Pore-scale multiple-contact miscibility measurements in a microfluidic chip.

Area of Science:

• Petroleum Engineering
• Chemical Engineering
• Geoscience

Background:

• Carbon dioxide enhanced oil recovery (CO2 EOR) is crucial for extending oil production and sequestering CO2 during the energy transition.
• Achieving miscibility between CO2 and oil, known as multiple-contact miscibility (MCM), is vital for efficient CO2 EOR.
• Current methods for assessing MCM rely on macroscopic visualization, lacking detailed insights.

Purpose of the Study:

• To introduce a "rock-on-a-chip" system for inferring the onset of multiple-contact miscibility.
• To provide a microfluidic platform for studying CO2-oil interactions under controlled conditions.
• To develop rapid measurement techniques for assessing MCM development.

Main Methods:

• Fabrication of a 2D microfluidic porous medium with a stochastic pillar distribution.
• Utilization of an analogue ternary system to simulate oil and CO2 MCM.
• Conducting experiments in both imbibition and drainage directions to investigate different rock wetting properties.

Main Results:

• Observation of distinct behaviors of trapped non-wetting ganglia during imbibition.
• Analysis of phase interface evolution during drainage as miscibility developed.
• Demonstration of how microfluidic observations can be converted into rapid miscibility measurements.

Conclusions:

• The "rock-on-a-chip" system effectively mimics CO2 EOR MCM processes.
• Microscopic observations provide valuable data for understanding and quantifying MCM development.
• This technology enables rapid, data-driven assessments for optimizing CO2 EOR operations.