The price of oil is falling because there was a huge amount of speculative activity in the price of oil, and that speculative activity is reversing. Speculative activity, I might add, that was fueled by the cheap money policy of the Fed. As the market begins to price in the fact that the era of cheap money (in the US) is over, and that the US dollar is potentially at the end of more than a decade of printing, commodities will all begin to come down (and many already have).
Unless you believe someone found oil on Uranus or that 1 billion cars suddenly were taken off the road, or other fundamental explanation to let us know why oil is suddenly far more available than it was a month and a half ago.
Some movement might also be a supply side issue. Maybe OPEC is drilling up a storm to drop prices for various reasons, ranging from a big FY to Russia to a big FY to the shale boys over here in North America. Or maybe cheap renewable energy is on the horizon.