New Orleans, La. – National Incident Commander Thad Allen says there's a chance that cement pumped down the well could have come back up the outer casing.
"We may be the victims of our own success here, in that once they looked at the results of the cementing from the static kill from the top, they raised the question of whether or not the cement that entered the reservoir might have actually gone back up the annulus and sealed that."
Allen says he must be convinced there's no way oil can come back up from the undersea reservoir.
"One way or the other the annulus will be sealed from the reservoir. Or question is, Did it already happen and do we know that, and will these pressure tests tell us that?
Allen says a relief well is now close enough to intersect the well from the bottom next week.
For NPR News, I'm Eileen Fleming in New Orleans.