Structure simulation and validation of Venezuela ultra heavy oil fractions

Venezuela Ultra heavy oil was separated into different fractions including saturate, aromatic, resin and n-pentane insoluble asphaltene. The fundamental properties of Venezuela ultra heavy oil' sub-fractions were measured by VPO, elemental analyzer, et al. Average structural parameters of each fraction were analyzed and model molecular structure was constructed using improved B-L method. Based on the molecular structure obtained, the density and viscosity of Venezuela ultra heavy oil' sub-fractions and heavy oil all-atom model were studied by molecular simulation. The results show that the simulation value and experimental value of density is close and the relative error is less than 3%. Moreover the trend of the simulation value of viscosity is consistent with the experimental value. The consistence of simulation and experimental value indicated that the model molecular structure of different fractions constructed by B-L method is reasonable. Therefore, molecular simulation could be used as a tool to evaluate the property of heavy oil fractions, and the result could justify the average molecular structure of heavy oil' sub-fractions. (C) 2016 Elsevier B.V. All rights reserved.