FOAMTREAT®HP is high-performance defoamer combined the advantages of both polyether and silicone used in water base drilling fluid, completion fluid and workover fluid, especially in reservoir drill-in fluid. The defoamer can be readily added to water-base fluids to prevent or control foaming, particularly when surfactant additives are used. The defoamer is compatible with brine systems and fluid-loss-control pills. FOAMTREAT®HP deformer has minimal impact on fluid rheology and performs well in both monovalent and divalent brines