One of the most effective ways to reduce carbon dioxide (CO2) emissions is sequestration in geological reservoirs. CO2 sequestration in coal formations enhances the methane production from coalbeds (ECBM) in addition to storing CO2. CO2 can be stored in coalbeds in three ways: free gas phase in the pore space or the cleat network system, adsorbed molecules onto the organic surface of the coal, and dissolved in the groundwater within the coal. The performance of this process is dependent on the wettability behavior of the coal–water–CO2 system. This paper presents an investigation of the effect of the formation water salinity on the wettability behavior of highly volatile bitumen coal. The captive bubble method was used to measure the contact angle in coal–water–CO2 systems at pressures up to 2000 psi. The contact angle (CA) was measured at different NaCl concentrations (0–20 g/L). The CO2 adsorption isotherm on the coal surface was examined at different water salinities (0–20 g/L NaCl). Zeta-potential mea...