The oil could have come from a rig, but if you look at the post storm imagery you see that the main flow has stopped and the remnant slick is a product of oil that collected on the upstream surface of obstacles, and is now getting washed off slowly.
That puts the main source inshore from Bolivar Peninsula, and I’ve yet to see or hear of a damaged rig in that area. The only petro-chem facilities I’ve noticed so far is the one mentioned earlier, near where Nauti spotted the cars and helicopter.
Could the source be something like a marina with diesel tanks that might have been destroyed?