某气田地面集输管线的腐蚀原因及控制措施

Corrosion Causes and Control Measures of Ground Gathering and Transportation Pipelines in a Gas Field

某气田在生产过程中,地面集输管线(包括三通、弯头、法兰等)发生多起穿孔或爆管事件,严重影响正常安全生产。通过管内腐蚀产物组成的能谱分析,管内多相流计算,腐蚀和冲蚀模型验证,腐蚀部位流场分析等,对该气田管线腐蚀的影响因素进行了研究。结果表明:管线和管件的穿孔或爆管主要是CO_(2)腐蚀和冲刷腐蚀引起的,管内介质流速较高时缓蚀剂的缓蚀效果会降低,通过流场与腐蚀数据耦合,明确了适合该气田工程应用的冲刷腐蚀临界流速,并提出了控制管线与管件腐蚀的防护措施。

During the production process of a gas field,there were many perforations or pipe bursts in the ground gathering and transportation pipelines(including T connecters,elbows and flanges),which seriously affected normal and safe production.The influencing factors of pipeline corrosion in this gas field were studied by energy spectrum analysis of corrosion product composition in the pipelines,calculation of multiphase flow in the pipeline,validation of corrosion and erosion model,and flow field analysis of corrosion site.The results show that the perforation and bursting of pipelines and fittings were mainly caused by CO_(2) corrosion and erosion corrosion.The inhibition effeciency of corrosion inhibitor decreased when the medium flow rate in the pipelines was high.By coupling the flow field with the corrosion data,the critical erosion velocity suitable for the engineering application of the gas field was determined.And the protection measures to control the corrosion of pipelines and fittings were proposed.