Preliminary assessment of CO₂ injectivity in carbonate storage sites

Depleted gas reservoirs are used for a large-scale carbon dioxide (CO₂) storage and reduction of the greenhouse gas released into the atmosphere. To identify a suitable depleted reservoir, it is essential to do a preliminary and comprehensive assessment of key storage factors such as storage capacity, injectivity, trapping mechanisms, and containment. However, there are a limited number of studies providing a preliminary assessment of CO₂ injectivity potential in depleted gas reservoirs prior to a CO₂ storage operation. The aim of this study is to provide a preliminary assessment of a gas field located in Malaysia for its storage potential based on subsurface characterization prior to injection. Evaluation of the reservoir interval based on the facies, cores, and wireline log data of a well located in the field indicated that the pore type and fabrics analysis is very beneficial to identify suitable locations for a successful storage practice. Although the results obtained are promising, it is recommended to combine this preliminary assessment with the fluid-mineral interactions analysis before making any judgment about reliability of storage sites.