| Abstract |
The technique of sequentially injecting low salinity water (LSW), nanoparticles (NPs), and surfactant (abbreviated collectively as LNS) into fractured carbonate reservoirs (FCRs) has been successfully applied in our previous work. In this study, the technique is further investigated experimentally to include other types of surfactants and NPs. The selection criteria used for assessing the two surfactants (Triton X-100 and C19TAB), which involve spontaneous imbibition (SI) experiments, interfacial tension (IFT), and contact angle (CA) measurements, are presented in the current work. The SI measurements are used to probe the potential of the individual LNS fluids to produce beyond the synthetic brine, while the IFT and CA results indicate the mechanisms involved during the interaction between the fluids. The cumulative oil recovered from the LNS injection cycles into the fractured core plug at 70 °C temperature, 3000 psi confining pressure, and 2100 psi back pressure is herein reported. The outcome of these experiments divulged that the injection of the cationic surfactants in the first LNS cycle aided the recovery of oil in the second cycle during the injection of the γ-alumina NPs. The introduction of the surfactant and NPs after the LSW injection in the first cycle assisted in recovering more oil from LSW injection in the second and third sequences. Overall, the cumulative oil recovery from the three cycles of the LNS sequential injection is approx. 18% of the original oil in place (OOIP) in addition to oil recovery from waterflooding, which shows the promising potential of this technique in oil production from FCRs. |
, Morteza Dejam 
