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Weight-lifting record.

Pioneering Spirit is the world's largest work vessel and the first that can remove oil platform topsides in a single lift. It could speed up North Sea decommissioning, reports Lydia Heida

"It has been a very long road to get this far," says Edward Heerema, president and founder of Allseas, who has dedicated nearly 30 years to the development of the giant work vessel Pioneering Spirit. "I'm a fanatical engineer, so it has given a lot of pleasure, but many worries as well."

Heerema developed the idea for Pioneering Spirit as long ago as 1987, but commissioning took place three decades later, in 2007. The vessel was built in South Korea by Daewoo and arrived in Rotterdam, the largest port in the Netherlands, for final outfitting in January 2015.

In August 2016, Pioneering Spirit completed its first commercial project, removing the 13,500-tonne Yme oil platform topside for Repsol in the Norwegian North Sea. With its double bow, the vessel can straddle a platform and lift a topside with eight sets of lifting beams.

But the primary target of Pioneering Spirit will be removing topsides much heavier than 10,000 tonnes--up to 48,000 tonnes--and jackets that weigh up to 25,000 tonnes. To be able to do this, Heerema and his team designed the largest work vessel in the world that is 382m long and 124m wide.

Owing to the sheer size of Pioneering Spirit, the vessel is very stable. In addition, its topsides lift equipment has been fitted with an active motion compensation system. This enables the ship to carry out a lift in waves up to 3.5m high.

"When it is properly activated, the yokes which will lift the platform make movements on the ship that bring them to a standstill relative to the platform," explains Heerema. "Then you can gently connect the yokes to the platform and do the fast lifting."

The lifting system was "by far the most complicated aspect of the ship to design and to build," according to Heerema. Each beam has a 3,000-tonne lift capacity and can move in three directions independent of the others. "In nine seconds they can push up the topside over a height of 2m thanks to a hydraulic system driven by high air pressure," says Heerema. "There is a lot of compressed air in the ship, which is released at the moment of the lift into the cylinders."

In addition, water drops out of four quick ballast tanks located high in the vessel's bow, which hold 11,000 tonnes of water, to give additional height. "That part of the lift takes 30 seconds," says Heerema. "But, all together, it is one operation."

Pioneering Spirit is also equipped to lay pipelines, with a pipelay tension capacity of 2,000 tonnes. This is double the capacity of Allseas' Solitaire and thereby surpasses it as the world's largest pipelay vessel. Heerema says: "It is now possible to lay large-diameter and extremely heavy pipes in water up to 3km deep."

Building Pioneering Spirit came with a price tag of $2.8 billion. "It is a shocking amount," says Heerema. "But you get used to the fact that it is going to cost much more than you initially assumed.

"We have been able to pursue our dream and to do this in our own way, since the company is not dependent on shareholders that have to agree with big steps. Your independence gives you a lot of possibilities, but you always have difficulty finding money."

Building the vessel was delayed by six years because of the technical complexity of the lifting system and the banking crisis that started in 2008. "Suddenly banks could not lend us enough money to start building, so we had to wait until the banking crisis was over," says Heerema.

Around 1,000 companies worldwide delivered significant parts for the ship, of which 50 are in the UK. Allseas drew up the conceptual design of Pioneering Spirit in-house, and UK-based Swan Hunter assisted in the basic design of the novel twin bows and the lifting systems. Swan Hunter's staff spent 160,000 hours working on these designs.

Gerard Kroese, managing director of Swan Hunter, comments: "Many aspects of the design had never been seen on such a scale before. The engineers had to overcome lots of challenges that involved the complex systems contained within the vessel and the sheer size and loadings that come with such a concept."

In 2009, Deltamarin Finland produced the complete detail design of Pioneering Spirit.

Over the next 30 to 40 years numerous large and complex oil platforms will have to be removed from the North Sea. These structures are made up of more than 4.5 million tonnes of steel, according to Roger Esson, chief executive of trade association Decom North Sea.

Traditionally, platforms are removed using a process known as "piece small," which entails cutting a topside into pieces weighing between 10 and 100kg and shipping them back to shore. Alternatively, "reverse install" is used: this means removing large modules in the reverse order from which they were installed. This second method was used to decommission the North West Hutton platform, near the Shetland Islands, in 2008. More than 20 lifts were needed to remove all the modules, the largest of which weighed 2,800 tonnes.

Esson says: "With every engineering project there are challenges. Pioneering Spirit will not just sail underneath the topside and lift it. There is actually a lot of engineering work that has to happen before that heavy lift can take place.

"These installations are lifted from the underside, but that is not the way they were designed to be lifted. So you have to make some fortifications to enable the single lift to happen."

Market research firm Douglas-Westwood's North Sea Decommissioning Market Forecast 2016-40 estimates the costs for removal in two different scenarios. The first assumes that current methods for platform decommissioning remain in use, and gives a cost of $82 billion.

The other scenario takes into account the impact that single-lift vessels, such as Allseas' Pioneering Spirit, might have. This could potentially lead to $12 billion in savings. "AD the work that normally would be done offshore can be taken onshore," says Ben Wilby, the author of this report. " So you cut out a lot of the costs."

Pioneering Spirit is quite appealing for that part of the market, according to Wilby. "There are really no other companies that can offer this service. But the vessel will have to offer quite a high day rate, in comparison to other ones, to come anywhere near profitability. Whether oil companies will accept that price will remain the question. These companies know how to push the price low."

Shell UK has already contracted Allseas to remove three topsides weighing between 16,000 and 30,000 tonnes, and a jacket from the Brent platforms in the British part of the North Sea. Pioneering Spirit will be able to do this in accordance with OSPAR 98 regulations.

Heerema says: "Probably in the summer of 2017--the date is up to Shell to decide --we will take away the Brent Delta platform which weighs 24,000 tonnes." This topside includes 10 tonnes of asbestos, 899 tonnes of paint, 31 tonnes of batteries and 3,446 fluorescent fights.

Natasha Obank, at Shell UK, says: "It will be the heaviest single-lift offshore ever. Once lifted, the Delta topside will transported to a near shore location, transferred on to a barge and then towed into Able UK's Seaton Port facility in Hartlepool, where it will be recycled."

Statoil has awarded Allseas the order for installing three large topsides for the Johan Sverdrup project in the central North Sea. Another project, the installation of the topside of Husky Energy's White Rose platform in Canadian waters, has been postponed because of the low oil price.

Allseas is already planning to build a new heavy lifter, Amazing Grace, with 72,000 tonnes lift capacity. "We are now in the engineering phase for which we will need a few more years," says Heerema, who has new ideas for the lifting system that are still secret. The estimated cost of Amazing Grace is $3.4 billion and the vessel could be operational in 2023.

Wilby says: "Having two vessels that can do this kind of work so quickly might capture the market for extra-large topsides. Allseas will be able to lift anything."

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Founded in 1985, Allseas is a Switzerland-based oil and gas industry contractor. In addition to Pioneering Spirit, the company operates three dynamically positioned pipelay vessels, a pipelay/multipurpose work barge, a support/trenching vessel and a survey ship. Allseas has offices in the Netherlands, Belgium, the US, India, Australia, Brazil, the UK and Portugal, and three fabrication yards in the Netherlands. The company has 2,500 employees.
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Title Annotation:Offshore: Decommissioning
Author:Heida, Lydia
Publication:Professional Engineering Magazine
Article Type:Cover story
Geographic Code:0NORT
Date:Nov 1, 2016
Words:1478
Previous Article:On the up and up.
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