Prediction of Volumetric Properties and (Multi-) Phase Behaviour of Asphaltenic Crudes

Asphaltenes flocculation is described as a thermodynamic transition inducing the formation of a new liquid phase with a high asphaltenic content; this phase being the asphaltenic deposit. The thermodynamic model selected is the Peng-Robinson Equation of State associated with the Abdoul and Péneloux group contribution mixing rules. The oil is modeled by 33 pseudocomponents. Mainly, the heavy F(11+) residue is represented as one pseudocomponent for the F11 - F20 cut and as 4 pseudocomponents for the F(20+) cut : Sat F(20+) , Aro F(20+) , Resinsand Asphaltenes . The physical properties of the Sat F(20+) , Aro F(20+)and Resinspseudocomponents are calculated using the group contribution methods of Avaullée, and of Rogalski and Neau, based on the knowledge of their molecular structure. The physical properties of the F11 - F20and Asphaltenespseudocomponents are fitted in order to reproduce correctly the bubble pressure, the relative volumes and the flocculated quantities at 303 K. The model gives the proportion and the composition of asphaltene deposits in the oil at different temperatures (303 - 403 K) within a relatively large pressure range (0. 1 - 50 MPa) including the bubble pressure of the considered crude