Associated Press: The “nightmare well” is dead. But the Gulf coast’s bad dream is far from over. Federal officials declared Sunday that the well where the Deepwater Horizon rig exploded had finally been killed. Workers drilled a relief well into the damaged one and drove a cement stake deep into its oily, black heart. Its official end came 11 years after Texaco first sank an exploratory well near that same spot 50 miles out in the Gulf of Mexico, then moved on after finding it unprofitable. When …