Egasser is a device used in drilling to remove gasses from drilling fluid which could otherwise form bubbles that removes all gases and vents them into the atmosphere at a safe distance from the drilling rig.
Reference Definition by Schlumberger Oilfield: Egasser is 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) and 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.
Related Definitions in the Project: The Upstream Engineering
