Shell: Grounded drilling rig sound and fit to be towed

(CNN) -- The Royal Dutch Shell oil drilling barge that ran aground off southern Alaska this week is sound and ready to be towed to safe harbor, a company official said Saturday, adding there is no evidence of any sheen in the vicinity.

The 266-foot-diameter Kulluk remains upright and there is no apparent threat to its stability, said Sean Churchfield, the incident commander and operations manager for Shell Alaska.

The fuel tanks appear intact, and naval architects report the vessel is sound and fit to tow, he said.

The Killuk ran aground off uninhabited Sitkalidak Island, about 200 miles south of Anchorage, on Monday night. The current tow plan calls for the barge to be towed 30 miles to the north to Kiliuda Bay for safe harbor and a more detailed assessment.

"The exact timing of a potential towing activity will depend on weather, tides and operational readiness," Churchfield told reporters in a news conference.

As much as 150,000 gallons of ultra low sulfur diesel and approximately 12,000 gallons of other petroleum products are on board the Kulluk, which had been working in the Beaufort Sea, off Alaska's North Slope, until October.

The vessel was being towed back to its winter home in Seattle when it ran into a severe storm off the Alaskan coast. The Coast Guard evacuated the Kulluk's 18-man crew Dec. 29, and it drifted for 10 hours the following day after the tug that was towing it lost power.

Monday night, tug crews had to cut the rig loose during a storm that whipped up 24-foot waves. That led to its grounding in an area where water depth is 32 to 48 feet.

The Kulluk is a blue and white circular rig with a helicopter landing pad and a tower in the middle. The steel vessel is double-hulled and designed for drilling in Arctic waters.

Most of the nearby shore is owned by a native Alaskan corporation on adjacent Kodiak Island, said Steven Russell, of Alaska's Department of Environmental Conservation. State officials are working with residents to watch for any environmental impact caused by the grounding.

Shell's Arctic exploration plans caused widespread concern among environmentalists and were held up after BP's Deepwater Horizon disaster in the Gulf of Mexico.

Shell says it's working at far less depth and lower pressures than the BP well that erupted off Louisiana, killing 11 men aboard and unleashing an undersea gusher that took three months to cap. The fuel on board the rig is used to power equipment and is not the result of the drilling operations Shell conducted off the North Slope, on the opposite side of the vast state from where the Kulluk now rests.

The U.S. Geological Survey estimates more than 90 billion barrels of oil and nearly 1,700 trillion cubic feet of natural gas may be recoverable by drilling. And the shrinking of the region's sea ice -- which hit record lows in 2012 -- has created new opportunities for energy exploration in the region.

Climate researchers say that a decrease in sea ice is a symptom of a warming climate, caused largely by the combustion of carbon-rich fossil fuels. The science is politically controversial but generally accepted as fact by most scientists.