Perpustakaan Digital ITB

The application of Low Salinity Water (LSW) as an injection fluid for enhanced oil recovery has attracted much attention due to its ease of application, environmental friendliness, and more economical cost. It became popular after previous studies discovered that low salinity conditions are more effective than high salinity conditions for recovering the remaining trapped oil in the reservoir. Through several mechanisms, LSW modifies the surface charge and interfacial properties of the crude oil-brine-rock (COBR), yielding more oil to be recovered. Combined with nanoparticles (NPs) as enhancing agents, the LSW-NPs nanofluid can improve the oil sweeping efficiency compared to LSW alone. Titanium Dioxide (TiO2) as nanoparticles has various advantageous properties, including high stability, low cost, and environmentally friendly (non-toxic) properties. However, the experimental data discussing the compatibility between LSW and TiO2 remains underreported, and the COBR interaction using the combination of LSW-TiO2 has been quite unexplored. This study aims to investigate the COBR interactions at various brine salinity of NaCl single salt (LSW of 500, 2000, 8000 ppm brine and compared it to 32000 ppm high salinity water) and combined it with TiO2 at low concentrations (0 ppm – 100 ppm). Each nanofluid is characterized by measuring its pH, conductivity, and zeta potential. The impact of salinity and TiO2 concentration on the interfacial tension and contact angle are also investigated using the light crude oil from Tempino Oilfield and the thin sections of Berea Sandstone samples. The XRD (X-Ray Diffraction) and AFM (Atomic Force Microscope) analysis are first conducted before the contact angle measurement to characterize the rock's mineral composition and surface roughness of the thin sections. The results suggest that TiO2 addition can reduce the contact angle from 63.5° using 32000 ppm NaCl brine to 27.9° using 500 ppm NaCl brine and 100 ppm TiO2. On the other hand, the TiO2 addition on LSW does not change the interfacial tension of crude oil-brine significantly. In terms of stability, TiO2 NPs are more stable at low salinity compared to high salinity conditions. However, this study observed the linear correlation between the zeta potential and contact angle, at which the higher zeta potential value correlates to the higher contact angle. The zeta potential represents the surface charge of the nanofluid, whereas the contact angle represents the nanofluid-rock interfacial properties. These findings can increase our understanding of the mechanism behind TiO2 addition to LSW and help us formulate the most beneficial concentration of LSW-TiO2 nanofluids to maximize oil recovery from subsurface formations.