## The Performance of Engineered Water Flooding to Enhance High Viscous Oil Recovery  
**[PERSON] 1\({}^{\copyright}\)**, [PERSON] 1, [PERSON] 1,*\({}^{\copyright}\)** and [PERSON] 2  
formations was studied by different experimental and modeling approaches. They prove the effectiveness of this technique in reducing the residual oil in various cases [3; 4]. This method is less investigated in carbonate rocks than in sandstones [5]. It was believed that the presence of clays is required for a successful LSW injection, but the recently promising implementations of LSW in carbonates are reported in papers [6; 7]. Different mechanisms are active during the oil recovery by LSWI in carbonates and sandstones [8; 9; 10]. For carbonates, there are different proposed mechanisms that affect the rock-fluid and fluid-fluid interactions. The rock-fluid interactions are recognized as the reason for wettability alteration. Mechanisms such as multi-ion exchange, mineral dissolution, change in surface charge, and the adhesion energy of CBR are the main mechanisms observed in the literature [2; 11; 12]. The Multi-Ion exchange mechanism is due to the presence of Ca\({}^{2+}\), Mg\({}^{2+}\) and SO\({}_{4}^{2-}\) ions and their interactions with oil and rock surface. The negatively charged SO\({}_{4}^{2-}\) approaches the positively charged carbonate rock surface and wetting water phase; while, Ca\({}^{2+}\)Mg\({}^{2+}\) reacts with negatively charged crude oil components and separates them from the rock surface, resulting in the wettability alteration [13]. For sandstone reservoirs, the polar compounds of oil (including asphaltene and resin content) with multivalent cations form a bond on a clay surface [2]. This statement cannot be confirmed for the carbonate case because of the lack of clay content. Another mechanism, mineral dissolution, occurs due to the difference in the ions composition in the injected water and the rock, which results in the movement of cations from the rock surface to the water, which leads to oil detachment and wettability alteration. This process is recognized as one of the independent wettability alteration mechanisms [14]. All listed mechanisms lead to the wettability alteration to a more water-wet state, resulting in the oil's detachment from rock surfaces. The success of this method depends on factors such as the injected water properties, the rock type, oil characteristics, and injection scenarios. All these parameters directly or indirectly affect the wettability change process. This topic is well covered by [PERSON] et al. [15]. Carbonates wetting state depends on the chemical properties (carboxylic material) of crude oil, reservoir conditions, and the reservoir rock composition. Hence, the wetting can be altered by affecting the CBR interactions, such as the salinity and the concentration of reactive ions in the injected water, also called potential determining ions (PDIs). Most of the review papers highlighted the critical criteria for successful LSWI implementation. In the paper of [PERSON] et al. [6], the authors went through several key parameters that affect the performance of LSWI in carbonates. The effect of temperature, injected water salinity and composition, the composition of oil sample (acid and base numbers), rock structure specifications, and aging duration were analyzed. The authors also proposed different mechanisms based on the media length scale. Another screening criteria was also discussed by [PERSON] et al. [16]. The salinity of injected brines, oil compositions, the wettability state of rock, and the connate water properties were considered for screening and predicting a favorable condition for LSWI performance in carbonates. They suggested that high clay content, optimum brine salinity, basic environment, presence of polar components in the oil, oil-wet state of the rock, and brackish connate water are required to achieve a successful LSWI.