COMPOSITION FOR ACID TREATMENT OF CRITICAL ZONE OF FORMATION (VARIANTS) Russian patent published in 2007 - IPC C09K8/74 

FIELD: oil and gas production.

SUBSTANCE: invention provides composition for chemical dissolution of rocks and mudding deposits in critical zone of oil, gas, and gas-condensate formation, which composition may also be used as process fluid when performing perforation and hydraulic rupture of formations. Composition is constituted by, vol %: (1) technical lignosulfonates 20-35, isopropyl alcohol or bottom residues of butyl alcohol production 3-5, 80% acetic acid 3-5, water-soluble demulsifier 2-4, and 20-28% aqueous hydrochloric acid solution - the rest; or (2) technical lignosulfonates 0.5-1, isopropyl alcohol or bottom residues of butyl alcohol production 3-5, Neonol "AF_9-12" or "ML-81", or "ML81B", or "FLEK-DG-002" 0.5-2, 80% acetic acid 3-5, water-soluble demulsifier 2-4, and 20-28% aqueous hydrochloric acid solution - the rest; or (3) technical lignosulfonates 0.5-1, isopropyl alcohol or bottom residues of butyl alcohol production 3-5, 80% acetic acid 3-5, water-soluble demulsifier 2-4, 70% aqueous hydrofluoric acid solution 6-10, and 20-28% aqueous hydrochloric acid solution - the rest; or (4) technical lignosulfonates 0.5-1, isopropyl alcohol or bottom residues of butyl alcohol production 3-5, 80% acetic acid 3-5, water-soluble demulsifier 2-4, 3-5% aqueous polyacrylamide solution or 3-5% aqueous solution of modified starch 3-10, and 20-28% aqueous hydrochloric acid solution - the rest.

EFFECT: widened control range for carbonate rock dissolution rate, dynamic viscosity, complete prevention of precipitation of mudding gel-like deposits, emulsification and complete withdrawal of reaction products from formation during well development operations.

4 cl, 2 tbl, 4 ex