Amphiphilic carbon dots and extended surfactants: Synergistic interfacial regulation, emulsification stability, and wettability reversal for enhanced oil recovery
Wu Y. Zheng Y. You F. Liu X. Zhang G.
10 February 2026Elsevier Ltd
Carbon
2026#249
In tertiary oil recovery from low-permeability and high-salinity reservoirs, conventional surfactants often face challenges such as insufficient interfacial activity and poor emulsion stability, underscoring the urgent need for innovative blend systems with synergistic interfacial regulation capabilities. In this study, a blend system was developed by combining amphiphilic nitrogen-doped carbon dots (ANCDs) with an anionic extended surfactant (C16P3E6S), and its performance in interfacial behavior modulation and enhanced oil recovery (EOR) was systematically investigated. The ANCDs, synthesized via hydrothermal treatment followed by long-chain alkyl modification, exhibited particle sizes below 5 nm and abundant surface polar groups (hydroxyl, amide, quaternary ammonium) along with hydrophobic segments, endowing them with excellent interfacial activity and self-assembly ability. When blended at mass ratios of 3:2 and 1:1, the resulting blend system formed charge-complementary mixed micelles, which maintained ultra-low oil–water interfacial tensions (as low as 8 × 10−4 mN/m) over a 7 %–12 % NaCl salinity range, while achieving emulsification rates exceeding 90 % and distinct wettability reversal behavior. Core flooding experiments demonstrated that the blend system achieved a maximum oil recovery improvement of 35.77 %, significantly outperforming the individual components. This superior EOR performance was attributed to multiple cooperative mechanisms, including interfacial tension reduction, enhanced emulsion stability, and wettability reversal control. This study provides a new material design approach and theoretical basis for the application of synergistic nano-surfactant blend systems in low-permeability reservoirs.
Amphiphilic carbon dots , Emulsification stability , Enhanced oil recovery , Extended surfactants , Interfacial regulation , Low-permeability reservoirs
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College of Chemistry & Environmental Engineering, Yangtze University, Jingzhou, 434023, China
Hubei Engineering Research Centers for Clean Production and Pollution Control of Oil and Gas Fields, Jingzhou, 434023, China
Kazakh-British Technology University, Almaty, 050000, Kazakhstan
College of Chemistry & Environmental Engineering
Hubei Engineering Research Centers for Clean Production and Pollution Control of Oil and Gas Fields
Kazakh-British Technology University
10 лет помогаем публиковать статьи Международный издатель
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