Permeability reduction factor maximum

Eigure 5.48 shows the permeability effect on the maximum permeability reduction factor, Ekrmax, predicted from Eq. 5.37. This figure shows that Fbjnax decreases with permeability, which is consistent with the observation that the polymer retention decreases with permeability, as shown in Figure 5.46. The laboratory-measured permeability reduction data at the polymer concentration... 

In Eq. 5.37, it is assumed that the maximum permeability reduction, E pmax, is 10, which is an empirical value. However, a permeability reduction factor higher than 10 was observed in low-permeability formations. 

Bondor et al. (1972) assumed that the permeability reduction is caused by polymer adsorption, and the adsorption process is irreversible. They further assumed the maximum permeability reduction corresponds to the polymer adsorptive capacity on the rock, AdC. The permeability reduction factor is linearly interpolated based on the ratio of the amount of polymer adsorbed to the adsorptive capacity ... 

The measured reduction in screen factor was 1%. Maerker s data also indicate that at 500 B/D, polymer screen-factor degradation should be at least 60% in the pilot. Pilot data indicate a 1 % reduction. On the basis of these comparisons, it is concluded that Nalco 3857 flowing in a high-permeability unconsolidated matrix may not experience the same level of degradation as the polyacrylamide used in Maerker s work. From Fig. 5, at a 600 ft/D velocity, a casing OD of 7 in., and a perforation length of 6 in., a maximum injection rate of 32 B-D/in. of perforation is predicted. This compares reasonably well with 16 B-D/in. that was achieved during pilot operations. 

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