No Access Submitted: 11 December 2014 Accepted: 13 March 2015 Published Online: 07 April 2015
Journal of Rheology 59, 703 (2015); https://doi.org/10.1122/1.4916531
more...View Affiliations
  • a)Author to whom correspondence should be addressed. Fax: +33 1 47 52 70 02. Electronic mail:

View Contributors
  • Rafael Mendes
  • Guillaume Vinay
  • Guillaume Ovarlez
  • Philippe Coussot
The solidification of waxy components during the cool down of waxy crude oils in pipelines may provide complex yield stress fluid behavior with time-dependent characteristics, which has a critical impact for predicting flow restart after pipeline shut-in. Here, from a previous set of data at a local scale with the help of Magnetic Resonance Imaging and a new full set of data for various flow and temperature histories, we give a general picture of the rheological behavior of waxy crude oils. The tests include start flow tests at different velocities or creep tests at different stress levels, abrupt changes of velocity level, steady flow, after cooling under static or flowing conditions. We show that when the fluid has been cooled at rest it forms a structure that irreversibly collapses during the startup flow. Under these conditions, the evolution of the apparent viscosity mainly depends on the deformation undergone by the fluid for low or moderate deformation and starts to significantly depend on the shear rate for larger values. Even the (apparent) flow curve of statically cooled waxy crude oils was observed to be dependent on the flow history, more specifically on the maximum shear rate experienced by the material. After being sufficiently sheared, i.e., achieving an equilibrium state, the rheological behavior is that of a simple liquid for shear rates lower than the maximum historical one. A model is proposed to represent those trends experimentally observed. In contrast with most previous works in that field, the model is built without any a priori assumption based on classical behavior of a class of fluids. Finally, it is shown that this model predicts the flow characteristics of these materials under more complex flow histories (sweep tests, sudden shear rate decrease) much better than the so far most often used (Houska) model.
  1. 1. Cawkwell, M. G., and M. E. Charles, “ Characterization of Canadian artic thixotropic gelled crude oils utilizing an eight-parameter model,” J. Pipelines 7, 251–264 (1989). Google Scholar
  2. 2. Chang, C., D. V. Boger, and Q. D. Nguyen, “ The yielding of waxy crude oils,” Ind. Eng. Chem. Res. 37, 1551–1559 (1998). https://doi.org/10.1021/ie970588r, Google ScholarCrossref, ISI
  3. 3. Chang, C., Q. D. Nguyen, and H. P. Rønningsen, “ Isothermal start-up of pipeline transporting waxy crude oil,” J. Non-Newtonian Fluid Mech. 87, 127–154 (1999). https://doi.org/10.1016/S0377-0257(99)00059-2, Google ScholarCrossref, ISI
  4. 4. Coussot, P., Rheometry of pastes, suspensions, and granular materials: Applications in industry and environment ( John Wiley & Sons, Inc., Hoboken, NJ, 2005). Google ScholarCrossref
  5. 5. Coussot, P., A. I. Leonov, and J. M. Piau, “ Rheology of concentrated dispersed systems in low molecular weight matrix,” J. Non-Newtonian Fluid Mech. 46, 179–217 (1993). https://doi.org/10.1016/0377-0257(93)85046-D, Google ScholarCrossref
  6. 6. Coussot, P., Q. D. Nguyen, H. T. Huynh, and D. Bonn, “ Viscosity bifurcation in thixotropic, yielding fluids,” J. Rheol. 46(3), 573–589 (2002). https://doi.org/10.1122/1.1459447, Google ScholarScitation, ISI
  7. 7. de Souza Mendes, P. R., “ Thixotropic elasto-viscoplastic model for structured fluids,” Soft Matter 7, 2471–2483 (2011). https://doi.org/10.1039/c0sm01021a, Google ScholarCrossref, ISI
  8. 8. Dimitriou, C. J., and G. H. McKinley, “ A comprehensive constitutive law for waxy crude oil: A thixotropic yield stress fluid,” Soft Matter 10, 6619–6644 (2014). https://doi.org/10.1039/C4SM00578C, Google ScholarCrossref, ISI
