某海上油田混输海管腐蚀原因分析

Corrosion Reasons Analysis of Subsea Pipeline in An Offshore Oilf ield

渤海某海上油田海底管道存在腐蚀问题,通过对目标管道进行内检测分析、路由勘察及流体组分检验,采用X射线衍射,观察并分析腐蚀产物形貌和化学成分,结合目标管道的运行工况与特点,并利用相关腐蚀实验,确定腐蚀原因。结果表明,管线主要风险为CO_(2)-H_(2)S腐蚀和Cl-腐蚀;同时存在严重的CaCO3结垢趋势,垢下腐蚀产物为硫酸盐还原菌等细菌的滋生提供有利环境,不排除存在硫酸盐还原剂等细菌因素的腐蚀;管道前4 km出现明显低洼,增加腐蚀风险。

The corrosion problem existed in the subsea pipeline of an offshore oilf ield in Bohai Sea.Based on intelligent internal detection technology,on-the-spot survey of pipeline route and multiphase flow analysis,the corrosion data was detected.The morphology and chemical composition of corrosion products were observed and analyzed by X-ray diffraction,combined with the operating conditions and characteristics of the target pipeline,and related corrosion experiments,the corrosion reasons were determined.The results show that the main risks of pipeline were CO_(2)-H_(2)S corrosion and Cl-corrosion.At the same time,there was a serious tendency of CaCO_(3) scaling,and the corrosion products under the scale provided a favorable environment for the growth of bacteria such as sulfate reducing bacteria,and the corrosion caused by bacterial factors such as sulfate reducing bacteria could be not ignored.The f irst 4 km of the pipeline was obviously low-lying,which increased the corrosion risk.