Method for preparing micro-nano oil-displacing agent from oily sludge and sand and prepared nano oil-displacing agent

The invention discloses a method for preparing a micro-nano oil-displacing agent by using oil sludge sand and a prepared nano oil-displacing agent, the prepared micro-nano oil-displacing agent does not remove crude oil in oil sludge, but removes large-particle-size oil sand (10 [mu] m or more), and then the oil sludge, the crude oil in the oil sludge, a dispersion-assisting substance and water are prepared into a composite micro-nano oil-displacing agent. The preparation method comprises the following steps: pretreating oily sludge sand; sulfonation process treatment; and carrying out micro-nano refining treatment. Finally, the composite micro-nano oil displacement agent composed of the micro-nano oil sludge, the micro-nano oil drops, the dispersion-assisting substance and the water is formed. The oil field waste oil sludge sand is recycled to be used as the micro-nano oil displacement agent, the oil sludge sand is deeply utilized, the risk of ground environment pollution is reduced, the oil sludge treatment