Well cementation cement slurry, modified resin for well cementation cement slurry and preparation method of modified resin

The invention provides well cementation cement slurry, modified resin for the well cementation cement slurry and a preparation method of the modified resin. The preparation method comprises the following steps: uniformly stirring epoxy resin and a hydrotropy emulsifier at a first preset temperature; after the obtained emulsion is heated to a second preset temperature, phosphorus pentoxide is added in multiple batches; under the condition of constant temperature, fumed silica and a siloxane coupling agent are added into the reacted emulsion, and the mixture is stirred to continue to react for a preset time; after the reaction is completed, cooling to room temperature, and adding a potassium hydroxide solution to adjust the pH value, so as to obtain the modified resin for the well cementation cement slurry. The epoxy resin is modified into the hydrophilic resin emulsion, so that the modified resin can participate in the hydration reaction of cement when being used for preparing the cement paste, the set cement