Frozen assets

For centuries the Northwest passage linking the Atlantic and the Pacific was little more than a myth that tempted only the most daring polar explorers.

Picking their way through the treacherous year-long ice of the high Arctic, many of these brave individuals, spurred on by the prospect of opening up new trade routes, died searching for this fabled sea crossing.

The passage was finally navigated for the first time in 1905, but it took Norwegian explorer Roald Amundsen two and half years of ice-bound hardship to achieve the feat and it did not bring the prospect of trans-Arctic shipping routes much closer to reality.

That is now changing fast. This year, for the first time in recorded history, the entire route became ice-free.

And although the ice is now re-freezing, the thaw has triggered a rash of territorial claims from everyone with a potential stake in the Arctic. In the summer, a Russian mini-sub planted a flag on the sea bed beneath the North pole in an aggressive show of sovereignty. In response, Canadian prime minister Stephen Harper announced he was investing billions of dollars in specially-adapted military patrol ships and a new deep-water port.

Beyond the prospect of controlling hugely important new shipping routes, perhaps the biggest reason for the increasingly hawkish stance of the countries in the region is the trillions of dollars worth of oil, gas and mineral reserves that are thought to lie beneath the Arctic ice.

But while the prize may be huge, the costs are also high, and behind the talk of an Arctic fuel bonanza lie a series of significant engineering challenges that cannot be solved overnight.

The Arctic environment is more technically and physically demanding than any other faced by the oil and gas industry. To locate, extract and transport the prizes beneath the ice, billions of pounds will need to be invested in specially designed drilling platforms, tankers and support ships that can operate safely and effectively in extreme conditions. The Engineer has learned that, to achieve this, something of a crash course in Arctic engineering is required.

Andrew Kendrick, vice-president of engineering consultant BMT Fleet Tech, has been involved in the engineering challenges of the Arctic for much of his career. He said the fossil fuels industry faces a considerable knowledge gap when it comes to Arctic ice. ‘We’re currently working for many of the oil companies directly on things to do with ice and they are desperately crying out for support from people who can give them some level of technical assistance’.

He said while the oil and gas industry built up some knowledge on ice the last time it looked at the Arctic during the late 1970s, much of this expertise was lost when the price of oil collapsed in the 1980s.

But why is there such a pressing need for expertise if the ice is melting? Why not wait for the danger to pass, then use traditional technologies? According to ice engineering expert Prof Claude Daley, this is not an option.

The knowledge gap is particularly pertinent for the tankers that will be part of LNG operations

Daley, who heads the ocean and naval architectural engineering programme at Memorial Universityin Newfoundland, said while some predictions suggest there will be no summer ice in the Arctic within the next 50-100 years, this is still beyond the horizon in terms of economic activity. ‘If there’s going to be economic activity within our lifetime it will definitely involve interacting with multi-year ice’, said Daley.

This is where the biggest challenge lies. Building up over several years, containing less brine and more air pockets than first-year ice, multi-year ice is thicker (up to 10m) and stiffer than ice that forms in the winter and melts in the summer: so-called first-year ice. As a result, it is exceptionally difficult for ice-breakers to navigate and clear.

Daley, who is also the director of the BMT-funded Ocean and Arctic Structures Research Programme, added that as the Arctic warms, the dangers posed by multi-year ice may even, in the short term, increase as huge blocks break off and drift into shipping lanes.

BMT’s Kendrick said the engineering challenges posed by multi-year ice are not well understood. ‘A lot of people try to treat ice either as water or as something like steel or soil — neither the marine structural engineers, the ocean engineers nor the civil engineers really can apply their knowledge directly.’

He said oil and gas companies going into the Arctic will need to employ a holistic approach that takes into account a range of operational issues: ‘If someone says “design me a drilling platform” the first question is how are you going to support it? What will you do in terms of ice management? What are your seasonal requirements? If it’s a floating structure are you prepared to allow it to disconnect under extreme circumstances or does it have to have 100 per cent operational availability — your costs can change by an order of magnitude depending on the answers.’

While data gathered from various government and commercial ice breakers means the behaviour of small ships in multi-year ice is relatively well understood, Kendrick said multi-year ice represents unsheltered territory for big tankers.

‘There are models, but extrapolating those from a 5,000-tonne ship at 10 knots to a 150,000-tonne ship at 15 knots we’re dealing with kinetic energies that go up by several orders of magnitude and how big the ice loads are on the ship in those circumstances is unknown. We don’t have any real full-scale data on how big ships going fast will react in ice.’

