Rock oil - Petroleum
The word petroleum means rock oil. The word petro means rock and ileum means oil. Petroleum is a thick black liquid found in huge reserves in subterranean rock strata.
It is believed that marine animals and plant bodies were buried under rocks due to earth upheavals millions of years ago. They were decomposed due to high pressure, heat and bacterial activities and transformed into petroleum
Petroleum is taken out from inside the earth by drilling deep wells. It is called crude oil. The crude oil is refined in refineries by fractional distillation. During the process of refining we get many products like petrol, diesel, kerosene, naphtha and tar. These petroleum products are brought to the oil refineries and industries to clean them from the impurities and make them pure for daily usage. Besides these petroleum is used to prepare plastics, hydrocarbon, medicines, etc.
It is also used to produce natural gas, LPG, etc. scientists of today have devised many experimental methods to produce petro but this is not very economical and is very expensive.
The major petroleum producers are the Soviet Union, Saudi Arabia, USA, Mexico, Venezuela, and china, Kuwait, Iran and Iraq. India petroleum is primarily found in Mumbai, Gujarat and Assam.