METHOD FOR PREPARING A HYDROCHLORIC ACID SOLUTION FOR ACID TREATMENT OF A WELL Russian patent published in 2019 - IPC C09K8/74 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the field of oil industry, in particular to preparation of a hydrochloric acid solution used in oil production technology for stimulation of formation fluid influx. Method of preparation of hydrochloric acid solution for acid treatment of well includes introduction of reagent-reducing agent into reagent solution to regulate contamination of formation with iron. Said reagent-reducing agent used is represented by Bunte salts of organic thiosulphuric acids of general formula RSSO₂X, where R=HOOCCH₂ or HOCH_2CH2; X=OMe, where Me is an alkali metal: sodium or potassium, which is added to a solution of hydrochloric acid in amount of 1.2–3.1 wt%.

EFFECT: eliminating loss of stabilizing capacity of acid composition with respect to iron ions during long-term storage, high effect of said stabilizing ability in well even with reduction of concentration of hydrochloric acid.

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