The geological CO2 storage capacity of the Jeju Basin, offshore southern Korea, estimated using the storage efficiency

We estimated the storage capacity for geological CO2 sequestration of the Jeju Basin off southern Korea, northern East China Sea using the storage efficiency and a deterministic, volumetric method. We analyzed seismic and well-log data to get the geological parameters and used the storage efficiency parameters for deep saline, nonmarine sediments in open systems. The time interval of the basin fill from 1.2 to 2.8 s two-way traveltime was selected for the depth zone for CO2 storage. This interval corresponds to the depth range of about 1200 m to about 3900 m and occurs mostly below the Late-Miocene unconformity which largely separates the thin nonmarine to shallow-marine sediments above and the thicker nonmarine sediments below. The time interval was divided into eight layers of equal time thickness of 0.2 s two-way traveltime to determine the representative porosity and the in situ pressure, temperature, and density of CO2 for different depth ranges. The estimated geological CO2 storage capacities for the rock volume in the eight-layer interval range from about 23.5 × 1012 kg (23.5 Gt) to about 687.0 × 1012 kg (687 Gt) with an average of about 196.0 × 1012 kg (196.0 Gt).