ABSTRACT Offshore oilfield reservoirs exhibit significant heterogeneity, and polymer gel chemical flooding is a key method for enhancing oil recovery. However, offshore operations are constrained by limited freshwater and often rely on high‐salinity or contaminated water sources, which severely affect gel formation. In this study, three polymer types (powder, water‐based emulsion, oil‐based emulsion) were systematically evaluated using six typical water sources: injection water, filtered injection water, filtered water containing particles/oil, seawater, and domestic water. Gel strength, viscosity, viscoelasticity, microstructure, and chemical bonding were characterized via gel strength code, rheometer, SEM, and FT‐IR. Results show that water quality, particularly salinity and the presence of particles and oil, significantly influences gel strength and three‐dimensional network formation. Powder and water‐based emulsion gels formed in various water sources, but gel strength decreased markedly under high‐salinity conditions. Oil‐based emulsion gels only formed effectively in freshwater; in high‐salinity environments, cross‐linking was inhibited. This study elucidates the intrinsic relationship among water composition, polymer dissolution behavior, and gel microstructure and macroscopic properties, providing an experimental basis for selecting polymer gel systems under limited freshwater availability in offshore oilfields.
Liu et al. (Tue,) studied this question.