Methodology of CO2 aquifer storage capacity assessment in Japan and overview of the project

Abstract

Abstract A systematic Japanese nationwide saline-aquifer CO 2 storage capacity assessment has been carried out. The project was subdivided into two parts (Missions 1 and 2). We first classified the candidate saline aquifers based on the type of geological structure and the abundance of available data. A total of 146 billion tons of CO 2 storage capacity was estimated for the entire country based on oil and gas exploration data using the volumetric method in Mission 1. The potential areas considered in the Mission 1 program are mostly offshore and located far from large scale CO 2 emission sources. Mission 2 involved storage capacity estimation for regions near large scale CO 2 sources, and the Mission 2 study areas were excluded from the Mission 1 capacity assessments. A total of 27 areas that involve nearby CO 2 sources were chosen for the study. A preliminary assessment was performed based on national-scale geological information, and promising sedimentary regions were selected for more detailed examination. Detailed studies were performed for 14 promising areas based on available existing geological data, and regional-scale storage capacities were estimated. A wide range of estimated storage capacities for the various areas emerged, from 10 million tons of CO 2 for the Hakodate Bay area to 4.2 billion tons of CO 2 for the Osaka Bay area, although the quantitative significance of these assessments must be considered to be only preliminary.