Hydrocarbon Dew Point - Relation of The Term GPM To The Hydrocarbon Dew Point

Relation of The Term GPM To The Hydrocarbon Dew Point

In the United States, the hydrocarbon dew point of processed, pipelined natural gas is related to and characterized by the term GPM which is the gallons of liquifiable hydrocarbons contained in 1,000 cubic feet (28 m3) of natural gas at a stated temperature and pressure. When the liquifiable hydrocarbons are characterized as being hexane or higher molecular weight components, they are reported as GPM (C6+).

However, the quality of raw produced natural gas is also often characterized by the term GPM meaning the gallons of liquifiable hydrocarbons contained in 1,000 cubic feet (28 m3) of the raw natural gas. In such cases, when the liquifiable hydrocarbons in the raw natural gas are characterized as being ethane or higher molecular weight components, they are reported as GPM (C2+). Similarly, when characterized as being propane or higher molecular weight components, they are reported as GPM (C3+).

Care must be taken not to confuse the two different definitions of the term GPM.

Although GPM is an additional parameter of some value, most pipeline operators and others who process, transport, distribute or use natural gas are primarily interested in the actual HCDP, rather than GPM. Furthermore, GPM and HCDP are not interchangeable and one should be careful not to confuse what each one exactly means.