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چکیده
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Nanostructured polymers (NSPs) due to the high water absorption, suitable dispersing in water, low initial viscosity, and deep penetration into the reservoir are potential alternative for common polymers in water shut-off processes. In this study, gelation kinetic of high molecular weight NSPs including copolymer of acrylamide (AAm) and 2-acrylamido-2-methylpropanosulfonic acid (AMPS) in combination with chromium (III) acetate was studied by bottle test and rheology measurements. Finally, the potential of the NSPs gel to block harsh condition fractures was investigated by performing core flow experiments. The gelation time of 82 h was observed for a gel system containing 5500 ppm of poly(AAm-co-AMPS) nanoparticle and copolymer/cross-linker ratio (CCR) of 20 under aging at 90°C and 87,000 ppm salinity. The results of core flow experiments showed that the NSPs gel has strong blocking capacity to reduce fracture permeability by two orders of magnitude. Furthermore, gel blocking efficiency was found to be depended on both the fracture opening and salinity difference between gel solvent and produced water.
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