Acidizing depressurization and increasing injection process with non-moving strings for water injection wells

Abstract

The invention discloses a method for acidizing depressurization and increasing injection with a non-moving pipe column for water injection wells. The steps are as follows: a. In terms of volume ratio, take 0.3-3 parts of weak acid acidizing liquid and mix with 99.7-97 parts of injection water; b. Inject the mixed solution into the water inlet pipeline through drip injection; c. Stop injecting the mixed solution when the set injection volume is reached and the pressure of the water injection well drops to 90% of the water injection pressure before construction; the weak Acidification liquid is: by weight percentage, its components are: acid liquid: 10-30%; stabilizer: 2-8%; corrosion inhibitor: 1-5%; surfactant: 6.5-17%; The volume is distilled water. This method expands the radius of acidizing plugging removal of water injection wells, alleviates scaling near the wellbore of water injection wells, and prolongs the validity period of water injection wells; realizes continuous mixing and acidification of immobile strings, and simplifies the construction process; synchronous water injection acidification does not affect the normal operation of water wells Production.

Description

technical field [0001] The present invention relates to the technical field of pressure-reducing and increasing-injection process methods for water injection wells, in particular to a method for acidizing and increasing injection in sandstone reservoirs in low-permeability oilfields, with large acidizing and plugging-removing radius, increased validity period, and continuous mixing without moving pipe strings. Acidification and water injection are carried out simultaneously without affecting the depressurization and increase injection process of normal production. Background technique [0002] At present, during the development of low-permeability oilfields, the oil recovery is enhanced by water injection as the formation energy decays. For example, the Chinese patent document with the publication number CN202250005U and the publication date of May 30, 2012 discloses a water injection well pressure-reducing and injection-increasing device. , used in oilfield water injection ...

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Problems solved by technology

[0003] However, during the production process of water injection wells, due to the incompatibility of injected water and formation water, scale will slowly form in the wellbore of water injection wells and near the wellbore, causing the water injection pressure of water injection wells to gradually increase, the injection volume to decrease, and finally to high pressure in water injection wells Insufficient injection, and the corresponding oil well energy is insufficient