METHOD FOR ACID TREATMENT OF BOTTOMHOLE WELL ZONE Russian patent published in 2017 - IPC E21B43/27 E21B43/22 C09K8/74 C09K8/64 C09K8/52 

FIELD: oil and gas industry.

SUBSTANCE: method for acid treatment of the bottomhole well zone involves pumping into the formation in an amount of 4-10 m³ per 1 metre of perforated formation thickness an acid-free oil emulsion of inverse type, containing, vol. %: emulsifier Devon-4v 1.0-4.0; hydrocarbon liquid 5.0-20.0; saturated aqueous solution of calcium chloride 3.0-80.0; mineralized water to 100; pumping into the formation in the amount of 1.8-2.5 m³ per 1 metre of the perforated formation thickness an oil-acid emulsion containing, vol. %: emulsifier Devon-4n 3.0-8.0; hydrocarbon liquid 10.0 to 20.0; saturated aqueous solution of calcium chloride 4.0-10.0; 12-15% aqueous hydrochloric acid solution up to 100; for the emulsion decomposition, the 5.0-20.0% aqueous solution of detergent composition Devon-5 is pumped in the amount of 10-20% of the volume of the previous oil-acid emulsion injection, wherein the emulsion and the detergent are pumped once or in alternating batches 2-3 times.

EFFECT: increasing the selectivity and depth of penetrating acid treatment of the formation, increasing the flushing degree of the bottomhole zone from the reaction products and pollutants, reducing the time to put the well into operation.

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