A Multifunctional Core-Shell Nanoemulsion-Mediated Disruption of Asphaltene Aggregates for Unconventional Reservoir...

Area of Science:

• Petroleum Engineering
• Materials Science
• Colloid and Surface Chemistry

Background:

• Tight heavy-oil reservoirs face challenges due to high oil viscosity and poor mobility caused by asphaltene aggregation.
• Conventional displacement agents suffer from adsorption loss and limited deep transport capacity.

Purpose of the Study:

• To synthesize and evaluate a novel core-shell nanoemulsion for enhanced heavy oil recovery.
• To investigate the mechanism of asphaltene disruption and viscosity reduction at the molecular level.

Main Methods:

• Synthesis of a core-shell nanoemulsion with controlled particle size.
• Evaluation of physicochemical properties, stability (thermal, salinity), and oil-water interfacial tension.
• Core flooding tests in oil-wet capillary models.
• Molecular dynamics simulations to elucidate the disruption mechanism.

Main Results:

• Nanoemulsion with 10-20 nm particle size, excellent dispersibility, and stability under reservoir conditions.
• Achieved ultralow critical micelle concentration (0.01%) and reduced oil-water interfacial tension to 7.3 × 10^-2 mN/m.
• Enhanced oil recovery by 37.1% and achieved 68.9% displacement efficiency in core flooding tests.
• Molecular dynamics simulations confirmed disruption of asphaltene π-π stacking and viscosity reduction.

Conclusions:

• The core-shell nanoemulsion effectively reduces heavy oil viscosity by disrupting asphaltene aggregation through targeted penetrant delivery.
• The hydrophilic shell minimizes rock adsorption, enabling deep migration in nanoporous media.
• This study provides a theoretically grounded strategy for efficient exploitation of tight heavy-oil reservoirs.