<p>Reservoirs are ideal locations for CO₂ sequestration. During the development of oilfields, CO₂ is injected, where a portion of the gas dissolves or diffuses into the crude oil and formation water, while another portion reacts with the rock, precipitating within the reservoir. The study of the interactions between CO₂ and reservoir fluids (formation water and crude oil) during the CO₂ flooding process, as well as the resulting precipitation patterns and their impact on reservoir properties and recovery rates, is of significant importance. This paper analyzes the results of a core displacement study on the interactions among CO₂, formation water, and rock, revealing the mechanisms by which carbon dioxide interacts with highly saline formation water and crude oil. It advances the development of CO₂ flooding theory and numerical simulation methods, enhances the understanding of the applicability and development patterns of CO₂ enhanced oil recovery techniques in low permeability reservoirs, and provides strong guidance for the field application of CO₂ flooding technology in low permeability reservoirs containing highly saline formation water. The quantitative characterization is beneficial for informing the development strategies for CCUS in reservoirs.</p>