When applied to extra-heavy oil,
conventional polymer surfactants
exhibit poor efficacy in reducing viscosity and have limited adaptability.
In this work, a novel amphiphilic polymer named PAADB was prepared
by incorporating 2-acryloylamino-2-methyl-1-propanesulfonic acid (AMPS),
benzyldimethyl [2-[(1-oxoallyl) zoxy] propyl] ammonium chloride (DML),
and poly(ethylene glycol) methyl ether acrylate (BEM) into the main
chain of acrylamide through free radical polymerization. PAADB exhibited
outstanding interfacial activity, water-phase thickening ability,
and emulsifying performance. The critical micelle concentration of
PAADB was approximately 2500 mg/L, with a viscosity of 84.69 mPa·s
at 50 °C. Additionally, interfacial tension experienced a notable
decrease from 46.53 to 14.56 mN/m. At an optimal concentration of
4000 mg/L, PAADB reduced the viscosity of extra-heavy oil by over
92% across various temperatures and by more than 93% for different
types of extra-heavy oil. PAADB demonstrated excellent emulsification
ability and emulsion stability, effectively dispersing crude oil to
create water-in-oil droplets measuring 35.33 μm in size. Meanwhile,
molecular dynamics simulations further unveiled the viscosity reduction
mechanism of PAADB. The hydrophilic groups within PAADB molecules
are regularly distributed on the water interface, while the hydrophobic
groups infiltrate the oil molecules to form a stable interfacial film.
PAADB and asphaltene spontaneously form a sandwich structure, reducing
intermolecular forces and disrupting the interlayer structure of asphaltene
molecules. In general, this novel amphiphilic polymer demonstrates
broad applicability and potential in extra-heavy oil recovery, providing
valuable insights for the development of new heavy oil viscosity reducers
(HOVRs).