Carbon Dioxide (CO2) Microbubble Suspension and Stabilization for Advancing Tertiary Oil Recovery

Maximizing oil recovery from existing fields is essential to satisfy global energy demands. Enhanced oil recovery (EOR) techniques, particularly those utilizing carbon dioxide (CO2) microbubbles (MBs), offer promising avenues for improving sweep efficiency and ultimately, oil recovery. This study investigates the influence of formulation and operational parameters on the stability of CO2 MBs within oil-in-water emulsions designed for EOR applications. Emulsions were formulated using the surfactant sodium dodecyl sulfate (SDS), sodium chloride (NaCl) brine, and light liquid paraffin oil. The stability of the CO2 MBs was evaluated at atmospheric pressure and room temperature by monitoring drainage rate and half-life. Results indicate that increasing SDS concentration and decreasing NaCl concentration significantly enhance MB stability. An optimal brine-to-oil ratio is crucial, with moderate gas flow rates promoting stability. Surface tension measurements further elucidated the effect of brine on stability. The study additionally explores the rheological behavior of the emulsions, examining the relationship between shear rate and viscosity for various influencing factors. The power-law model was employed to analyze the flow behavior of the emulsions. Dynamic light scattering measurements provided insights into the size distribution of the MBs, aiding in the understanding of their stability behavior.