Preliminary Assessment of CO2 Storage Capacity in Deep Saline Aquifers of the Mekong Delta, Southern Vietnam: a Volumetric Approach

Geological storage of CO₂ in deep saline aquifers (DSAs) is a key strategy for climate change mitigation. This study provides a preliminary assessment of the storage potential of Miocene aquifers in the Mekong Delta, southern Vietnam, using a first - order v olumetric method combined with Monte Carlo simulations. Two regionally extensive reservoirs, n1 - 2,3 and n1 - 1, were evaluated based on screening criteria including depth, salinity, porosity, thickness, and sealing capacity. Results show that the n1 - 2,3 aquifer offers very large theoretical storage capacity, with probabilistic estimates ranging from 70 to 250 Gt of CO₂, but with significant geological uncertainty. In comparison, the n1 - 1 aquifer demonstrates smaller capacity (1.1 – 4.0 Gt CO₂) but more pre dictable outcomes, suggesting its suitability for near - term pilot - scale deployment. These findings represent the first probabilistic capacity estimates for the Mekong Delta and provide a foundation for advancing site - specific characterization and fut ure CCS planning in Vietnam.