As about as stupit as it gets
Nuk it what you get is a cracked or cratered sea floor...
Basically creating a open pit mine sea floor down in to the that oil reserve.......one total mess
Your trying to seal and bury it, not open it up more
Personal long term I think they will go with a modified dome...leaving the dome open at first and establish a foundation in the sea floor, a seal at the base before you close the top to stop the oil
Drive in to the sea floor A large open medal tube around the well head...basically like a bridge piling
Then you fill the inner area with underwater concrete... to establish a foundation in the sea floor
Once that set up ...the tube bridge piling, now around the well head, has a top that can be fitted after and sealed.