Treated gas streams often need to be compressed in order to be delivered to the transport pipeline.

In other cases, the feed gas streams must be compressed at treatment plant inlet to compensate a declining well-head pressure (depletion). Alternatively, in crude oil or condensate production the off gas streams will be either re-injected into wells or re-injected for gas lift in order to improve the crude oil production.

This is achieved by means of Gas Compression Units that are based on use of compressors which can be alternative or centrifugal depending on gas flow, delivery pressure and pressure ratio. The compressor driver can also be of different types. Normally the alternative compressors are driven by gas engines or electric motors while the centrifugal compressors are driven by electric motors or gas turbines.

If the Compression Stations are standalone units, these will be equipped with all the required utilities such as fuel gas, electric power generation, instrument air, etc.