DRY ACID COMPOSITION FOR ACID TREATMENT OF CARBONATE AND TERRIGENOUS RESERVOIRS AND METHOD OF ITS USE Russian patent published in 2019 - IPC C09K8/74 E21B43/27 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry. Dry acid composition for acid treatment of carbonate and terrigenous reservoirs contains, wt%: ammonium chloride 40.0–60.0; ampholyte surfactant "Nefteonol VES " 0.2–1.5; corrosion inhibitor "ICU-128", which is a quaternary ammonium compound, 0.1–0.4; sulfamic acid – the rest, wherein the surfactant and the corrosion inhibitor are deposited on the surface of sulphamic acid and ammonium chloride by stirring in a dry mixing reactor. In the method of acid treatment of wells with an aqueous solution of dry acid composition, fresh or mineralized water is pumped into the well, to which 3–6 wt% of the above dry acid composition is added.

EFFECT: low rate of hydrolysis of sulphamic acid and the possibility of using a dry acid composition at temperatures of up to 90 °C without formation of secondary precipitation, manufacturability of preparation, expressed in possibility of composition proportioning at pumping of fresh or mineralized water into well without addition of additional components.

2 cl, 4 tbl