So, I’m guessing that the problem is that the wellhead actually brings the oil above the seabed where it can float to the surface, since there are oil seeps all over the floor of the Gulf. One thought I guess would be to heat the chokepoint in the funnel to keep it from icing.
However, I really fail to see how this can be worse than Chernobyl. Chernobyl irradiated a huge swath of countryside with a form of energy inimical to life, rendering the area uninhabitable for decades. This is a long-chain carbon substance (i.e. organic chemistry), which is known to be processable by bacteria. In a few years, this stuff will have sunk back into the ground. Yes, it may get into groundwater in a few areas, but most of it will stay near the shore, where bacteria will consume it. How can this be any worse than the many asphalt seeps, tar pits, and other similar naturally occurring things?
Maybe that’s correct for the long term but for the short term the effects on the Gulf ecology are devastating if this remains uncontrolled. That’s how see it anyway.
Your idea of heating the choke point in the funnel makes sense. By lowering a special heating element in the proximity of the iced up funnel, just the elevated water temperature in the area should warm up the water in the area and transmit that heat into the chamber to melt the ice. A better idea would be to raise that chamber and fit it with a heating element.