Compressing is gas pressure increase with the help of a compressor.

Compression is one of the main operations during hydrocarbon gases transmission through gas trunklines, their injection into oil and gas bearing structures for formation pressure maintenance (with a view to enhance oil and condensate recovery), in the process of gas liquefaction and gas injection into underground gas storage facilities.

Gas compression is also performed at compressed natural gas (CNG) filling stations for motor fuel production.

Compression is performed in one or several stages; compressor type and capacity are determined depending on the amount of compressed gas and a required degree of pressure increase (compression rate). Compression is accompanied by gas temperature increase and, as a rule, requires subsequent gas cooling.