Preparation method of thickening agent, thickening agent, fracturing fluid and application of fracturing fluid

Abstract

The invention discloses a preparation method of a thickening agent, the thickening agent, a fracturing fluid and application of the fracturing fluid, and belongs to the technical field of fracturing.The preparation method of the thickening agent comprises the following steps: dissolving pentaerythritol and pyridine in trichloromethane in a protective gas atmosphere, stirring, slowly adding 2-bromopropionyl bromide, reacting, filtering, and drying to obtain a brominated precursor; dissolving the brominated precursor in trichloromethane, stirring, adding potassium ethyl xanthate, reacting, filtering, and drying to obtain a chain transfer agent; carrying out a polymerization reaction on the chain transfer agent, a polymer monomer and an initiator to obtain a reaction product; and dissolvingthe reaction product with ethyl acetate, precipitating with n-hexane, and then carrying out solvent volatilization and drying treatment to obtain the thickening agent. The thickening agent is non-toxic and environment-friendly, and the viscosity of a supercritical CO2 fracturing fluid can be greatly improved when the thickening agent and ethanol are used as a cosolvent.

Description

technical field [0001] The invention relates to the technical field of fracturing, in particular to a preparation method of a thickener, a thickener, a fracturing fluid and applications. Background technique [0002] With the increasing intensity of exploration and development of oil and gas fields, unconventional oil and gas resources have become the focus of development at home and abroad. Unconventional oil and gas resources are a type of clean and high-quality energy, among which unconventional natural gas such as tight gas and shale gas have huge exploitation potential. [0003] In addition, hydraulic fracturing is an important means of shale gas exploitation, but for the characteristics of poor physical properties and low permeability of shale gas reservoirs, conventional fracturing fluids have the problem of incomplete gel breaking, which can easily cause pore blockage. while supercritical CO 2 Fracturing fluid has gradually emerged as a new type of fracturing fluid...

AI Technical Summary

Problems solved by technology

[0004] However, due to the supercritical CO 2 The fracturing fluid has the problem of low viscosity, so it is generally necessary to add a thickener to increase the viscosity

Although, in the prior art, the polymers of fluorine and silicon can be used as supercritical CO 2 Thickener for fracturing fluid, however, fluorine is highly toxic, and polymers containing fluorine and silicon are high in cost and difficult to degrade, which are likely to cause great harm to the formation environment, etc.

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