CO2与原油混相及非混相条件下渗流机理差异

Difference of flowing mechanism in miscible and immiscible phase of CO_2 and crude oil

在CO_2的资源化利用获得广泛认识的同时,CO_2提高采收率技术得到深入发展。研究CO_2驱替过程中气、液组分变化有利于发现CO_2-原油混相或非混相状态对渗流特征影响的原因。采出程度、含水及气油比等变化规律显示CO_2在孔隙中具有独特的渗流特征。相同驱替量的情况下,非混相状态较早进入含水快速上升期,采出程度平缓增长,而混相状态的采出程度则保持较长时间的线性增长。组分分析结果显示,CO_2驱替过程中油、气组分变化具有相似的变化规律。除此之外,混相状态的CO_2易于与油相组分作用,而非混相状态的CO_2则偏向于与气相组分作用,说明混相或非混相状态时CO_2与原油的作用方式不同。

CO_2 is increasingly applied as a resource,and CO_2 EOR technology has been developed further.Study of the changes in gas/liquid composition during CO_2 flooding process is helpful to understand how miscible or immiscible CO_2-oil affects fluid flow through porous medium.The changes of reserve recovery percent,water cut and GOR indicate that CO_2 has a peculiar flowing characteristic in pore.With the same flooding volume,immiscible displacement shows fast increasing of water cut in an early time and the reserve recovery appears a flat increase;however in miscible displacement,the reserve recovery keeps linear increasing for a long time.Composition analysis shows similar changes in oil and gas composition during CO_2 flooding process.In addition,CO_2 in miscible phase tends to interact with oil component,while CO_2 in immiscible phase tends to interact with gas component,thus showing different interaction between CO_2 and crude oil in misci CO_2 ble and immiscible phases.