作者： Mingwei Zhao; Xuguang Song; Wenjiao Lv; Yining Wu; Caili Dai

Key Laboratory of Unconventional Oil & Gas Development, Ministry of Education, School of Petroleum Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, China

Shandong Key Laboratory of Oilfield Chemistry, School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China

摘要：In this work, carbon-based nanofluid was prepared composed of hydrophilic carbon nanoparticles (CNPs) and Tween-80 to enhance oil recovery through spontaneous imbibition in tight reservoirs. The CNPs were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), ¹HNMR, interfacial tension and wettability measurements. The particle size of CNPs was <10 nm and CNPs nanofluid showed excellent stability at high temperature and high salinity. CNPs nanofluid exhibited a stronger ability to reduce interfacial tension and change wettability than brine. The ¹HNMR imaging showed that CNPs had seeped into the core. The spontaneous imbibition tests showed that the spontaneous imbibition oil recovery of CNPs nanofluid can reach 24%, compared with 11% oil recovery of NaCl solution. CNPs nanofluid can efficiently enhance oil recovery, which was ralated to capillary force and structural disjoining pressure. CNPs nanofluid has great potential for enhancing oil recovery, especially in tight reservoirs.