Axess Engineering completes Caisson Replacement Project for Wintershall

Axess Engineering has successfully completed the replacement of seven caissons at Wintershall’s Brage offshore platform in October 2018. The caisson replacement project was one large brick in Wintershall’s life time extension project, enabling the 25-year old jacket installation to keep producing to 2030 and beyond.

Corrosions that have developed inside the caissons have jeopardised its integrity. Given the high-level of risks and uncertainties, Wintershall needed an alternative solution to replace the caissons in the safest and most cost-efficient way possible.

Axess has introduced a completely new way of approaching this pervasive challenge. In 2017, the Engineering team carried out an innovative and climate-efficient method of replacing the caissons–

reducing the use of support vessels and performing the lifting operations below the platform deck with the aid of a specialised Construction ROV (CROV).

Axess developed a method according to the High-Risk Application, Annex K in NORSOK R002. This added safety measures such as lifting above pressurised equipment, double load path, fail-safe, etc. Axess also made a lifting system to catch potential parts that have fallen off after a breakage in one of the caissons. The lifting clamps were custom-designed to provide a complete material handling solution—a more factory way of thinking rather than the conventional offshore project approach.

Fredrik Rakvåg, Service Development Manager at Axess, said: “Together with our partner, we have designed and pre-fabricated a CROV with cleaning, cutting, torqueing, and clamp capabilities. It was also built with hot-stab tooling interaction so it could change out subsea equipment by itself.”

The capabilities of the bespoke CROV exceed the weather-sensitive limitations of large ROV systems on IMR vessels as it can clamp itself to the structure and can carry out mechanical work within a greater operational window. Not only is the solution a much cheaper alternative to the US$100,000 IMR vessel day rate, it also concurrently reduces CO2 emissions.

“This has been the largest EPCI contract in the history of Axess. Congratulations to everyone involved in this project! We want to thank Wintershall for the confidence in our innovative solution and engineering capabilities. This strategic partnership opens a market opportunity for the Axess Engineering’s methodology in the Oil and Gas industry,” added Rakvåg.

Axess also installed a caisson on the Brage platform in 2012/2013—the price tag for that project was approximately the same as replacing the seven caissons in 2017/2018. The key differences were:

  • The interface between Wintershall and Axess
  • Method-based approach compared to the traditional set up
  • Finding a more innovative solution to the major cost drivers

Both projects were completed without any harm to personnel or assets, however, the overall HSE risks and financial aspect of the recent project were much lower compared to the project in 2012/2013.

Get in touch with our Engineering team. Email us at [email protected] for more information about the project.

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