When gas is drawn from the earth, it is a mixture of several gases and liquids. Commercial natural gas is mainly composed of methane. However, it also contains ethane, propane and butane in accordance with the specifications for natural gas in each country in which it is distributed.
Therefore, before natural gas is marketed, some NGLs, including LPG (propane & butane) are separated out, depending on the ”wetness” of the gas produced: NGLs represent 1 to 10% of the unprocessed gas stream. Worldwide, gas processing is the source of approximately 60% of LPG produced.