PETROLEUM

HOW WAS THE PETROLEUM MADE ?

Petroleum (rock oil) was first used in 1556 in a treatise published by the German mineralogist George Bauer, known as Georgius Agricola.Petroleum is a naturally occurring, flammable liquid found in rock formations in the earth consisting of a complex mixture of hydrocarbons of various molecular weights, plus other organic compounds.

COMPOSITION

The proportion of hydrocarbons in the mixture is highly variable and ranges from as much as 97% by weight in the lighter oils to as little as 50% in the heavier oils and bitumens.

The hydrocarbons in crude oil are mostly alkanes, cycloalkanes and various aromatic hyddrocarbons while the other organic compounds contain nitrogen, oxygen and sulfur, and trace amounts of metals such as iron, nickel, copper and vanadium.

The exact molecular composition varies widely from formation to formation but the proportion of chemical elements vary over fairly narrow limits as follows

CARBON	82-87%
HYDROGEN	11-15%
SULFUR	0.01-6%
OXYGEN	0-2%
NITROGEN	0.01-3%