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

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. [Copyright &y& Elsevier]