Yes and a few years ago I read a science report affirming the same. Can't remember the report or where I got it but it seem that the hot center of the earth somehow is like a furnace and decomposition will continue on earth for an unlimited time. I might have misunderstood it since science is not my bag.
http://en.wikipedia.org/wiki/Abiogenic_petroleum_origin
Not everyone accepts the theory, but it sure is interesting.
Oil is a b-product of the natural decomposition of organic material. Put under intense pressure and heat, oil is created from the slurry. As long as life exists on the planet, we will have oil.