Implementation of Surfactant for Alternating Injection with Low Salinity Water and & gamma;-Alumina Nanoparticles in Fractured Carbonate Reservoirs: An Experimental Study

The technique of sequentially injecting low salinitywater (LSW),nanoparticles (NPs), and surfactant (abbreviated collectively as LNS)into fractured carbonate reservoirs (FCRs) has been successfully appliedin our previous work. In this study, the technique is further investigatedexperimentally to include other types of surfactants and NPs. Theselection criteria used for assessing the two surfactants (TritonX-100 and C(19)TAB), which involve spontaneous imbibition(SI) experiments, interfacial tension (IFT), and contact angle (CA)measurements, are presented in the current work. The SI measurementsare used to probe the potential of the individual LNS fluids to producebeyond the synthetic brine, while the IFT and CA results indicatethe mechanisms involved during the interaction between the fluids.The cumulative oil recovered from the LNS injection cycles into thefractured core plug at 70 & DEG;C temperature, 3000 psi confiningpressure, and 2100 psi back pressure is herein reported. The outcomeof these experiments divulged that the injection of the cationic surfactantsin the first LNS cycle aided the recovery of oil in the second cycleduring the injection of the & gamma;-alumina NPs. The introductionof the surfactant and NPs after the LSW injection in the first cycleassisted in recovering more oil from LSW injection in the second andthird sequences. Overall, the cumulative oil recovery from the threecycles of the LNS sequential injection is approx. 18% of the originaloil in place (OOIP) in addition to oil recovery from waterflooding,which shows the promising potential of this technique in oil productionfrom FCRs.