Characterization of carbon storage systems in central Taiwan and its offshore area

Abstract Geological carbon storage is widely used to reduce CO 2 emissions to the atmosphere. Cenozoic rock strata up to 8 km in thickness, consisting of thick sandstone and shale layers in central Taiwan and offshore areas, where major emitting sources are located, are investigated for their carbon storage potential. Four carbon storage systems are characterized in the aspects including the spatial distribution of lithologies, formation thicknesses, depths, permeability, and porosity of the reservoirs, using data from 22 boreholes and a few seismic sections. Three sites, the Taichung Power Plant (TPP), Changhua Coastal Industrial Park (CCIP), and Mailiao Taisu Industrial Park (MTIP), are selected for detailed site characterization. The storage systems, each composed of a caprock and reservoir pair, are (1) R1 system of the lower Cholan Formation (Fm); (2) R2 system from the Chinshui Shale (Sh), Kueichulin Fm, to Nanchuang Fm, and Kuanyinshan Sandstone (Ss); (3) R3 system from the Talu Sh to Peiliao Fm and Shihti Fm; and (4) R4 system from the Piling Sh to Mushan Fm and Wuchishan Fm. The four systems above show spatial depth variations and lateral changes in the lithofacies of caprocks and reservoirs, leading to different storage systems from site to site. Our results indicate that central Taiwan and offshore areas are ideal for the geological sequestration of CO 2 and that their capacity to host CO 2 requires further investigation.