A forest of wind turbines, which turn electricity generators. Oil Oil is found all over the world, from the Middle East to Alaska. Some oil fields are in the sea - but onshore fields are in places covered by the sea millions of years ago. A well is sunk to a pocket of trapped oil. The well is bored using a drillstring lowered from a derrick.
Oil is made of tiny plants and animals that lived in warm seas.
As they died, they were slowly buried beneath the mud of the sea-bed. The heat from deep underground and the increasing weight of mud above turned them into oil. The rock holding oil is porous - it has holes like a sponge. Pressure forces the oil up until it meets solid, non-porous rock, when it becomes trapped in a huge pocket underground. Oil usually comes out of the ground as thick, black crude oil.