Antifoam / Defoamers
Antifoam / Defoamer
Antifoams are introduced in cement slurries to decrease foaming and minimze air entrainment during mixing
High energy cement preparation introduces a considerable amount of air into the slurry. This can affect density and cause suction and cavitation problems at the pump. Anti-foam agents cause the air to break-out rapidly by lowering the surface tension of the air bubbles.
Many additives cause foaming problems, but if slurry foams excessively, during mixing, centrifugal pump will air lock, and mixing must be stopped. Therefore antifoams are introduced in cement slurries to decrease foaming and minimise air entrainment during mixing. Excessive foaming can also result in an underestimation of the density downhole and cavitation of the mixing system. The additives modify the surface tension in the cement slurry so that foaming is prevented or the foam breaks up.