Cationic viscoelastic surfactant and preparation and application thereof

Abstract

The invention discloses a cationic viscoelastic surfactant and preparation and application thereof. The preparation method of the cationic viscoelastic surfactant comprises the following steps: firstly, mixing long-chain fatty acid with dimethylaminopropylamine according to a certain proportion, adding a catalyst solution to obtain a required amide product intermediate A by a series of reaction; allowing reflux condensation reaction of epoxy chloropropane and water at a certain proportion to be carried out in oil bath of 100 DEG C to obtain colourless and transparent 3-chloro-1,2-propylene glycol aqueous solution, namely an intermediate B; heating the intermediate A in oil bath for melting, and dropwise adding an aqueous solution B to obtain the required viscoelastic surfactant by a series of reaction; the surfactant can be mixed with a potassium chloride solution according to a certain proportion to obtain clean fracturing fluid which is low in cost and excellent in performance, besides, the clean fracturing fluid has excellent high-temperature resistance, shearing resistance, and excellent solid-carrying performance, is automatic and thorough in gel breaking, causes little damage to the reservoir stratum and has the characteristic of wide application range.

Description

technical field [0001] The invention relates to a cationic viscoelastic surfactant and its preparation and application, and belongs to the technical field of fracturing fluid for reservoirs in the oil exploitation industry. Background technique [0002] Surfactants that can form viscoelastic fluids in aqueous solution are currently called viscoelastic surfactants. Compared with the water-based fracturing fluid system with guar gum as the main thickener, this kind of clean fracturing fluid with surfactant as the thickener has more excellent comprehensive performance, such as: ① Less dosage and lower cost ; ②Outstanding performance, the VES clean fracturing fluid can withstand high temperature above 100℃; ③Low friction, good sand-carrying performance; ⑤ easy biodegradation, green environmental protection, safe use, etc., and it exhibits unique rheological properties, such as viscoelasticity, high viscosity under low shear, shear thinning, triggering and excellent viscosity-te...

AI Technical Summary

Problems solved by technology

Aiming at the problem of poor temperature resistance of clean fracturing fluids at home and abroad, Ding Haoming et al. developed a new zwitterionic surfactant, and used it as the main agent to compound a new type of fracturing fluid

Its formula is 4.0% FRK-VES + 0.3% dilute hydrochloric acid + 4.0% KCl solution + 1.0% sodium benzoate, but the temperature resistance of this fracturing fluid is not excellent

Zhou Peiling et al. used erucic acid and 3-dimethylaminopropylamine to synthesize nonionic surfactant thickener VES-A. Under the action of methanol, the mass fraction of surfactant could reach 2.4%-3.8%, and AMPS was 0.025%-0.048%. The apparent viscosity of the solution is greater than 30mPa·s. After adding a certain amount of gel breaker, the gel will be broken within 60-120 minutes, but its temperature resistance is only 95°C

The above examples prove that so far, a lot of research is being done on the development of clean fracturing fluids in China, but there are still some problems in such research, and more improvements are needed

[0006] At present, the VES clean fracturing fluid system used in the domestic field has poor temperature resistance, which limits the popularization and application of this technology

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