Page 231 - Formation Damage during Improved Oil Recovery Fundamentals and Applications

Using Nanofluids to Control Fines Migration in Porous Systems 205

Figure 4.16 Comparison of water saturation profiles for cases with different nanofluid
treatment radius prior to low-salinity waterflooding (Yuan et al., 2018b).

keeping the mobility-control assisted by fines migration to improve the
performance of low-salinity waterflooding (both in terms of EOR and
well injectivity) (Yuan and Moghanloo, 2018a; Yuan et al., 2018b).
Fig. 4.16 presents the profiles of water saturation in a radial flow system
for cases with three different nanofluid treatment radiuses, at the same
injected pore-volume (0.2). Nanofluid treatment can accelerate the move-
ment of injected water by reducing the fines migration/straining effects.
Without the effects of fines straining to improve mobility control, the propa-
gation of waterflooding approximates the case of conventional waterflooding
without fines migration, leading to the early breakthrough of injected water
as a negative result. However, the increase of pressure drop can be controlled
by nanofluids utilization, which mitigates the damage of fines migration as
the low-salinity waterflooding continues. In Fig. 4.17,withthe extensionof
the nanofluids treatment radius, the mitigation performance of injection
pressure loss could be enhanced, but the trend of pressure loss mitigation
slows down. Thus, the problem of fines migration weakens with the increase
of distances away from the injection well, it is therefore not necessary to
apply excessively large radiuses of nanofluids treatments. Therefore, by
weighting the balance between the maintenance of well injectivity (minimiz-
ing pressure drop) and enhanced oil recovery, the optimal radius of nanofluid
treatment can be determined as 0.10, approximately (Yuan et al., 2018b).