Carbon dioxide storage in a heterogeneous conglomerate formation: an experimental investigation at core-scale

The first onshore carbon dioxide (CO2) storage project in South Korea is planned to inject CO2 into a conglomerate formation (~1 km deep). Unlike sandstone formations that are generally considered for sequestration targets, the conglomerate reservoir is characterized to be poorly sorted and highly heterogeneous. Two core samples were obtained from the target reservoir and pore characteristics were evaluated by using micro X-ray CT image analyses. Furthermore, multiphase flow experiments were performed at in-situ reservoir conditions with a core-flooding system. The integrated X-ray scanning system allowed us to capture the dynamic transport of CO2 in the core sample. The initial-residual (IR) characteristic curve was used to describe the residual trapping potential of the conglomerate rock. The results showed that the conglomerate formation has a potential be an alternative CO2 storage formation.