actually, while pumping more oil would be a limited possiblity, global refining capacity is limited. No new refineries have been built in the US since the 70s, i think and many of them are outdated. The oil industry is stretched to the max, from drilling rigs to pipeline steel to tankers. Orders for drills - not a lot of companies make these - are filled up several years ahead. Yes, OPEC does limit output, but they don't control all of the oil that comes on the market. Russia has 11% of the world's production and it's not OPEC. Norway, with some 4% is not OPEC, the US, with about 9% of global production and 20% of refining, is not OPEC.
Also, while there's some possibility to increase production and there's plenty of oil being left untouched right now, a lot of it isn't worth the trouble at the current prices. Maybe when it goes up to a 100 dollars a barrel, it will be worth blasting wholes into the frozen tundra, but it just isn't viable right now.