CO 2 capillary trapping behaviour in glass sand packed heterogeneous porous media during drainage and imbibition revealed by magnetic resonance imaging

• Published in: RSC advances Vol. 6; no. 103; pp. 101452 - 101461
• Main Authors: Teng, Ying, Liu, Yu, Jiang, Lanlan, Lu, Guohuan, Wang, Dayong, Song, Yongchen
• Format: Journal Article
• Language: English
• Published: 2016
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C6RA18324G

Geological CO 2 sequestration is considered to be a promising technique for mitigating anthropogenic CO 2 emissions. The study of the trapping mechanisms is of great importance for understanding the storage potential and safety. Capillary trapping is one of the major trapping mechanisms of CO 2 storage in saline aquifers that relates to the capillary number. In this work, we used magnetic resonance imaging to investigate the capillary trapping behavior of gaseous or supercritical CO 2 in a water saturated sand pack. Fluid was injected into packed bed to investigate how capillary number impacts upon residual saturation at reservoir pressure and temperature. Porosity and water distribution were evaluated by using the intensity analysis of magnetic resonance imaging. Water saturation was directly obtained from MRI intensity during drainage and imbibition. Variation of water and CO 2 saturation was discussed under different fluids injection volumes and capillary number. From the results, we can see that under same CO 2 phase state, the residual CO 2 saturation retains at a relative stable value despite how the capillary number changes during drainage and imbibition. The sweep efficiency of gCO 2 was lower than scCO 2 and the residual scCO 2 saturation far exceeded residual gCO 2 saturation. Capillary desaturation curves give residual saturations as a function of capillary number.