Where does the gushing oil come from?

The New York Times explains in Tracing Oil Reserves to Their Tiny Origins. One (I think important) thing lacking is mention about how much recoverable oil exists in all those coastal reserves as compared to how quickly we're using up the world's oil.

Another paper, the L.A. Times, points to evidence of the limits, in Sarah Palin's back yard, in:

The flow has slowed through the trans-Alaska oil pipeline .

There's only so much oil thar. NPR presented 2 segments on 8/18: Hungry For Oil: Feeding America's Expensive Habit and Can U.S. Take The Heat Of Canada's Oil Practices?