Mobilization of by-passed oil by viscous crossflow in EOR processes

K. S. Sorbie*, A. Skauge

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

20 Citations (Scopus)


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.

Original languageEnglish
Title of host publication20th European Symposium on Improved Oil Recovery
PublisherEAGE Publishing BV
ISBN (Electronic)9789462822788
Publication statusPublished - 8 Apr 2019
Event20th European Symposium on Improved Oil Recovery 2019 - Pau, France
Duration: 8 Apr 201911 Apr 2019


Conference20th European Symposium on Improved Oil Recovery 2019
Abbreviated titleIOR 2019

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Energy Engineering and Power Technology


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