▎ 摘　　要

The usage of nanoparticles in enhanced oil recovery (EOR) has been numerous due to their captivating ultra -small size and eccentric thermal, electrical, and interfacial modification properties. However, nanoparticles in their bare form could suffer from several drawbacks due to possible stability issues. The incorporation of a synergist into the preparation of nanofluid has been a promising approach to alleviate stability issues. In the present study, a novel fusion nanofluid (FN) composed of a cellulose nanocrystal (CNC), and an amphiphilic graphene oxide-based Janus nanosheet (AMGO) is presented. We synthesized the CNC using enzymatic hydro-lysis and ultrasonic processing from the cellulosic waste extracted from Eucheuma cottonii, a marine-based crop. Moreover, we synthesized the AMGO from a green immobilization method. Subsequently, the CNC and AMGO were combined via sonication to form FN. The CNC, AMGO, and FN were characterized appropriately using spectroscopy and microscopy techniques. As controls, CNC and AMGO were tested alongside FN in terms of rheological properties measurements, contact angle measurements, and the core flooding experiment on Berea and Edwards White core samples. Based on the rheology measurements, FN exhibited a more elastic behavior than CNC, demonstrating better dispersibility that could be attributable to the formation of a more resilient 3D network structure via hydrogen bonding synergisms between CNC and AMGO. Furthermore, FN reduced contact angles from similar to 166 degrees to similar to 35 degrees in the Berea, and similar to 172 degrees to similar to 25 degrees in the Edwards White, signifying excellent favorable wettability alteration in both rock types. Through core flooding experiments, FN attained additional oil recoveries of 22.96% and 12.24% from Berea and Edwards White, respectively, which were up to 16.04% and 3.37% more than the control runs. As opposed to CNC, the injection of FN did not result in excessive pressure drop readings, attributing to the better dispersibility and better wettability alteration abilities. Nonetheless, the developed FN comprising CNC and AMGO could be referenced for the future design of greener nanofluid with optimistic EOR efficacies.