This work aims to examine alkali solutions' performance and different types of nanofluids in terms of fluid-fluid interaction based on carbonate reservoir data that the OMV company provided. The interactions of low total acid number (TAN) crude oil, the composition of nanofluids, and alkali solution were studied using compatibility tests, phase behavior evaluation, and interfacial tension (IFT) measurements. At first, the compatibility screening (salinity scan) test was used to examine the influence of different alkali and nanofluids. Then, the phase behavior experiments were performed at a 1:1 oil-water ratio using low TAN crude oil. In total, almost 36 different combinations with triplicates were tested. Finally, IFT experiments were performed using a spinning-drop tensiometer, and the results were compared at approximately 150 minutes of observation. Sodium carbonate (Na2CO3) was used as the alkaline agent. Six types of nanomaterial were also used. The first three types of nanofluids have the names S1, E100, and P100, and contain silicon dioxide nanoparticles with different surface modifications. In contrast, one other had the name R1, which contains combination solvent, surfactants, and surface-modified silicon dioxide nanoparticles. The last two types of nanofluids were named A1 and A2, and they consist of silicon dioxide and aluminum oxide nanoparticles with different surface modifications. Moreover, two synthetics brine were prepared. The first brine is rich in divalent cations such as Ca+2 and Mg+2 and was named real brine. While the second brine was called softened brine, and it contains a deficient concentration of divalent cations. Precipitations were observed during the compatibility tests in most cases when using solutions containing nanomaterials and alkali fluids using the real brine. IFT measurements have shown that nanomaterials are significantly efficient in reducing IFT, despite the low TAN oil. However, nanofluids containing surfactants showed the best performance in generating IFT reduction, which has the lowest IFT value (0.17mN/m) compared to other nanofluids. Finally, a high emulsion volume was observed directly after mixing the samples for the phase behavior evaluations. Besides that, nanofluids alone were unable to generate considerable emulsion volume.