元坝高含硫站场排污管线腐蚀风险及技术对策

Corrosion Risk and Technical Countermeasures of Sewage Pipelines in High Sulfur Stations in Yuanba

元坝气田天然气中高含硫化氢、中含二氧化碳,且气井普遍产出凝析水和地层水,溶解了硫化氢气体的气田水进入天然气集输系统站场内的排污管道,导致抗硫碳钢排污管内腐蚀环境恶劣,存在较大的腐蚀风险。通过室内实验和现场试验评价分析,认为抗硫碳钢A333须有缓蚀剂配合使用才能满足含硫湿酸气环境下的腐蚀控制需求;在没有缓蚀剂保护的内腐蚀环境下,抗硫碳钢A333以局部腐蚀为主,腐蚀呈现点蚀扩大和坑蚀现象,平均腐蚀速率达到1 mm/a以上。针对现场排污管线腐蚀风险,制定了元坝气田站场排污管线腐蚀控制技术对策和研究方向,为同类含硫气田站场排污管线材质优选和腐蚀控制方案确定提供了借鉴和参考。

The natural gas in Yuanba Gas Field has high H2 S and moderate carbon dioxide,and gas wells commonly produce condensate water and formation water.The gas field water dissolved in hydrogen sulfide gas flows into the sewage pipeline in stations of natural gas gathering and transportation system,which will results in the serious internal corrosion environment for the anti-sulfur carbon steel sewage pipeline and brings great corrosion risk.Through the laboratory experiment and the analysis and assessment of the field test,it is known that anti-sulfur carbon steel A333 can meet the corrosion control demands under the environment of sulfur-containing wet acid gas only with the use of corrosion inhibitor;in the internal corrosion environment without inhibitor protection,anti-sulfur carbon steel A333 in mainly appears local corrosion,and its corrosion presents enlarging point corrosion and pitting,with the average corrosion rate of above 1 mm/a.In view of the corrosion risk of the field sewage pipeline,technical countermeasures and research direction of the corrosion control in the sewage pipeline in Yuanba Gas Field station are formulated,which can provide reference for the selection of the material and the corrosion control scheme for the sewage pipeline in the same kind of sulfur-containing gas field stations.