Abstract: At present, numerical simulations cannot calculate the distribution of CO₂ in oil, gas, and water and the effect of CO₂ dissolved in water on the physical properties of the reservoir. In response to this problem, the innovative application of the integrated numerical simulation of CO₂ displacement and sequestration can simulate the distribution of CO₂ in oil, gas and water, the effect of dissolved CO₂ on sequestration, and the whole process of CO₂ displacement and sequestration on the basis of the coupled oil-gas flash evaporation and the solution and dissolution of CO₂ in water. It was found in the study that CO₂ dissolved in formation water developed into carbonic acid dissolved rock, leading to an increase in reservoir permeability, and the longer the action duration, the more obvious the dissolution effect; the solution and dissolution of CO₂ in the water affected the cumulative oil production and CO₂ sequestration. In the study of CO₂ displacement and sequestration, it was necessary to consider both the solution and dissolution effects in order to reflect the actual production. The numerical simulation study was conducted in the Lower Sha 1 reservoir in Pucheng Oilfield, and proved that the integrated numerical simulation method of CO₂ displacement and sequestration is accurate. This study can become certain reference and guidance for scheme design of CO₂ displacement and sequestration project and the evaluation of CO₂ sequestration potential.

Key words: CO₂ displacement and sequestration, integrated numerical simulation, dissolution, dynamic permeability, coupling