Natural gas processing
is a complex industrial process designed to clean raw natural gas by separating impurities and various non-methane hydrocarbons and fluids to produce what is known as 'pipeline quality' dry natural gas.
Natural gas processing begins at the well head. The composition of the raw natural gas extracted from producing wells depends on the type, depth, and location of the underground deposit and the geology of the area. Oil and natural gas are often found together in the same reservoir. The natural gas produced from oil wells is generally classified as “associated-dissolved,” meaning that the natural gas is associated with or dissolved in crude oil. Natural gas production absent any association with crude oil is classified as “non-associated.” In 2004, 75 percent of U.S. wellhead production of natural gas was non-associated.
Most natural gas production contains, to varying degrees, small (two to eight carbons) hydrocarbon(any class of compound containing only hydrogen and carbon; examples are methane gas (CH4), benzene
(C6H6)) molecules in addition to methane
. Although they exist in a liquid state at underground pressures, these molecules will become gaseous at normal atmospheric pressure. Collectively, they are called condensates or natural gas liquids
(NGLs). The natural gas extracted from coal reservoirs and mines (coalbed methane
) is the primary exception, being essentially a mix of mostly methane and carbon......