A hydrogel was prepared by crosslinking aqueous solutions of sulfonated polyacrylamide/chromium triacetate for use in water shut off operations. Gel swelling and the effects of salinity, injection time and flow rate on residual resistance factor (Frr) were investigated. In the presence of electrolytes, gel swelling decreased by about 80%. Results showed that oil permeability increased as injection time increased. The results also indicated that the effect of gel treatment increased with decreasing injection rate. However, when sand packed was water flooded by formation water, Frrw decreased by about 26%. According to the results, Disproportionate Permeability Reduction (DPR) was the result of gel swelling by water injection and dehydration by oil injection.
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