Laboratory experiments on core-scale behavior of CO2 exolved from CO2 -saturated brine

Abstract

Abstract During the process of carbon dioxide storage in deep saline aquifers a large quantity of brine will become saturated with dissolved CO2. Although saturated brine is denser than pure brine, there are several plausible mechanisms by which CO2-saturated brine could be transported to a shallower depth, where the CO2 would come out of solution (exsolve), forming a mobile gas phase. In this paper we describe preliminary results of laboratory experiments performed in order to observe the formation of exsolved CO2 as the pressure experienced by the core sample was gradually decreased from reservoir conditions (∼124 bars or 1800 psi). X-ray CT scanning was used to measure CO2 saturation and observe its spatial distribution within the core sample as a function of time and pressure.