What is a gas gathering system?
The gas from a natural gas well is collected using gathering lines. The lines are usually medium size (18 inch diameter) steel pipes buried four feet underground and carry unodorized raw gas at a pressure of approximately 715 psi. Similar to a tree branch type pattern, gathering lines collect gas from smaller lines and move it to a central collecting point such as a gas processing facility, storage tanks awaiting movement to the main pipeline, or marine terminal. When the quality of the gas is not suitable for the main pipeline, it is fed to a gas processing plant.
How does a gas gathering system work?
A gas gathering system works on the principle of gas moving from a higher pressure to a lower pressure. A reciprocating compressor is used to create a pressure differential by pulling the gas from the wells and pushing it into the gathering system. The compressor is driven by an electric motor where power is available or a gas fired engine using a small amount of gas from the feed lines.
Why is a reciprocating gas compressor a good choice?
Corken Reciprocating Gas Compressors work well for this application especially on higher pressure applications where screw or rotary vane compressors are not as effective. Shale gas wells particularly need compression to make them work. The wells tend to produce at a high rate initially but drop off quickly so compressors are used to keep them producing at an acceptable rate.
Corken offers a complete line of oil-free compressors in vertical and horizontal versions. Depending on the flow requirements, standard ductile iron construction with PTFE elastomers and aluminum gaskets are recommended. A D-Style (double packed) oil-free compressor is used often; however, a T-Style triple packed oil-free compressor is recommended when there is H2S in the gas mix. A MC1002 corrosion and wear-resistant coating is needed if there is corrosive gas in the mixture. Individual users may have specific requirements indigenous to their application.