Potential for significantly improving comprehensive performance of oil-well cement by a new type of latex

In this study, a new type of soap-free inorganic/organic composite latex (SBML-II) was prepared by soap-free emulsion polymerisation method using sodium p-styrenesulfonate (SSS) and modified silicon dioxide as copolymer emulsifiers, which were characterised by Fourier transform infrared spectrometer, transmission electron microscope, thermo-gravimetric analysis and other means. Then the latex was employed to prepare polymer latex modified oil-well cement, and the influence of the latex on the basic properties of cement slurry, mechanical properties and microstructure of cement matrix was evaluated. The characterisation of SBML-II showed that the synthesised latex presents a typical core-shell structure and possesses better dispersibility, stability and thermal stability than conventional latex (SBML-I). At the same time, the SBML-II latex forms a membranous morphology more easily than SBML-I at the same temperature and has better compatibility with additives and resistance to ions. Performance evaluation in cement slurry and cement matrix showed that the SBML-II has a good dilution effect on cement slurry and excellent potential to improve the mechanical properties of the cement matrix. Meanwhile, the addition of SBML-II is helpful to improve microstructure, owing to film formation in the cement matrix.