Evaluation of the efficiency of polyether-based antifoams for crude oil

During petroleum extraction it is common for associated gas and water to be present. While the petroleum is flowing in pipes or being processed in gravitational separators, in order to break the water/oil (w/o) emulsions, these phases are subjected to agitation and shear forces. Due to the presence of natural lipophilic emulsifiers in the oil, it occurs as undesired foaming and this requires the addition of chemical foam inhibitors, or antifoams. In this work we evaluated the efficiency of commercial polyether-based antifoams in two crude oil samples with different compositions. The antifoams tested were samples of poly(ethylene oxide)-poly(propylene oxide) block copolymers (PEO–PPO) and silicones grafted with PEO and PPO chains (polyether silicones). The tests to evaluate the antifoaming performance of these agents in the oil samples were conducted using a method developed to mimic the operating conditions in gas–oil separators. The most polar polyester silicone performed the best in breaking down the foam formed in the oil.