Viscous crossflow

The importance of fluid crossflow between layers, and the enhanced viscous crossflow effects of the polymer in the reservoir have been discussed. In order to study this crossflow behaviour in the laboratory, we must be able to design experiments that show these effects in a correctly scaled way. However, it is well known that there are other crossflow effects which occur, both in the field and in experimental systems, and it is important to consider how these relate in magnitude to the viscous crossflow. All crossflow effects are summarised in Figure 8 and are described below ... 

Enhances the Viscous Crossflow Effect in Heterogeneous Systems... 

Overall, results are quite well reproduced. Figure 26 shows that there is very good agreement between the calculated and experimentally observed flow ratios, (Qbl/Qcl)> for the 10 1 and 2 1 viscosity ratio floods. We can combine these, and other results of our findings into a picture of viscous crossflow, which is shown schematically in Figure 27. This figure indicates why the flow ratio, does not drop immediately in the initial part... 

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... 

One obvious mechanism in polymer flooding is the reduced mobility ratio of displacing fluid to the displaced fluid so that viscous Angering is reduced. When viscous Angering is reduced, the sweep efficiency is improved, as shown in Figure 1.2. This mechanism is discussed extensively in the waterflooding literature it is also discussed in Chapter 4. When polymer is injected in vertical heterogeneous layers, crossflow between layers improves polymer allocation in the vertical layers so that vertical sweep efficiency is improved. This mechanism is detailed in Sorbie (1991). 

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