  9. 9. Ding, J., J. Zhang, H. Li, F. Zhang, and X. Yang, “ Flow behavior of Daqing waxy crude oil under simulated pipelining conditions,” Energy Fuels 20, 2531–2536 (2006). https://doi.org/10.1021/ef060153t, Google ScholarCrossref
  10. 10. Dullaert, K., and J. Mewis, “ A structural kinetics model for thixotropy,” J. Non-Newtonian Fluid Mech. 139, 21–30 (2006). https://doi.org/10.1016/j.jnnfm.2006.06.002, Google ScholarCrossref, ISI
  11. 11. Ekweribe, C., F. Civan, H. S. Lee, and P. Singh, “ Effect of system pressure on restart conditions of subsea pipelines,” in SPE Annual Technical Conference and Exhibition (2008), Vol. 3, pp. 1754–1775, SPE 115672. Google ScholarCrossref
  12. 12. El-Gendy, H., M. Alcoutlabi, M. Jemmett, M. Deo, J. Magda, R. Venkatesan, and A. Montesi, “ The propagation of pressure in a gelled waxy oil pipeline as studied by particle imaging velocimetry,” AIChE 58, 302–311 (2012). https://doi.org/10.1002/aic.12560, Google ScholarCrossref
  13. 13. Hénaut, I., and F. Brucy, “ Description rhéologique des bruts paraffiniques gélifiés,” Congrés du Groupe Français de Rhéologie, 2001. Google Scholar
  14. 14. Hénaut, I., O. Vincké, and F. Brucy, “ Waxy crude oil restart: Mechanical properties of gelled oils,” in SPE Annual Technical Conference and Exhibition (1999), SPE 56771. Google ScholarCrossref
  15. 15. Houska, M., “ Engineering aspects of the rheology of thixotropic liquids,” Ph.D. thesis, Faculty of Mechanical Engineering, Czech Technical University of Prague- CVUT, 1981. Google Scholar
  16. 16. Jia, B., and J. Zhang, “ Yield behavior of waxy crude gel: Effect of isothermal structure development before prior applied stress,” Ind. Eng. Chem. Res. 51, 10977–10982 (2012). https://doi.org/10.1021/ie301047g, Google ScholarCrossref
  17. 17. Kané, M., M. Djabourov, and J. L. Volle, “ Rheology and structure of waxy crude oils in quiescent and under shearing conditions,” Fuel 83, 1591–1605 (2004). https://doi.org/10.1016/j.fuel.2004.01.017, Google ScholarCrossref, ISI
  18. 18. Kané, M., M. Djabourov, J. L. Volle, J. P. Lechaire, and G. Frebourg, “ Morphology of paraffin crystals in waxy crude oils cooled in quiescent conditions and under flow,” Fuel 82, 127–135 (2003). https://doi.org/10.1016/S0016-2361(02)00222-3, Google ScholarCrossref
  19. 19. Lin, M., C. Li, F. Yang, and Y. Ma, “ Isothermal structure development of Qinghai waxy crude oil after static and dynamic cooling,” J. Pet. Sci. Technol. 77, 351–358 (2011). https://doi.org/10.1016/j.petrol.2011.04.010, Google ScholarCrossref
  20. 20. Lopes-da-Silva, J. A., and J. A. P. Coutinho, “ Analysis of the isothermal structure development in waxy crude oils under quiescent conditions,” Energy Fuels 21, 3612–3617 (2007). https://doi.org/10.1021/ef700357v, Google ScholarCrossref
  21. 21. Magda, J. J., H. El-Gendy, K. Oh, M. D. Deo, A. Montesi, and R. Venkatesan, “ Time-dependent rheology of a model waxy crude oil with relevance to gelled pipeline restart,” Energy Fuels 23, 1311–1315 (2009). https://doi.org/10.1021/ef800628g, Google ScholarCrossref, ISI
  22. 22. Marchesini, F. H., A. A. Alicke, P. R. de Souza Mendes, and C. M. Ziglio, “ Rheological characterization of waxy crude oils: Sample preparation,” Energy Fuels 26(5), 2566–2577 (2012). https://doi.org/10.1021/ef201335c, Google ScholarCrossref
  23. 23. Mendes, R., G. Vinay, G. Ovarlez, and P. Coussot, “ Reversible and irreversible destructuring flow in waxy oils: An MRI study,” J. Non-Newtonian Fluid Mech. (published online). https://doi.org/10.1016/j.jnnfm.2014.09.011, Google Scholar
  24. 24. Mewis, J., and N. J. Wagner, “ Thixotropy,” Adv. Colloid. Interface Sci. 147–148, 214–227 (2009). https://doi.org/10.1016/j.cis.2008.09.005, Google ScholarCrossref, ISI
