利用CT技术研究重力稳定注气提高采收率机理

重力稳定注气(GAGD)已被证明是一种低成本且能大幅提高采收率的有效技术。笔者以80～200目石英砂混填制作的填砂模型为研究对象，利用CT扫描测量三相流体饱和度技术，开展了高含水后期重力稳定注气提高采收率实验研究。实验结果表明，水驱后采用顶部垂直注气方式能进一步提高采收率7.45%以上。通过CT扫描测量流体饱和度方法可以观察到，由于气液之间的重力差异，注入气驱扫区域内的液体持续向下运移，致使之前水驱形成的残余油“聚并”而形成“富集带”，随着注入气逐渐向底部推进。

Research of enhancing oil recovery mechanism of GAGD using CT scanning method

Gas assisted gravity drainage (GAGD) has been proved an effective EOR technology with low cost and high recovery percentage. In this paper we carried out an experimental investigation on the enhanced oil recovery mechanism of GAGD in high water-cut stage by means of three-phase saturation measurements based on CT scanning, which was conducted with a sand model randomly filled with 80-200 mesh quartz sands. Experimental results suggested that GAGD in high water-cut stage could enhance oil recovery at least by 7.45%. Due to the gravity difference between gas and liquid, the residual oil previously formed by waterflooding accumulating into an “oil bank”,the oil enrichment zone and advance of “oil bank” by injection gas could be observed through threephase saturation measurement using CT scanning method.