Pore-scale Displacement Mechanisms Investigation in CO2-brine-glass Beads System

Abstract

Continuous increasing of CO2 emission is observed to a main potential reason of global warning, while CO2 geological sequestration (CGS) offers a promising technique to solve this huge environmental challenge that the world has to face today. There are, however, still some unsolved problems in CGS procedure, which is determined by pore-scale displacement mechanisms. In this study, we investigate the drainage and imbibition process of CO2-brine-glass beads system under reservoir conditions. A micro-focused X-ray computed tomography (micro-CT) machine with high resolution was introduced to imaging CO2/brine displacement and analyse the pore-scale mechanisms. The result shows that, CO2 is continuous and brine phase remains in small pores and throats in drainage. The shape of CO2/brine meniscus indicates that glass beads behave intermediate wet. While in imbibition, the effect of pore-scale displacement mechanisms become significant, piston-like front was observed at pore scale, CO2 phase is cracked and forms isolated ganglia by snap off events.