If the oil is down a few thousand feet the surface temperatures won't matter - it will still be quite warm. If you need something hotter why not bring in a number of the small nuclear power plant technologies to produce steam. If nothing else, why not stick a few refurbished nuclear subs out there? These could be portable and cheap sources of a whole lot of BTU's.
The greens will scream naturally but why not answer their paranoid rantings with the argument that this is the best way for us to avoid a whole series of future Iraq style wars. This line of argument won't make them any happier but it might convince the sane in the rest of the nation to go along. In one fairly simple and inexpensive play we could undercut nearly all the enemies of this nation for decades to come.
The problem is that the way they get the nuke plants on subs and carriers so compact is by using weapons-grade (>90% U-235) uranium as fuel, versus the 3% civilian grade
If you're carrying nuclear weapons anyway, there is no need for additional security for the fuel. It's very different in a civilian setting. You cannot use military nuke plants in an unsecured civilian environment