Crews nearly 25 feet away from intercepting damaged BP oil well

A relief well is “almost touching” BP’s blown-out well in the Gulf of Mexico, meaning that officials could declare the source of the nation’s largest offshore oil spill killed by Sunday, a top government official said Wednesday.

Crews working on the relief well, which is expected to pump cement into the damaged well in order to plug it for good, were within 20 to 25 feet of its designated intercept point deep underground, Thad Allen, the national spill response chief, said from Kenner, La.

Once the damaged well is intercepted, experts will run tests to determine the condition of its outer ring, called the annulus. From there, they will decide whether cement needs to be pumped into the annulus.

The well’s inner core has already been secured with a shot of cement and mud, but experts are unsure whether that work sealed off the annulus from the underground oil reservoir.

“The final question in this whole killing of the well has been the condition of the annulus,” Allen said. “We think we’re going to need to pump cement, but that will not be verified until we actually do the intercept.”

The well has not leaked oil since mid-July, but the final plugging of the annulus has long been touted as an important final step in the process of “shutting in” the well. After cement is pumped in, it will take time to cure and tests will be conducted to determine whether it has adequately done its job.

In Washington, Interior Secretary Ken Salazar issued an order requiring oil and gas companies to plug nearly 3,500 nonproducing wells and dismantle about 650 production platforms no longer in use. The action is intended to prevent catastrophic leaks at wells that in some cases have been abandoned for decades.

“As infrastructure continues to age, the risk of damage increases. That risk increases substantially during storm season,” said Michael Bromwich, director of the Bureau of Ocean Energy Management, Regulation and Enforcement.

richard.fausset@latimes.com

The Associated Press contributed to this report.