Page 228 - Formation Damage during Improved Oil Recovery Fundamentals and Applications

202 Bin Yuan and Rouzbeh G. Moghanloo

Figure 4.13 Water-saturation profile in the radial flow system at different time.

waterflooding front-saturation also varies at different locations within the
test core (reservoir) because of velocity-dependent fines migration effects.
With the attenuation of fines migration effects where slower velocity occurs
far away from the inlets in the radial flow system, the difference of water-
flooding front-saturation caused by fines migration decreases. However, the
differences of front movement velocities continue increasing as injected
water moves toward to the outlet. Second, within the region affected by
the nanofluid treatment, the usage of nanofluids can slow down the move-
ment of injected fluid further through enhancing the attachment of mobile
fines. However, in the remote regions of the core (reservoir) where slower
fluid velocities prevail, nanofluid treatment accelerates the advance of the
waterflooding front to surpass that of case without nanofluid control. This
phenomenon can be attributed to the attenuation of fines attachment and
straining effects caused by the decreases of total mobile fines quantities in
the formation fluids after the injected fluids have already passed through
the nanofluid-treated region. Consequently, the attenuation of fines attach-
ment and straining effects then impairs the improved mobility-control by
the damage of water-phase relative permeability.
Fig. 4.14 presents the comparison of inlet-outlet pressure drop among
the above three cases. The effects of fines migration and associated