To illustrate the level of guesswork in current models, Daley pointed to the Hibernia oil platform off the coast of Newfoundland.

‘This has been designed for a load level of about 500 mega-Newtons — but we don’t have any data we have any faith in for forces above about 20 mega-Newtons and that’s really scarce data. The good stuff that we base most of our models on is up to around five mega-Newtons — there’s two orders of magnitude between what we’re really confident in and what the design point is. Luckily that structure’s never been hit but if we go into the Arctic we’re going into harm’s way.’

With a recent study carried out by Wood Mackenzie and Fugro estimating that up to 75 per cent of the Arctic’s fossil fuels are natural gas this knowledge gap is, claimed Kendrick, particularly pertinent for the large number of oil majors considering setting up Arctic liquefied natural gas (LNG) operations.

‘It’s a huge risk and investment for them to make because it’s not like an oil tanker operation where if you miss a trip you can usually turn off the taps without disastrous things happening. If you’re trying to run an LNG train you really need to have a guaranteed throughput. Companies have been talking in terms of fleets of 20 high-ice class LNG ships that would be available simultaneously. Somebody has to take the risk of investing in this equipment.’

Daley agreed that the constant throughput demanded by LNG represents perhaps one of the sternest challenges for Arctic fuel exploration: ‘You need the marine equivalent of a pipeline, which means constant go, ship after ship after ship, all year round. and that is not the way that Arctic activity currently happens — it’s all-seasonal. The idea that we have 150,000-tonne vessels moving through heavy ice all year round is somewhat daunting but the prize is there.’

While the oil majors contemplate their next move, Daley’s team at Memorial University is concentrating on advancing its own understanding of the complex and unpredictable material properties of ice.

Daley said that to develop the next generation of high-ice class vessels, it’s essential to get to the heart of the interaction between ice and man-made structures. ‘When ice hits a structure you tend to get a cascade of fractures, millions of cracks forming. There’s a whole cascade of failure going on and we’re trying to understand the contact process. If you’re looking at a ship whacking into an iceberg and you’re wondering what ultimate capacity you can have so that the thing can be damaged but at least sail home again, you have to model that crumpling.’

He is drawing up plans for two experiments, one which will put an instrumented panel on to a small ship that will be sailed into an iceberg and another that will involve taking a chunk of multi-year iceberg ice back to the laboratory and dropping it on to a structure to study the impact.

Daley said through these kind of studies his team hopes to gain an insight into the fundamental physics of ice/structure contact when both the ice and the structure are failing. And despite his years of experience, the mysterious nature of the interaction between ice and engineered structures shows just how big an engineering challenge the fossil fuels business faces. ‘The scientific challenge of this is really quite a big deal. These systems that we are trying to study are fundamentally non-linear and they’re interacting with each other. There isn’t any general mathematics that can give you any general solutions. We’re dealing with very high-order non-linear transient problems and those interacting aspects of that — there aren’t any general theories to work with.’

Through a number of its own projects BMT is also advancing its understanding of the engineering qualities of ice. Of particular use, said Kendrick, is a range of onboard monitoring systems and techniques that can measure in real-time the ice-loads on a structure.

‘We are now seeing and developing quotations for several people who want to install monitoring systems on a new generation of drilling and production platforms. If you’re dealing with a moored drill ship, you want to put some sort of monitoring system in the anchoring arrangement to see if it’s being overstressed,’ he said.

‘If you’re dealing with ships, you may want to be doing acceleration monitoring to make sure that the equipment is within safe limits or to get an impression of what the global forces are.’

In a recent development in this area Norway equipped its offshore arctic patrol vessel the Svalbard with fibre-optic gauges rather than traditional strain gauges. ‘That’s the technology of the future because they’re more robust and you can put them in fuel tanks without worrying about setting off he gases with the electricity,’ said Kendrick.

In another project, BMT examined the performance of a specially-developed Arctic evacuation vessel. Kendrick explained that one of the issues the oil companies are keen on exploring is what happens when things go wrong on an Arctic platform or tanker. ‘Can we get the people off safely? In the winter solid ice cover makes its easy, but in mixed ice conditions if you bail out in a lifeboat, will it survive the ice conditions?’

Known as the Totally Enclosed, Motor Propelled Survival Craft (TEMPSC) this small, heavily instrumented boat was tested in the Northumberland Strait between the Canadian mainland and Prince Edward Island and used by BMT to provide valuable data on the stresses and strains experienced by a life-raft adrift in the Arctic.