Corrosion repair on a North Sea operator’s platform

Client Challenge

A North Sea operator had a platform which was experiencing significant corrosion on the west side stairs. This corrosion threatened the integrity and safety of the stairs, necessitating immediate attention to prevent further deterioration and potential safety hazards. Additionally, five 3” stanchion supports were suffering wall loss due to external corrosion, requiring preventative measures to avoid further damage. The complexity of the project was compounded by weather delays and equipment limitations, which impacted the feasibility of completing all necessary repairs in a single mobilisation.

What we did
To address the challenges posed by the corroded stairs and stanchion supports, we mobilised a team of two skilled rope access technicians to the platform. The repair process was meticulously planned and executed in several stages to ensure comprehensive and lasting results:
Surface preparation: The technicians performed thorough surface preparation to achieve ST3 cleanliness, essential for the effectiveness of the subsequent repair layers.
Primer application: After preparing the surface, a 3K primer was applied to the repair area, forming a strong foundation for the following layers.
Layer application: The technicians applied five layers of our carbon-fibre SRS cloth, combined with a 2K LT resin system (Low Temperature – suitable for North Sea applications). To reinstate full structural support to the gratings placed on top, the underside of the top lip of the beams received ten layers of cloth.
Stanchion support repair: Two layers of 2K LT were applied to the five 3” stanchion supports experiencing wall loss due to corrosion, as these supports had no structural loading.

Results
The repair work carried out resulted in full reinstatement of the integrity and safety of the affected areas. The application of the carbon-fibre SRS cloth and the flexible wet layup process ensured a durable and effective solution to the corrosion problem, despite challenging geometry and access conditions.
Enhanced structural integrity: The under-deck stairs now have restored integrity, with the Technowrap repair providing robust protection against further corrosion. The stairway is now back in use, eliminating the hazard potential for staff on the asset.
Preventive measures: The stanchion supports were effectively safeguarded from further corrosion, extending their operational life and preventing potential future issues.

Additional verification: Due to the structural loadings in the stairway, and the level of wall loss across the beams, a review of the design calculations, repair methodology, and close out reports was carried out by Lloyd’s Register. They
requested additional information on the justification for the design, considering the lifetime of the repair, required loadings and material condition and properties of the staircase and stanchion supports.
The successful review by Lloyd’s Register once again proved the composite wrap solution is valid for structural components and where a cold works solution is needed.
Professional execution: Despite the challenges posed by weather, our technicians completed the critical parts of the project efficiently and to high standards, ensuring minimal disruption to the platform’s operations.

The effective mobilisation and execution of this repair project further highlights our expertise in addressing complex corrosion issues in challenging offshore environments, providing operators with a reliable partner for maintaining their assets.