If those fields are so great, why is CA bankrupt?
Therein lies the problem...the oil is still in the ground and likely to remain there for some time.
There are a few reasons.
Environmentalists in California are ferocious. They’ve teamed up with enviro-nazis in the government to prevent citizens from keeping their land. The BLM and American Land Conservancy together were trying to buy land in Kings County claiming it was for a wildlife preserve. There was a fish that caused the San Joaquin Valley to lose access to irrigation water - just so happens there is lots of oil under some of those farms.
This oil is covered by a layer of chert; a very hard sedimentary stone that is difficult to drill through.
http://geology.com/rocks/chert.shtml
Then, after drilling through the chert, the oil itself is very viscous and under low pressure. Gushers are few and the oil can be difficult to extract.