AM/AA/MMA nano/micron-sized polymer particles are prepared by distillation precipitation polymerization method and characterized using Fourier transform infrared spectroscopy, scanning electron microscopy and laser particle size instrument. The effect of NaCl mass concentration on the hydration expansion property of polymer particles and the effect of hydration time on the migration plugging property of polymer particles are investigated. The oil displacement experiments are carried out in different permeability cores. The experimental results show that AM/AA/MMA polymer particles are regular spherical and the dry particle size is about 500 nm. The polymer particle size gradually increases with the increase of hydration time; But after 200 h, the size of the particle is no longer increased. The expansion ratio of polymer particles decreases gradually with the increase of NaCl mass concentration; when the NaCl mass concentration increases from 5 g/L to 20 g/L, the expansion ratio is reduced by 1.01. The pugging effect of polymer particles on core may enhance with the increase of hydration time; From 24 h to 120 h, the core plugging rate is increased by 40.62%. The injection of 0.5 times pore volume polymer particles solution with 1.5 g/L mass concentration can increase by an average of more than 9% of the recovery rate. With the increase of permeability, the enhanced oil recovery increases gradually. But the enhanced oil recovery will remain constant when the permeability is higher than 50×10^-3 μm².

distillation precipitation polymerization  /  nano/micron-sized polymer particles  /  hydration expansion  /  migration plugging  /  recovery rate