Synthesis and rheological property of various modified nano-SiO2/AM/AA hyperbranched polymers for oil displacement

In this study, various modified nano-SiO2 functional monomers (nano-SiO2-KH540-MAH) were prepared and reacted with acrylamide (AM) and acrylate (AA) to synthesize a water-soluble hyperbranched copolymer (nano-SiO2/AM/AA) for medium- and low-permeability reservoirs and heterogeneous reservoirs by using the redox free-radical polymerization strategy. The HCl‒CH3CH2OH titration expectedly demonstrated that the monomers underwent a controlled modification. The copolymers were characterized by a series of experiments, including IR, 1H NMR and DLS methods. Furthermore, it was shown that, compared with the rheological properties of various modified copolymers, Polymer-40 has a better viscosity and elasticity due to the better molecular structure. An indoor displacement test demonstrated that the mobility control ability and the EOR ability had a favorite relationship with rheology. The RF, RRF and EOR of Polymer-40 were higher than the same parameters of other modified copolymers.