Polymer Nanospheres Prepared by Metal Nanoparticles Initiation: Prospects for Application in Enhanced Oil Recovery

ABSTRACT Recent developments in enhanced oil recovery (EOR) have identified polyacrylamide (PAAm) nanospheres as a promising material for reservoir applications. The incorporation of copper nanoparticles (Cu NPs) into these nanospheres is anticipated to substantially enhance EOR performance. In this work, Cu NPs were employed as an alternative to conventional initiators for the synthesis of Cu NPs/PAAm nanospheres. The formation mechanism of Cu NPs/PAAm nanospheres was investigated, and their EOR performance was evaluated. Experimental results revealed that Cu NPs can be effectively employed in the synthesis of Cu NPs/PAAm nanospheres, achieving an average utilization efficiency of over 85%. The Cu NPs/PAAm nanospheres exhibited an average particle size of approximately 20 nm, significantly smaller than that of conventional redox PAAm nanospheres (> 35 nm). This size reduction substantially improved the oil droplet removal rate. During microchannel displacement experiments, Cu NPs/PAAm nanospheres outperformed redox PAAm nanospheres, maintaining a displacement efficiency exceeding 80% under injection conditions. This work provides valuable insights for advancing EOR technology.