The Petroleum, term derived from Latin meaning Stone Oil, is a mixture of different hydrocarbons which, depending on their chemical nature and concentration, give it different colors, ranging from yellow to black (from here the "Black Gold" term is derived). The process of formation of hydrocarbons, called "Neftogenesi", occurs geologically 8 to 100 million years ago.

Petroleum was formed millions of years ago and is the most used energy source in the world today. It was not always this way and probably will not be in the future. But for now the situation is this. A "race" is going on between the Petroleum and Natural Gas. In the 70's the gap between the two sources was much larger. This difference has dropped dramatically over the years, so much so that you could assume that Natural Gas will overtake Petroleum.