LAUSR

Abstract To reduce water cut and improve sweep efficiency of water flooding, a novel pore-scale microsphere (NMPS) as profile control agent was firstly prepared through inverse emulsion polymerization technology. Then, its physical properties were investigated, including morphology, particle size distribution, elasticity, swelling property and long-term stability. Subsequently, the plugging and transport characteristics of NMPS were studied through dual parallel core displacement experiments. And then, oil displacement efficiency was evaluated through dual parallel core displacement experiments and nuclear magnetic resonance (NMR) experiment. Experimental results demonstrated NMPS possessed favorable elasticity, water swelling property, dispersibility and long-term stability with an initial average particle size of 7.58 μm. Also, NMPS could effectively plug high permeability channel and regulate heterogeneity. Moreover, NMPS effectively diverted subsequent injected water into low permeability zone and improve sweep efficiency. As a result, 10.83–31.6% of crude oil was produced during NMPS flooding and subsequent water flooding. It was believed that NMPS was a promising candidate for heterogeneity reduction and oil recovery enhancement. Graphical Abstract