Synthesis and performance evaluation of polycarboxylate dispersant for oil well cement

Although polycarboxylate (PCE) is widely used in the concrete industry, its application in cementing engineering is restricted owing to its poor temperature resistance and strong retardation effect on oil well cement. Hence, in this study, a sulfonated polycarboxylate (SPC) dispersant suitable for oil well cement was synthesised by performing free-radical polymerisation using omega-hydroxy polyethylene glycol ether, acrylic acid, and 2-acrylamide-2methylpropanesulfonic acid as raw materials, and its molecular structure was characterised by using Fourier transform infrared spectroscopy, gel permeation chromatography, and 1H-nuclear magnetic resonance spectroscopy. The rheological properties, thickening curve, and compressive strength of the SPC cement slurry were studied. The hydration products of the SPC cement slurry were analysed by using X-ray diffraction, and the microstructure of the cement stone was examined by using mercury intrusion porosimetry and scanning electron microscopy. The results showed that SPC has good dispersion performance and can effectively reduce the particle size and improve the workability and rheological properties of cement slurry. In addition, SPC has a less retardation effect on the cement slurry than conventional PCE, which can reduce the number of detrimental pores in cement stone, increase compactness, and improve the early compressive strength of cement stone.