The main energy sources for vehicles and industrial engines derived from petroleum, coal and natural gas. The third type of fuel is formed from the decomposition of organic compounds derived from the bodies of small organisms that live in the ocean millions of years ago. Slow process of decomposition takes place under high temperature and pressure, and produces a complex mixture of hydrocarbons. Some mixtures are in the liquid phase and is known as petroleum. While some are in the gas phase and are called natural gas.

How do the experts find the location of petroleum? Initially, they saw the instructions on the surface of the earth. Petroleum is usually found under the dome-shaped surface. The location can be on land (formerly the ocean) or offshore. They then conduct seismic surveys to determine the structure of rocks beneath the surface. Furthermore, they do little drilling to determine the presence or absence of oil. If no, then does some drilling to estimate whether the amount of petroleum is economically viable to be taken or not.

Drilling to take crude oil (and gas) offshore can be done in two ways, namely:

- Planting pipelines on the seabed and pumping of oil (and gas) to the mainland. This method is used when the distance of the oil fields are close enough to the mainland.

- Create platforms where the crude oil (and natural gas) is then taken by tanker to the mainland. See Oilfield Equipment For Sale

On land, petroleum (and natural gas) was taken to oil refineries (refinery) to be processed.