Petroleum: Petro means rock and oleum means oil. Thus petroleum means rock oil as it is obtained from the Earth (either ocean floor or continental crust). The natural unprocessed form of petroleum is called crude oil. Petroleum was formed from the dead remains of aquatic animals. The bodies of these animals got buried in the ocean floor. They got covered with sand and clay. Slowly, minerals inside these remains under extreme conditions and absence of oxygen changed into petroleum. Crude oil is a mixture of various constituents such as petrol, diesel, lubricating oil, petroleum gas, paraffin wax, etc.
Natural gas: Natural gas is a fossil fuel which is in gaseous form. The formation process of natural gas is similar to that of petrol and its stores are procured along with crude oil. Natural gas-rich sedimentary basins are found all over the world. Some of natural gas fields are: the deserts of Saudi Arabia, the humid tropics of Venezuela and the freezing Arctic. It is used for burning and incineration in industries, transport purposes, and as an alternative fuel for cars, buses, trucks and other vehicles. The compressed form of natural gas (CNG) is used for power generation.
