Exploring CO2 storage with impurities in deep saline aquifers through computational experiments

Abstract

This research delves into understanding how injecting gas mixtures affects the movement and destiny of CO2 components over time and space using computational experiments. The study starts by examining the thermodynamic properties of the fluids, integrating them into a reservoir model. A detailed workflow based on this model explores how various gas mixture components, alongside reservoir and engineering factors, influence CO2 migration and its behavior. Results from computational experiments reveal that N2 promotes the radial spread of CO2, yet its dissolution weakens CO2 solubility. When considering different impurity gases, H2 leads to the farthest lateral migration of CO2, followed by N2. H2S results in the shortest lateral migration due to its higher solubility. Moreover, a sensitivity analysis highlights key parameters like the ratio of injection gas mixtures (e.g., CO2: N2 = 0.25:0.75, 0.5:0.5, and 0.75:0.25), reservoir permeability (ranging from 5 mD to 500 mD), and injection rates (ranging from 10000 m3/day to 100000 m3/day) that need consideration to optimize gas mixture injection strategies in these environments. These findings contribute to a better understanding of injecting gas mixtures into deep saline aquifers, aiding in the development of more effective strategies for CO2 storage.