长庆油田H转油站集输管线腐蚀原因分析

Corrosion analysis of gathering and transportation pipeline of H transfer station in Changqing oilfield

长庆油田H转油站站内集输管线及阀组管线材质为20号钢,站内集输管线在高矿化度、高含水、低CO2和低H2S腐蚀环境下发生腐蚀穿孔,腐蚀位置在集输管线底部。利用超景深光学数码显微镜、扫描电镜(SEM)和电子能谱(E DS)等方法对集输管线中挂片表面腐蚀产物的形貌及成分进行了观察和分析,并对20号钢管线服役环境和腐蚀因素进行了讨论。结果表明:20号钢管线腐蚀的主要原因是H2S腐蚀、CO2腐蚀和Cl-腐蚀,在其共同作用下造成集输管线腐蚀穿孔。

The material of the gathering pipeline and valve group pipeline in the H transfer station of Changqing oilfield is 20#steel.The gathering pipeline was corroded and perforated under the corrosive environment of high salinity,high water cut,and low partial pressure of CO2and H2S.The corrosive location was at the bottom of the gathering pipeline.The morphology and composition of corrosion products on the surface of hanging pieces in gathering pipeline was observed and analyzed through ultra-depth-of-field optical digital microscopy,scanning electron microscopy(SEM)and electronic energy spectrum(EDS).The service environment and corrosion factors of the 20#steel pipeline were discussed.The results showed that the leading causes of corrosion of the 20#steel pipeline were H2S corrosion,CO2corrosion and Cl-corrosion,which resulted in corrosion perforation of the gathering pipeline under the combined action of H2S corrosion,CO2corrosion and Cl-corrosion.