Page 95 - Formation Damage during Improved Oil Recovery Fundamentals and Applications

Formation Damage by Fines Migration: Mathematical and Laboratory Modeling, Field Cases 77

modeling using commercial reservoir simulators (Zeinijahromi et al.,
2013). The method was applied for optimization of injected water com-
positions for smart waterflooding, and also for technologies of produced
water reduction by injection of small banks of low-salinity/fresh water.
Regarding water-production control, injection of small portions of
fresh water into watered-out producer-wells before their abandonment,
injection of small portion of fresh water above the water-oil contact
(WOC) or water-gas contact (WGC) before the production, or huff-n-
puff with a small portion of fresh water can decrease water-cut by
10 20% during a 4 8 month period, in oil and gas wells.
Injection of small fresh-water banks into watered-out gas or oil wells
just before their abandonment yields significant deceleration of encroach-
ing water fingers, leading to the prolongation of the lifetime of up-dip
producer wells and improved sweep efficiency (Zeinijahromi et al., 2015;
2013). Other methods of deliberate fines-migration stimulation with con-
sequent induction of permeability damage by small fresh-water bank
injection include huff-n-puff (Zeinijahromi and Bedrikovetsky, 2016) and
injection just above the WGC or WOC to reduce water coning
(Zeinijahromi et al., 2015).
To summarize, the abovementioned results on fines migration in two-
phase flow, the fines-assisted low-salinity waterflooding is a mobility-
control EOR method, on the contrary to low-salinity waterflood with
wettability alteration and S or reduction. Permeability decrease due to low-
salinity water in already swept areas can yield a significant increase in the
reservoir sweep efficiency. Injection of small volume banks of low-salinity
(fresh) water during commingled oil and water production can signifi-
cantly decrease water cut.
Yuan and Moghanloo (2017) and Yuan et al. (2018c) derived analyti-
cal models for waterflooding with nanoparticles accounting for fines
release. Fines detachment is described by the nanoparticle-concentration-
dependent maximum retention function. The splitting technique is used
for exact integration of two-phase systems with fines migration.
The current chapter presents exact solutions for 1D coreflooding with
stepwise increasing velocity and stepwise decreasing salinity with match-
ing laboratory data and tuning model parameters. The derived analytical
model for inflow performance of production wells with fines migration
uses the model parameters, retrieved from the laboratory tests, for field-
scale predictions. The same data are used for injectivity decline prediction
during low-salinity water injection using the analytical model. Exact solu-
tions are also obtained for fines-migration systems with delay in fines