Blockage-removing and dissolution-promoting solid acid, and preparation method and application thereof

Abstract

The invention provides blockage-removing and dissolution-promoting solid acid, and a preparation method and an application thereof. The blockage-removing and dissolution-promoting solid acid comprisesthe following components in parts by mass: 10-80 parts of a glycolide-lactide copolymer, 1-50 parts of adipic acid, 1-30 parts of hydrolyzed polymaleic anhydride, 1-15 parts of polyvinyl alcohol, 1-15 parts of polyoxyethylene and 1-15 parts of a plasticizer. The method for preparing the blockage-removing and dissolution-promoting solid acid comprises the following steps: mixing the glycolide-lactide copolymer, the adipic acid, the hydrolyzed polymaleic anhydride, the polyvinyl alcohol, the polyoxyethylene and the plasticizer according to selected parts by mass, and carrying out melt extrusionmolding so as to obtain the blockage-removing and dissolution-promoting solid acid. The blockage-removing and dissolution-promoting solid acid is used for blockage removal of oil and gas fields, is convenient to process, free of pumping and proper in dissolution rate, can slowly release acid, does not generate the situation that the effects of blockage removal and dissolution promotion are difficult to be exerted at a specific position due to over fast dissolution, also does not generate the situation that the construction efficiency is reduced due to over slow dissolution, and is high in dredging rate to blockages under an oil-gas well, small in corrosion to a well wall and simple in preparation method operation.

Description

technical field [0001] The invention belongs to the technical field of plug-removing agents for oil fields, and in particular relates to a plug-removing and dissolution-promoting solid acid, a preparation method and application thereof. Background technique [0002] In oilfield exploration and development, bridge plugs are usually used to block the lower well section during the construction of oil and water wells in layered fracturing, layered acidizing, and layered oil testing. After layered fracturing is completed, it is necessary to remove or dissolve the bridge plug way to unblock. In oil and gas fields where magnesium alloy soluble bridge plugs are used for fracturing, it is often possible that the magnesium alloy bridge plug cannot be dissolved. On the one hand, the salinity of the bottom water is not enough; The mixture of magnesium hydroxide residue and sediment impurities may form dense plugs to block oil wells and further inhibit the dissolution of magnesium alloy...

AI Technical Summary

Problems solved by technology

Usually, in this case, the blockage can only be directly drilled and cleared by the drill bit, or acid liquid such as hydrochloric acid is injected into the oil well to corrode the blockage such as magnesium alloy, but since common liquid acids such as hydrochloric acid are liquid, it is necessary to Using a pump to forcibly pump to the location of the downhole blockage is difficult and costly; and common solid acids such as citric acid quickly become liquid acids during the downhole process due to their extremely fast water solubility. In addition, hydrochloric acid, Citric acid has strong acidity, and it is easy to corrode the well wall when it is used to dredge blockages

[0003] Chinese patent document CN105647496A discloses a kind of expandable biopolymer temporary plugging profile control agent and its preparation method. The temporary plugging profile control agent consists of biodegradable polymer, reinforcing agent, toughening agent, foaming agent and crosslinking agent , water blocking agent, coupling agent, functional auxiliary agent and carrier agent, in which the biodegradable polymer can be polylactide (polylactic acid), which is shaped to have a certain Solids with granularity can be used to plug oil and gas fields and remove plugging by themselves in high-temperature and high-humidity environments. However, this temporary plugging profile control agent is only used as a temporary plugging agent and has the function of self-plugging removal. It is not dedicated to plugging removal. If it is used for blocking removal, a certain temperature needs to be applied to promote the release of acid, and the release and dissolution rate of acid is slow, the dissolution rate of magnesium alloy is slow, and the ability of descaling and blocking removal is poor.

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