The scope of work included the flushing of subsea pipelines and manifolds, disconnecting flowlines and umbilicals from trees, removing risers and midwater arches, and recovering FPSO moorings. Once disconnected, DeepOcean also managed the towing of the FPSO.
The spool disconnection and blind flange installation represent pioneering achievements in diverless operations.
“This project is a standout achievement for DeepOcean. We have a world-leading track record in finding unique ways to execute complex subsea operations using our in-house design, technology, and tooling expertise. The bespoke tooling created for this scope of work allowed us to perform the entirety of the scope using diverless methodologies that produced exemplary outcomes. Everyone involved in the design, build, and offshore operations should be extremely proud of what they have achieved,” said Robin Mawhinney, Managing Director, DeepOcean UK.
The project has been delivered by DeepOcean’s team in Aberdeen, UK, with support from the company’s office in Haugesund, Norway, as required. The project is nearing completion with the recovery of mooring chains and removal of the risers and mid-water arches to be completed prior to year-end.
Gryphon Alpha was the North Sea’s first purpose built, permanently moored FPSO, and was originally commissioned by operator Kerr McGee. The asset was later acquired by Maersk Oil and then by TotalEnergies through its 2018 merger. Although the field was initially expected to have a lifespan of just ten years, it has exceeded expectations, producing more than 250 million barrels of oil equivalent over three decades of operation.
“As DeepOcean prepares to complete the final phase of this decommissioning project, we remain highly committed to delivering safe, efficient, and reliable operations that will reinforce a very proud legacy for Gryphon Alpha and everyone who has supported her over the years,” added Mawhinney.
