Theoretical estimations of carbon geological storage capacities in the deep aquifer in Songliao Basin: Insights from spatial stochastic simulation.

Accurately assessing the carbon dioxide (CO2) storage capacity of deep saline aquifers is critical for the implementation of carbon geological storage (CGS) project, especially considering the sparsity and heterogeneity of hydrogeological data. In this study, we developed variogram models for key parameters influencing CO2 dissolution storage capacities, such as porosity, temperature, pressure, and concentration of NaCl, then conducted 100 Sequential Gaussian Simulations (SGSs) for each parameter to derive the spatial distribution of CO2 solubility. This grid-based stochastic simulation approach provides a more accurate representation of spatial heterogeneity than using average values, and we further assessed CO2 storage capacity uncertainty across 100 simulations. The findings indicated that, within a 95% confidence interval, the theoretical storage capacity ranges from 3.38 Gt to 9.39 Gt. Moreover, the SGS-based approach mitigates the smoothing effect commonly associated with Ordinary Kriging. The assessment of potential sites for CGS based on 20-year storage shows that, compared to the P50 scenario, the P90 scenario increases transportation costs by 27.66% for power plant A and 21.88% for power plant B, while the P10 scenario reduces costs by 12.77% for A and 6.25% for B. Overall, this study provides a reliable theoretical assessment in CO2 storage capacity, offering valuable insights for decision-makers in managing the risks and opportunities of CGS projects.