California is the 4th largest producer of oil in the country. Most of the oil comes from the San Joaquin Valley surrounding the Bakersfield area. Here are few aerial photographs of the Kern River Oil Field, just to the east of Bakersfield. As you can see, this land is barren except for oil pumps, called pump jacks. Chevron & Occidental have the majority of oil fields, but the Bureau of Land Management also has a big oil site.
See more photos here
Kern River Oil Field in Bakersfield, California