ANCHORAGE - BP has launched a shutdown of dozens of oil wells on the North Slope as part of an effort to improve safety in the aging oil field.
The oil giant said Wednesday the shutdown will reduce production by about 20,000 barrels a day. Slope production has averaged 811,000 barrels per day so far this month.
A review of some 2,000 wells in the huge Prudhoe Bay field, as well as the neighboring Endicott field, found that about 70 oil wells need improvements, BP Alaska spokesman Andrew Van Chau said.
The review involved experts not only from London-based BP but from other major Prudhoe owners including Conoco Phillips and Exxon Mobil. BP runs Prudhoe, the continent's largest oil field, on behalf of the partners.
Problems found in the wells include the potential for leaks of oil, oily water or dangerous natural gas, as well as engineering or equipment shortcomings. The review also looked at field operating procedures.
Each well will be overhauled at a cost of about $2 million each, putting the total price tag at $140 million.
"Our focus is on safety," Van Chau said. "We're looking at being on the North Slope for the next few decades."
Van Chau said the process of shutting down the wells began last week.
Although BP plans to bring back the most productive wells as soon as work is complete, it could take until the middle of next year to restart them all.
John Norman, chairman of the Alaska Oil and Gas Conservation Commission, which regulates oil well operation, said Wednesday his agency encouraged refurbishing the 70 wells, though he said none is out of compliance or unsafe.
Although the production decline hurts - the state collects millions of dollars in taxes and royalties on North Slope oil production - Norman said BP has "very valid reasons why they're undertaking this action."
The basic problem, Norman said, is that Alaska's oil fields are showing some age.
"Many of the wells at Prudhoe Bay are now 30-plus years old. You can imagine that any piece of equipment at that age can develop problems," he said.
A general problem with many of the wells on BP's refurbishment list is pressure buildup in the holes. Such pressure must be managed to prevent dangerous ruptures, especially when a well is restarted after a maintenance or other shutdown.