Preparation and stabilization mechanism of carbon dots nanofluids for drag reduction

• Published in: Petroleum science Vol. 17; no. 6; pp. 1717 - 1725
• Main Authors: Wu, Yi-Ning, Li, Yuan, Cao, Meng-Jiao, Dai, Cai-Li, He, Long, Yang, Yu-Ping
• Format: Journal Article
• Language: English
• Published: Beijing China University of Petroleum (Beijing) 01.12.2020; KeAi Publishing Communications Ltd
• Subjects: Aggregation; Alternative energy sources; Carbon; Carbon dots; Drag reduction; Earth and Environmental Science; Earth Sciences; Economics and Management; Energy Policy; Flooding; Industrial and Production Engineering; Industrial Chemistry/Chemical Engineering; Injection; Ions; Mineral Resources; Nanofluids; Oil and gas fields; Oil fields; Oil recovery; Original Paper; Permeability; Pressure; Pressure reduction; Renewable energy; Resources; Stability; Surface energy; Temperature; Salt tolerance; Stabilization mechanism; Carbon dots; Drag reduction; Nanofluids
• ISSN: 1672-5107; 1995-8226
• DOI: 10.1007/s12182-020-00503-4

During the development of low or ultra-low permeability oil resources, the alternative energy supply becomes a prominent issue. In recent years, carbon dots (CDs) have drawn much attention owing to their application potential in oil fields for reducing injection pressure and augmenting oil recovery. However, carbon dots characterized of small size, high surface energy are faced with several challenges, such as self-aggregation and settling. The preparation of stably dispersed carbon dots nanofluids is the key factor to guarantee its application performance in formation. In this work, we investigated the stability of hydrophilic carbon dots (HICDs) and hydrophobic carbon dots–Tween 80 (HOCDs) nanofluids. The influences of carbon dots concentration, sorts and concentration of salt ions as well as temperature on the stability of CDs were studied. The results showed that HICDs are more sensitive to sort and concentration of salt ions, while HOCDs are more sensitive to temperature. In addition, the core flooding experiments demonstrated that the pressure reduction rate of HICDs and HOCDs nanofluids can be as high as 17.88% and 26.14%, respectively. Hence, the HICDs and HOCDs nanofluids show a good application potential in the reduction of injection pressure during the development of low and ultra-low permeability oil resources.