As of Tue, Aug 17, 2010 BP is on standby to get government approval to drill final 50 feet to intersect MC252 well annulus (space between rock formation and well casing) at about 800 feet above oil reservoir.

Below are quotes from BP’s briefing with Kent Wells on sealing Macondo well (Aug 10, 2010):

“We do know that we pumped about 200 barrels of cement or so out of the casing. Did it go into the reservoir? Did some go into the reservoir? Did some go up in the annulus? That’s an unknown.”

“We’re planning to intersect the well about 800 feet above the reservoir. And where we are right now with the relief well, we’re just at the shoe of the outer casing. And so we’re now going to start to go down to the place where we can intersect the annulus. And the annulus we’re describing is the annulus between the casing of the Macondo well and just the rock formation. It’s not an annulus between casing and casing. We’re going to intersect it at a point where it’s basically rock and then there’s an annulus and then there’s casing. And that’s where we plan to intersect.”

“And what we don’t know is exactly what we’ll find in that annulus. It could be mud. It could be oil. It could be cement. We just don’t know.”

Sources:
BP’s Briefing with Kent Wells on Aug 10, 2010:    http://bit.ly/c5Cysu  
BP’s Press Releases with Kent Wells:  http://bit.ly/cqaiRk