Understanding the rheological properties of an emulsion is necessary to determine the long term effect on oil production. Most hydrocarbon reservoirs contain water, which is produced along with oil as free water, or in an emulsion. An emulsion is a mixture of two or more liquids that are immiscible. The most common oilfield emulsion is water droplets dispersed in oil. One of the main factors to consider about emulsions is its stability, which is determined by the duration of time it takes for the immiscible liquids to separate; this can last anywhere from minutes to days to even months. The stability of the emulsion is affected by properties such as the amount of water in the emulsion, presence of resins and other emulsion stabilizing compounds, fine solid particles in the oil, temperature, droplet size and distribution among others. Emulsions can cause high pressure drops in flow lines because of its high viscosity, resulting in plugged pipes, and a multitude of other problems. These issues may result in a decrease in production or even temporary shut-down of wells. Emulsions can occur in nearly every phase of oil production from within the hydrocarbon reservoir to the petroleum refining process.
Gomez, S. (2016, April). Quantifying the Effect of Temperature on Emulsion Stability and Flow. Poster session presented at the University of Oklahoma's Undergraduate Research Day, Norman, OK.