Petroleum Geochemistry
Author Phoomphavis Boonsrirojna      Editor Poomisant Srimaharaja

Have you ever heard words like alkane, alkene or alkyne?
Do you know that paraffin is a synonym for alkane?
Do you know that we use a lot of alkane-compounds in our daily life?
In this article we will cover most of them.
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​Why are they so important?
Hydrocarbons are organic compounds with diverse chemical compositions. The various molecules have many different properties which leads to a variety of different uses. Some hydrocarbons are used for fuel, in most of our vehicles, and some types are used in products such as cosmetics, lubricants, etc.
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​Which of them are important?
These are the ones that we think are really interesting!

1. Alkanes (C_nH_2n+2)
Common name: Paraffin
Naturally, Alkanes are commonly found in the reservoir, petroleum production.
Example: Methane (CH₄): Methane is used as a fuel, but mostly not for vehicles. Methane is usually used for oven, house, heater, etc.
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Methane in liquid form, or LPG

Methane is also used in vehicles, but in fluid form that we call liquefied natural gas (LNG) or natural gas.
It is also used for rocket fuel and as a chemical feedstock.
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Methane is very useful and it is used in many industries.

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2. Alkenes (C_nH_2n)
Common name: Olefin, Olefine
Naturally, Alkenes aren't found in the reservoir.
Example: Ethane (C₂H₄): the most important organic feedstock in the petrochemical industry.
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Different uses of ethelene.

For example, a product of the petrochemical industry that is very important for our daily life is plastic. These days plastic is everywhere around the world! Such as your table, your chair, even your laptop, everything! Not only Ethylene, but Propene and Butadiene are also types of Alkenes that are very important in many industries. If you are interested in details about Alkenes, you can find out more! Alkene-Wikipedia

Alkenes are different form Alkanes because Alkenes exhibit double bonds that make them unsaturated or unstable. That's why we do not find Alkenes naturally, but we can find them in chemical processes in the industry.
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Double bonds in Alkenes

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3. Alkynes (C_nH_2n-2)
Common name: Ethyne (C₂H₂) is called Acetylene
Example: Acetylene (C₂H₂): unsaturated (see Alkenes). Acetylene exhibits triple bonds, so it is unstable which means we don't usually find it naturally in the reservoir, but we can find it in chemical processes. Acetylene is usually used for welding, portable lighting, plastics and acrylic acid dericatives (chemical feedstock), and many more (such as Wacker process).
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Acetylene torch flame

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​4. Aromatics
This hydrocarbon is very unique because it has a special structure that is described as cyclic and exhibits resonance bonds. Even though Aromatics have double bonds, their resonance effect makes the Aromatics stable and they can be found naturally in the reservoir, like Alkanes.
Importance of Aromatic compounds: Aromatics are usually used as feedstock for many industrial products such as Polyester and Nylon
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Nylon armor

Polyester Fabric

​Polyester materials, which we can find in our daily life are for example polyester fiber and polyester fabric. What your cloths are made of! There are many things that you use everyday but maybe you just don’t know that it’s made of Polyester.

Nylon is very useful and is used in many industries. One that is really interesting is Nylon armor that is very flexible but light. We can find Nylon armor in our daily life for example; the armor that police officers use. (and yes! It can be seen in many Hollywood movies)
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Basic structures for Alkanes, Alkenes, Alkynes and Aromatic hydrocarbons.

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​Summary
Alkanes, Alkenes, Alkynes, and Aromatics. Do you think these are the types of hydrocarbon compounds that we found in oil and gas production?
Well, mostly Alkanes and Aromatics can be found naturally in oil and gas reservoirs. Alkanes have only single bonds and Aromatics have a special structure (resonance bonds). These bonds in Alkanes and Aromatics have low energy. The result is these bonds are very stable, so they can be found naturally.
So, where can we find the two other types of hydrocarbon compounds? Because most hydrocarbon compounds that have double or triple bonds aren't stable, we can only find them in the production of petroleum products. 

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If you want to learn more,
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References
chemgapedia.de
wikipedia.org/wiki/Alkene
wikipedia.org/wiki/Methane
wikipedia.org/wiki/Alkane
wikipedia.org/wiki/Acetylene
wikipedia.org/wiki/Aromaticity
wikipedia.org/wiki/Nylon
sparknotes.com

Pictures
mthai.com
technologystudent.com
alleghenyfront.org
wikimedia.org
reference.com
iacpublishinglabs.com