Natural gas has emerged as an essential part of our nation’s energy industry, providing a viable, clean alternative to oil and coal. Recent discoveries of abundant reserves across the U.S. have driven the need for greater exploration, infrastructure and delivery of natural gas to consumers. With this rapid growth, companies have found new opportunities and jobs have been created.
The midstream natural gas industry is the link between exploration and production of raw natural gas and the delivery of its components to end-user markets. It consists of natural gas gathering, compression, dehydration, processing, amine treating, fractionation and transportation. Pipeline-quality natural gas and mixed natural gas liquid (NGL) components are then sold to end users.
Natural Gas Gathering
A gathering system typically consists of a network of low-pressure, small-diameter pipelines that collect natural gas from the wellhead and transport it to processing or treating plants for processing, treating, and/or dehydration, for redelivery to larger diameter pipelines for further transportation to end-user markets.
Natural gas processing is the separation of natural gas into pipeline quality natural gas and a mixed NGL stream through either an absorption, mechanical or cryogenic process. The heavier components which make up the NGL stream are typically ethane, propane, isobutane, normal butane and natural gasoline.
Natural gas transportation consists of moving pipeline-quality natural gas from gathering systems, processing or treating plants and other pipelines and delivering it to wholesalers, end users, local distribution companies and other pipelines. Mixed natural gas liquids (NGLs) are typically transported via NGL pipelines or by truck to fractionators, which separate the NGLs into their components.
Natural gas compression is a mechanical process in which gas at a lower pressure is boosted, or compressed, to a desired higher pressure, allowing the gas to flow into a higher-pressure, downstream pipeline where it will be transported to end-user markets. Field compression is typically used to lower the gas pressure at entry into the gathering system while maintaining or increasing the exit pressure, providing sufficient pressure to deliver gas into a higher-pressure, downstream pipeline.
Natural gas treating entails the removal of impurities such as water, sulfur compounds, carbon dioxide and nitrogen. The amine treating process involves a continuous circulation of a liquid chemical called amine that physically contacts with the natural gas. The gas and amine are separated and the impurities are removed from the amine by heating. The treating plants are sized according to the amine circulation rate in terms of gallons per minute (GPM).
Dehydration is the process during which water is removed from the gas; also called Glycol Absorption
Natural gas liquid (NGL) fractionation facilities separate mixed NGL streams into saleable or purity NGL products including ethane, propane, normal butane, isobutane and natural gasoline.
A place to store natural gas supplies for use at a later time. Storage can be an old gas field, a developed salt dome or a liquefied natural gas tank.