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.