CN112708038B

CN112708038B - Thickening agent and preparation method and application thereof

Info

Publication number: CN112708038B
Application number: CN201911025481.0A
Authority: CN
Inventors: 苏智青; 李应成; 沙鸥; 夏燕敏; 孙慧; 许汇; 王兰; 朱益兴
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2019-10-25
Filing date: 2019-10-25
Publication date: 2022-07-12
Anticipated expiration: 2039-10-25
Also published as: CN112708038A

Abstract

The invention discloses a thickening agent and a preparation method and application thereof. The thickening agent contains an acrylamide monomer structural unit, an anionic monomer structural unit, a nonionic monomer structural unit, an active monomer structural unit and an optional cationic monomer structural unit, wherein the active monomer structural unit comprises an active monomer structural unit I, an active monomer structural unit II and an active monomer structural unit III, and the active monomer structural unit I is selected from one or more of the formulas (I); the reactive monomer structural unit II is selected from one or more of the formula (II); the reactive monomer building blocks III are selected from one or more of the formulae (V), and optionally formulae (III) and (IV). The emulsion type thickening agent has excellent tackifying capability, temperature resistance and salt resistance, and high dissolving speed.

Description

Thickening agent and preparation method and application thereof

Technical Field

The invention belongs to the field of fracturing fluids, and particularly relates to a thickening agent, and a preparation method and application thereof.

Background

As an important measure for stratum reformation of an oil-gas reservoir, fracturing is rapidly developed and widely applied, the efficiency is remarkably increased, fracturing construction is carried out in 7 months in 2004 by taking 11-53 wells of a Chinese oilfield as an example, 663 tons of oil are increased in the current year, namely 4.42 tons of oil are increased daily, the daily income is about 16575 yuan calculated by 75 dollars of crude oil per barrel, and the income is increased by about 250 ten thousand in the current year.

The thickening agent is a main component in the fracturing fluid and mainly plays a role in increasing the viscosity of the fluid, improving the sand carrying capacity of the fluid and helping to make a crack. In the application, the fracturing fluid thickening agent mainly takes natural polymers such as guanidine gum and the like as main components, part of synthetic polymers are also used as thickening agents for fracturing fluids, the most commonly used fracturing fluid in China is water-based fracturing fluid, and the hydrophobically associating thickening agent is used as a polymer system with stronger thickening capability in polymers for oil displacement, so that the emulsion type acrylamide thickening agent in the prior art has unique thickening capability under high-temperature and high-salt conditions. In addition, after a hydrophobic association structure is introduced into the existing emulsion type thickening agent, the association structure is influenced by a large amount of emulsifying agents and crude oil, and the thickening capability is easily damaged. In addition, emulsion type products are affected by a large amount of emulsifiers and oils, and the association structure is easy to be damaged, so the hydrophobic association products mainly appear in a dry powder form. The synthesized dry powder polymer needs special dissolving equipment and has complex preparation process. The current volume fracturing makes the fracturing construction put higher demands on the instant dissolution of the polymer.

Disclosure of Invention

The invention aims to solve the technical problem of the prior art and provides a thickening agent, a preparation method and application thereof. The emulsion type thickening agent has excellent tackifying capability, temperature resistance and salt resistance, and high dissolving speed.

To this end, the invention provides, in a first aspect, a thickener comprising acrylamide monomer building blocks, anionic monomer building blocks, nonionic monomer building blocks, reactive monomer building blocks, and optionally cationic monomer building blocks, wherein the reactive monomer building blocks comprise reactive monomer building blocks I, reactive monomer building blocks II, and reactive monomer building blocks III,

wherein the reactive monomer structural unit I is selected from one or more structural units shown in a formula (I); the reactive monomer structural unit II is selected from one or more structural units shown in a formula (II); the reactive monomer structural unit III is selected from one or more structural units shown in a formula (V), and optional structural units shown in the formula (III) and structural units shown in a formula (IV),

wherein each R is₁The same or different, each independentlyIs selected from hydrogen atom or C₁～C₂₈A hydrocarbon group of (a); each R₂、R₃And R₄Same or different, each independently selected from C₁～C₂₈A hydrocarbon group of (a); r is₅Selected from hydrogen atoms, amino groups, carboxylic acid groups, sulfonic acid groups, sulfuric acid groups, phosphoric acid groups, mercapto groups or halogens; each a and each b are the same or different and are respectively and independently 0-40, and the positions of the chain segments of a and b can be changed; x, Z are each independently selected from ester group, amide group, methylene group, oxygen atom, -CH₂-O-or-NH-; y is selected from ester group, methylene, oxygen atom, -CH₂-O-or-NH-; m^-Selected from fluoride, chloride, bromide or iodide.

