Effect of Wettability Alteration in Chemical Enhanced Imbibition Using Surfactants with Different IFT Magnitudes for Carbonates

Introduction A large amount of carbonate reservoirs are characterized as preferentially oil-wet or intermediate wet (Okasha et al., 2007). In such reservoirs, the spontaneous imbibition of injection fluid into the carbonate matrix represents an important recovery mechanism. The enhancement of imbibition can be achieved by reduction of interfacial tension between oil and water phases, and wettability alteration of rock surface. Among the two factors, wettability alteration is considered dominating when conducting spontaneous imbibition, and many imbibition experiments have been reported in the literature targeting the wettability alteration to enhance oil production using different methods (Al-Hadhrami and Blunt, 2001; Zhang et al., 2006). Optimizing the salinity and ionic composition of injection brine can alter the wettability of carbonate rock surface because of surface charge alteration and microscopic anhydrite dissolution (RezaeiDoust et al., 2009). It was also reported that the favorable low salinity SmartWater/polymer synergy extends to spontaneous imbibition (AlSofi et al., 2019). The trials of optimized brine injection confirmed that in-house research results can be replicated at the well level (Yosef et al., 2012). Nanoparticles have been studied extensively for their wettability alteration ability. The presence of nanoparticles in the three-phase contact region creates a wedge structure, resulting in the removal of oil from the surface (Nazari et al., 2015).