Physicochemical and stability Studies of Fe2O3/SiO2 Composite Nanofluid Foam for Enhanced Oil Recovery

Crude oil extraction from reservoirs has evloved to include the injection of chemical agents to enahnce oil recovery. Surfactant foam has been widely recognised as an effective gas-blocking and diverting agent, with demonstrated success in Foam-Assisted Water-Alternating-Gas (FAWAG) technology. Howevever, foam performance, particularly in terms of foamability and stability, can be significantly enhanced in the presence of nanoparticles (NPs). In this study, iron oxide/silica (Fe2O3) composite NPs with ratios 1:1, 1:2 and 2:1 was formulated with cocamidopropyl betain (CAPB) surfactant to determine the optimal nanofoam composition based on foam height and stability. The 2:1 Fe2O3/SiO2 ratio produced the highest initial foam height when combined with 0.3% v/v CAPB. Further optimization of CAPB concentration (0.1-0.3% v/v) revealed that 0.2% v/v CAPB generated the most stable foam system. The effect of pH and salinity on foam physical properties were subsequently investigated. In addition, the chemical interactions between Fe2O3/SiO2 NPs and CAPB were analysed using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Nanoparticle stability tests indicated that CAPB effectively prevented Fe2O3/SiO2 aggregation through steric stabilization. Increasing salinity from 1 to 3 % w/v reduced foamability but improved foam stability, even in the presence of oil. Foam morphology analysis showed that the F2O3/SiO2-CAPB system under salinity conditions produced smaller and more uniformly distributed bubbles, indicating enhanced foam stability. FTIR spectra confirmed the presence of characteristic peaks of Fe2O3 and SiO2, along with peak variations associated with CAPB incorporation. XRD analysis further demonstrated that CAPB adsorption did not alter alpha-Fe2O3 crystalline structure. Overall, the Fe2O3/SiO2-CAPB nanofoam system exhibited optimal foamability and stability at 0.2% v/v CAPB and 0.3% v/v/ of the 2:1 Fe2O3/SiO2 composite. The formulation also showed salinity tolerance up to 3% w/v NaCl in both the presence and absence of diesel, indicating its strong potential as a nanofluid foam for laboratory-scale Enhanced Oil Recovery (EOR) applications.