OK, I've read that they're trying to drill "relief wells."
It looks like they plan to drill down and "intersect the wellbore" on the leaking well 13,000 feet below the ocean bottom.
What I want to know is how do they manage to hit such a small target that far down? Do they really know the position of the well bore and bit closely enough to make a pipe a few feet wide hit another pipe 13,000 feet below? Is there some sort of "sniffer" on the end of the relief well bit that can detect the bore of the other well?