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.