What is natural gas?

Characteristics, formation, and production

Natural gas is a colourless, odourless fossil energy carrier, gasiform under normal environmental conditions. It forms during the decomposition of organic materials – mostly plants – under the surface and the depths of the seas, over milliions of years. Under the surface, through fractions of rocks it wandered into fields of porous rocks surrounded by cap-rocks. These fields are located from a couple-metre-depth under the surface to even 5.000-metre depth. An advantage of natural gas is that it is easy to exploit and its transportation is safe, given a proper infrastructure. It is most often located at oil fields, but sites of pure natural gase are not rare either. It is widely located in sedimentary rocks, but can also be found in vulcanic rock sas well.

Natural gas is a flammable gas mixture, mostly consisting of methane and higher-order hydrocarbons (ethane, propane, butane, etc., as well as so called inert gases, e.g.: CO2, N2). Its density is smaller than that of air, so it flows upwards in its free state. Composition of Rssian natural gas currently typical in Hungary:

Typical components of natural gas in Hungary
(main components in %)

Metane (CH4)


Etane (C2H6)


Propane (C3H8)


Butane (C4H10)


Nitrogen (N2)


Carbonic acid gas (CO2)


Natural gas is stored by porous rocks located under barrier layers. Gas fields are located by complex geophysical measurements. Following the successful drilling, extraction happens through gas wells. Extracted natural gas is often not purely gaseous, and it does not arrive to the surface in the demanded quality, so incidental accompanying materials and pollutants must be separated, while natural gas must be prepared for transportation.