Numerical assessment of ocean current and acidification effects on CO₂ bubble leakage from shallow subsea storage

Carbon capture and storage (CCS) is a critical strategy for mitigating greenhouse gas emissions. Although subsea CO₂ storage offers substantial potential, the risk of gas leakage and subsequent bubble plume formation in shallow waters poses a serious threat to marine ecosystems by inducing localized acidification. This study employs Computational Fluid Dynamics (CFD), using the Euler–Euler multiphase model, to simulate the ascent and dissolution of CO₂ bubbles under the influence of ocean currents. The model was validated against data from the QICS field experiment. The results indicate that, when mass transfer through dissolution is activated, bubble size decreases significantly, reaching a range of 2.00–9.91 mm at 30 cm above the seabed, compared with the initial maximum diameter of 12 mm. This reduction in bubble volume slows the rising velocity of the bubbles and leads to a higher concentration of dissolved CO₂ in the benthic layer, thereby posing potentially severe ecological risks to marine environments.