Carbonated produced water injection (CPWI) might be considered an efficient alternative to handle the largest waste stream while enhancing the oil recovery and storing carbon dioxide (CO2) underground. This study was an attempt to get a deeper understanding of the oil recovery process through synergy between spontaneous imbibition and isothermal titration calorimetry (ITC) experiments. The results from the spontaneous imbibition experiments showed 7% to 11% additional oil recovery in comparison with plain produced water. Rock–fluid and fluid–fluid interactions, evaluated by isothermal titration calorimetry (ITC) experiments, confirmed that the CPW interactions with oil+EFB+chalk and oil+EFB systems are much more exothermic than those with plain PW in those systems. The synergy between spontaneous imbibition and ITC experiments provides an improved understanding of carbonated water injection in carbonate reservoirs.