The process of tertiary oil recovery leads to the formation of water-in-oil (w/o) emulsions. Demulsifiers split these emulsions, thus enabling dewatering and desalination of the crude oil. Dewatering is necessary in order to save energy required for processing crude oil, to avoid corrosion problems during preparation for the refinery, and to reduce pressure variations when transporting oil through pipelines.

Interfacial rheological measurements using the oscillating drop method were carried out in order to select suitable demulsifiers for use in practice. This method predicts the structural mechanical stability and therefore the decay of the w/o emulsion when using demulsifiers. The optimized demulsifier was tested in practice in crude oil drilling fields and led to a lower salinity of the oil and a reduction in pump pressure.