Abstract:Based on reversible addition fragmentation chain transfer (RAFT) aqueous polymerization, the micro/nano-polyacrylamide gel dispersions for profile-controlling and flooding were prepared to solve the problems of complicated preparation processes of common profile-controlling and flooding agents and the need to add organic solvents. A new water-soluble RAFT agent was synthesized, and then polyacrylamide gel dispersions were prepared by using the RAFT agent in water. The effects of reactant ratio, polymerization temperature, polymerization time and solid content on its properties were investigated. The rheological and viscoelastic properties of gel dispersions were tested. The temperature response, salinity responsiveness and pH responsiveness of gel dispersions were characterized. The results showed that the viscosity of gel dispersions decreased with the increase of temperature and decreased with the increase of pH value, but had little effect, and their viscosity was almost not affected by mineralization. Finally, the microstructure and particle size were characterized by atomic force microscope (AFM), scanning electron microscope (SEM) and nano particle analyzer. The results showed that the gel dispersion was irregular globular structure. The micron diameter of the gel dispersions was 0.92 ~ 6.13 μm and the diameter of the nanoparticles was 48 ~ 76 nm, which confirmed that the molecular scale of gel dispersions prepared by RAFT aqueous polymerization was micro/nano scale.