Corrosion Protection Program for High Temperature Subsea Pipeline

Abstract A subsea pipeline has been installed with a novel corrosion protection scheme. The pipeline and associated components have been protected from corrosion with a combination of a high temperature pipeline fusion bonded epoxy coating, a thermal spray aluminum coating and sacrificial cathodic protection anodes. Due to the high operating temperature of the pipeline, anode bracelet installation on the pipeline was not desirable. A cathodic protection attenuation model was used to design the anodes for the pipeline. The model indicated that the sacrificial anodes could be installed at either end of the two-mile pipeline. To assure adequate corrosion control was achieved by the cathodic protection system, a sophisticated in-situ monitoring system was installed. Also, a diver inspection was conducted to measure cathodic protection performance. This paper presents the corrosion control design approach used for each of the major components including the risers, pipeline and buried expansion boxes. The design basis will be compared to the results of the in-situ and diver gathered monitoring data.