One thing I am wondering about...did the rig sink down on top of the wellhead? If so the devices to close the well might have been damaged.
Just a question.
I have run a bunch of oceanographic research cruises into that area (in fact, I recall sailing past that rig several times), and I have always been amazed it the level of technical complexity involved in those things.
I believe the rig settled 1500 feet from the bore hole.