Fractionation and characterization of heavy oil and bitumen are essential steps for phase behaviour modeling and the simulation of bitumen production, refining, and upgrading processes. Typically, the bitumen is divided into several pseudo-components in order to tune an equation of state (EoS) and then utilize it for the process modeling and reservoir simulation. The interaction coefficients and critical properties of the pseudo-components are commonly tuned using experimental laboratory oil PVT data. Measuring of this data is very expensive and time consuming, especially for heavy oils. Characterization based on experimental distillation data has the potential to eliminate the need for time consuming laboratory oil PVT data.
In this study, we present an effective model for the characterization of heavy oil and bitumen using experimental distillation data. Batch distillation without reflux is modeled to regenerate the experimental distillation curve using the residue curve map method. The Peng-Robinson equation of state (PR-EoS) and NRTL activity model are applied to calculate the fugacity and activity coefficients in the gas and liquid phases, respectively.
The proposed model was able to accurately regenerate the experimental distillation curve. The properties of the characterized fractions and the binary interaction coefficients obtained from the model were used to estimate solubility of light solvents (CH4, C2H6, CO2, N2) in the Athabasca bitumen. Good agreement between the experimental and the estimated solubilities reveals that the proposed approach is a reliable predictive tool for heavy oil and bitumen characterization.
The proposed model provides an accurate and simple method for characterizing heavy oil and bitumen. The only data required is the experimental distillation curve. Since this model does not require experimental oil PVT data, it can be applied quickly and inexpensively compared to other methods available in the literature. The presented approach will find many applications and has potential to become the superior method for phase behaviour studies of heavy oil and solvent systems.