In fact, the Monterey is thought to hold over 400 billion barrels of oil, according to the U.S. Geological Survey. That's nearly half the conventional oil in all of Saudi Arabia.
And don't forget the Green River Formation that weighs in at 3 Trillion barrels, with 1 Trillion recoverable with todays technology
Note: 1 Trillion barrels is about equivalent to the entire worlds known oil reserves.
BTW. Saudi Arabia Ghawar (largest oil field) is starting Enhanced Oil Recovery methods to keep their flow rates up. They are also leaving the era of cheap oil.
http://www.bloomberg.com/apps/news?pid=newsarchive&sid=aTxNvtaH8JF8