Natural Gas Derived from Oil Wells of Two Types

It is obtained from wells dug in the oil-bearing regions. It is also called as ‘Marsh gas’. It accumulates in underground reservoir either with or without petroleum oil.
The gas which is coming out from the well is known as cashing head gasoline and it is a good source of petrol
Natural gas is an excellent fuel because it has high calorific value and burns with a non-luminous flame.
Approximate composition of natural gas is:

CH 4 =70%90%

C 2 H 6 =5%10%, H 2 =3%

and the rest is

CO+CO 2

Natural gas is a mixture of methane and higher hydrocarbons such as n-propane, n-butane, isobutane, isopentane etc.

Natural gas derived from oil wells are of two types.

S. No	Wet natural gas	Dry natural gas
1.	It is obtained from oil producing wells. When natural gas occurs along with crude oil, it is called as wet natural gas.	When the petroleum well contains only gas and no oil, the gas is called as dry natural gas.
2.	Wet gas contains mixtures of methane and higher hydrocarbons like n- propane , n- butane, isobutane, isopentane and a little percentage of gasoline.	The dry gas mainly contains methane and does not contain any gasoline vapour.
3.	The approximate composition of wet gas is CH₄ = 80% 95% C₂ H₆and others hydrocarbons = 5% 20%	The approximate composition of dry gas is CH₄ = 96% , C₂ H₆ = 0.8% and N₂ = 3.2%
4.	Its contains higher percentage of heavier, unsaturated molecules and hence its calorific value is higher	It contains lower percentage of heavier unsaturated molecules and its calorific value is comparatively low.