Effect of shear action on the microcosmic structure and performance of functional polymer used in oil displacement

Comb-shaped polymer and reactive polymer are two kinds of polymers widely used in the tertiary recovery process at present and their viscosity and viscoelasticity are important indexes for evaluating the oil displacement efficiency. To investigate the effect of shear action on the properties of polymer solutions, the macroscopic and microcosmic properties of the comb-shaped polymer and reactive polymer, before and after shearing through the simulated hole cut, were compared. The results showed that at high-speed shearing and tensile stress, the viscosities of the comb-shaped polymer and the reactive polymer are decreased by 40.73% and 70.10%, respectively. With a shear frequency of 0.02 Hz, the interfacial dilatational elasticities of the comb-type polymer and the reactive polymer are reduced by 19.03% and 68.03%, respectively. Compared with the reactive polymer, the comb-shaped polymer still exhibits a loosen network structure and is present as aggregates dispersed in the solution after shearing, though its super-molecular structure is partially destroyed; the particle size of the comb-shaped polymer, as measured by DLS and AFM, is only slightly reduced. These suggest that the comb-shaped polymer has a superior shear performance to the reactive polymer.