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Northern ChallengeReturn of drilling to the Arctic puts focus on spill prevention

It’s been an inauspicious start to a new round of exploration drilling in the North American Arctic. Having spent six years and $4.5 billion in preparations, fought off environmental opposition and court challenges, sustained equipment problems and been further delayed by lingering ice last summer, Royal Dutch Shell plc spudded two wells in the Beaufort and Chukchi Seas, north of Alaska. But the delays forced the
company to cut short its drilling with only the top sections of the two wells—short of any oil-bearing zones—penetrated before its drill ships retreated back south.

To make matters worse, Shell faced a barrage of unhelpful new headlines when one of those vessels—the 30-year-old Kulluk, in which it has invested
 $292 million to retrofit—broke away from tugboats in rough seas and ran aground off remote Sitkalidak Island, Alaska. Though no major spill occurred, it did prompt a new, high-level assessment review of Shell’s Arctic drilling program by the U.S. Interior Department. And it only added to a string of mishaps that also included damage to its new Arctic Challenger spill response barge during sea trials in Puget Sound and the near grounding of its second drilling rig, the Noble Discoverer, when it slipped its moorings in port in Alaska last fall.

With old memories of the Exxon
Valdez oil tanker spill offshore Alaska in 1989 (America’s second worst) and fresh memories of the 2010 BP p.l.c/Deepwater
Horizon spill in the Gulf of Mexico (America’s biggest spill) on their minds, many observers are questioning whether anything has changed to prevent another disaster on the high seas.

Many in the industry say they have, with lessons learned from both of those spills playing into improvements in technology to both prevent new spills and deal with those that could occur.

“There has been a lot done” to improve spill-response technology, according to Arctic spill expert Steve Potter, principle consultant with Ottawa-based SL Ross Environmental Research Ltd., whose experience dates back to work with Arctic drilling pioneer Dome Petroleum Limited in the 1980s when test spills were conducted in the Beaufort Sea.

“There was a period of time when people were not interested in the Arctic and research really wasn’t being done on it. But it has been revived as interest has returned. The oil companies take a long lead on this. We have known of their interest for 10 years and have been doing research in several areas to refine the techniques developed. We now understand the behaviour of oil in cold conditions and ice a lot better.”

Shell’s drilling of its Burger and Sivulliq prospects mark the first U.S. Arctic offshore exploration drilling in two decades. Other supermajors, including ConocoPhillips Company and Statoil ASA,
are expected to follow in the next few years.

Activity on the research side has also picked up. Last January, the International Association of Oil & Gas Producers announced the formation of the Oil Spill Response Technology Joint Industry Program (JIP) made up of nine inter­national oil companies to expand industry knowledge of and capabilities in Arctic oil spill prevention and response. The JIP has undertaken research into in situ burning and aerial ignition systems, dispersant use under realistic field conditions, use of chemical herders, mechanical recovery, trajectory modelling in ice, remote sensing and environmental effects in Arctic conditions. Work will involve several experimental controlled-oil releases in the field to verify research results.

In 2011, the Centre of Arctic Resource Development (CARD) was established by the Centre for Cold Ocean Resources Engineering, a research corporation of Memorial University in Newfoundland, with $16.5 million in funding from the oil industry (partners in the Hibernia offshore project and Suncor Energy Inc., oper­ator of the Terra Nova oilfield) and the Research & Development Corporation of Newfoundland and Labrador. CARD’s long-term research on ways to develop Arctic resources includes study of ice mechanics and loading, ice management and station-keeping in ice.

Statoil, which is ramping up exploration in the Barents Sea, announced it is tripling its Arctic technology research budget and developing a drill rig
tailored to Arctic conditions, while activity also picks up in the Russian Arctic, where Exxon Mobil Corporation has teamed with Rosneft to spend billions exploring in the remote Kara Sea north of Siberia.

Though Arctic exploration stagnated for several years before the recent uptick, there have been a number of important technological advances and improvements over the past two decades, says Potter, who has authored and co-authored a number of papers on the topic as well as managed field trials in ice-clogged waters, most recently in Norway. Though considered somewhat controversial, he has called for new experimental spills to be performed in the Beaufort Sea to further advance the science.

Though they may seem low-tech and environmentally unfriendly, in situ burning (ISB) and the use of dispersants applied by air or ship to break up the oil remain the most effective means of dealing with medium to large spills, he says. “We have made quite a number of advances in both those, particularly specific to the Arctic.”

Oilandice

In ISB, about 80–95 per cent of oil is eliminated as gas, one to 10 per cent as  soot and one to 10 per cent remains as residue that can be recovered after  burning,  according to Shell, which says burning can eliminate 1,000 barrels of oil per hour in a burn area 100 feet in diameter.

Potter says water temperatures in the Arctic are “not really an issue,” and that, for the current exploration, it is primarily done in open water during the summer season, when ice is less of a factor.

The effectiveness of ISB and dispersants was borne out in the Deepwater Horizon spill, which has changed opinions on the techniques, Potter says. “At least for people in North America, it was a coming of age for the use of dispersants. Europeans have long held a more liberal view to their use and I think people now in North America realize that for a very large spill, it’s definitely got to be considered an option. In situ burning was also shown to be very ef­fective with use of fire-resistant booms, and I think it was a coming-of-age for that technology as well.”

As it turned out, controlled in situ burning played a major role in containing the Deepwater Horizon spill, successfully burning between 220,000 and 310,000 barrels of oil and surpassing the total amount collected by skimmers, the National Oceanic and Atmospheric Administration estimates.

