THERMODYNAMIC MODEL OF PETROLEUM FLUIDS CONTAINING POLYDISPERSE ASPHALTENE AGGREGATES

New version of thermodynamic aggregation model of asphaltene-containin g crude is formulated and analyzed with regard to characteristics of r esin molecule shape and deformation of the resin shell of the asphalte ne aggregates. The relation between the shape factors and elastic cons tants is discussed, and their effect on the size distribution of aspha ltenic aggregates is considered. The model is applied to describe asph altene precipitation from petroleum fluid upon its dilution with a liq uid alkane. The effect of dilution on the asphaltene particle size dis tribution is studied. The model calculation has shown that the behavio r of asphaltenic crude varies dramatically with the change of molecula r characteristics of resins.