Extending the life of a pipeline

Prolonging the Life of Pipelines with Safety

Many pipelines are reaching the end of their original service life, but operators want to keep them running safely. Procainsa offers specialised solutions to extend the life of these pipelines, ensuring safe and reliable operations.

IMPLEMENTATION USING SACRIFICIAL ANODES

Pipeline Life Extension with Security

Procainsa SA carried out the life extension of a pipeline in accordance with ISO/TS 12747:2011, which establishes guidelines for assessing the feasibility of extending the life of the pipeline beyond its initial design. This specific case focuses on an offshore gas pipeline. The implementation of a new cathodic protection system with sacrificial anodes in a protective structure was key in this process.

The subject pipeline is a 18” pipeline was constructed with a steel type API 5L X52 and was commissioned in the early 90’s. Its MAOP was 120bar and currently its operating pressure is 55bar. Its product is gas.

Initially the current state of pipe integrity was studied. The existing documentation is obsolete, only Operation data could be used, which discarded fatigue problems.

It was necessary to wait until the next year to carry out a new inspection campaign, where ROV and ILI inspections were carried out, the future integrity of the pipeline was analysed: future threats identification, extension life assessment and remaining pipeline life assessment.

After study the inspection data, corrosion rate assessment, cathodic protection survey, it was established that the pipeline can continue to operate safely, provided it maintained the same system of operation and inspection.

The only problem detected was in the cathodic protection system of an additional structure, where the anodes were completely consumed.

Following the DNV-RP-B401 standard, a new cathodic protection system was designed using Al-Zn-In Alloy sacrificial anodes.

Finally, a table was drawn up with the IMR (inspection, maintenance and repair) tasks for the pipeline for the coming years.