A Novel Nanosurfactant for EOR: Amphiphilic Carbon Quantum Dots (ACDs)

In the process of spontaneous imbibition to enhance oil recovery (EOR) in low permeability reservoirs, nanoparticles have shown great potential due to their excellent properties. In this study, four novel amphiphilic carbon quantum dots (ACDs) were synthesized by the pyrolysis of citric acid and four long-chain primary amines. The results of high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) confirmed the successful synthesis of ACDs with an average particle size of 3.4 nm. The results show that the synthesized ACDs have excellent stability, interfacial rheology, and wettability reversal ability. In the spontaneous imbibition experiment, the recovery of the ACD solution was 22.10% higher than that of deionized water. In addition, the influencing factors in the imbibition process were studied in combination with nuclear magnetic resonance (NMR) results. Finally, it is considered that the imbibition process is related to the combined effect of small size, low interfacial tension, and the wettability reversal ability of ACDs. The developed ACDs provide a promising solution for spontaneous imbibition to the EOR, especially in low permeability reservoirs.