烃组分对CO2驱最小混相压力的影响

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

关键词:  烃组分  CO₂混相驱  最小混相压力  表面张力  MMP预测模型

Key words:  hydrocarbon component  CO₂ miscible flooding  minimum mixing pressure  surface tension  MMP prediction model

摘要:

针对CO₂-EOR原油组分对混相能力影响的问题,应用界面张力消失法设计了不同碳数烃组分、不同族烃组分、不同含量烃组分混合模拟油与CO₂的最小混相压力实验,分析不同族烃组分与CO₂最小混相压力的变化规律,探寻原油中影响CO₂驱最小混相压力的关键组分。研究表明:原油中不同组分与CO₂的最小混相压力不同,相同碳数烃组分最小混相压力依次为:烷烃、环烷烃、芳香烃；同族烃的碳数越小,最小混相压力越小；相同碳数烃类的混合组分模拟油的最小混相压力小于单一烃组分的最小混相压力；原油中低碳数烷烃含量增加,最小混相压力降低,高碳数芳香烃含量增加,最小混相压力升高。该研究结果为多种类型油藏实施CO₂驱提高采收率提供了数据材料及理论支撑。

Abstract:

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.