The invention relates to surface cationized
silicon dioxide nanoparticles. A preparation method comprises the following steps: weighing dialkyl dimethyl
tertiary amine and putting the dialkyl dimethyltertiary amine into a three-neck flask; adding absolute ethyl
alcohol, and stirring and slowly heating the mixture in an
oil bath pan; continuing to dropwise add 3-chloropropyltrimethoxysilane, and introducing
nitrogen for a period of time; maintaining the temperature, and carrying out
reflux reaction to obtain a
silicon dioxide particle modifier; uniformly mixing absolute ethyl
alcohol, purifiedwater and
ammonia water, putting the mixture into a three-neck flask, stirring the mixture, and uniformly mixing and quickly pouring tetraethoxysilane, the prepared
silicon dioxide particle modifierand absolute ethyl
alcohol into the three-neck flask; increasing the stirring speed for a period of time, reducing the stirring speed when the solution is milky white, continuously performing a reaction for a period of time, and terminating the reaction; and centrifuging, washing,
drying and crushing the
reaction product to obtain white powdery cationized
nano silicon dioxide particles. The foam stabilizer can generate a synergistic effect with a surfactant to achieve an effect of stabilizing foam, so that the
adaptation degree to a high-temperature stratum environment is greatly improved.