OS DEFOAM S - Silicone based Defoamer




Foaming of water based muds can be very costly and disruptive to the whole drilling process. Excessive foaming causes pump problems and can lead to well control issues when mud pit volumes cannot be monitored properly. Foaming is difficult to break down because it is stabilised by the surface elasticity and surface viscosity of its film. Silicones have low surface and interfacial tensions and act as very efficient defoamers.  Drilling muds containing dissolved salts and some shale inhibition products are more prone to foaming and defoamers should be programmed on these wells. Defoamer and Antifoam are interchangeable terms when applied to drilling muds.


Product Information 

OS DEFOAM S is a blended formula of high molecular weight silicones suspended in a proprietary water based medium and is used as a multi-purpose drilling defoamer.


Typical Physical Properties 

Appearance   -   White opaque liquid                       

Pour Point   -   2oC (± 3oC)

S.G. @ 20oC   -   0.96 – 1.06                             

pH   -   6.0 – 8.0

Flash Point (PMCC)   -   Greater than 150oF                

Viscosity @ 20oC   -   Less than 1000 cps

Solubility   -   Water dispersible, drilling fluid dispersible



OS DEFOAM S flows easily over the foam film seeking out openings between the foam-stabilising surfactants and the liquid-air interface. The low surface tension of the OS DEFOAM S causes the foam wall to thin and then collapse. Silicone defoamers are generally more persistent than the organic defoamers and are effective for longer.



OS DEFOAM S is effective in all water based drilling fluids, including Zinc Bromide fluids and is formulated to have no inherent side effects on the drilling fluid rheology. OS DEFOAM S is effective in both solids free and solids laden drilling fluids. The usage rate is a function of the severity of the problem but is expected to be in the range of 0.2 – 0.5 pounds per barrel of drilling fluid.  OS DEFOAM S can be diluted on site with water for more effective foam control and requires no special equipment for dilution.



OS DEFOAM S is packaged in 55 US gallon drums and 5 US gallon pails.



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