A study summarized in a paper Potter co-authored, Beaufort Sea Oil Spills State of Knowledge Review and Identification of Key Issues, notes that: “Significant improvements have been made in the past 20 years in the areas of fire-resistant booms for in situ burning on water and field tests have shown the viability of using booms to contain and burn oil in ice concentrations of up to one- to three-tenths.... Significant advances have also been made in quantifying and characterizing emissions from ISB fires, and decision making models and protocols have been developed accordingly.”

Laboratory and field testing have demonstrated chemical dispersants “can be used effectively in cold waters, in wat­ers where ice is present and in brackish waters, which may be of concern in areas affected by the Mackenzie River outflow,” the study found. “The use of additional mixing energy from a ship’s propellers has been shown to be beneficial for aiding dispersion in dense ice concentrations.” Use of oil-mineral aggregates has also “shown promise in greatly enhan­cing the dispersion and degradation of oil spilled in ice.”

Where some ice cover is present, it can actually be used to advantage, Potter adds, by slowing the spreading and degradation of the oil. “Oil can get trapped in the ice, which seems to concern a lot of people, but it doesn’t concern me. Oil doesn’t move when it’s in the ice. You don’t have the same sea conditions that you have in open water, so the oil doesn’t weather and it doesn’t emulsify as readily. That can be an advantage that you want to use—it is a hindrance, but it is also an advantage. The ice is a relatively benign environment, ecologically speaking, and when it is released from the ice you can deal with it.”

Chemical “herding” of the oil is another promising new technology. “It’s a chemical that you apply to the perimeter of a slick that would tend to herd it, so you don’t have to use booms. That was another part of the experiments performed in Norway, where we were allowed to spill oil and use herders to burn it in place. Once you get oil hot, it wants to spread out even more, but while the fire was going, the herder was keeping it in place, so that was very interesting.”

The use of chemical herders to assist in burning in open areas between ice floes has been demonstrated to be effective in concentrations up to 70 per cent­ ice. “It’s a technology that has been around for 30 years, but nobody had used it in ice, so this application is new. We have developed new herders that are more effective. [How long it lasts] depends on the conditions—we are working on ones that last longer, long enough to do a burn,” he says.

Though mechanical skimmers may not be ideal for medium to large spills in the Arctic, where infrastructure for supporting on-water operations remains limited, that technology has improved as well with development of skimmers designed for operation in ice. They could be a good alternative in niche areas, such as in concentrations of brash ice in a ship track or around fixed facilities.

In surveillance and monitoring, where limitations remain in tracking oil trapped in deformed ice and between floes, research is ongoing to develop sensors using technologies such as ground-penetrating radar and nuclear magnetic resonance.

PREVENTATIVE MEASURES

Shell, meanwhile, says it has taken unprecedented measures to ensure a spill does not occur as its exploration ramps up, with up to four layers of defence to prevent an uncontrolled blowout. The company, which drilled 11 exploration wells in the Beaufort and Chukchi seas in the 1980s and early ‘90s, hopes to drill up to six wells there in the next few years.

Last season’s drilling targeted the Burger prospect, located in 140 feet of wat­er 70 miles offshore in the Chukchi, and Sivulliq, located at about 100-foot depth 16 miles offshore in the Beaufort.

Since the Alaskan wells are being drilled in shallow water under relatively low pressure—by comparison, the Deepwater Horizon well was drilled in over 5,000 feet of water with downhole well pressures about four times that of the Arctic wells—the company says the weight of the drilling mud offers the first line of defence against a blowout.

Atop the well and 40 feet beneath the sea floor sits a 200-tonne blowout preventer (BOP) with an extra set of shear rams (in case one fails) capable of cutting the drill pipe in half to seal the well. The BOP can be activated by the drilling vessel or, should that fail, by remotely operated vehicle that can trigger a remote panel located away from the wellsite that serves as a backup control. And should that fail, divers would be available to descend the shallow water and trigger the remote stab panel, according to Shell.

And if the BOP still fails, the lower marine riser section of the BOP could be cut away and a new assembly lowered into place and connected for direct
metal-to-metal containment. This capping system, modelled after the apparatus that eventually stopped the Deepwater Horizon blowout, is a key addition to its response fleet. Shell could then either close in the well using traditional kill methods inside the BOP or flow the oil and gas to the surface for storage and disposal.

The final line of defence is the specially designed spill containment dome. The Arctic Challenger barge carries the dome, which can be lowered to sit above a leak to suck up the oil, and equipment for separation and processing the hydrocarbons at surface.

The company meets the required same-season relief well drilling capability
by drilling both wells simultaneously, allowing one rig to quit its own well and join the other in the event of an uncontrolled blowout, and should the first rig be rendered incapable of drilling the relief well. Both the Kulluk and the Discoverer are outfitted with secondary BOPs and backup drill pipe for relief well drilling capability.

Shell’s assembled fleet of vessels includes additional oil spill–response vessels pre-staged between the drill rig and the coast in the event any spill is not fully contained on site. If there is chance of landfall, aircraft, wind and current models would help predict the locations at risk and additional oil containment booms, boats and skimmers would intercept the oil before it reaches land.

The measures have not convinced environmental groups, however, which have stepped up calls for an end to exploration in the fragile Arctic environment amid the missteps already encountered by Shell. Whether next summer’s drilling proceeds as planned depends on Shell’s assessment of any damage to the Kulluk and the new review of its oper­ations in the Arctic. Early indications are that while there is no evidence of a hull breach, the Kulluk sustained water damage and lost its electric generators.

“At this stage, it’s too early to gauge any impact on our ongoing exploration plans, but with the Kulluk now safely recovered, we’ll carry out a detailed assessment of the vessel to understand what those impacts might be,” says Marvin Odum, Shell’s director of the upstream Americas business and president of Shell Oil Company.

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