Evaluation of geological CO₂ storage potential in Saudi Arabian sedimentary basins

Carbon capture and storage (CCS) technologies are needed as a crucial technology for Saudi Arabia to reach its net-zero goal by 2060. This study represents the first comprehensive evaluation of geological CO₂ storage capacities in the sedimentary basins of Saudi Arabia. Our study relied on collecting and analyzing hundreds of data sets from public domains, which were carefully selected based on their quality and relevance to ensure reliability. We evaluated the suitability and storage capacity of 17 basins and sub-basins throughout the country for CO₂ storage in deep saline aquifers as well as future depleted oil and gas reservoirs using the CO₂-SCREEN tool. Our evaluation shows that the most suitable basins are located in the eastern part of the country, including the Eastern Arabian Basin and the Interior Homocline-Central Arch. On the other hand, Western Saudi Arabia is characterized by less favorable basins, except for the three moderately suitable onshore basins, namely the Umm Luj, Yanbu, and Jeddah basins. Uncertainties were considered by performing Monte Carlo simulations. At the 50th percentile uncertainty, the estimated total effective storage capacities in deep saline aquifers, future depleted oil reservoirs, and non-associated gas reservoirs are ∼432, ∼5, and ∼ 9 gigatons (Gt), respectively. Most of the country's storage capacity is located in the eastern region, displaying an uneven distribution of storage resources nationally. For full transparency, we share all the calculation sheets utilized. The methodology adopted for estimating the potential capacity aligns with the effective storage capacities defined by the Carbon Sequestration Leadership Forum (CSLF). The capacity estimates account for technical, geological, and engineering constraints. Nevertheless, it is crucial to note that the practical storage capacity estimate requires the incorporation of additional societal, economic, and regulatory factors, which were not taken into consideration in this study. Consequently, there is a pressing need for additional research, particularly prospect-level evaluations entailing drilling, testing evaluation, and monitoring wells. These comprehensive investigations will significantly contribute to our comprehension of reservoir and seal characteristics, assess injectivity performance, and provide profound insights into CO₂ behavior, effectively mitigating uncertainties. The storage capacity estimates presented in this study furnish crucial information for policymakers and industry leaders engaged in addressing carbon emissions in Saudi Arabia.