OilOil is found in the ground. It is extracted from the ground by drilling. First, photographs of likely places are taken from airplanes and information about them is received from satellites. Then, geological maps and rocks from the area are examined by scientists. After explosions are made on the earth’s surface, vibrations are measured by special instruments. Next, drills are used to extract samples of rocks and to bring natural oil to the surface. As soon as oil is taken in pipes to a refinery, unwanted substances are removed there. Finally, pure oil, such as petrol, is produced.