Rheological characterization of crude oil-water emulsions

The polymer-surfactant packages are dissolved in brine and injected into the reservoir in the CEOR (Chemical Enhanced Oil Recovery) processing, where oil in water type emulsions with different stability are formed. The flow properties of emulsions and their phase separation could be significantly influenced by the flow rate of the fluid phases in the pores of the reservoir rock. The goal of this research was to determine the dynamic viscosity of settled oil-water emulsions. The measurement methods of emulsions were completed with assessment of the phase viscosity characteristics of settled emulsions by using a Brookfield rotational viscometer. Based on the test results it was found that the visually observed phase boundaries were different from that the border determined by the change of dynamic viscosity measured along the liquid column height. The latter method allows a more precise determination of the phase boundary and the ratio of the different phases.