某油田FPSO压载水舱内壁腐蚀原因分析

Corrosion Analysis of FPSO Ballast Tank Inner Wall in An Oil Field

经现场调研,某油田FPSO压载水舱内壁发生涂层失效与腐蚀现象,且涂层剥落及腐蚀情况发生在局部典型位置。为了总结涂层失效及腐蚀发生规律,并对典型位置开展腐蚀原因分析,通过对2S与3FS两个压载舱室进行宏观分析、涂层厚度检测、壁厚测量等方法进行检测分析。结果表明,两个舱室的涂层剥落及腐蚀现象存在共性问题,舱室第2~6层分段合拢口焊缝附近、龙骨附近涂层剥落及腐蚀较为严重,与现场涂装质量及海水浸入工况有关;压载水舱与油舱侧相邻壁板局部腐蚀较多,主要原因是油舱侧壁板温度较高,氧腐蚀加快造成的。由于涂层剥落及腐蚀在局部发生,失效隐患主要是腐蚀穿孔,建议后期制定合理的施工维修作业规程,及时恢复防腐涂层,根据涂装规格书的要求,严格控制涂层施工质量。

After field investigation,the coating failure and corrosion occurred on the inner wall of FPSO ballast tank in an oil field,and the coating exfoliation and corrosion occurred in local typical locations.In order to summarize the failure and corrosion regularity of the coating,and to analyze the corrosion reason of the typical position,the macro analysis,the coating thickness detection and the wall thickness measurement of the two ballast tanks 2s and 3FS were carried out.The results show that there are some common problems in the coating spalling and corrosion of the two cabins.The spalling and corrosion of the coating near the weld and Keel of the 2~6 layers of the cabin are serious,the local corrosion of the side panels of the ballast tank and the oil tank is caused by the high temperature of the side panels of the oil tank and the acceleration of the oxygen corrosion.Because the coating spalling and corrosion occur locally,and the failure potential is mainly corrosion perforation,it is suggested that the reasonable construction and maintenance operation rules should be formulated in the later stage,and the anticorrosive coating should be restored in time,according to the requirements of the coating specifications,strictly control the quality of coating construction.