Application of the PC-SAFT Equation of State to Asphaltene Phase Behavior

Abstract

A method to characterize crude oil including asphaltenes using the perturbed chain form of the statistical associating fluid theory (PC-SAFT) is presented. The theory accurately predicts the bubble point, density, and asphaltene precipitation onset for the oil. Examples show that the theory predicts asphaltene instability due to changes in pressure, temperature, and fluid composition. Further work demonstrates the effect of asphaltene polydispersity and resins on the phase behavior of asphaltenes. The approach demonstrates that laboratory and field observations of asphaltene phase behavior can be explained based only on molecular size and van der Waals interactions