Crude oil is formed by the decomposition of organic matter in absence of air over a long period of years and also by some catalytic reactions.
Some terms used in petroleum
It is the process of breaking down larger molecules of hydrocarbons into smaller molecules at a very high temperature or under intense pressure and even the presence of catalyst.
It is the measure of the performance of petrol in the engine. It is also termed rating.
It is tapping sound heard in the engine of a car which makes it to loss power.