时差示扫描量热分析表明HNBR和FKM具有较好的相容性;在热空气介质中,试样D具有最高的拉伸强度保持率以及扯断伸长率保持率,表现出最好的耐老化性能,在矿化水介质中,水介质明显抑制了热氧老化反应,在100~120℃的矿化水中5种橡胶材料的扯断伸长率随老化时间延长变化率均较小,表现出较好的抗老化能力。然而在150℃的矿化水中,NBR试样E的扯断伸长率衰减较快,试样D的扯断伸长率保持率最佳,可作为油田分层注采井高温长效密封材料使用。

Five types of rubber materials for packer cartridges from nitrile rubber(NBR),hydrogenated nitrile rubber(HNBR),and HNBR/fluoro rubber(FKM),were selected as the research objects.Their thermal stability,glass transition temperature,and aging resistance of the rubber materials in hot air medium and mineralized water medium were investigated.The results showed that the rubber specimen D exhibited the best thermal stability performance by the action of FKM,meanwhile,the DSC curve indicated that HNBR and FKM had a good compatibility.In hot air medium,HNBR/FKM specimen D showed the best aging resistance with the highest aged tensile strength retention and the elongation at break retention,and it was more accurate to evaluate the aging resistance of rubber by the elongation at break retention than the tensile strength retention.In hot mineralized water medium,the thermal oxygen aging reaction was obviously inhibited by the water medium.In the mineralized water at 100~120℃,the elongation at break of the five rubber materials exhibited a small change rate with the aging time,and five samples showed good anti-aging ability.However,in mineralized water at 150℃,the elongation at break of the NBR sample decreased rapidly,and the elongation retention rate of sample D was the best,which could be used as a high temperature and long-term sealing material for separate injection-production wells.