Synthesis and properties of temperature-tolerance resistant hydrophobically associating polymer suspension agent using response surface method

Abstract

Aiming at the problem that the oil well cement slurry is easy to settle and lose its stability under high temperature environment, and combining with the characteristics of traditional cement admixtures "thickening at low temperature and thinning at high temperature", we developed a kind of high-temperature resistant cement suspension agent. A quadripolymer suspension agent P-AN18 was synthesized by free radical polymerization using 2-Acrylamido-2-methylpropane sulfonic acid (AMPS), acrylamide (AM), quaternary ammonium salt monomer N-N octadecyl dimethyl allyl ammonium chloride (DMAAC-18), and high-temperature resistant monomer N-Vinyl-2-Pyrrolidinone (NVP). The synthesis conditions were optimized using the response surface method (RSM) innovatively, the response surface graph (3D) showed the influence of independent variables on the rheological properties and density difference of cement slurry influence. The hydrophobic association structure and high-temperature resistance mechanism of P-AN18 were analyzed by infrared spectroscopy, nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), nanoparticle size analyzer, fluorescence probe test and scanning electron microscope (SEM) in a freezing environment. The effect of P-AN18 on maintaining the stability of cement slurry system at high temperature was evaluated. The results showed that the polymer suspension P-AN18 has good temperature resistance and compatibility with cement slurry. At 200 ℃, P-AN18 can keep the cement slurry system stable, and the density difference between the upper and lower part of the solidified cement column is less than 0.01 g/cm 3 . P-AN18 provides a new method for controlling the settlement stability of high-temperature cement slurry, which is expected to be used to improve the safety and cementing quality of deep well cementing. • Predicting density contrast using RSM model. • Characterizing Polymer suspensions from macro and micro perspectives. • Effective prevention of thermal thinning and particle settling of cement slurry.