Polyacrylamide, silica, and other nanoparticles have all been realized in the field of enhanced oil recovery. Researchers often explore the mechanisms of spreading behavior and simulated displacement to develop more efficient types of nanoparticles. In this study, copper quantum dots were introduced into a acrylamide copolymerization system to obtain composite nanospheres and its structure, topographic, and application performance were characterized. The results show that the composite nanospheres have a particle size of around 25 nm, are uniformly loaded with copper particles, and have good temperature resistance. The spreading ability on the quartz flake surfaces and displacement effect in microchannels of composite nanospheres, acrylamide copolymer nanospheres, and copper quantum dots were compared by nanofluid spreading experiments and microchannel chip oil displacement experiments. The results indicate that the composite nanospheres can effectively reduce the water contact angle, promote the spreading of aqueous phase, and accelerate the oil droplet removal process; the accelerating effect is stronger than other samples. Its oil displacement effect is also the strongest, and it is minimized by the influence of channel size, temperature, and dispersing medium, with better stratigraphic adaptability. This work supports the practical application of copper quantum dot/polyacrylamide composite nanospheres in the oilfield.
Keywords: composite nanospheres; copper quantum dot; polyacrylamide; simulated displacement; spreading behavior.