ACID COMPOSITION FOR TREATMENT OF WELLS IN CARBONATE AND TERRIGENOUS RESERVOIRS, AND ACID TREATMENT METHOD OF BOTTOM-HOLE ZONE OF FORMATION WITH ITS APPLICATION Russian patent published in 2015 - IPC C09K8/74 E21B43/27 

FIELD: oil and gas industry.

SUBSTANCE: acid composition for acid treatment of production and injection wells in carbonate and terrigenous reservoirs contains the following, wt %: hydrochloric acid (24% or 36%) 25.0-50.0, alkyl benzene sulphonic acid containing in an alkyl group 12-14 atoms of carbon, 0.1-2.0, citric acid 0.5-3.0, acetic acid 3.0-12.0, methyl alcohol 3.0-10.0, OS-20 preparation 0.5-2.5, IKU-118 corrosion inhibitor 1.0-5.0, hydrofluoric acid (40%) 0.0-7.5, Feriks iron stabiliser 0.0-5.0, and water is the rest. An acid treatment method of the bottom-hole zone of a carbonate, terrigenous or mixed formation involves pumping to the well of the acid composition in the amount of 1.0-5.0 m³ per 1 m of perforated thickness of the formation, its forcing-through into the formation, exposure for the reaction during not more than 8 hours and further removal of reaction products; as an acid composition, there used is the above said composition or its solution in fresh water at the ratio of the above said composition to fresh water, which is equal to 1:1-1:2 respectively. The treatment method is developed in claims.

EFFECT: creation of a composition for acid treatment, which has low corrosion rate at formation temperatures; considerable improvement of efficiency of acid treatment.

3 cl, 3 tbl, 4 ex