Core-Shell Nanohydrogels with Programmable Swelling for Conformance Control in Porous Media

Area of Science:

• Petroleum Engineering
• Materials Science
• Chemical Engineering

Background:

• Conformance control in waterflooding enhances oil production by redistributing water flow.
• Preformed gel particles redirect flow but face limitations in reservoir penetration and shear stability.
• Nanoscale materials offer potential for improved deep reservoir conformance control.

Purpose of the Study:

• To develop and evaluate core-shell nanohydrogels with delayed swelling for enhanced oil recovery.
• To investigate the flow diversion capabilities of these nanohydrogels in porous media.
• To assess their potential as conformance control agents in oil reservoirs.

Main Methods:

• Fabrication of core-shell nanohydrogels with controlled delayed swelling behavior.
• Microfluidic experiments using a 3D porous medium micromodel with confocal microscopy visualization.
• Core flood experiments to evaluate permeability reduction and flow diversion in reservoir samples.

Main Results:

• Nanohydrogels exhibited a 200-fold volume increase after 30 days under reservoir conditions.
• Swollen nanohydrogels reduced micromodel permeability and diverted flow to low-permeability regions.
• Core flood experiments confirmed significant permeability reduction and fluid flow diversion.

Conclusions:

• Core-shell nanohydrogels demonstrate effective flow control in porous media.
• Delayed swelling behavior allows for deeper reservoir penetration and targeted conformance control.
• These nanohydrogels show promise as advanced conformance control agents for oil recovery.