It was a political move, but sadly it was pretty clever.
Oil prices have been falling and because the economy is more awful than "expected" the price looked set to continue dropping as investors are going elsewhere. Soon consumers are going to really notice the price in gas has gone down - and now Obama will try to claim credit. You can count on the media to breathlessly report on the falling gas prices and link it to Hussein releasing oil from the Strategic Petro Reserve.
I believe that you have nailed it. He, I presume, is praying that nothing happens to raise retail prices before the election.