【企画講演／募集型企画】 ゼロエミッション社会構築にむけたCCS/CCUS技術開発

[1K0201-08-06] マイクロバブル化したCO₂を用いた石油増進回収技術の検討

○ナム グエン ハイ レ¹、菅井 裕一¹、ロナウド ンゲレ¹、佐々木 久郎² (1. 九州大学、2. 未来工学研究所)

司会：藤井 孝志（産総研）

キーワード：石油増進回収、CO2マイクロバブル、界面活性剤、ポリマー、安定性

An interest in the application of CO₂ microbubbles (CO₂ MBs) in enhanced oil recovery grows due to their blockage ability in the highly permeable zone. The CO₂ MBs have been characterized as a core of CO₂ gas with a shell consisted of multilayers surfactant molecules and a viscous aqueous layer. This unique structure allows CO₂ MBs to remain under severe conditions of high pressure and high temperature. The bubble size of CO₂ MBs plays an essential role in the pore plugging mechanism during EOR operation.
This study investigates the effect of Xanthan Gum (XG) polymer concentrations and Sodium Dodecyl Sulfonate (SDS) surfactant concentrations on the size distribution of CO₂ MBs by using optical microscopy and statistical approach. CO₂ microbubbles fluids were prepared by using a high-speed homogenizer with diffusing CO₂ gas into an aqueous solution. A detailed bubble size distribution analysis supports the Weibull distribution as a better fit to experimental observations than the Log-normal or Normal distributions. The results show that surfactant concentrations have a profound impact on bubble size. Bubble size distribution of CO₂ MBs shifted to lower diameter by increasing surfactant concentrations. The polymer concentration increment was also found to reduce bubble size slightly. However, higher polymer concentration improves the BSD, which is advantageous to the stability of CO₂ MBs. The most stable CO₂ MBs were generated at 5 g/L of XG polymer and 3 g/L of SDS surfactant for the range of experiments.