Published: Aug 09, 2010 10:55 AM EDT
Updated: Aug 09, 2010 7:55 AM EDT

NEW ORLEANS (AP) - The oil that poured into the Gulf for more than 12 weeks has been forced back underground and BP engineers expect to spend this week drilling the final leg of a relief well to complete the "bottom kill" designed to permanently seal the leaking well.

BP and the government have said for months that intersecting the blown-out well and shoving more mud and cement into it is the ultimate solution to making sure it never spews crude into the ocean again.

The oil is already back at its source, thanks to the "static kill," which involved thousands of gallons of mud and cement being poured last week through a cap that had been keeping the crude out of the water since July 15. The cement cap poured on top of the oil hardened enough over the weekend so engineers could begin digging the final 100 feet of the well again, according to a news release from the company.

Before the weekend began, BP Senior Vice President Kent Wells said he expected drilling to resume Sunday night, but the company didn't verify if that had happened.

No one at BP or with the government has been willing to declare victory over the spill before the relief well is finished, but retired Coast Guard Adm. Thad Allen, the government's point man overseeing the cleanup operation, said there is virtually no chance the oil will leak again.