Oil is a liquid that is made up of organic molecules. However, in the context of the worlds
energy sector oil, or more specifically, crude oil is the liquid fossil fuel that is extracted from
the ground. Roughly 1/3 of the worlds primary energy comes from this primary fuel.
Oil known as petroleum or crude oil, is a thick black liquid composed primarily of hydrogen and carbon.
Oil also contains trace elements of Sulphur, nitrogen and oxygen.
Oil deposits were formed millions of years ago, when dead marine organisms sunk to the bottom
of the ocean and were buried under deposits of sedimentary rock. Subject to intense heat and pressure
these organisms underwent a transformation in which they were converted to oil over millions of years.
This process is similar to the process of natural gas formation, however oil forms under a limited range of temperature while natural gas forms a wider range. This limited range of temperatures is called the “oil window”.
