Visualization and Measurement of CO2 Flooding in Porous Media Using MRI

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• 作者：Yuechao Zhao ; Yongchen Song ; Yu Liu ; Haifeng Liang ; Binlin Dou
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2011
• 出版时间：April 20, 2011
• 年：2011
• 卷：50
• 期：8
• 页码：4707-4715
• 全文大小：1148K
• 年卷期：v.50,no.8(April 20, 2011)
• ISSN：1520-5045

文摘

CO₂ flooding is used extensively as a commercial process for enhanced oil recovery. In this study, the visualization of CO₂ flooding in immiscible and miscible displacements in a high-pressure condition was studied using a 400 MHz MRI system. For CO₂ immiscible displacement, the phenomenon of CO₂ channelling or fingering was obviously due to the difference in fluid viscosities and densities. Thus, the sweep efficiency was small, and the final residual oil saturation was 37.2%. For CO₂ miscible displacement, the results showed that pistonlike displacement occurred, and the phenomenon of the miscible regions and CO₂ front was obvious. The viscous fingering and gravity override caused by the low viscosity and density of the gas were restrained effectively, and the velocity of the CO₂ front was uniform. The sweep efficiency was high, and the final residual oil saturation was 13.5%, indicating that CO₂ miscible displacement could recover more oil compared with CO₂ immiscible displacement. Finally, the average velocity of the CO₂ front was evaluated by analyzing the oil saturation profile. A special core analysis method was applied to in situ oil saturation data to directly evaluate the effect of viscosity, buoyancy, and capillary pressure on CO₂ miscible displacement.