N80钢在油田采出液中腐蚀行为的静态和动态模拟研究

模拟研究了井下环境N80钢在油田采出液(主要是CO2水溶液)中的静态和动态腐蚀行为。用光学显微镜、SEM、XRD对N80钢表面腐蚀产物膜的表面形貌、横截面形貌、结构及成分进行了分析。探讨了N80钢点蚀的形成和发展原因。讨论了井下采出液中各种离子对腐蚀行为的影响，结果表明，N80钢表面腐蚀产物膜的形貌及其结构对金属的进一步腐蚀有严重影响。腐蚀产物膜疏松、不完整或损坏、脱落时，会诱发局部点蚀而导致严重的穿孔破坏，点蚀坑会在腐蚀产物膜下产生，这也是N80钢在实际应用中被破坏的主要形式。试验中，N80钢在静态条件下的平均腐蚀速率略高于动态条件下的平均腐蚀速率，而其局部腐蚀在动态条件下则比静态时严重的多，这和试样表面腐蚀产物膜的破坏有关，动态条件下由于流体剪应力的作用，部分腐蚀产物膜破坏和剥落，造成了严重的局部腐蚀。

Static and Dynamic Analog Study of Corrosion Action of N80 Steel in the Extraction Liquid of Oil Field

It is an analog study of static and dynamic analog study of corrosion action of N80 steel in the extraction liquid (mainly CO2 water solution)of oil field under condition of well. It is analyzed that surface shape,cross section, structure and composition of surface corrosion produced films of N80 steel by optical microscope, SEM and XRD and discussed the forming and developing cause of spot corrosion of N80 steel. It is discussed each hydronium effect to corrosion action of extraction liquid under wells and the results show that the shape and its structure of surface corrosion produced films of N80 steel to metal has serious effect of further corrosion. When corrosion produced films is loosened, incomplete or shatter and shelled, it will induce part spot corrosion resulted serious perforation destroy and spot corrosion pit will produced under corrosion produced film. This is also the main form of being damaged of N80 steel in actual application. The average corrosion speed rate of N80 steel under static conditions is higher than that of dynamic conditions during test, however, its part corrosion in dynamic conditions is more seriously than that of dynamic conditions and this has the relation of destroyed surface corrosion produced films of specimen, due to shearing strength effect of fluid under dynamic conditions and part corrosion produced films destroyed and shelled and causes serious partial corrosion.