Dissolution behavior of interacting CO2 microbubbles analyzed using Arbitrary Lagrangian-Eulerian approach

• Interacting microbubble CO₂ (MBCO₂) dissolution is complex and hard to quantify. • MBCO₂ dissolution was simulated using the Arbitrary Lagrangian–Eulerian method. • A single 20 μm MBCO₂ disappears in approximately 50 ms. • The interacting MBCO₂–water system reaches CO₂ saturation within a short timescale. • MBCO₂ injection increases CO₂ storage efficiency and reduces injectivity risks. CO₂ microbubble (MBCO₂) injection may broaden the applicability and reduce the injectivity-related risks of carbon capture and storage. However, the MBCO₂ dissolution process is complex and difficult to experimentally quantify. MBCO 2 dissolution was numerically analyzed using the arbitrary Lagrangian–Eulerian (ALE) method to quantitatively examine dissolution phenomena, including bubble shrinkage, gas migration between phases, and bubble interference using simulations. A single MBCO 2 quickly dissolves and disappears under bottom-hole conditions. One MBCO₂ with a diameter of 20 or 50 µm disappears in approximately 50 or 260 ms, respectively. This difference in dissolution time arises from increases in interfacial surface area and interfacial CO₂ flux per unit area as the bubble size decreases. Furthermore, sensitivity analyses show that the CO₂ solubility and dissolution rates are slightly lower in saline water (3.5 wt.% salinity), and the dissolution still occurs within tens of milliseconds. The main dissolution behavior of MBCO₂ is robust to various bubble sizes and salinity conditions, suggesting the injection conditions are less prone to drying out. Although bubble interference produces residual CO₂ with a high void ratio, the system reaches CO₂ saturation at a similar speed. The dissolved N 2 and O 2 in the liquid phase has limited effects on CO 2 dissolution. These findings suggest that MBCO₂ injection promotes rapid CO₂ dissolution and effectively increases CO₂ storage efficiency. This study provides quantitative insights into bubble dissolution considering the effects of bubble interference and dissolved gas, which are difficult to experimentally observe.