<![CDATA[The rising global energy demand drives the development of more efficient and environmentally friendly enhanced oil recovery (EOR) technologies. Nanofluids based on multi-walled carbon nanotubes (MWCNTs) stabilized by the surfactant sodium dodecyl sulfate (SDS) can improve oil recovery by altering rock wettability and increasing the viscosity of the injected fluid. This study investigates the effects of two synthesis parameters of the MWCNT/SDS nanofluid in two stages: MWCNT mass concentration and sonication time. In the first stage, nanofluids were synthesized at varied MWCNT concentrations (0.0002–0.001 g/100 mL) under 20 minutes of sonication. In the second stage, the best-performing concentration was used while the sonication time was varied (10–60 minutes). Nanofluid performance was evaluated through contact angle, viscosity, and colloidal stability tests. The results show that increasing the MWCNT concentration decreased the contact angle from 47.73° to 31.22° and increased the viscosity from 0.9414 to 1.0384 cP. At the best-performing concentration (0.001 g/100 mL), prolonging the sonication time reduced the contact angle to 19.22° at 60 minutes, increased the viscosity to 1.0770 cP, and improved the colloidal stability (stable up to 36 hours). The combination of an MWCNT concentration of 0.001 g/100 mL and a sonication time of 60 minutes produced the MWCNT/SDS nanofluid with the best characteristics within the tested range for EOR applications.]]>
