Carbon dioxide acidification blocking agent and non-flowback process for residual liquid after acidification

Abstract

The invention relates to a carbon dioxide acidification blocking remover and a process of not reversely discharging raffinate after acidification. The blocking remover comprises a reagent A which is prepared by directly mixing hydrochloric acid, hydrofluoric acid, glacial acetic acid, polyoxyethylene alkyl phenol ether, citric acid, a corrosion inhibitor, a mutual solvent and a clay stabilizer to form a homogeneous solution and a reagent B prepared by mutually mixing carbonate, a surfactant, an iron ion complexing agent, a demulsifier and clean water which are stirred for 1 hour at normal temperature. The process of not reversely discharging raffinate after acidification comprises the following steps: when an oil well is deblocked, first, injecting a medicament A into an oil layer; then, isolating the clean water by layers; then, injecting a medicament B into the oil layer; and finally, injecting clean water to extrude a mixture in a shaft to the stratum, then, injecting an acidizer into a loop space to a perforated interval, closing the well for 4-6 hours, opening the well, observing the pH value (control range from 6-7), periodically injecting the acidizer till raffinate is fully discharged out of the stratum, and finally, injecting clean water to extrude the mixture in the shaft into a dryline.

Description

technical field [0001] The invention relates to a chemical additive used in the field of oil recovery in oilfields, in particular to a carbon dioxide acidification plug-removing agent and a process for non-flowback of raffinate after acidification. Background technique [0002] The working conditions of oil (water) wells depend on many factors: the heterogeneity of the geological section, the quality of drilling and inducing oil flow in the oil-producing layer, the technological factors closely related to the oil well production in the development process of the oil field and many other factors. Other factors, etc., when the production layer is drilled, the permeability of the near-well zone has significantly deteriorated. Compared with the original situation of the formation, its permeability is only 50%. Heavy distillate deposition fouling, and some insoluble precipitates (salts) produced in the near-wellbore zone and production wells due to the interaction of water and va...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of single action and poor plugging effect of the plugging remover in the prior art. The present invention provides a carbon dioxide acidification plugging removal agent, which combines acidification, chemical heat generation and self-rising foam at the bottom of the well. The plugging removal technology is organically combined and widely used for increasing production and injection of oil and water wells. Our company's carbon dioxide composite plugging removal and scaling technology is a combination of chemical treatment agents injected at a predetermined depth in the formation. carbon dioxide gas

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