Experimental Investigation of Crude Oil Emulsion Physicochemical Properties and Demulsifier Dosage Prediction

Abstract One of the common methods of reducing or eliminating the emulsion is the use of different chemical demulsifiers depending on the type of crude oil and water cut. This method is widely used in Kuwait Oil Company (KOC) at wellheads and gathering centers (GC). However, some wells have practice increases of demulsifier dosage as a result of increase in water content. Consequentiality, KOC initiated a program for optimization of chemical consumption for water/oil emulsion separation in the surface facilities at West Kuwait. As a result, of one year oil field statistical analysis of crude oil emulsion collected data. The results indicate that there are four oil wells of a different physical property could be very helpful for our study. Such properties include emulsion viscosity, size of water droplets, surface active materials, resin to asphaltene ratio (R/As), emulsion temperature. Over and above the demulsifier efficiency and dosages were evaluating using the calculated emulsion separation index (ESI) and interfacial tension measurement. As a result the oil field laboratory test indicates that the viscosity of emulsion increases to at least from 12 to17% of its original value based on dry condition. The average droplet size distribution near to (1–10) μm was highly effect on emulsion stability. Moreover the emulsion behavior was linked closely to the film form around the water droplets that are believed to result from the adsorption of high-molecular-weight polar molecules (asphaltene) and fine inorganic solids. There surface-active behavior that makes them good emulsifiers. Also it was found there are a consistent relationship between emulsion stability and relative resin to asphaltene content R/As for all four of the field samples under study. The crude oil of high emulsified water, near 30%, contains low (R/As, 0.84). However, as resins to asphaltene ratio increased the emulsion become unstable and emulsified water decrease up 9 %. This relationship could be used as the method to indicate the more likely oil field areas of strong emulsions and the suitable practical methods for treatment. Also from the well head operating conditions collected data; emulsion temperature, well head pressure, salinity of emulsified water and IFT. From the laboratory bottle test and oilfield crude oil emulsions data. The demulsifiers dosage was predicted using the proposed empirical model. In addition it could be used as a good tool for the new or the incumbent demulsifier evaluation.