Synthesis and Performance Analysis of Temperature‐Resistance and Salt‐Tolerance Polymer <scp>AM</scp>/<scp>NVP</scp>/<scp>DMDAAC</scp>

ABSTRACT The primary issues with pre‐crosslinked particle water shutoff agents are their susceptibility to decomposition at high temperatures and diminished swelling performance in highly mineralized environments. The PAVC was prepared using acrylamide (AM), N‐vinyl‐2‐pyrrolidinone (NVP), and dimethyl diallyl ammonium chloride (DMDAAC) as monomers, with N,N′‐methylenebisacrylamide (MBA) as a crosslinker and 2,2′‐azobis(2‐methylpropionamide) dihydrochloride (V50) as an initiator through solution polymerization. Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis were employed to characterize the structure and morphology of the synthesized PAVC particles. Performance tests showed that the PAVC exhibits excellent thermal stability, with a swelling ratio of 12.89 g/g at 130°C without losing strength. The polymer exhibits strong salt resistance, with a minimal difference in swelling ratio only 0.58 g/g between 3 × 10 4 mg/L and 15 × 10 4 mg/L NaCl solutions, and just 0.98 g/g between 1 × 10 4 mg/L and 5 × 10 4 mg/L CaCl₂ solutions. The PAVC exhibited good oil–water selectivity, swelling minimally in kerosene (expanded 0.3 g/g at 30 h). In simulated formation water at 120°C and a concentration of 20 × 10 4 mg/L, the PAVC achieved a plugging rate of 97.2% and showed excellent resistance to scour capability.