Rapid Screening of Basins for Geological CO2 Storage Using Dynamic Common Risk Segment Mapping

Saline aquifers possess significant storage capacity for CO₂, offering a potential resource for mitigating anthropogenic climate change due to CO₂ emissions. However, identifying suitable storage sites across regions that may be several tens or hundreds kmacross can be extremely time consuming both computationally and in terms of human resources. This study introduces a Dynamic Common Risk Segment (D-CRS) workflow to efficiently screen large-scale saline aquifers and rapidly pinpoint promising locations for further detailed study. This technique relies on generating maps related to storage capacity, storage security, and fluid flow, while also estimating the risks and hazards associated with each potential site.

A 3D static model in Southeast Asia was used to evaluate the applicability of D-CRS in a geologically complex region characterized by multiple faults, existing hydrocarbon reservoirs, and legacy wells. The region of interest is approximately 50km by 30km across containing saline aquifers in nine intervals of generally low net-to-gross fluvial reservoirs together with three hydrocarbon fields. Maps of CO₂ injection rate, pressure propagation time, and storage capacity were generated for each potential storage zone within this region. These maps were then translated into a traffic light format using threshold values derived from other Carbon Capture and Storage (CCS) projects or specific to the region of study. For each zone, a composite D-CRS map was created by overlaying the previously generated maps of storage capacity, pressure propagation time, and injection rate. This composite map facilitated the identification of the most promising storage sites for subsequent detailed studies and analysis.

Storage capacity maps indicated that nearly 40% of the region exhibited low storage potential, while approximately 30% demonstrated favorable storage capacity. Injection rates varied significantly, ranging from less than 0.01 Mt/yr to 2 Mt/yr across different locations, influenced by factors such as permeability, thickness, and maximum allowable pressure. Notably, almost 20% of the region displayed acceptable potential injection rates exceeding 0.2 Mt/yr, whereas over 40% exhibited rates below 0.04 Mt/yr. Furthermore, maps illustrating the pressure propagation time from potential CO₂ injection sites to the nearest hazardous areas were analyzed for each prospective storage interval. These maps revealed a wide range of propagation times, from less than a day to several years. Approximately 30% of the grid cells demonstrated propagation times under a month, while over 50% exceeded a year. These results were validated through comparison with full reservoir simulations conducted at selected sites. The implementation of the D-CRS workflow facilitates a more efficient allocation of resources by concentrating characterization and study efforts on the sites with the highest potential and lowest risk.

D-CRS is a robust and powerful tool for rapid screening, enabling efficient exploration of prospective basins. It delivers a comprehensive set of dynamic maps that represent storage capacity and security, guiding engineers towards informed decisions. By integrating these maps into a single, color-coded composite, D-CRS provides a valuable insight for selecting the most promising sites for further characterization and detailed study.