Quote from GTS:
No, it means that when they pumped cement down from the top it didn't make it all the way to the bottom so they want to cement the bottom so that the well is sealed top to bottom.
Seriously, isn't it time to lay off all this conspiracy crap about the well still leaking - if it were leaking oil then there would be an oil slick at the site... don't you think someone would have noticed that over the past month?
no! not if it was leaking 5000 ft down