  25. 25. Møller, P. C. F., S. Rodts, M. A. J. Michel, and D. Bonn, “ Shear banding and yield stress in soft glassy materials,” Phys. Rev. E 77, 041507 (2008). https://doi.org/10.1103/PhysRevE.77.041507, Google ScholarCrossref, ISI
  26. 26. Oh, K., M. Jemmett, and M. Deo, “ Yield behavior of gelled waxy oil: Effect of stress application in creep ranges,” Ind. Eng. Chem. Res. 48, 8950–8953 (2009). https://doi.org/10.1021/ie9000597, Google ScholarCrossref, ISI
  27. 27. Ovarlez, G., S. Rodts, X. Chateau, and P. Coussot, “ Phenomenology and physical origin of shear localization and shear banding in complex fluids,” Rheol. Acta 48, 831–844 (2009). https://doi.org/10.1007/s00397-008-0344-6, Google ScholarCrossref, ISI
  28. 28. Philips, D. A., I. N. Forsdyke, I. R. McCracken, and P. D. Ravenscroft, “ Novel approaches to waxy crude restart: Part 1: Thermal shrinkage of waxy crude oil and the impact for pipeline restart,” J. Pet. Sci. Technol. 77, 237–253 (2011a). https://doi.org/10.1016/j.petrol.2010.11.009, Google ScholarCrossref
  29. 29. Philips, D. A., I. N. Forsdyke, I. R. McCracken, and P. D. Ravenscroft, “ Novel approaches to waxy crude restart: Part 2: An investigation of flow events following shut down,” J. Pet. Sci. Technol. 77, 286–304 (2011b). https://doi.org/10.1016/j.petrol.2011.04.003, Google ScholarCrossref
  30. 30. Pignon, F., A. Magnin, and J. Piau, “ Thixotropic colloidal suspensions and flow curves with minimum: Identification of flow regimes and rheometric consequences,” J. Rheol. 40, 573–587 (1996). https://doi.org/10.1122/1.550759, Google ScholarScitation, ISI
  31. 31. Rønningsen, H. P., “ Rheological behaviour of gelled, waxy North Sea crude oils,” J. Pet. Sci. Eng. 7, 177–213 (1992). https://doi.org/10.1016/0920-4105(92)90019-W, Google ScholarCrossref, ISI
  32. 32. Rønningsen, H. P., B. Bjorndal, A. B. Hansen, and W. B. Pedersen, “ Wax precipitation from north sea crude oils. 1. Crystallization and dissolution temperatures, and Newtonian and non-Newtonian flow properties,” Energy Fuels 5, 895–908 (1991). https://doi.org/10.1021/ef00030a019, Google ScholarCrossref
  33. 33. Sestak, J., M. E. Charles, M. G. Cawkwell, and M. Houska, “ Start-up of gelled crude oil pipelines,” J. Pipelines 6, 15–24 (1987). Google Scholar
  34. 34. Tanner, R. I., Engineering Rheology ( Oxford University, Oxford, 2000). Google Scholar
  35. 35. Teng, H., and J. Zhang, “ Modeling the thixotropic behavior of waxy crude,” Ind. Eng. Chem. Res. 52, 8079–8089 (2013). https://doi.org/10.1021/ie400983e, Google ScholarCrossref, ISI
  36. 36. Venkatesan, R., N. R. Nagarajan, K. Paso, Y. B. Yi, A. M. Sastry, and H. S. Fogler, “ The strength of paraffin gels formed under static and flow conditions,” Chem. Eng. Sci. 60, 3587–3598 (2005). https://doi.org/10.1016/j.ces.2005.02.045, Google ScholarCrossref, ISI
  37. 37. Visintin, R. F. G., R. Lapasin, E. Vignati, P. D'Antona, and T. P. Lockhart, “ Rheological behavior and structural interpretation of waxy crude oil gels,” Langmuir 21, 6240–6249 (2005). https://doi.org/10.1021/la050705k, Google ScholarCrossref, ISI
  38. 38. Wachs, A., G. Vinay, and I. Frigaard, “ A 1.5D numerical model for the start up of weakly compressible flow of a viscoplastic and thixotropic fluid in pipelines,” J. Non-Newtonian Fluid Mech. 159, 81–94 (2009). https://doi.org/10.1016/j.jnnfm.2009.02.002, Google ScholarCrossref
  39. 39. Wang, Y., and Q. Huang, “ Evaluation of measurement methods of waxy crude oil thixotropy,” J. Dispersion Sci. Technol. 35(9), 1255–1263 (2014). https://doi.org/10.1080/01932691.2013.838781, Google ScholarCrossref
  40. 40. Zhao, Y., L. Kumar, K. Paso, H. Ali, J. Safieva, and J. Sjöblom, “ Gelation and breakage of model wax-oil systems: Rheological properties and model development,” Ind. Eng. Chem. Res. 51, 8123–8133 (2012). https://doi.org/10.1021/ie300351j, Google ScholarCrossref
  1. © 2015 The Society of Rheology.