1. n. [Drilling]

A device that removes air or gases (methane, H₂S, CO₂, and others) from drilling liquids. There are two generic types that work:

• by both expanding the size of the gas bubbles entrained in the mud (by pulling a vacuum on the mud)
• by increasing the surface area available to the mud so that bubbles escape (through the use of various cascading baffle plates).

If the gas content in the mud is high, a mud gas separator or "poor-boy degasser" is used, because it has a higher capacity than standard degassers and routes the evolved gases away from the rig to a flaring area complete with an ignition source.

See related terms: desander,  gas separator