Lysine Crosslinked Polyacrylamide─A Novel Green Polymer Gel for Preferential Flow Control

Area of Science:

• Polymer Chemistry
• Geoscience
• Environmental Science

Background:

• Acrylamide-based polymer gels are used for subsurface preferential flow control.
• Traditional crosslinkers like chromium (III) and phenol-formaldehyde pose environmental risks.
• Stringent regulations necessitate the development of eco-friendly alternatives.

Purpose of the Study:

• To develop and characterize a novel green polymer gel system using l-lysine as a crosslinker.
• To investigate the impact of various parameters on gelation behavior and thermal stability.
• To evaluate the plugging efficiency of the polyacrylamide/lysine gel in high-permeability sandstone.

Main Methods:

• Systematic study of lysine and polymer concentration, salinity, pH, and temperature effects.
• Elucidation of gelation mechanism and crosslinking density.
• Sandstone core flooding experiments to assess plugging efficiency and fluid selectivity.

Main Results:

• The polyacrylamide/lysine system exhibits controllable gelation above 80 °C with tunable gelation times.
• Achieved elastic modulus exceeding 400 Pa and stability at 80-130 °C for over 200 days.
• Demonstrated over 1000-fold permeability reduction in sandstone cores, with higher reduction for water than oil (Frrw = 2 * Frro).

Conclusions:

• The novel polyacrylamide/lysine gel system offers a viable, environmentally friendly alternative to toxic crosslinkers.
• This green gel system is suitable for preferential fluid control in various subsurface applications.
• Potential applications include water management in oil and gas, enhanced geothermal systems, and carbon capture and sequestration.