The gas supply chain begins with extracting gas from wells. The extracted gas is processed to separate the methane from the liquids and other gases that may be present, and to remove any impurities. More commonly gas fields and processing facilities are located some distance from the cities, towns and regional centres where the gas is consumed. High pressure transmission pipelines are used to transport gas from the source of extraction over long distances from production fields to major demand centres. Distribution pipelines deliver gas from points along the transmission pipelines to industrial customers and from gate stations to consumers in cities, towns and regional communities.
The following diagram shows the gas supply chain and the relationship between the data items presented.