Organic-inorganic hybrid fluid loss agent for oil well cement as well as preparation method and application of organic-inorganic hybrid fluid loss agent

The invention discloses a preparation method and application of an organic-inorganic hybrid fluid loss agent for oil well cement, and the preparation method comprises the following steps: adding 2-acrylamide-2-methylpropanesulfonic acid, an acrylamide monomer, a carboxylic acid monomer and sodium p-styrenesulfonate into distilled water, uniformly stirring at normal temperature, and adjusting the pH value; after an initiator is added, heating reaction is carried out, and the liquid anionic polymer fluid loss agent is obtained; and mixing the liquid anionic polymer fluid loss agent with magnesium-aluminum hydrotalcite, stirring at 65-75 DEG C for 6-8 hours, settling, washing with water, centrifuging, freeze-drying and grinding to obtain the organic-inorganic hybrid fluid loss agent for oil well cement. According to the invention, water is used as a dispersion medium, the preparation process is simple, the cost is low, the fluid loss agent can effectively reduce the fluid loss of cement slurry at a high temperat