Fluorescent polyacrylamide nanospheres for concentration detection and fluorescent visual oil displacement experiments

Polyacrylamide nanospheres are widely applied enhancing oil recovery polymers in low-permeability oilfields. However, it is difficult to detect polyacrylamide nanospheres concentration in the produced fluid. In this study, fluorescent polyacrylamide nanospheres were synthesized via a reverse phase microemulsion method by the copolymerization of acrylamide and pyranine derivative. The structure, fluorescence properties, and oil displacement mechanisms of fluorescent polyacrylamide nanospheres were researched. The results indicated that the fluorescence intensity of the nanospheres had a distinct linear relationship with the concentration at a certain concentration range. The relative error of standard curve method was less than 1%. Alkaline conditions and aging process could diminish fluorescence intensity while temperature and ionic species had slightly effect on it. The oil displacement phenomenon of the nanospheres in T-shaped microchannel, oil-water interface, and glass plate were observed clearly. This work provides support for the practical applications of fluorescent polyacrylamide nanospheres in oilfields.