Creation of natural gas – The occurrence of the Natural gas in the earth takes place in the form of natural gas deposits.  The distribution of the natural gas is scattered and cannot be predicted with certainty. The various reservoirs of the natural gas vary a lot in their geologic history. The creation of natural gas took place from the organic matter over millions of years. The organic matter used in the process belonged to marine or coastal ecosystems. The decomposed organic matter from dead plants and animals got covered in layers of sediments and mud gradually. The continued deposition of the decomposed organic matter in the layers piled on top of previous layers led to the increase in pressure and temperature. This increased pressure and temperature transformed the organic matter gradually into methane-rich gas and oil. This natural gas rise towards to earth’s surface after its formation through pores and fissures till the time they got trapped between the less permeable rock layers and created reservoirs of natural gas.

Composition of raw natural gas – The natural gas in its natural form consists of following ingredients.

(1) The natural gas consists chiefly of methane (CH4) that is regarded as the shortest as well as lightest hydrocarbon molecule.

(2) Apart from methane, natural gas also consists of different amounts of higher molecular weight gaseous hydrocarbons.  The raw natural gas comprises of 20 % volume of ethane, normal butane, isobutene, pentanes and higher molecular weight hydrocarbons. They are collectively called as a NGL (Natural Gas Liquids), when they are processed and purified into finished by-products.

(3)Mercaptans such as methanethiol (CH3SH) and ethanethiol (C2H5SH)

(4) Acid gases like carbon dioxide (CO2) and hydrogen sulphide (H2S)

(5) Gases like Nitrogen (N2) and Helium (He).

(6) Water in form of water vapour and liquid water.

(7)Liquid hydrocarbons

(8)Mercury in elemental form and in form of compounds.