At places where crude oil is found, huge, hollow chisels drill several hundred metres deep in the Earth to reach the rocky layers containing oil. In some cases, the oil shoots out because of the pressure of the natural gas, which is found frequently with crude oil. Pumps are used to bring the oil to the surface if the pressure is not adequate. The oil is then transported to the big harbours with ships or through pipelines—hundreds of kilometres long. Sometimes it is also transported directly to a refinery, where it is processed further.
