Just watched the Jesse Ventura video about the planned depopulation of the Gulf - this is what I came up with:

BP Macondo drilling was done to breach a salt cavern - they drilled a lateral line and breached the cavern, then blew the rig up.

Waited for nature to take its course.

The oil from Macondo is now filling the cavern and causing the sink hole. (by the way, every sink hole I have ever seen was a gaping hole, not a filled cavern)

People will have to leave their beloved homes, as the area is no longer inhabitable. BP and other oil companies will move in and extract the now easily retrievable oil. They don't even have to drill for it now.

Only explanation for how the same oil found at BP Macondo is now in the salt cavern.