Synthesis via Reversible Addition–Fragmentation Chain Transfer Polymerization and Deep Control Property of Amphiphilic Self-assembled Poly(ethylene oxide)-block-polystyrene

Deep profile control is crucial for enhancing oil recovery due to the depletion of oil and gas resources in the near-well zone. However, using waterflooding to displace the oil in far-well zones with low permeability faces challenges related to limited swept volume and low recovery efficiency. In response, we synthesized PEO-b-PS amphiphilic self-assembled polymer nanoparticles using the reversible addition–fragmentation chain transfer polymerization (RAFT) method. The PEO-b-PS polymers with PS as the core-forming block and PEO as the outer stabilizer self-assemble into uniform spherical particles in water with a size of 100 nm, as demonstrated through DLS/AFM/TEM experiments. These PEO-b-PS nanoparticles do double duty as plugging agents in water breakthrough channels and oil displacement agents once encountering oil. The NMR online displacement experiment shows that the PEO-b-PS nanoparticles can migrate into in-depth formations and plug preferential water pathways. In addition, following the plugging of preferential water pathways, the PEO-b-PS amphiphilic self-assembled polymer emulsifies crude oil and enhances the oil displacement efficiency. Overall, this PEO-b-PS amphiphilic self-assembled polymer offers a pragmatic solution for enhanced oil recovery.