Compositional model for predicting asphaltenes flocculation

The aim of this work is to propose to the oil industry a compositional thermodynamic model able to predict the operating conditions which induce asphaltenes flocculation. The proposed model describes this flocculation as a thermodynamic transition inducing the formation of a new liquid phase with a high asphaltenic content and formed by all the components initially in the crude: the asphaltenic deposit. Asphaltenes are represented as a pseudocomponent essentially made of carbon and hydrogen. Since this model is not able to calculate flocculation conditions in a predictive manner, a procedure which consists in fitting some physical properties of the pseudocomponents introduced in the analytical representation of the asphaltenic crudes is proposed. The obtained results show that this flocculation model is well-adapted for the description of the thermodynamic properties (saturation pressures, relative volumes, flocculation curves) of asphaltenic crudes within a relatively large range of temperature (30–150°C) and pressure (0.1–50 MPa), covering the majority of conditions met in oil production.