CO_2驱注气井封隔器橡胶材料腐蚀力学性能研究

Experimental Study on the Impact of Corrosion on the Rubber in Packers in a CO_2 Injection Well

由橡胶组成的封隔器胶筒是封隔器的核心部件,其性能直接关系到封隔器密封性能的好坏。CO2驱注气井中,CO2对橡胶材料的腐蚀易导致封隔器密封失效,进而引起环空带压,危及注气井的安全生产。为此,借助高温高压釜模拟井底真实环境进行了丁腈橡胶和氢化丁腈橡胶两种材料的腐蚀试验,分析比较了气相和液相腐蚀条件下橡胶腐蚀后材料力学性能和腐蚀形貌的变化。研究表明,丁腈橡胶和氢化丁腈橡胶在腐蚀后其拉伸性能均明显下降,硬度也有一定降低,液相环境下的腐蚀较气相环境下的腐蚀更加严重。因此,在工程设计中应充分考虑实际工况对橡胶力学性能的影响,不应以原始状态下橡胶的力学性能为依据。该研究成果可为CO2驱注气井及其他同类气井封隔器胶筒材料的选择提供参考。

As the core part of the packer ,packer rubber has direct relationship with the sealing function of packer .CO2 corrosion on the rubber material can cause sealing failures and induce sustained casing pres-sure ,thus affecting the safety of production of a CO2 injection well .Corrosion experiments were conducted on NBR and HNBR under simulated environment in high temperature high pressure autoclave .Compari-sons were made on the mechanic performances and shape of the rubber materials through corrosion of gas and liquid phase .Results showed that the tensile properties of nitrile rubber and HNBR decreased signifi-cantly and the hardness was also reduced after corrosion .The corrosion in the liquid phase environment was much more severe than that in the gaseous phase environment .Effects of actual conditions on the mechanic performances of rubber materials ,instead of the mechanical performance under its initial state ,should be considered in making engineering design .The research results can provide references for the selection of rubber material in CO2 injection well .