what is crude oil

Crude oil is a fossil fuel that is extracted from the earth and refined into various products such as gasoline, jet fuel, waxes, asphalt, lubricating oil, plastics, and other consumer goods. It is a mixture of hydrocarbons that exists in liquid phase in natural underground reservoirs and remains liquid at atmospheric pressure after passing through surface separating facilities. Crude oil and other petroleum products are mixtures of hydrocarbons that formed from the remains of animals and plants that lived millions of years ago in a marine environment before dinosaurs existed. Over millions of years, the remains of these animals and plants were covered by layers of sand, silt, and rock. Heat and pressure from these layers turned the remains into what we now call crude oil or petroleum. Crude oil is typically obtained through drilling, where it is usually found alongside other resources, such as natural gas and saline water. Crude oil is composed of hydrocarbons, which are mainly hydrogen and carbon, and other elements such as nitrogen, sulfur, oxygen, and metals in small amounts.