In a second aspect, the present invention provides a method for preparing a thickening agent, comprising:

a) mixing an acrylamide monomer, an anionic monomer, a nonionic monomer, an active monomer, a cosolvent and a solvent, and optionally a cationic monomer, and adjusting the pH value to 5-10 to obtain an aqueous solution I;

b) dissolving an emulsifier in an oil solvent to obtain an oil solution II;

c) mixing an oxidant and an initiator to obtain an aqueous solution III, mixing the aqueous solution III with the aqueous solution I obtained in the step a), then mixing the aqueous solution I with the oil solution II obtained in the step b), and emulsifying to obtain an emulsion;

d) mixing the emulsion with a solution containing a reducing agent, carrying out redox reaction, and mixing with a phase transfer agent;

wherein the active monomer comprises an active monomer I, an active monomer II and an active monomer III,

wherein the active monomer I is selected from one or more structures shown in a formula (VI); the active monomer II is selected from one or more of structures shown in a formula (VII); the active monomer III is selected from one or more structures shown in a formula (X), and an optional structure shown in a formula (VIII) and a structure shown in a formula (IX),

wherein each R is₁Same or different, each independently selected from hydrogen atom or C₁～C₂₈A hydrocarbon group of (1); each R₂、R₃And R₄Same or different, each independently selected from C₁～C₂₈A hydrocarbon group of (a); r₅Selected from hydrogen atoms, amino groups, carboxylic acid groups, sulfonic acid groups, sulfuric acid groups, phosphoric acid groups, mercapto groups or halogens; each a and each b are the same or different and are respectively and independently 0-40, and the positions of the chain segments of a and b can be changed; x, Z are each independently selected from ester group, amide group, methylene group, oxygen atom, -CH₂-O-or-NH-; y is selected from ester group, methylene, oxygen atom, -CH₂-O-or-NH-; m^-Selected from fluoride, chloride, bromide or iodide.

In a third aspect, the present invention provides a thickener prepared by the above method.

In a fourth aspect, the present invention provides the use of a viscosifier as described above in a fluid and/or prepared according to the method described above in a fracturing process.

Detailed Description

In order that the present invention may be more readily understood, the following detailed description of the invention is given by way of example only, and is not intended to limit the scope of the invention.

As mentioned above, the existing emulsion type acrylamide thickening agent has poor salt tolerance, after a hydrophobic association structure is introduced into the emulsion type thickening agent, the association structure is influenced by a large amount of emulsifying agents and crude oil, the tackifying capability is poor, and the dry powder polymer is complex to dissolve and slow in dissolving speed. At present, the research and development of an emulsion type thickening agent which has excellent tackifying capability, temperature resistance and salt resistance and can be quickly dissolved is needed.

The first aspect of the present invention provides a thickening agent comprising an acrylamide monomer structural unit, an anionic monomer structural unit, a nonionic monomer structural unit, a reactive monomer structural unit, and optionally a cationic monomer structural unit, wherein the reactive monomer structural unit comprises a reactive monomer structural unit I, a reactive monomer structural unit II, and a reactive monomer structural unit III,

wherein each R is₁Same or different, each independently selected from hydrogen atom or C₁～C₂₈A hydrocarbon group of (a); each R₂、R₃And R₄Same or different, each independently selected from C₁～C₂₈A hydrocarbon group of (a); r₅Selected from hydrogen atoms, amino groups, carboxylic acid groups, sulfonic acid groups, sulfuric acid groups, phosphoric acid groups, mercapto groups or halogens; each a and b are the same or different and are respectively 0-40 independently, and the positions of the chain segments of the a and the b can be exchanged; x, Z are each independently selected from ester group, amide group, methylene group, oxygen atom, -CH₂-O-or-NH-; y is selected from ester group, methylene, oxygen atom, -CH₂-O-or-NH-; m^-Selected from fluoride, chloride, bromide or iodide.

