Petroleum.

Crude oil is usually found in underground areas called reservoirs. They are composed mainly of hydrocarbons and organic compounds.
Sometimes, petroleum and crude oil are used to mean the same thing, but petroleum itself is a broad range of petroleum products including crude oil itself. 
We use the term 'petroleum products after crude oil is refined in a factory.
Crude oil can exists either deep down in the earth's surface or deep below the ocean beds. Oil drills mounted in the oceans are known as "offshore dills".
The process of generating electricity from crude oil is very similar to that of thermal coal, which we saw in the previous page.

• Oil is burnt in turbines in power stations to produce extreme heat, which is used to create high-pressure steam.
• This steam is used to spin a turbine very fast by pushing against metal blades.
• The blades turn a generator containing wires and magnets and magnetic field produces electricity. 
• The electricity flows to a transformer, which changes it to very high voltage electricity. The transformer also regulates the amount of electricity that is produced and supplied.
• Electricity is sent to homes, factories and other places in the world.

Crude Oil can be used for other things too:

A great chunk of all the total crude oil in the world is processed as gasoline, which we use for our cars.

Because crude oil is liquid in nature, spills from offshore drills and fuel tankers harm the environment a lot, especially marine life.