Use of Scott-Magat Polymer Theory for Determining Onset of Precipitation of Dissolved Asphaltene in the Solvent + Precipitant Solution

Abstract

The Scott-Magat polymer theory, which assumes that polymers have heterogeneous structure and takes into ac- count the polydispersity in the molecular weight of polymers, is a method to model asphaltene precipitation conditions. The traditional Scott-Magat polymer theory based models assume that the precipitated phase consists of asphaltene only. In the present work, we introduce a model based on the Scott-Magat polymer theory assuming that the precipitated phase consists of asphaltene and non-asphaltene components and the oil phase is free of asphaltene (Due to low concentration of asphaltene in the oil phase). It is shown that the latter model is similar to a previously reported thermodynamic model in the literature based on the Flory-Huggins polymer theory (R. Cimino, S. Correra, P.A. Sacomani, C. Carniani, “Thermo- dynamic Modelling for Prediction of Asphaltene Deposition in Live Oils”, SPE 28993, Presented at the SPE International Symposium on Oilfield Chemistry held in San Antonio, TX, USA, 14-17 February 1995), in which it is assumed that as- phaltene has a homogeneous structure and the precipitated phase consists of asphaltene and non-asphaltene components and the oil phase is free of asphaltene.