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Chelating agents have the ability to capture metal ions from brine. This process helps to decrease the salinity of injected water and prevents the formation of scale precipitation in reservoirs. When chelating agents are diluted in seawater (SW), they exhibit similar properties to low-salinity water (LSW) and can be effectively used as an alternative for LSW flooding. In this study, diethylenetriaminepentaacetic acid (DTPA)/SW system was used to modify the sandstone rock wettability and enhance oil recovery, without requiring any filtration procedures. The effectiveness of different DTPA concentrations was evaluated through different laboratory experiments, including wettability alteration, sequential flooding, and zeta potential analysis. The compatibility tests demonstrated that sandstone could be used with various concentrations of DTPA. Wettability alteration and zeta potential analyses revealed that DTPA concentrations above 5 wt% led to a more negative rock surface charge and significantly increased water-wet conditions. The flooding experiments showed that injecting 7 wt% DTPA/SW solution after SW injection can recover up to 22% of the original oil in place. Increasing oil recovery is attributed to the chelation properties of DTPA, which capture metal ions from the sandstone and brine, resulting in enhanced sandstone matrix dissolution and improved oil displacement. This was confirmed by analyzing the DTPA flooding effluent using inductively coupled plasma, which revealed an increase in the concentration of various metal ions in the effluent, indicating rock dissolution. Finally, based on experimental results, 5 wt% of DTPA chelating agent was considered the optimal concentration. [ABSTRACT FROM AUTHOR]