Cementing Plugs

Plugs are used during cementing operations to help remove dispersed mud and mud sheath from the casing inner diameter and minimize the contamination of cement. A bottom plug is pumped ahead of the cement slurry and behind the spacer. It wipes any remaining dispersed mud from the inner diameter of the casing as it moves down the string. The top plug wipes center from the inner diameter of the casing and then seal at the float collar, resting on the on the bottom plug and causing a pressure increase at the surface including that the cement has been displaced. Top and bottom plugs are always different color. Bottom plugs are red and top plugs are black.