We believe that the main target oil for all EOR methods is essentially “bypassed oil” at several length scales from the pore scale, to the core scale, to the bed-form scale, to the reservoir layer scale; indeed, at all the scales of heterogeneity present in an oil reservoir. Thus, a waterflood applied as a secondary recovery process will “bypass” oil at all of these scales leaving behind potentially mobile oil, resulting in a lowered recovery factor. The role of most EOR processes – and here we specifically focus on polymer flooding and WAG – is to improve oil recovery by producing as much of this bypassed oil at all scales as is physically possible.

Conventional polymer flooding is often described as simply “mobility control” implying that a viscous oil linear displacement efficiency may be improved by viscosifying the injected brine. In fact, this is a secondary effect in most polymer floods in the field, even for viscous oils. Frequently, a more important mechanism is viscous crossflow (VX), not just in layered reservoir systems (where it is indeed an efficient mechanism), but in any heterogeneous reservoir system. Where there is heterogeneity at the pore scale, core scale and upwards, this viscous crossflow mechanism is generally present and is the main, or at least an important, contributor to oil recovery improvement.

In this paper, we will use examples from various studies of polymer displacements at the pore, core and field scales to demonstrate the above claims. Furthermore, recent work now shows that the VX mechanism also plays an important role in near-miscible WAG which will also be described briefly here.


Article metrics loading...

Loading full text...

Full text loading...


