Petroleum is a mixture of several hydrocarbons and chemicals. The composition will vary depending on where the petroleum was found. In fact, you can find out where a certain sample of petroleum came from through chemical analysis. However, there are some characteristic properties that are common to all varieties of petroleum.

Common hydrocarbons

Four kinds of hydrocarbons can be extracted from petroleum. They are paraffins (ranging from 15 to 60 percent content), napthenes (30 to 60 percent content), aromatics (3 to 30 percent content) and asphaltics (what remains). These hydrocarbons are separated by fractional distillation.

Composition by elements

The major component of crude oil is carbon (83 to 87 percent). The other elements are hydrogen (10 to 14 percent), nitrogen (0.1 to 2 percent), oxygen (0.05 to 1.5 percent), sulfur (0.05 to 6 percent) and even some metals (below 1 percent). The common metals are vanadium, copper and iron.

Viscosity and color

The viscosity and color of petroleum differs according to the place where it is extracted. Mostly, it is blackish or dark brown in color, but it can also be red, green or yellow. Petroleum can also be divided into heavy and light crude. Light crude oil is less dense than heavy crude oil. The difference is mainly because of the presence of light hydrocarbons. Unfortunately, the world is running out of light crude oil reserves and refineries are being forced to process heavy crude oil