Ni-W镀管在CO_(2)注入井工况下的适用性研究

Study on the Applicability of Ni.W Coated Tubing in CO_(2)Injection Well Environments

为研究Ni-W镀管材料在CO_(2)注入井工况下的适用性,采用高温高压腐蚀模拟实验,结合扫描电镜、激光共聚焦显微镜及X射线衍射仪研究了Ni-W镀层的腐蚀行为。结果表明,在含有杂质的超临界CO_(2)注入工况下Ni-W镀层具有一定的耐均匀腐蚀能力,但存在局部腐蚀风险;在地层水反流的CO_(2)注入井工况下,微量的H_(2)S会诱发Ni-W镀层发生较为严重的腐蚀失效,造成镀层开裂和局部破损;在存在地层水反流的高含氧CO_(2)注入井工况下,Ni-W镀层会形成微裂纹,并在内外镀层界面形成腐蚀产物。

For sludyng the applicabilily of Ni-W coaing in CO_(2)iniecion wels,the comosion behaviors of Ni-W coalings were sludied by hieh temperature and high-pressure corrosion simulation experiments combined with scanning electron microseope(SEM),laser confocal microscope and X-ray diractometer(XRD).Results showed that the Ni-W coating had centain wniform comosion resistance uder the condi tion of supereriical CO_(2)containing impurities injection condition,but there was locaized corrosion risk.In the case of CO_(2)injection well with formation water rellux,a small amount of H_(2)S would induce severe corrosion failure of Ni-W coatings,resulting in cracking and local damage of the coating.In the case of high oxygenated CO_(2)iniection well with formation water relux,micro-cracks would be formed in Ni-W coatings and corrosion products would be generated at the inner and outer coating interfaces.