Antartica oil would be hard to extract anyway...

There probably is oil under Antarctica, but extracting it would not be easy or cheap. It would be difficult (though not impossible) to keep the oil exploration and drilling teams alive in such a climate. And once you get the oil to the surface, what then? A pipeline would need to be built to the coast, and once there, a major port would have to be built. None of that infrastructure exists right now and it would costs billions of dollars to build it. It can certainly be done, but again, it'll be difficult in more ways than one and possibly not economically viable at current prices.

One other potential problem could be international law. I'm not sure what's on the books regarding Antarctica, but there may or may not be treaties prohibiting any economic development on the continent.