Visualization and quantification of two-phase flow in transparent miniature packed beds

Area of Science:

• Multiphase flow in porous media
• Microfluidics and interfacial phenomena

Background:

• Understanding fluid flow in porous media is crucial for applications like enhanced oil recovery.
• Confinement effects in natural porous media significantly alter multiphase flow dynamics.
• Capillary forces often dominate fluid displacement at low flow rates.

Purpose of the Study:

• To visualize and analyze the flow of British Petroleum (BP) oil displacing an aqueous surfactant phase in confined porous media.
• To investigate the impact of confinement on multiphase flow behavior at low capillary numbers.
• To establish an empirical correlation for oil travel distance based on experimental observations.

Main Methods:

• Utilized optical microscopy to observe two-phase flow (BP oil and aqueous surfactant) in transparent, natural porous media.
• Employed microscopic packed beds created by packing water-wet cryolite grains in glass microchannels.
• Studied primary drainage at varying capillary numbers (10^-6 to 10^-2).

Main Results:

• Observed burst motion and capillary fingering phenomena at low capillary numbers, indicating capillary force dominance.
• Discovered a linear relationship between breakthrough time and capillary number on a log-log scale.
• Developed an empirical generalized correlation between oil travel distance (x) and time (t).

Conclusions:

• Confinement significantly influences multiphase flow behavior in porous media.
• The established correlation provides a predictive tool for oil travel distance in similar systems.
• The findings offer insights into fluid displacement mechanisms under capillary-dominated conditions.