Ryosuke Okuno

The University of Texas at Austin 

Aqueous CO2 bubble dispersion for enhanced oil recovery

Conventional CO₂ injection can suffer from unfavorable mobility ratio, gravity segregation, and early breakthrough. Aqueous CO₂ bubble dispersions offer a water-continuous alternative that carries CO₂ both molecularly in the aqueous phase and within dispersed CO₂-rich bubbles, then releases a CO₂-rich phase in situ through changes in pressure, temperature, composition, and fluid contact. This talk presents a thermodynamic framework linking generation and oil displacement through minimum supersaturation pressure, gas-release capacity, and released-gas volume. High-pressure measurements reveal polydisperse bubbles spanning nanometers to micrometers, broadening the framework for interpreting aqueous bubble dispersions. In tertiary Berea-sandstone corefloods, a dispersion generated above the supersaturation threshold produced 23.3% OOIP incremental recovery, whereas an ambient-pressure-generated fluid became undersaturated at displacement conditions and recovered only 0.3% OOIP. These results identify CO₂ carrying and release capacity as central design variables and provide a basis for process design and field deployment.