VISCOELASTIC COMPOSITION FOR USE IN OIL AND GAS PRODUCTION TECHNIQUES Russian patent published in 2021 - IPC E21B43/00 C09K8/60 

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: proposed invention relates to oil and gas industry, in particular, to thickened water-based compositions for performance of technological operations, such as hydraulic fracturing of formation, directed acid treatment, limitation of water influxes, well killing, and so forth. Viscoelastic composition for use in oil and gas production technologies includes a zwitterionic surfactant, an inorganic water-soluble salt or a combination of inorganic water-soluble salts and water. Additionally, it contains alkanolamine and can contain trivalent metal organic salt, which is represented by chromium acetate, and salts of trivalent metals are used as inorganic water-soluble salts: aluminium (III) chloride or iron (III) chloride, and monovalent metal salts, such as sodium chloride, or potassium chloride, or sodium nitrate, and/or bivalent metals - calcium chloride, can be used, or magnesium chloride, or calcium nitrate, or a mixture of monovalent and/or divalent metal salts. Alkanolamine used is monoethanolamine, or diethanolamine, or triethanolamine, or dimethylethanolamine, or a mixture thereof. Composition is used at following ratio of components, wt. %: Neftenol VUPAV Zwitter-ionic surfactant 1.0–5.0; aluminium (III) chloride, or iron (III) chloride, or chrome (III) acetate 0.01–0.5; sodium chloride, or potassium chloride, or sodium nitrate, or mixture thereof 0.0–20.0; calcium chloride, or magnesium chloride, or calcium nitrate, or mixture thereof 0.0–40.0; monoethanolamine, or diethanolamine, or triethanolamine, or dimethylethanolamine, or mixture thereof 0.01–0.5; fresh water is the balance.

EFFECT: technical result is obtaining more viscous systems with lower concentration of surfactants, which significantly reduces consumption of reagents during process operations on wells.

1 cl, 2 tbl, 7 ex