Oil treatment in the oilfields is an integral part of the main processes associated with the extraction, gathering and transportation of commercial oil. The quality of the produced crude oil affects both the efficiency and the operational reliability of the main pipeline transport, and the product quality obtained from this oil in oil refineries. At later stages of oil field development, the water cut of produced oil increases substantially and may reach 90% or even more. The presence of mineral salts, resins, paraffin, and mechanical impurities in the produced fluids, which may act as emulsifiers, also contributes to the forming of stable water-oil emulsions. As a result, produced oil does not meet industry quality standard for the product. Repeated cycles of oil treatment lead to additional costs. The solution to this problem is to use highly effective DEMULTRIM demulsifiers.