[jonascord]

I wondered about that. Yesterday, did they cut off the pipe string ABOVE the BOP? If so, the damaged BOP is still there, restricting access to the well head. How deep in the sea floor is the BOP before you can get to the drill pipe?

[The Cajun]

The BOP sits on top of the seafloor, it is tied to the casing string which runs into the earth to approx 18,000 feet. The drill pipe (much smaller than the casing) is stuck in the BOP and runs thousands of feet into the casing (don't know exactly how much drill pipe they had in hole (casing) at time of disaster).
Real simplified explanation.