We all know oil (petroleum) as its use has spread all around the world for several decades. The actual meaning of the word ‘petroleum' is ‘rock oil'. It has a strong smell and a yellow to black color; it can only be found in underground reservoirs. Why is oil so expensive and why does its price affect the world economy? How Is Oil Formed? That's the key question that will enable you to understand its value and importance. The majority of scientists follow the biogenic theory; petrol results from the heating and compression of some organic remains. In other words, zooplankton and algae (small sea plants and animals) that lived and died at the bottom of the sea environment, mixed with mud, were covered with layers of silt and sand (sediment). As sediment increased through time and made them bury deeper; this created the anoxic conditions necessary for their transformation to a new kind of material called kerogen as both heat and pressure increased massively. However, if the temperature exceeds a certain point called the ‘oil window' then all this rare oil turns into gas!!!

Petroleum is very rare as the majority of this liquid escapes through the earth and has been consumed by bacteria. People are left to look for the relatively small percentage of reservoirs that contain oil that has not yet been escaped to the surface of the earth. There are certain conditions under which a reservoir is formed; a rich organic material buried deep into the rock, a permeable rock where this oil can be accumulated and finally, a seal (cap rock) to prevent the oil from escaping to the atmosphere. So, next time that someone asks you ‘How Is Oil Formed?' you know the answer. Nature can never fail to surprise us with its ways. There are some other theories that were denied and not applicable like in the past it was thought that oil is formed by the meteor striking the earth million years ago. There were some rumours also that the oil was gifted to the humans by the aliens. These are the theories that are not applicable now but the main theory is running and this also tells us in nature there is nothing vain. If you think that nature have made something useless then you are wrong. We also see that if there is end of one thing there can be the start so we thought that the life once ended is useless but now we know that the ended life is nothing but the start of a new resource.