胜利油田集输管线腐蚀结垢机制研究

Study on scale and corrosion mechanism of oil pipelines in Shengli Oilfield

胜利油田集输管线结垢腐蚀现象严重,影响油田正常生产。采用水质水性、X射线衍射(XRD)分析方法对胜利油田三条典型集输管线的水样和垢样进行分析。结果表明,胜利油田集输管线集输水以氯化钙水型为主,具有高矿化度、含高价Ca^(2+)等特点,且含有较高浓度的溶解氧和二氧化碳,易对管线造成腐蚀。结垢产物以CaCO_(3)为主,伴生有少量的MgCO_(3),腐蚀产物以FeOOH、FeCO_(3)为主。高浓度成垢离子Ca^(2+)是造成集油管线生成CaCO_(3)的主要原因,而溶解氧和二氧化碳是引起管线腐蚀产物FeOOH和FeCO_(3)的主要因素。

Scale formation and corrosion in gathering pipelines of Shengli Oilfield are very serious,and if gathering system’s scale formation and corrosion occurs at the same time,it will affect the normal production of Oilfield.By the analysis methods of water quality and waterborne and XRD,the paper conducted the cause analysis of corrosion and scale formation on the water quality and scale formation sample collected from three gathering pipelines in Shengli Oilfield.The results showed that:the gathering pipelines in Shengli Oilfield were mainly in the water type of calcium chloride with the characteristics of high-salinity,Ca^(2+)and etc,and with the factors of dissolved oxygen and carbon dioxide that were easy to corrode the pipelines.The scale products were mainly CaCO_(3) accompanied with a small amount of MgCO_(3),and the corrosion products were mainly FeOOH and FeCO_(3).The reason for the scale formation of the pipelines was that they were rich in scaling ions,and dissolved oxygen and carbon dioxide were the main factors of pipelines’ corrosion.By mechanism analysis of scale samples we could conclude that CaCO_(3) was generated by the reaction between Ca^(2+) and HCO_(3)^(-).FeOOH and FeCO_(3) were generated by dissolved oxygen and carbon dioxide that water contains corroding pipelines.