1) Crude source 2) Energy source 3) Field 4) Gasoline source 5) Setting for big rigs 6) Site of valuable deposits 7) Well-covered ground 8) Where derricks rise 
the surface area overlying an oil reservoir or reservoirs. The term usually includes not only the surface area, but also the reservoir, the wells, and the production equipment 
[n] - a region rich in petroleum deposits (especially one with producing oil wells)
noun a region rich in petroleum deposits (especially one with producing oil wells)