Microbubble carbon dioxide injection for enhanced dissolution in geological sequestration and improved oil recovery

摘要

Microbubble CO2 can be generated by injecting CO2 through special porous filters attached to borehole casing or gas tubing. When injecting microbubble CO2 into saline aquifers, dissolution of injected CO2 into formation water can be accelerated up more than 20%, compared to conventional CO2 injection. As a result, microbubble CO2 injection will minimize the free CO2 fraction in the subsurface and consequently contribute to the long term safety of large-scale CO2 storage. Microbubble CO2 injection will also lead to effective use of pore space within the reservoirs. P-wave velocity and resistivity changes obtained when injecting CO2 in microbubble and normal bubble sizes into artificial brine-saturated porous sandstones indicate more pore water displaced by the injected microbubble CO2 in terms of sweep efficiency. Combined effects of enhanced dissolution and sweep efficiency in microbubble CO2 injection can reduce the potential risk of CO2 leakage from the subsurface and enable us to store more CO2 in same reservoirs compared to normal CO2 injection as well as economic benefit of achieving higher oil recovery.