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The history of oil drilling in California is actually quite interesting, IMO. Google “California Oil History” for some very interesting sites.
Lots of Los Angeles, specifically including downtown (where the “Superman” building is) were heavy oil producing areas possibly into the forties and fifties. I used to live on the beach in Los Angeles, and where I lived, Playa del Rey and Venice was absolutely peppered with hundreds and hundreds of derricks well into the 1920’s.
Fair amount here http://www.aapg.org/explorer/2007/03mar/oil_history.cfm
What is also interesting about oil production in California is that much of the modern techniques to get hard-to-extract oil—namely steam and CO2 gas injection—were developed in California oilfields. It is this very technology that has tremendously extended the life of many oilfields around the world.