CMC of Individual Surfactants 1.Ahmadi, B., Sahraei, E., & Mohammadi, A. H. (2025). Investigation of the synergistic effects of SiO2 and Al2O3 nanoparticles with SDS and CTAB surfactants on the stability and improving phase behavior of water-oil emulsions. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 705, 135726. https://doi.org/10.1016/j.colsurfa.2024.135726 2.Akram Al-Asadi, Rodil, E., & Soto, A. (2022). Nanoparticles in Chemical EOR: A Review on Flooding Tests. Nanomaterials, 12(23), 4142–4142. https://doi.org/10.3390/nano12234142 3.Jain, S., Pachisia, H., Sharma, A., Patel, S., Patel, S., & Ragunathan, B. (2022). A systematic review – Chemical EOR using surfactants and polymers. Materials Today: Proceedings. https://doi.org/10.1016/j.matpr.2022.03.60 4.Lu, J. (2024). Flow Behavior and Mechanism Insights into Nanoparticle-Surfactant-StabilizedNitrogen Foam for Enhanced Oil Recovery in the Mature Waterflooding Reservoir. ACS Omega. https://doi.org/10.1021/acsomega.4c06023 The best concentrations determined from the screening experiments were 2000 ppm SDS and 350 ppm CTAB for the flooding experiments. The operating concentrations are the ones selected based on the surface tension screening and not highest concentration of the surfactant used injection. Mixed Surfactant CTAB: SDS Performance Sand-Pack Flooding Performance CTAB: SDS formulation produced the highest incremental oil recovery under both salinity conditions despite containing only 20 ppm surfactant.. Oil Recovery Behaviour The CTAB: SDS (0.3:0.7) formulation consistently produced the highest cumulative oil production under both salinity conditions. The SDS formulation exhibited the lowest cumulative oil production even be the highest surfactant concentration which is 2000 ppm. Oil production increased rapidly during the early stages of flooding before gradually reaching a plateau at approximately 50% recovery which indicates that conventional water flooding was unable to mobilize capillary-trapped residual oil Based on laboratory results, CTAB: SDS (0.3:0.7) formulation will be used as surfactant for surfactant flooding in optimum concentration which 20 ppm. Pure and Mixed Surfactant Systems The concentration of NaCl decreased the CMC of the individual surfactants and the mixed surfactants needed considerably lower concentrations of NaCl to give the CMC The CMC performance was optimum for CTAB: SDS (0.3:0.7) which 25 ppm and this formulation was chosen for the sand-pack flooding experiments Surfactant– Nanoparticle Formulation Surfactants lower the surface tension between oil and water by forming micelles at the Critical Micelle Concentration (CMC) (Lu, J., 2024). Silica nanoparticles improve surfactant stability, reduce adsorption onto porous media and enhance oil displacement efficiency.,Proper selection of surfactant composition and salinity is essential to maximize oil recovery performance (Ahmadi et al., 2025). Enhanced Oil Recovery (EOR) Conventional water flooding leaves approximately 50–70% of the original oil trapped within reservoir pores due to capillary forces (Akram Al-Asadi et al., 2022). Chemical Enhanced Oil Recovery (EOR) using surfactants improving the displacement of residual oil. The effectiveness of surfactant flooding depends strongly on reservoir salinity and surfactant formulation (Jain et al., 2022) Details Specification Model Shape Cylinder Model Material Acrylic Perspex Porous Media Sand Length (cm) 20 Inner diameter (cm) 2 Bulk Volume 62.83 ELUCIDATING THE IMPACT OF SALINITY ON OIL RECOVERY IN SAND-PACK FLOODING WITH SURFACTANT– NANOPARTICLE FORMULATIONS Muhammad Amirul Aimi Azman *, Tengku Amran Tengku Mohd *1 2 School of Chemical Engineering, College of Engineering, Universiti Teknologi MARA, 40450 Shah Alam,1,2 INTRODUCTION RESULTS Determine the optimum CMC and the optimum molar ratio of mixed surfactants by evaluating the surface tension response under different salinity conditions. Evaluate the oil recovery efficiency of surfactant–nanoparticle formulations under varying salinity conditions using sand-pack flooding experiments. OBJECTIVES Critical Micelle Concentration (CMC) analysis using Du Noüy Ring method NaCl for brine with conc. 10,000 ppm and 30,000 ppm. Surfactant of surfactant SDS and CTAB with varying concentrations Experiment conducted at room temperature and atmospheric pressure. Sand with grain sizes 150 μm to 250 μm. Parrafin oil used for laboratary test Reservoir salinity significantly influences surfactant behaviour and CMC Limited studies directly correlate surfactant screening (CMC) with actual oil recovery performance in sand-pack flooding. The optimum mixed surfactant formulation for different salinity conditions remains insufficiently understood. An integrated evaluation of salinity, surfactant formulation, and silica nanoparticles is required to improve chemical EOR efficiency. PROBLEM STATEMENT SCOPE OF RESEARCH METHODOLOGY Increasing NaCl concentration decreased the CM