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Kulluk hearing brought out key issues Testimony to Coast Guard provided fascinating insights into the circumstances surrounding the grounding of Shell’s drilling rig Alan Bailey Petroleum News
The U.S. Coast Guard has yet to publish the results of its investigation into the circumstances surrounding the Dec. 31 grounding of the Kulluk, Shell’s Arctic floating drilling platform. But a nine-day public hearing in Anchorage, gathering testimony for the investigation, provided some fascinating insights into the events that led to the Kulluk ending up on the shore of a remote island on the northern coast of the Gulf of Alaska.
Chain of events The broad outline of that chain of events was already well known. On Dec. 27, 2012, during a tow from Dutch Harbor in the Aleutian Islands to the U.S. West Coast, the towline parted between the Kulluk and the vessel towing it, Shell’s anchor handling vessel, the Aiviq. An emergency towline was subsequently hooked up between the two vessels. But early on Dec. 28 the Aiviq lost power in all four of its engines. Later that day the Guardsman, a support vessel, arrived on scene and took the Aiviq and Kulluk under tow in a tandem configuration.
On the morning of Dec. 29 the tow from the Guardsman failed. By noon of that day, following repairs to the Aiviq’s engines, three of the engines were back in operation. But by that time the Nanuq, Shell’s Arctic oil spill response vessel had arrived on scene and, together with the Aiviq, succeeded in bringing the Kulluk under tow again.
But with the weather worsening towards a severe storm, eventually with a 55- to 64-knot gale and 35- to 45-foot seas, vessels attempting to tow the Kulluk to safety experienced multiple towline failures and were ultimately unable to pull the Kulluk against the wind. The drilling platform ran aground on the evening of Dec. 31.
Detailed testimony presented at the Coast Guard hearing, as reported in a series of articles in the Anchorage Daily News, provided insights into various factors relating to the grounding.
Moved for maintenance Shell has said that it needed to move the Kulluk south from Alaska for maintenance work in a West Coast shipyard in preparation for drilling in the Beaufort Sea in 2013 (following the Kulluk grounding the company postponed its drilling plans to 2014 at the earliest). Sean Churchfield, Shell’s operations manager in Alaska, told the hearing that work needed on the Kulluk included the replacement of cranes.
Although Shell has said that the timing of the rig move was mainly determined by the need to complete the maintenance work in good time for the 2013 drilling season, Churchfield told the hearing that Shell had wanted to move the rig out of Alaska before the end of the year to avoid having to pay state property taxes for the rig — taxes are based on a company’s inventory in the state on Jan. 1. However, according to a February Associated Press report, state officials have said that, as a drilling vessel operating outside state waters, the Kulluk would not have been assessed state taxes.
Norman Custard, Shell’s team lead for emergency response in Alaska, told the hearing that the tow had been expected to take 18 to 24 days and that no one had forecast seas in excess of 30 feet during the period of the tow. Marc Dial, a tow master with Offshore Rig Movers, who had been in charge of the tow of the Kulluk north to Dutch Harbor in June 2012, testified that a winter transit through the Gulf of Alaska could be conducted safely.
Crew on board But why did Shell have a crew of 18 on board the Kulluk during the winter tow? During the first day of the hearing Custard testified that a prime concern from the outset of the towing incident had been the safety of the crew and the need to evacuate the crew from the drilling rig.
Dial said that Shell’s warrantee surveyor who had examined the towing system for the company’s insurance underwriters had insisted that a crew needed be on board the Kulluk.
According to Capt. Jon Skoglund, master of the Aiviq, the requirement to have a crew on the Kulluk caused Noble Drilling Corp., the company providing the crew, to insist that the tow take a route relatively close to the coast, rather than a direct route across the middle of the Gulf of Alaska. Noble wanted a route that would enable the evacuation of crew members from the Kulluk, if necessary, Skoglund said. In the event, following the failure of the tow with the Aiviq, the Kulluk’s crew had to be evacuated by Coast Guard helicopter.
But the direct, more southerly route across deep water would have lessened the risk of a grounding and would have allowed the use of a longer tow line, with the long line sinking deep into the sea to absorb buffeting from rough weather, Skoglund testified.
Towline parted Todd Case, a Noble rig manager, testified that at the time when the tow line parted on Dec. 27 the Kulluk had been moving slowly over giant, long swells and had not been pitching or rolling violently. Bobby Newill, the Aiviq’s third mate, described the weather as “moderate” at the time of the tow failure.
Case commented that he thought that there should have been two tugs, rather than just the Aiviq, conducting the tow. But Rodney Layton, captain of the Alert, a tug that assisted the Aiviq in trying to pull the Kulluk to safety on Dec. 31, described the hazards of using two tugs in heavy seas, with the two vessels operating in relatively close proximity and coming off swells at different times.
It is clear from testimony presented at the hearing that the tow parted because of the failure of a large shackle used to connect the towline to the Kulluk’s tow gear. But, with the shackle now lying on the seafloor somewhere in the Gulf of Alaska, it is unlikely that anyone will ever establish whether the shackle broke, or whether the cotter pin that closed the shackle simply came out, releasing the towline.
Shackle inspected Anthony Flynn, an oil and gas technical consultant with GL Noble Denton, was Shell’s warranty surveyor for the tow. Flynn testified that he had inspected the shackle prior to the tow and that at that time the shackle’s cotter pin had been in place. The tow master, a Shell representative, an engineer and others had all inspected the tow gear, Flynn said.
Apparently the shackle had a 120-ton rating, a rating higher than the 85-ton rating specified in the Kulluk tow plan. According to an Associated Press report on the Coast Guard hearing, William Herbert, under contract with Shell from Delmar Systems Inc., had also inspected the shackle prior to the departure of the Kulluk from Dutch Harbor and had found the shackle to be in good condition. Herbert said that the 3-inch diameter towline, with a breaking strength of 85 tons, should have broken rather than the shackle, should the tow system have been subjected to excessive stress.
Slime in fuel The multiple engine failure in the Aiviq on Dec. 28 appears to have resulted from the clogging of the engines’ fuel injectors by a slimy material in the fuel, according to testimony by Carl Broekhuis, the Aiviq’s chief engineer. Broekhuis said that he suspected that a fuel additive had caused the problem. However, Coast Guard investigator Keith Fawcett when questioning Skoglund, the Aiviq’s captain, commented on a common practice of adding biocide to vessel fuel to prevent the formation of algae and slime. Skoglund said that he was not aware of any biocide being used to treat the Aiviq’s fuel tanks.
The Coast Guard has taken samples of the Aiviq’s fuel for analysis but has not yet published the analysis results.
Apparently the Aiviq was carrying spare fuel injectors but, nevertheless, had to obtain additional injectors to restore engine operations, using fuel from an uncontaminated tank. Edison Chouest, the company owning the Aiviq, had flown the additional injectors to Kodiak in the company owner’s private jet, with the Coast Guard then delivering the injectors to the Aiviq, Broekhuis said.
During the hearing the Coast Guard indicated that it anticipated publishing its inquiry report in early July but the agency has since said that the publication date will be delayed.
The Anchorage Daily News contributed to this story.
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