Assessing CO2 Storage Capacity of a Steeply Dipping, Fault Bounded Aquifer and Effect of Impurity in CO2 Stream

Abstract A small scale injection project into an offshore aquifer near shoreline has begun which is seeking the connection with a capture project in Korea. The Pohang basin was selected as a site for a small-scale pilot project and detailed site characterization has been undertaken to establish a geological model for the site since 2013. A potential reservoir for CO 2 injection was found at a depth more than 730 meters in the southern offshore part of the Pohang basin from seismic surveys and one exploration well. The seismic interpretation revealed the reservoir is a steeply dip and horizontally fault bounded aquifer. In this study, numerical reservoir simulations were carried out for assessing CO 2 storage capacity especially in the dipping reservoir regarding the reactivation pressure of the bounded faults. At the same time, to investigate the effect of impurity in CO 2 stream was one of our goals. Captured CO 2 streams contain various levels of impurity which vary depending on the combustion technology and CO 2 sources. Specifically for geological storage, the non-condensable gases in CO 2 streams are not favorable because they can decrease density of the injected CO 2 stream and can affect buoyancy of the plume. The effect of the non-condensable gases on storage capacity, injectivity and plume migrations were tested in the reservoir.