Experimental and theoretical determination of minimum miscibility pressure of supercritical CO2 and alkanes at nanoconfinement

• Published in: Chemical engineering science Vol. 302; p. 120828
• Main Authors: Tao, Linyang, Liu, Weijie, Shi, Jiawei, Guo, Yaohao, Qin, Wanjun, Bao, Bo
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 05.02.2025
• Subjects: CO2 enhancing oil recovery; Minimum miscibility pressure; Modified PR-EOS; Nanoconfinement; Nanofluidic; Minimum miscibility pressure; Modified PR-EOS; CO2 enhancing oil recovery; Nanoconfinement; Nanofluidic
• ISSN: 0009-2509
• DOI: 10.1016/j.ces.2024.120828

•Measuring the MMP at nanoscales using nanofluidic technology.•Combining theoretical and experimental approaches to study nanoconfinement effects.•The nanoconfinement effect leads to a reduction in the MMP.•Fast determining, cost-effectivity, visualization, and user-independence. The minimum miscibility pressure (MMP) is crucial for CO2 Enhanced Oil Recovery (EOR). However, accurately determining MMP within nanoconfinement has been challenging due to intricate molecular interactions and reduced permeability. This study leveraged nanofluidic technology to determine MMP for supercritical CO2-alkanes at the nanoscale by observing the vanishing interface, noting a 5.1 % reduction for CO2-octane at 30 nm versus 1 μm at 80 ℃. It further explored the impact of alkane type and temperature on nanoconfinement, elucidating the underlying mechanisms. Additionally, a theoretical method was developed to estimate MMP ranging from 10 to 1000 nm, aligning well with the experimental results. The findings highlight the lower nanoscale MMP values compared to the bulk phase. This research presents methods for investigating thermodynamic properties under nanoconfinement, providing insights into the abnormal behaviors of fluids at the nanoscale and contributing to EOR.