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Crude oil

Crude oil, also known as petroleum or sometimes as black gold, is a black, brown, yellowish or sometimes greenish liquid found in some formations beneath the surface of the earth. It is formed of various lengths and weights of hydrocarbon molecules which may or may not have impurities such as sulfur, oxygen and nitrogen.

Historically, crude oil was believed to have curative properties, a container of the liquid was sent to Roman Emperor Charles V as a cure for his gout. Seneca Indians used crude oil as body paint, ancient Sumatrans and pre-Columbian Indians believed in its curative powers. In the Caspian Sea, Marco Polo refers to this substance as a treatment for camel mange. It was used as ships' caulking; cement for the pyramids and crude lamps such as the one carried by Cicero, the Roman orator. Ancient Mesopotamians used crude oil for jewelry setting adhesive and embalming the dead.

Crude oil is commonly believed to be formed of long ago compression and heating of various organic materials, such as prehistoric plankton and algae which sank to the bottom of the ocean was covered over by layers of sand and mud and compressed to form first a waxy substance known as kerogen. More heat and pressure resulted in the formation of liquid and gaseous hydrocarbons. When these were trapped under a cap rock or seal rock layer a reservoir of hydrocarbons resulted.

These reservoirs are tapped by mining or drilling, to access and pump the crude oil to be further processed. At the refinery, crude oil is classified as sweet oil if it has low sulfur content or sour oil if the content of sulfur is relatively high and must be removed in order to comply with emission standards set by state and federal government statute.

Dozens of different products are formed or refined from crude oil with almost 84 percent of every barrel of crude oil going into fuel products of some sort. The remainder forms other products such as plastic. Crude oil hydrocarbons range in size from the smallest one – methane which is a gas lighter than air. Hydrocarbons with five or more carbons are liquids while very long chains are solids like wax or tar.

The major classes of hydrocarbons available in crude oil include paraffins which are straight or branched chain molecules which are liquid or gaseous at room temperature. Examples are butane, hexane, pentane, methane, isobutene and propane. Aromatics are typically ring structures containing six carbon atoms with alternating double and single bonds. They are usually liquid, as in benzene or naphthalene. The third group of hydrocarbons in crude oil is the naphthenes. These are ringed structures with one bond only between the carbon atoms. They are usually liquid at room temperature. Examples are cyclohexane and methyl cyclopentane


Supply and demand of crude oil at present is about 54 million gallons daily and the demand figure is expected to rise considerably over the new three to five years as more nations are becoming industrialized.