CO2 Storage Capacity Assessment of Deep Saline Aquifers in the Mozambique Basin

Abstract

Abstract This study is the first of its kind that made an assessment of theoretical storage capacity within the deep saline aquifers in the Mozambique Basin. An integrated approach that involved geographic information systems analysis and field data assessment was adopted to estimate the storage capacity. Geological characterization was conducted based on available geological cross-sections supported by well stratigraphy data and data from well-logs. Four separate saline aquifers in the depth ranges of 800 m to 3,500 m below surface were recognized in the basin, each having its own sealing shale layers. The theoretical low- and high-end CO 2 storage capacity for the saline rock formations were estimated using volumetric approach. The integrated approach that involved use of GIS tools and field data has resulted in more robust estimates which reduced the spatial uncertainty and thus constrained CO 2 storage capacity estimations. It also avoided the unrealistic extrapolation throughout the basin, while promoting a proper accounting for the possibility to store CO 2 in multiple overlaying formations. We believe that the digital storage atlas developed should provide a basis for further work to reduce the uncertainty in the estimates and also provide support to policy makers on future planning of CCS projects in the country.