Rheology of diluted heavy crude oil saturated with carbon dioxide

The viscosity of heavy crude oils strongly affects their producibility and recovery from oil reservoirs. Thus, the viscosity of heavy crude oils with dissolved gases at different shear rates is valuable knowledge for heavy crude oil exploitation. However, most publications only present viscosity measurements at one specific shear rate, and only a few papers in the literature have reported the rheological measurements over a range of shear rates. In this study, viscosity measurements of CO2-saturated heavy crude oils were performed as a function of the shear rate, at a temperature of 25 °C and pressures up to 220 bar. The experimental apparatus is a unique circulation system, which is able to measure the viscosity of CO2-saturated mixtures. A novel high-pressure rheometer with a flow-through Couette geometry was developed to measure the viscosity at a range of shear rates. The experimental results show that the addition of CO2 to heavy crude oil at the given temperature and pressures reduces the viscosity ...