Repair yard reports offshore construction success
The subsea mid water arch prepares to leave the A&P Tyne yard
A&P Tyne says that it is building on its success in a new business sector with the completion of another subsea structure for an offshore oil and gas field.
The Mid Water Arch – used to support control cables as they rise from the seabed to the surface – has left the ship repair and fabrication yard at Hebburn, UK, bound for a North Sea oil field. According to the yard, for the last six months, 50 men have worked daily on the project to cut, shape and weld the shell-like structures wrapped around two pressurised buoyancy cylinders. The entire structure is built in steel and the yard built the gravity base, clump weights and piles that will secure it to the seabed, weighing a total of 600tonnes.
A 1000 ton crane was needed to lift the yellow-painted structure – which is 17m long, 15m wide and 7m high – onto a barge to sail to the final assembly location. The base, clump weights and piles followed onboard a coaster. The subsea arch is headed for the Athena development in the Outer Moray Firth, which will be operated by Ithaca Energy. The field is expected to produce around 22,000 barrels of oil per day once production starts, towards the end of 2011. The subsea arch will support control cables from the well-heads to an FPSO vessel on the surface.
This is the second such order secured by A&P, earlier this year it completed two buoyant subsea structures for an African offshore oil field. Project director Iain Campbell said: “This job was totally different in that the Athena arch is supported by pressurised steel cylinders as opposed to the polymer buoyancy units the earlier subsea arches were built around. The pressure vessel buoyancy tanks are a new design and required very high standards of welding and fabrication. In fact the project required us to meet extremely high standards in all aspects. As it’s suspended underwater the arch is painted to NORSOK coating standards so it will last for 25 years. It was very challenging but everything came together and the whole project went extremely well. Towards the end of the project we were working on it around-the-clock to incorporate additional design changes and ensure it was ready in good time. The oil and gas sector is an expanding market for us and one we are handling very well, delivering quality products to a high-standard, within a tight timeframe.”
A&P Tyne Sales & Marketing Manager Martin Robertson said: “It’s the first mid water arch of its type that we’ve built at the yard and it’s gone extremely well. It’s another step into an important new market for us and the successful completion of each order helps grow our reputation. We are in discussions with a number of potential clients in the oil and gas sector and are looking forward to securing more work of this type.”
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