Page 77 - Formation Damage during Improved Oil Recovery Fundamentals and Applications

Low-Salinity Water Flooding: from Novel to Mature Technology 59

slug sizes of nanofluids to retain fines in the near-wellbore zones,
i.e., 0.10 and 0.20 of the flowing system for each layer, respectively, as
indicated in Fig. 2.12.
After nanofluid-slug treatments are injected into each layer, the move-
ment of injected fluids becomes accelerated. However, the increase of
injection pressure loss could be adequately controlled due to the
prevention of fines migration/detachment near the wellbores. In addition,
despite the changes of the moving velocity of the flood front through
each layer, the ratio of front-location along each layer, R (Eq. (2.14)),
shows no significant changes after nanofluid treatment. This suggests that
nanofluid pretreatment for the near-wellbore region does not negatively
affect the improvement of sweep efficiency attributed to fines migration
for layered heterogeneous reservoirs. Indeed, it can help mitigate the
increase of injection pressure loss and thereby maintain well injectivity.
The only potentially negative consequence of nanofluid treatment is that
it may advance the breakthrough of injected water by accelerating the
movement of injected water within the nanofluid-treated region
(Fig. 2.17).

Figure 2.17 Injection pressure drop and flood-front location ratio (R, Eq. (2.14)) for
cases with and without nanofluid pretreatment.