VISCOELASTIC LIQUIDS CONTAINING HYDROXYETHYL CELLULOSE Russian patent published in 2013 - IPC C09K8/584 C09K8/70 E21B43/22 E21B43/267 

FIELD: chemistry.

SUBSTANCE: invention relates to viscoelastic liquids for underground formation fracturing. The viscoelastic liquid for enhancing productivity of a hydrocarbon-containing formation contains an anionic surfactant, a cationic surfactant, hydroxyethyl cellulose and water; volume ratio of the cationic surfactant in the solution the anionic surfactant in the solution ranges from 0.5:1 to 10:1 (per 50 vol. % solution of cationic surfactant and 40 vol. % solution of anionic surfactant). Foamed or activated viscoelastic liquid for enhancing productivity of a hydrocarbon-containing formation contains sodium xylene sulphonate, N,N,N,trimethyl-1-octadecaammonium chloride, hydroxyethyl cellulose, nitrogen or carbon dioxide and water; content of the internal phase in the liquid ranges from 5 to 63% for activated liquids and from 63 to 96% for foamed liquids. The method of enhancing productivity of a hydrocarbon-containing formation, through which a well passes, involves pumping said viscoelastic liquid through the well. The method of fracturing an underground formation involves pumping said foamed or activated viscoelastic liquid into the formation at pressure which is sufficient to fracture the formation. The invention is developed in subclaims.

EFFECT: improved operating characteristics of the liquids.

21 cl, 6 ex, 3 dwg