Transportation

Once oil is produced, it needs to be transported to refineries and onward to consumer markets. The largest portion of crude and refined oil transportation is conducted by sea. Nearly half the world's seaborne trade consists of crude oil or petroleum products. The largest tankers carry 3 million barrels of crude oil, which is more than 480 million litres. Products such as fuel oil, naphtha, jet fuel, and lubricating oils travel in smaller tankers with separate compartments for different products.

The most convenient way to move oil overland is pumping it through pipelines. Roughly one third of the petroleum products produced by European and North American refineries travel to market by pipeline. The United States, for example, has over 350,000 kilometres of pipeline, with pumping stations at regular intervals that keep the oil moving at about 8 km per hour. Some of these pipelines are massive steel conduits more than a metre in diameter, while others are plastic tubes a few centimetres across.

They form delivery systems as vast and complex as the railroads, highways or electric utilities. However, pipelines are largely invisible, buried a metre or more underground.

Crude oil and refined products are also transported by tanker, barge, railway and truck. Large users, such as power stations and chemical manufacturers, receive bulk deliveries directly from refineries. The petrol in your car may take a more roundabout route to its destination. It goes from the refinery to a distribution terminal or bulk plant, which may store it briefly before sending it by truck to the service station where you buy it.