  1. Betté, S., Hartman, K. J. and Heinemann, R. F.
    , [1991] Compositional modeling of interfacial tension effects in miscible displacement processes, Journal of Petroleum Science and Engineering, 6(1), 1–14.
    [Google Scholar]
  2. Coats, K. H.
    , [1980] An Equation of State Compositional Model, SPE Journal, 20(05), 363–376.
    [Google Scholar]
  3. Clifford, P.J.
    , [1988] Simulation of Small Chemical Slug Behavior in Heterogeneous Reservoirs. Presented at the SPE/DOE Enhanced Oil Recovery Symposium, Tulsa, Oklahoma, 17–20 April 1988. SPE-17399-MS. http://dx.doi.org/10.2118/17399-MS
    [Google Scholar]
  4. Clifford, P.J. and Sorbie, K.S.
    , [1985] The Effects of Chemical Degradation on Polymer Flooding. SPE 13586 Presented at the SPE Oilfield and Geothermal Chemistry Symposium, Phoenix, Arizona, 9–11 March 1985. https://doi.org/10.2118/13586-MS
    [Google Scholar]
  5. de Loubens, R., Vaillant, G., Regaieg, M., Yang, J., Moncorgé, A., Fabbri, C. and Darche, G.
    , [2018] Numerical Modeling of Unstable Waterfloods and Tertiary Polymer Floods Into Highly Viscous Oils, SPE 182638-PA, SPE Journal, 23 (05), October2018.
    [Google Scholar]
  6. Fayers, F.J.
    , [1988] An Approximate Model with Physically Interpretable Parameters for Representing Miscible Viscous Fingering, SPE13166-PA, SPE Res. Eng., 3 (02), May1988.
    [Google Scholar]
  7. Huang, Y., Ringrose, P. S. and Sorbie, K.S.
    , [1995] Capillary Trapping Mechanisms In Water-Wet Laminated Rocks, (SPE28942), SPE (Reservoir Engineering), 1995
    [Google Scholar]
  8. Huang, Y., Ringrose, P. S., Sorbie, K.S., and Larter, S. R.
    , [1996] The Effects of Heterogeneity Wettability on Oil Recovery from Laminated Sedimentary Structures Wettability on Oil Recovery from Laminated Sedimentary Structures, SPE Journal, pp. 451–461, December 1996.
    [Google Scholar]
  9. Kortekaas, T.F.M.
    , [1985] Water/Oil Displacement Zone Characteristics in Crossbedded Sandstones, SPE 12112, SPE Journal, 25 (6), December1985.
    [Google Scholar]
  10. Koval, E.J.
    , [1963] A Method for Predicting the Performance of Unstable Miscible Displacement in Heterogeneous Media, SPE Journal, 3 (02), June1963.
    [Google Scholar]
  11. Laoroongroj, A., Gumpenberger, T. and Clemens, T.
    , [2014] Polymer Flood Incremental Oil Recovery and Efficiency in Layered Reservoirs Including Non-Newtonian and Viscoelastic Effects, SPE 170657, SPE Annual Technical Conference and Exhibition, 27–29 October 2014, Amsterdam, The Netherlands. https://doi.org/10.2118/170657-MS
    [Google Scholar]
  12. Maselmeh, S.K., Blom, C.P.A., Vermolen, E.C.M., Bychkov, A. and Wassing, L.B.M.
    , [2011] Simultaneous Injection of Water and Polymer (SIWAP) to Improve Oil Recovery and Sweep Efficiency from Layered Carbonate Reservoirs, SPE 144865, Proceedings of the SPE Enhanced Oil Recovery Conference, 19–21 July 2011, Kuala Lumpur, Malaysia. https://doi.org/10.2118/144865-MS
    [Google Scholar]
  13. Pickup, G.E. and Hern, C.Y.
    , [2002] The development of Appropriate Upscaling Procedures, Transport in Por. Med., 46, pp. 119–138, February 2002.
    [Google Scholar]
  14. Pope, G.A.
    , [1980] The Application of Fractional Flow Theory to Enhanced Oil Recovery, SPE Journal, 20 (03), June1980.
    [Google Scholar]
  15. Seright, R.S., Wang, D., Lerner, N., Nguyen, A., Tochor, R.
    , [2018] Can 25-cp Polymer Solution Efficiently Displace 1,600-cp Oil During Polymer Flooding?, SPE 190321, SPE Journal, 23 (06), December2018.
    [Google Scholar]
  16. Shotten, M., Stephen, K. and Giddins, M.A.
    , [2016] High-Resolution Studies of Polymer Flooding in Heterogeneous Layered Reservoirs”, SPE 179754, SPE Conference on Oil and Gas West Asia, Muscat, Oman, 21–23 March 2016. https://doi.org/10.2118/179754-MS
    [Google Scholar]
  17. Skauge, A., and Aarra, M.
    , [1993] Effect of Wettability on the Oil recovery by WAG, Proceedings 7th European Symposium on Improved Oil Recovery, Moscow, Vol 2, 452–5, 1993.
    [Google Scholar]
  18. Skauge, A., Ormehaug, P.A., Gurholt, T., Vik, B., Bondino, I. and Hamon, G.
