“Offshore structures such as Gyda consist of large quantities of valuable materials that are in high demand on the world market, both as there is a need for more construction materials, but also because the production of reused steel, copper and aluminum emits far less CO2 than the production of new materials, said Bengt Hildisch, SVP Decommissioning in Aker Solutions.  

The Repsol operated Gyda field was shut down in the autumn of 2021. Both jacket and topside were delivered to Stord by Allseas’ Pioneering Spirit in the summer of 2022. At delivery, the total weight of the platform and substructure was around 28,000 tonnes.  

Safe and efficient dismantling 

Recycling an offshore giant like Gyda is meticulous work. The transportation itself was spectacular. Pioneering Spirit, the world’s largest construction vessel and the vessel with the highest lifting capacity in the world, is one of the very few capable of handling such a task. Once the topside was safely skidded onto the dismantling pad, a comprehensive effort started to safely remove all hazardous waste, salvage reusable equipment, and clean the topside, before removing the large flare and derrick.  

To ensure safe and productive deconstruction of Gyda, the Aker Solutions decommissioning team developed a machine-based method to dismantle the Gyda platform. By bringing section after section of the large platform down to the ground and within reach of the heavy-duty cutting equipment, they ensured an efficient and controlled demolition process.  

Johan Fredriksson described the process: “We peeled the platform layer by layer, ensuring a safe and controlled dismantling. Placing structures on the ground is a key part of Aker Solutions’ machine-based method, enabling safe and efficient dismantling. The HSSE benefit lies in reducing manual labor and minimizing work at height.”

Twelve toppling operations were executed on Gyda. The largest, on October 19, 2023, sent the 18,000-tonne topside to the ground. Approximately 50 kg of explosives were used, distributed across 28 charges placed on the legs and diagonal braces.  

“These are complicated operations, that require extremely careful and precise engineering and planning activities. In many cases, dismantling structures is far more difficult than constructing them. I am impressed with the team at Stord and pleased that we managed to complete the project with good HSSE results,” said Hildisch.  

A major contribution to sustainability 

The completion of the Gyda project underscores Aker Solutions’ commitment to sustainability and circular economy principles. Recycled steel from Gyda has resulted in 40,758 tonnes less CO2 emissions compared to producing new steel, highlighting the crucial role of recycling in reducing industrial carbon footprints. 

The journey of Gyda 

The Gyda platform was originally installed on the Repsol-operated Gyda field in the southern North Sea near Ekofisk. Production began in 1990 and was shut down in the fall of 2021. Aker Solutions (then Kvaerner) signed a contract with Allseas on September 20, 2019, for offshore preparations, reception, dismantling, and recycling of the Gyda platform. In 2022, the platform deck and substructure, weighing a combined 28,000 tonnes, were transported to Aker Solutions’ decommissioning facility in Stord by Pioneering Spirit.  

Completing the circle 

The Gyda platform was built at multiple Norwegian yards in the late 1980s. The steel substructure was delivered by Aker Solutions’ yard in Verdal, while the topside was constructed by Aker Solutions’ yard in Egersund and Worley Rosenberg in Stavanger.

While dozens of pieces of machinery, equipment and utilities have been reused, the aluminum from Gyda’s helicopter pad will find new life as a bridge in the Norwegian city of Trondheim. After dismantling at Stord, the materials were sorted by Stena Recycling, remelted by Hydro Aluminum and sent to Leirvik AS for construction of the new bridge. The 55-meter pedestrian and bicycle bridge, which was ordered by the Norwegian Public Roads Administration, will be made entirely of recycled materials from Gyda.  

Benchmark for future decommissioning projects 

As offshore oil and gas installations reach the end of their lifecycle, responsible decommissioning will remain crucial for environmental stewardship. The global offshore phase-out presents vast opportunities, with around 10,000 operational production platforms worldwide.  

The successful completion of the Gyda project sets a new benchmark for future decommissioning initiatives. By achieving a near-total recycling rate and significantly reducing emissions, Aker Solutions demonstrates the viability of sustainable offshore decommissioning. The project also highlights the engineering and logistical expertise required to manage such complex dismantling operations. 

The Gyda project exemplifies how innovative approaches can transform old structures into valuable recycled materials, contributing to a greener, more sustainable future.