Shell will conclude its Arctic offshore drilling operations Wednesday and will begin moving vessels out of the Beaufort and Chukchi seas, a company spokesman said Oct. 24.
"We are still drilling, but we can't make a statement on progress," at this point, spokesman Curtis Smith said in an email.
Shell's drillship Noble Discoverer is working in the Chukchi Sea off Alaska's northwest coast while another vessel, the Kulluk, a conical drilling structure, is working in the eastern Alaska Beaufort Sea.
The U.S. Bureau of Safety and Environmental Enforcement has given Shell permission only to do well preparation, or "top-hole" drilling on exploration wells in both the Chukchi and Beaufort seas. This involves excavation at the sea bottom and installation of a blow-out preventer, the drilling of a "pilot hole" to test for shallow gas, and the drilling and installation of casing to about 1,400 feet.
Shell is prohibited from drilling deeper to potential hydrocarbon bearing zones until a specialized spill response barge, the Arctic Challenger, is in the Arctic.
The barge is still at a Washington state shipyard after being delayed in its trip to the Arctic by inspections and certifications taking longer than expected.
Shell will be able to complete its initial exploration wells next summer when the Arctic Challenger is moved north along with Shell's drill fleet.
Shell's initial targets in both the Chukchi and Beaufort are considered promising. A discovery of gas and some oil was made by Shell at the Burger prospect in the Chukchi Sea when Shell last explored there in 1991. The company's current program, where drilling began Sept. 9, is aimed initially at confirming and further testing that discovery, Shell officials have said in briefings.
In the Beaufort Sea Shell its drilling its initial well at its "Sivulliq" prospect Oct. 4, near an oil discovery, "Hammerhead," made by Unocal in the 1980s. Arco made another 1980s oil discovery nearby, at "Kuvlum." Both were uneconomic to develop at the time.