Synthesis of covalently linked copolymer-laponite hybrid via one pot reaction as an ultra-high temperature suspension stabilizer for oil well cement

Under ultra-high temperature conditions in cementing engineering, sharp slurry viscosity drop, polymer additive decomposition and accelerated solid particle thermal motion collectively trigger severe instability, leading to marked density inhomogeneities and mechanical strength loss in set cement and threatening cementing operational safety. To address this problem, a novel ultra-high-temperature suspension stabilizer, PADNV-L hybrid, was fabricated via a one-pot reaction in this study. Specifically, laponite was incorporated into the long-chain thermothickening copolymer through covalent bonding interactions, and the organic-inorganic hybrid synergistic effect was harnessed to enhance the ultra-high temperature performance of the suspension stabilizer. The ¹H NMR, FTIR, XPS, and TGA characterizations confirmed the successful synthesis of the co-polymer (AMPS-DEAA-NVP) (namely PADN) and the Organic-inorganic hybrid polymeric material p(AMPS-DEAA-NVP-laponite) (namely PADNV-L hybrid).Comprehensive evaluations revealed that the cement slurry containing 0.5% PADNV-L polymer possesses superior stability at 200℃ compared to that containing 0.5% PADN polymer. Furthermore, the PADN-L modified slurry exhibited superior rheological and compressive properties compared to systems incorporating other polymer additives or lacking a suspension stabilizer. Through the combination of Zeta potential analysis on cement slurry supernatants and microstructural characterization of the cement, the suspension stabilization mechanism governing the PADNV-L hybrid in oil well cement (OWC) slurries was systematically revealed. The PADNV-L hybrid forms an adsorption layer on the surface of the cement particles upon addition. Furthermore, the organic-inorganic hybrid forms a three-dimensional spatial network structure in solution, enabling effective particle adsorption and support. The nucleation effect of nanoparticles promotes cement hydration, refines the pore structure of the cement stone, and consequently enhances its mechanical properties.