SEATTLE - From the air, the Arctic drill ship Kulluk looks like a giant bowling pin seated on a shallow bowl.
With the centerpiece of the ship, the 160-foot derrick, Shell Oil hopes to send down drill bits and pipe to tap vast oil reserves below the Beaufort Sea off Alaska's north coast. But it's the funnel-shape hull, with its flared sides, that makes the ship appropriate for Arctic Ocean waters, according to the company.
"This conical shape is designed so that if ice starts to run under it - ice moves in the Arctic - if that ice starts to run under it, what that cone does is deflect the ice downward and breaks the ice up into small pieces," said Brent Ross, Shell Offshore Wells manager. "So in essence, you have a big drilling rig on a hull that's shaped like an ice-breaker."
If the oil giant gets its final federal permits and overcomes court challenges by environmental groups, the Kulluk and a second drill ship, the Noble Discover, will be i n Alaska waters this year opening up America's next petroleum frontier.
The U.S. Geological Survey estimates Arctic waters hold 26 billion barrels of recoverable oil and 130 trillion cubic feet of natural gas. The United States consumed 18.8 million barrels per day of petroleum products during 2011, according to the U.S. Energy Information Administration.
Shell's drilling plan calls for two exploratory wells by the Kulluk in the Beaufort Sea and three exploratory wells by the Noble Discoverer in the Chukchi Sea and, sometime in the future, a pipeline link to the trans-Alaska pipeline.
Shell in 2008 spent $2.1 billion on leases in the Chukchi but has yet to drill a well. The company estimates it has spent more than $4 billion preparing for Arctic offshore drilling, including about $100 million for the latest modifications to the Kulluk, which has been berthed in Seattle for about 10 months.
Environmental groups contend Shell and other oil companies have not pr oven they can clean up crude oil spilled in ice-choked ocean waters. They say federal regulators should not have conducted lease sales in a region that lacks basic infrastructure such as deep water ports and staging facilities to launch a cleanup. Environmental and Alaska Native groups this month asked a federal appeals court to reject an air permit granted by the Environmental Protection Agency to Shell for the Kulluk, claiming the drill ship and its support vessels will put harmful pollutants into the skies.
The Kulluk, which must be towed to and from drilling sites, was built in 1982 for a Canadian company and designed for northern conditions.
Below the water line, the hull continues flaring inward and then outward at the bottom of the cone. A dozen anchor wires that come out there are below the active ice level, Ross said.
"The rig can stay in place, regardless of having ice running under it," he said.
That's a safety feature that won't likely be tested t his year. The company plans to drill only in open water. Shell's exploration plan approved by federal regulators allows drill ships to be on site July 15, but Shell must stop drilling into hydrocarbon zones about Sept. 24, 38 days before ice is likely to move in, to have time in open water to fix a wellhead blowout.
The diameter of the Kulluk is 266 feet. It can operate in water 60 to 600 feet deep with a drilling depth to 20,000 feet. Shell's Beaufort wells will be less than 10,000 feet, Ross said.
In open water, the Kulluk is designed to maintain its location in storm conditions associated with waves up to 18 feet while drilling and 40 feet while disconnected.
The Kulluk, under previous owners, drilled eight wells in the Canadian Beaufort and four in U.S. waters, the last in 1993. As prospects waned, it was idle for 14 years at McKinley Bay in Canada's Northwest Territories.
Shell bought the drill ship in 2005. The integrity of the double hull was not compr omised, Ross said.
"One of the things that storing it in the high Arctic, it's very, very dry, conditions are somewhat analogous to storing jet engines in the desert of Arizona," he said. "That dryness has protected that rig, and as we've gone through it, very, very little corrosion in the hull."
The latest modifications focused on replacing and repairing drilling equipment and cranes, replacing the engines and converting the rig for zero-discharge when drilling.
Generators on board were 1982 vintage and had to be replaced to meet Shell's air permit requirements. New generators are equipped with what's essentially a big catalytic converter similar to what's on motor vehicles. They will reduce nitrous oxide to low levels and use a screen system to remove particulate, he said.
The Kulluk also had its paint color changed from orange to blue, a preference of whalers.
A crew of 70 can run the drill ship, but the rest of the more than 100 beds will be filled with marine mammal observers, air monitors, staff from the federal Bureau of Safety and Environmental Enforcement or other regulators, Ross said.
Modifications to the Kulluk will be completed by June 1. A decision on a sail-away date, or a possible stop in the Aleutian Islands port of Dutch Harbor, has not been set.
"We will take stock of ice conditions and make a decision whether to go straight north or maybe stop briefly in Dutch until ice conditions are favorable," Ross said.