Considering intentsive pumping activity for several decades now, those fields are bound to be depleted. Of course they cannot pump more. Which OPEC country would decline to pump more at this price??????
Demand is up everywhere in the world.
While some people are switch to smaller cars and hybrids, we still travel by air as much as always and there are many more houses to heat with oil.
Meanwhile China is rapidly building many more cars, to the point where they have shortages now.
Global demand is certainly going up. That affects the price for everyone in the world, US and others.