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

Abstract

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.

Description

technical field

[0001] The invention belongs to the field of chemical products for oil and gas field development, and in particular relates to a capsule slow-release acid for oil-water well reconstruction and a preparation method thereof. Background technique

[0002] Acidizing is one of the main means of increasing production of oil and gas wells and increasing injection of water wells. The use of acid liquid can remove the pollution near the bottom of production wells and water injection wells, remove the clogging substances in pores or fractures, or communicate the original pores or fractures in the formation to improve Formation permeability, so as to achieve increased production and injection.

[0003] Conventional acidification mostly uses various liquid acids. At present, the better acidification method is to use slow acid acidification. Slow acid slows down the consumption of acid radical ions through chemical reaction, prolongs the action time and radius of action...