抗硫缓蚀剂在长庆油田含硫区块某转油站的应用效果研究

Application Effect of Special Anti-sulfur Corrosion Inhibitors in a Gathering Station of Changqing Oilfield

长庆油田含硫区块某转油站站内集输管线及阀组管线材质为20#碳钢,针对站内集输管线在高含水、高H2S分压、高矿化度和高CO2分压腐蚀环境下常常发生穿孔泄漏的腐蚀问题,开发了抗硫专用缓蚀剂,完成了现场试点应用。采用腐蚀挂片监测装置进行对比试验,结果表明,在现场应用过程中抗硫缓蚀剂的缓蚀率达到99.87%,点蚀速率降低两个数量级。采用SEM-EDS等对现场挂片的腐蚀产物成分、结构进行分析。结果表明,未加注缓蚀剂时,腐蚀产物可以分为FeCO3为主的内层和FeS为主的外层。加注缓蚀剂时腐蚀产物为FeS,原始机械划痕清晰可见,腐蚀非常轻微。但是当油泥和Sr、Ba沉淀附着在表面时,仍然有局部腐蚀发生,但是局部腐蚀风险较低。

The pipeline material steel used in the gathering station in the sulfur-containing block of Changqing Oilfield is 20#carbon steel.The corrosion of the pipeline in the station is serious under high water content,high H 2S partial pressure,high salinity and high CO2 partial pressure.Corrosion problems with perforated leakages often occur.A kind of special anti-sulfur corrosion inhibitors for this serious corrosion was developed and applied at the gathering station.Comparing the monitoring results,it was found that the corrosion inhibition rate of this corrosion inhibitor reached 99.87%during the field application.The composition and structure of the corrosion products were analyzed by SEM-EDS.The results showed that the corrosion products can be divided into the inner layer of FeCO3 and the outer layer of FeS without corrosion inhibitor.When the corrosion inhibitor is added,the original mechanical scratches are clearly visible,and the corrosion is very slight,resulting in the corrosion product FeS.However,when the sludge and the Sr and Ba precipitates adhere to the surface,there was still a risk of local corrosion.