Interfacial tension prediction of silica nanoparticle addition at elevated temperature using dynamic simulation

Foam flooding is introduced in the Enhance Oil Recovery as improvement method in surfactant flooding recovery processes. Foam flooding will take place in tertiary recovery of oil at reservoirs to increase the crude oil recovery in oil industry. To increase the oil recovery, sweep efficiency of residual oil need to increase but there is one challenge existed in foam flooding. The main issue in foam flooding is foam stability. Surfactant used in this study is sodium dodecyl sulfate (SDS) and is known as a foaming agent. The price of SDS is low and economical friendly. SDS is used along with water and carbon dioxide to produce foam through direct injection to the reservoir. However, the stability of the foam still be low and the structure of the form film will rupture when it is directly in contact with oil. To improve the stability of foam, silica nanoparticle is used during injection of foam. The nanoparticle of silica will support the structure of foam film by attaching closely with surfactant along the form film that contact with oil. The form film stability will increase. There are many factors that affect the stability of the foam especially the condition of oil reservoir itself. The extreme condition including temperature and pressure at the reservoir affect to the stability of the foam and become limitation factor to study. Therefore, molecular dynamic simulation is introduced to depict the formation of foam film in order to emulate actual condition with some assumption of parameter and variable. The temperatures used in this simulation are 400K and 450K. Mean square displacement of the molecules in all system is higher at 450K compared the results at 400K. The gradient of the mean square displacement graph gradient is proportional to the diffusion coefficient. Therefore, diffusion coefficient result is in the order of CO₂ > Hexane > SDS > SiO₂ at 450K compared with 400K. Diffusion coefficient is increased when temperature increased. Interfacial tension decreased when temperature increased while SDS molecules and SiO₂ molecules increased.