Influence of hydrocarbon components on the minimum miscibility pressure of CO₂ flooding

Using interfacial tension vanishing experiment, the minimum miscibility pressure of the CO₂ flooding was carried out on different simulated oil or hydrocarbons for the effects of crude oil compositions on miscibility capability in CO₂-EOR. This paper analyzes the variation law of minimum miscibility pressure of heterogeneous hydrocarbon components in CO₂ flooding, and then explores the key components which influence the minimum miscibility pressure of CO₂ flooding in crude oil. The result shows that the minimum miscibility pressure of the different component of crude oil mixed with CO₂ is different. The order of the minimum miscibility pressure of the same carbon number hydrocarbon components is: alkane, naphthenic hydrocarbon, aromatic hydrocarbon. The smaller the carbon number of the same hydrocarbon is, the smaller the minimum miscibility pressure is. The minimum miscibility pressure of the same carbon number mixed component is less than the minimum miscibility pressure of the pure hydrocarbon. As the content of low carbon alkanes in crude oil increased, the minimum miscibility pressure decreased. However, when the content of high carbon aromatic hydrocarbons increased, the minimum miscibility pressure increased. This research results supply data and theory supports for CO₂-EOR in different kinds of reservoir.