Predicting the Viscosity of Oil Emulsions Depending on the Degree of Water Cut

In oil production, the formation of oil emulsions due to reservoir water breakthrough is widely observed. Since the viscosity of these emulsions, which are considered polydisperse systems, can increase sharply depending on the degree of water cut, they create considerable difficulties in well-gathering systems and also increase hydraulic losses. The rheological properties of oil emulsions depend on the phase ratio, flow velocity, degree of dispersion, and numerous other parameters. There is no generalized model for the rheological description and determination of the properties of oil emulsions, which belong to anomalous and rheologically complex systems. Therefore, a diagnostic method for determining the viscosity of stable emulsions, taking into account the effect of increasing water content, is of great importance. In this article, the existing empirical expressions currently used for diagnosing the rheological properties of oil emulsions are examined. It has been determined that their application in oilfield practice is associated with certain difficulties and, in most cases, they are not considered suitable for solving engineering problems. In the article, a mathematical model has been developed, tested, and shown to provide good results for determining and predicting the viscosity of structurally stable oil emulsions depending on the degree of water cut.