Petroleum: Source, Formation and Classification

Petroleum is a fossil fuel, formed from trees plants, bacteria and algae. Over a million years, under the earth, due to high heat and pressure, fossils converted into high-carbon usable fuels.

Petrol: Crude comes from where? 

Have refuelled your car? …… Ohhh No??? You must need to go to the Petrol or fuel station, and refill it. But have thought about that, petrol comes from where? Petrol and petroleum oil are the most important energy sources in our daily life. Nowadays, we can say that without petrol our life would be motionless.

Petrol is a British English word, it is a fuel derived from crude oil which is used as fuels are a stable source of energy instead of renewable energy sources (solar energy, wind energy).
Crude oil is extracted from some miles depth of the earth using giant drilling machines. The reservoirs are found beneath the earth and sea surface. And then in a refinery, it is refined by a refinement process, where crude oil is transformed into Fuels like Gasoline, Diesel, Various types of gaseous products like LPG (Liquefied Petroleum Gas), CNG (Compressed Natural Gas), lubricants oil and many more by-products of petroleum also.
Before the discovery of mineral oils, wood and coals were the main sources of fuel. And for small purposes oil was resourced from natural resources like groundnut and fatty oil from animals and fish.

Do you know!!!
World’s largest refinery plant is situated in India called as Jamnagar Refinery. This refinery plant having refining capacity of 1.24 million barrel oil per day. 

It is located in Jamnagar district of Gujarat, India. This refinery is owned by Reliance Industries Limited.

Petroleum Refinery.
Petroleum Refinery.


Measuring unit for Mineral oil is Barrel. One barrel is equals to 159 liters (Approximately), and 35 Imperial gallon or 42 US gallons.

Crude oil: Pump Jack Oil

What is Petroleum and how is formed it?

Dark black or brown liquid (sometimes yellowish, reddish, greenish) is found under the Earth’s surface, which is known as Mineral Oil OR Crude Oil. This variation in colours depends upon mixtures of chemicals. By fractional distillation processes, it is refined into various types of fuels. Petroleum word comes from the Latin word, “Petra” becomes “rocks” and “Oleum” becomes “Oil”.  Petroleum includes solid and gaseous hydrocarbons and crude oil. In an underground oil reservoir, the amount of gas, liquid and solid depends upon subsurface conditions.

Petroleum is a mixture of various larger hydrocarbons. Crude oil contains hydrocarbons, alkanes, nitrogen, oxygen, sulphur and such amounts of metals as copper, iron, nickel etc.

Petroleum is a non-renewable energy source, like coal and natural gases. There is no any way to replace it because it took millions of years to form under the earth’s layers. Once it is extracted and consumed we do have not any option for replacement.
Finding alternatives to Petroleum is so much mandatory for us, and industries have the aim to find them.


Crude Oil Sucker Pump
A Pumpjack Operating at an Oil Well


Also Read: 

Formation of Petroleum:

Petroleum is a fossil fuel, formed from trees plants, bacteria and algae. Over a million years, under the earth, due to high heat and pressure, fossils converted into high-carbon usable fuels.

Million years ago due to geographical movements and devastating earthquakes, living creatures, trees and plants on the earth went under the ground. Over years, those organic elements are compressed under heavy pressure and temperature. In absence of oxygen under the layers of the earth, this organic matter is converted into a waxy substance known as Kerogen. Over time, that Kerogen is transformed into catagenesis and this also transforms into hydrocarbon, due to high heat and pressure.
This hydrocarbon is composed of Hydrogen (about 13 to 15% by weight) Carbon (about 82 to 85 % by weight) and other elements such as Nitrogen (0.3 to 0.6 %), Sulphur, Oxygen and metals like nickel, copper, iron etc. Due to this variation, extracted crude has various petroleum products like fuel, heavy oil, light oil, gases, plastics, and bituminous. While light oil contains higher hydrocarbon instead of heavy oil. And bituminous has lesser hydrocarbons and other substances present. So, it is always required to refine that crude oil to make useful petroleum products.


IC engine.
IC engine.


Do you know!!!
Gasoline or Petrol is also known as Motor Spirit, which is used to run IC Spark Ignition engines.





Sulphur basis classification of petroleum:

Sulphur is an impurity in crude oil. If the quantity of sulphur in petroleum is less than 0.5%, it is called “sweet”. If sulphur is more than 0.5% in petroleum, it is called “sour”. Sulphur is harmful to machinery during the refining process. It will corrode metals. And also harmful to the environment. So, “sour” petroleum requires more refining instead of “sweet”. Due to that, sweet petrol has more value.

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