Accelerating CO₂ Dissolution Trapping in Deep Saline Aquifers through a Microbubble Injection Strategy

To enhance carbon storage capacity in deep saline aquifers, the optimization of the microbubbles’ CO2 (MB CO2) injection strategy for enhancing carbon storage capacity in tight reservoirs is carried out to address issues related to the limited utilization of reservoir pores. This work directly observes the effect of variable injection conditions ranging from 0.05 to 0.3 mL/min on CO2 transport in saturated cores at 320 K with a pressure of 12.5 MPa. From the spatiotemporal evolution of the fluid phase distribution, the capillary fingering pattern is observed in all cases, while MB CO2 with greater mass transfer rates shows greater mobility within tiny pores. The flow of MB CO2 in sandstones is characterized by a channeling pattern, which is determined by stratification and property differences of the core. The results confirm that CO2 saturation increased by 11.2% at gas breakthrough time and 15.5% at steady state using the MB CO2 injection strategy. Differences in local CO2 saturation levels are seen as a function of the injection distance. By altering the flow rate of the displacement phase, the most favorable results are found at capillary number (Ca) Ca = 3.30 × 10–10 with a medium injection rate. The average CO2 saturations are found to be above 11.9 and 7.5% for higher and lower injection rates, respectively.