Encapsulated sustained-release acid for oil-water well reconstruction and preparation method thereof

The invention discloses an encapsulated sustained-release acid for oil-water well reconstruction and a preparation method thereof. The encapsulated sustained-release acid comprises a capsule core and a sustained-release supporting layer coated on the outer layer of the capsule core, wherein the capsule core is a soluble or meltable solid acid, the sustained-release supporting layer comprises a sustained-release wall material and a supporting wall material, the sustained-release wall material is an organic fatty acid or a derivative thereof, the supporting wall material is acrylic resin or a derivative thereof, and the solid acid is solid hydrochloric acid powder or citrate. The encapsulated sustained-release acid is a spherical granule with the particle size of 0.15-0.25 mm. The encapsulated sustained-release acid also comprises an adhesive spray-coated on the capsule core, wherein the adhesive is water-soluble vegetable gum or a derivative thereof, and is specifically guar gum, hydroxypropyl guar gum or carboxymethyl hydroxypropyl guar gum. According to the invention, the control mode of the acid radical ion consumption is simple and accurate; the preparation process is simple; and the encapsulated sustained-release acid is reliable in performance, safe for transportation and carrying, and convenient for use, and can be used for reducing the probability of underground tool acid corrosion and operation personnel damage in the application.