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Subsea 7’s latest heavy construction vessel: the Seven Arctic

Oilfield Technology,

As oil and gas operators venture further offshore and technology allows for more complex subsea installations, there is a growing demand for a new generation of heavy construction vessels (HCVs). Cecilia Rehn, Editor of Oilfield Technology recently talked with Dr Stuart Smith, Subsea 7’s VP Technology & Asset Development, and David Mair, the company’s Group VP Business Development, about the company’s latest HCV, the Seven Arctic.

The vessel is designed to address the operational challenges for subsea construction within ultra-deepwater and hostile environments. “As a leader in the marketplace, for us the Seven Arctic represents the type of sophisticated capability that customers have come to expect from Subsea 7. We see the offshore industry growing tremendously over the next 10 years, and predict that subsea production will be on par with that from platforms in 2030. We see the Seven Arctic helping us to meet with this demand,” said David Mair.

Seven Arctic features

The new HCV will be equipped with a 325 t Huisman Vertical Pipelay System, a 7000 t MAATS underdeck basket for storage of flexible pipe/umbilical and a new design, 900 t Huisman Rope-Luffing Knuckle-Boom Crane. The benefit of this is to maintain knuckle boom functionality for offshore construction activity, while not suffering weight penalty and the associated impact on ship stability when operating conventional knuckle boom crane designs.

The crane’s large lift capacity is matched by significant workability advantages. With an unrivalled 58 m radius it can move equipment from every corner of the deck, thereby reducing the need for deploying skidding systems, and allow the vessel to maximise its operational time.

Subsea 7's latest HCV, the Seven Arctic.

Noting that the Seven Arctic will bring an important step change in subsea construction capability, Dr Stuart Smith added that the “the sophisticated crane and the underdeck basket (at 7000 t it is the largest for Subsea 7) will provide clients the opportunity to install larger, heavier infrastructure components more quickly. It will reduce mobilisations, resulting in more cost-efficient operations.

“A specific advantage is is that the principal crane is both very capable and also flexible. It has distinct modes for 300 t, 600 t and 900 t lifts so the capability can be tailored to give the best efficiency for the work at hand,” Smith added.

Construction and design

The preliminary vessel design was conducted jointly with Wärtsilä, while the detailed design and construction will be completed by Korean company Hyundai Heavy Industries (HHI). This will be the second vessel that HHI will build for Subsea 7. In November 2012, Subsea 7 signed a contract with HHI to build a new Dive Support Vessel which will join the fleet in by the end of 2015.

Future outlook

Subsea 7 has begun talks with clients regarding the Seven Arctic and the news of its features has been positively met. Designed for the deepwater markets, the vessel will be equally at home operating in the Gulf of Mexico, the North Sea, offshore Brazil, or the west coast of Africa. “In the post-Macondo world, the offshore oil and gas industry is constantly looking for safer operations and more efficient solutions. We believe that Subsea 7 is ready continue to innovate, support and remain a global enabler of offshore and subsea production,” Mair said.

Written by Cecilia Rehn

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