COMPOSITION FOR PREPARATION OF VISCOELASTIC PROCESS LIQUID FOR HYDRAULIC FRACTURING AND VISCOELASTIC PROCESS FLUID FOR HYDRAULIC FRACTURING OF FORMATION Russian patent published in 2016 - IPC C09K8/68 E21B43/22 E21B43/26 

FIELD: oil industry.

SUBSTANCE: invention relates to oil production, in particular, to technological water-based fluids and compositions for its preparation used in different formation conditions as process fluid-propant carrier for hydraulic fracturing (FHF). Composition contains viscoelastic surfactant (SF) based on quaternary amines with solvent, viscosity amplifier - sodium salicylate, organic decomposer - carbamide or thiourea, and surfactant is a viscoelastic dimeric SF of following structure:

,

where R₁ and R₆ are identical or different, denote alkyl groups C₁₂-C₁₈ and/or amidopropilamines of following structure-(CH₃)₂N(CH₂)₃NCOC_12-18H_22-37; R₂, R₃, R₄, R₅ is methyl group; R₇ is C₃H₆O; A₁ and A₂ are chlorine anions (Cl^-). Viscoelastic process fluid for FHF contains said composition and water, wherein weight ratio of composition and water is 1:(1.6÷30) respectively.

EFFECT: technical result consists in creation of viscoelastic process liquid for FHF, having improved viscoelastic properties at high temperature of 70 °C and more even in fresh or subsaline water, and providing fast and complete loss of viscosity after hydraulic fracturing.

4 cl, 2 tbl, 8 ex