    , [2012] 2-D Visualisation of Unstable Waterflood and Polymer Flood for Displacement of Heavy Oil”, SPE154292, Proceedings of the 18th SPE Improved Oil Recovery Symposium, Tulsa, Oklahoma, USA, 14–18 April 2012
    [Google Scholar]
  19. Skauge, A. and Sorbie, K.S.
    , [2014] Status of Fluid Flow Mechanisms for Miscible and Immiscible WAG, SPE 169747, Proceedings of the SPE EOR Conference at Oil and Gas West Asia, 31 March–2 April 2014, Muscat, Oman.
    [Google Scholar]
  20. SkaugeArne, Salmo, Iselin
    , [2015] Relative Permeability Functions for Tertiary Polymer Flooding, 18th European Symposium on Improved Oil Recovery in Dresden, Germany, 16. April, 2015
    [Google Scholar]
  21. Skauge, A., Sorbie, K.S. and Wang, G.
    , [2019] Modelling the Transition between Immiscible and Miscible WAG, Proceedings of the EAGE 20th European Symposium on IOR, Pau, France, 9–11 April 2019.
    [Google Scholar]
  22. Sorbie, K.S., Wat, R.M.S. and Rowe, T.C.
    , [1987] Oil Displacements in Heterogeneous Cores; Analysis of Recovery Mechanisms” SPE16706, Proceedings of the 62nd SPE Annual Fall Conference, Dallas, Texas, 27–30 September, 1987
    [Google Scholar]
  23. Sorbie, K.S., Parker, A. and Clifford, P.J.
    , [1987] Experimental and Theoretical Study of Polymer Flow in Porous Media, SPE14231-PA, SPE Reservoir Engineering, 2 (03), August1987.
    [Google Scholar]
  24. Sorbie, K.S.
    , [1991]. Polymer Improved Oil Recovery. CRC Press.
    [Google Scholar]
  25. Sorbie, K.S., Sheb, M., Hosseini, A. and Wat, R.M.S.
    , [1990] Scaled Miscible Floods in Layered Beadpacks Investigating Viscous Crossflow, The Effects of Gravity and the Dynamics of Viscous Slug Breakdown, SPE20520, Proceedings of the 65th SPE Annual Fall Conference, New Orleans, LA, 23–26 September, 1990.
    [Google Scholar]
  26. Sorbie, K.S. and Seright, R.S.
    , [1992] Gel Placement in Heterogeneous Systems with Crossflow, SPE 24192, Proceedings of the SPE/DOE EOR Symposium, Tulsa, Oklahoma, 22–24 April 1992.
    [Google Scholar]
  27. Sorbie, K.S. and van Dijke, M.I.J.
    , [2010] The Mechanism of Oil Recovery by Water-Alternating-Gas Injection at Near-Miscible Conditions in Mixed Wet Systems, SPE 129837, Proceedings of the SPE Improved Oil Recovery Symposium, Tulsa OK, 24–28 April 2010.
    [Google Scholar]
  28. Stephen, K., Pickup, G.E. and Sorbie, K.S.
    , [2001] Local analysis of changing force balances in immiscible incompressible two-phase flow, Transport in Porous Media, 45 (1), pp. 63–88.
    [Google Scholar]
  29. Vik, B., Kedir, A., Kippe, V., Sandengen, K., Skauge, T., Solbakken, J. and Zhu, D.
    , [2018] Viscous Oil Recovery by Polymer Injection: Impact of In-Situ Polymer Rheology on Water Front Stabilization, SPE 190866, SPE Europec featured at 80th EAGE Conference and Exhibition, Copenhagen, Denmark, 11–14 June 2018.
    [Google Scholar]
  30. Wang, G., Pickup, G.E., SorbieK.S. and Mackay, E.J., and Skauge, A.
    , [2019a] Analysis of Near-Miscible CO2-WAG Displacements: the Distinction between Compositional and Interfacial Tension Effects, SPE 193907, Proceedings of the SPE Reservoir Simulation Conference, Galveston, Texas, 10–11 April 2019.
    [Google Scholar]
  31. Wang, G., Pickup, G.E., SorbieK.S. and Mackay, E.J.
    , [2019b] Detailed Assessment of Compositional and Interfacial Tension Effects on the Fluid Behaviour During Immiscible and Near-miscible CO2 Continuous and WAG Displacements, forthcoming publication, Transp. in Por. Med., 2019.
    [Google Scholar]
  32. Zapata, V.J. and Lake, L.W.
    , [1981] A Theoretical Analysis of Viscous Crossflow, SPE 10111, Proceedings of SPE Annual Technical Conference and Exhibition, 4–7 October 1981, San Antonio, TX.
    [Google Scholar]
  33. Zhou, Y., Muggeridge, A. H., Berg, C. F. and King, P. R.
    , [2015] Quantifying Viscous Cross-flow and its Impact on Tertiary Polymer Flooding in Heterogeneous Reservoirs. In IOR 2015 - 18th European Symposium on Improved Oil Recovery European Association of Geoscientists and Engineers, EAGE. Doi : 10.3997/2214‑4609.201412152
    https://doi.org/10.3997/2214-4609.201412152 [Google Scholar]

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error