Viscosity models for bitumen–solvent mixtures

Olalekan S. Alade*, Dhafer A. Al Shehri, Mohamed Mahmoud, Samuel Olusegun, Lateef Owolabi Lawal, Muhammad Shahzad Kamal, Ayman Al-Nakhli

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

10 Scopus citations


Viscosity is the resistance of a material to continuous deformation exerted by shear force. High viscosity, which is sometimes greater than 1 million mPa s, at the initial reservoir conditions, is a major challenge to recovery, production, and transportation of bitumen. Addition of organic solvents or diluents with bitumen leads to significant viscosity reduction and forms the basis for the steam/solvent-assisted recovery methods of extra-heavy oil and bitumen. Therefore, modeling and predicting viscosity of bitumen–solvent mixture has become an important step in the development of solvent-assisted system. The aim of this article is to present a concise survey of the various viscosity models that have been proposed to predict the viscosity of bitumen–solvent mixtures, and make comparative discussion on their applicability. Available reports revealed that the accuracy of a model to predict the viscosity of bitumen–solvent mixtures depends on various factors including the type and concentration of solvents, and the properties of the bitumen. Thus, no model has been found to have absolute capability to predict the viscosity for all mixtures. Therefore, there is room for further improvement on the viscosity modeling of bitumen–solvent system for wider applications.

Original languageEnglish
Pages (from-to)1505-1520
Number of pages16
JournalJournal of Petroleum Exploration and Production Technology
Issue number3
StatePublished - Mar 2021

Bibliographical note

Publisher Copyright:
© 2021, The Author(s).


  • Bitumen
  • Bitumen–solvent mixture
  • Mixing rules
  • Thermophysical properties
  • Viscosity

ASJC Scopus subject areas

  • General Energy
  • Geotechnical Engineering and Engineering Geology


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