ABSTRACT
Petroleum is a complex mixture of hydrocarbons that occur in the Earth in liquid, gaseous, or solid forms. The word
petroleum
is often restricted to the liquid form, but it also includes natural gas and the solid bitumen. The word
petroleum
, or
“rock oil,” derives from the Latin
petra
(rock or stone) and
oleum
(oil) and was first used in 1556 in a treatise published by Georg Bauer [1].