Petroleum/Oil

Oil is a naturally occurring, toxic, flammable liquid that is mixed with hydrocarbons (chemical compounds containing only hydrogen and carbon) . Oil is formed with the remaining of animals and plants that have been here over one million years. Heat and pressure from these layers helped the remains turn into what we today call crude oil. Petroleum is recovered mostly through oil drilling. As found in the earth, oil may have a variety of properties. Oil fuel, in all of its usable forms, is a refined product unlike; coal and natural gas which can often be burned in their natural condition.

Oil is a thick, dark brown or black liquid. It is found in rock layers of Earth's crust. Oil is currently the most commonly used source of energy in the world.

Petroleum formation underground, see description of diagram below

See description of diagram

How Oil Forms

The way oil forms is similar, in many ways, to coal. Tiny organisms like plankton and algae die and settle to the bottom of the sea. Sediments settle over the organic material. Oxygen is kept away by the sediments. When the material is buried deep enough, it is exposed to high heat and pressure. Over millions of years, the organic material transforms into liquid oil.

Mining Oil

The United States produces only about one-quarter as much oil as it uses. The main oil producing regions in the U.S. are the Gulf of Mexico, Texas, Alaska, and California.

Geologists look for oil in folded layers of rock called anticlines. Oil moves through permeable rock and is trapped by the impermeable cap rock.

Types of Oil

Oil comes out of the ground as crude oil . Crude oil is a mixture of many different hydrocarbons. Oil is separated into different compounds at an oil refinery. This is done by heating the oil. Each hydrocarbon compound in crude oil boils at a different temperature. We get gasoline, diesel, and heating oil, plus waxes, plastics, and fertilizers from crude oil.

These fuels are rich sources of energy. Since they are mostly liquids they can be easily transported. These fuels provide about 90% of the energy used for transportation around the world.

Gasoline

Gasoline is a concentrated resource. It contains a large amount of energy for its weight. This is important because the more something weighs, the more energy is needed to move it. If gasoline could only provide a little energy, a car would have to carry a lot of it to be able to travel very far. Or the car would need to be filled up frequently. So a highly concentrated energy resource is a practical fuel to power cars and other forms of transportation.

Let's consider how gasoline powers a car. As gasoline burns, it releases most of its energy as heat. It also releases carbon dioxide gas and water vapor. The heat makes the gases expand. This forces the pistons inside the engine to move. The engine makes enough power to move the car.

Using Oil

Using gasoline to power automobiles affects the environment. The exhaust fumes from burning gasoline cause air pollution. These pollutants include smog and ground-level ozone. Air pollution is a big problem for cities where large numbers of people drive every day. Burning gasoline also produces carbon dioxide. This is a greenhouse gas and is a cause of global warming. Similar pollutants come from other forms of oil.

[CC BY 4.0] UNLESS OTHERWISE NOTED | IMAGES: LICENSED AND USED ACCORDING TO TERMS OF SUBSCRIPTION