Shell has filed a revised exploration plan with the Bureau of Ocean Energy Management for exploration drilling in Alaska's Chukchi Sea in the open water season of 2015, company spokeswoman Meg Baldino told Petroleum News today. The company has not yet made a final decision on whether to proceed with the drilling in 2015 but is filing the plan in readiness, should it decide to move ahead. "Today, we submitted revisions to our previously approved Chukchi Sea exploration plan to the Bureau of Ocean Energy Management; this step is necessary to keep our 2015 exploration options viable," Baldino said in an email announcing the plan submission. Under Shell's plan, the company envisages using the drillship Noble Discoverer and the Transocean semi-submersible rig, the Polar Pioneer, to drill in the Chukchi. Unlike in a previous plan, in which the Polar Pioneer was to be stationed in Dutch Harbor in the Aleutian Islands as a backup rig, under the new plan both rigs will be deployed to the Chukchi, Baldino told Petroleum News. Shell's Chukchi Sea exploration has been targeting the Burger prospect, about 80 miles offshore the western end of the North Slope. "We continue to take a methodical approach to this exploration phase and will only proceed with a program that meets the conditions necessary to proceed safely and responsibly," Baldino said. Under the terms of an order from the federal District Court in Alaska, in an appeal against the validity of the 2008 lease sale in which Shell purchased its Chukchi Sea leases, the Bureau of Ocean Energy Management can review Shell's plan but cannot make a decision on whether to approve the plan. An approval decision can only be made after the agency has completed revisions to the lease sale environmental impact statement and then issued a new decision on whether the lease sale should have been held. - ALAN BAILEY