Investigation of non-chemical CO2 microbubbles for enhanced oil recovery and carbon sequestration in heterogeneous porous media

Non-chemical CO2 microbubble (MB) is a promising environmentally friendly technology for enhanced oil recovery (EOR) and carbon sequestration. Understanding the interaction between non-chemical CO2 MB and oil phases in porous media is crucial for optimizing the design of CO2 MB to enhance both EOR and carbon sequestration efforts. This study explores the impact of oil on the conformance control of non-chemical MB and conducts a case study on their potential for EOR and carbon sequestration in a heterogeneous reservoir. First, experimental results reveal that MB's conformance control is impacted by the presence of oil, with varying degrees of impairment depending on oil composition. Then, reservoir simulations demonstrate that MB outperforms conventional CO2 flooding and water-alternating-gas (WAG), achieving a final recovery of 77.48% of original oil in place compared to 66.79% of original oil in place for CO2 flooding and 68.19% of original oil in place for WAG. Sensitivity analyses highlight the importance of parameters such as gas-liquid ratio of MB, reservoir heterogeneity, and reservoir thickness in MB's EOR performance. Finally, CO2 storage efficiency analyses show that MB exhibits superior CO2 storage efficiency, with higher structural and solubility trapping compared to WAG. The study concludes that MB technology holds promise for EOR and carbon sequestration, contributing to efforts toward carbon neutrality and sustainable oil recovery practices. These findings provide valuable insights for optimizing MB applications in field-scale operations and advancing toward a more environmentally sustainable energy industry.