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 STUDY

The pipeline in question, with a diameter of 18”, was built with API 5L X52 steel and commissioned in the 1990s. Its initial MAOP was 120 bar, but it currently operates at 55 bar transporting gas.

First, the integrity status of the pipeline was assessed. The existing documentation was outdated, so only operating data were used, which ruled out fatigue problems.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.

IDENTIFICATION OF FUTURE THREATS

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.