In the present invention, in the formula (II), the formula (III) and the formula (V), it is preferable that a and b are not 0 at the same time. For example, in formula (II), a and b are not 0 at the same time.

In the invention, the position of the a chain segment and the b chain segment can be changed, namely the position of the a chain segment and the position of the b chain segment in the formula (II), the formula (III), the formula (V), the formula (VII), the formula (VIII) and the formula (X) can be changed,

for example, formula (II) may be:

for another example, formula (III) may be:

for another example, formula (V) may be:

in the present invention, in the structural units represented by the formula (I), the formula (II), the formula (III), the formula (IV) and the formula (V), each R is₁、R₂、R₃And R₄May be the same or different.

In the present invention, in the structural units represented by the formulae (II), (III) and (V), each of a and b may be the same or different.

According to a preferred embodiment of the invention, each R₁Each independently selected from hydrogen atom, C₆～C₁₈Alkyl or C of₆～C₁₈An aromatic group of (a); each R₂、R₃And R₄Each independently selected from C₆～C₁₈Alkyl or C₆～C₁₈An aromatic group of (a); a. b is independently 3-14.

According to a preferred embodiment of the present invention, in the thickener, the content of the acrylamide monomer structural unit is 25 to 75 parts by weight, the content of the anionic monomer structural unit is 0.1 to 25 parts by weight, the content of the nonionic monomer structural unit is 0.1 to 15 parts by weight, the content of the reactive monomer structural unit is 0.001 to 15 parts by weight, and the content of the cationic monomer structural unit is 0 to 15 parts by weight.

Further, according to a preferred embodiment of the present invention, in the thickener, the content of the reactive monomer structural unit I is 1 to 13 parts by weight, the content of the reactive monomer structural unit II is 1 to 13 parts by weight, and the content of the reactive monomer structural unit III is 1 to 13 parts by weight.

Further, according to a preferred embodiment of the present invention, in the thickener, the content of the structural unit represented by formula (V) is 1 to 13 parts by weight, the content of the structural unit represented by formula (III) is 0 to 12 parts by weight, and the content of the structural unit represented by formula (IV) is 0 to 12 parts by weight.

According to a preferred embodiment of the present invention, the anionic monomer structural unit is a structural unit derived from an anionic monomer selected from the group consisting of acrylic acid, alkali metal salts of acrylic acid, ammonium salts of acrylic acid, methacrylic acid, alkali metal salts of methacrylic acid, ammonium salts of methacrylic acid, vinylsulfonic acid, alkali metal salts of vinylsulfonic acid, ammonium salts of vinylsulfonic acid, p-vinylbenzenesulfonic acid, alkali metal salts of p-vinylbenzenesulfonic acid, ammonium salts of p-vinylbenzenesulfonic acid, maleic acid, alkali metal salts of maleic acid, ammonium salts of maleic acid, fumaric acid, alkali metal salts of fumaric acid, ammonium salts of fumaric acid, vinylbenzenesulfonic acid, alkali metal salts of vinylbenzenesulfonic acid, ammonium salts of vinylbenzenesulfonic acid, allylsulfonic acid, alkali metal salts of allylsulfonic acid, ammonium salts of allylsulfonic acid, allylbenzenesulfonic acid, allylsulfonic acid, and mixtures thereof, One or more of an alkali metal salt of allylbenzenesulfonic acid, an ammonium salt of allylbenzenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, an alkali metal salt of 2-acrylamido-2-methylpropanesulfonic acid, and an ammonium salt of 2-acrylamido-2-methylpropanesulfonic acid.

According to a preferred embodiment of the present invention, in the anionic monomer, the alkali metal salt is selected from one or more of lithium salt, sodium salt and potassium salt. For example, the sodium salt may be sodium acrylate, sodium methacrylate, sodium vinylsulfonate, sodium p-vinylbenzenesulfonate, sodium maleate, sodium fumarate, sodium vinylbenzenesulfonate, sodium allylsulfonate, sodium allylbenzenesulfonate, sodium 2-acrylamido-2-methylpropanesulfonate. Lithium and potassium salts are similar to sodium salts.

According to a preferred embodiment of the present invention, in the anionic monomer, the ammonium salt is a salt having an ammonium ion and/or an organic amine salt. Wherein the salt having ammonium ion can be ammonium acrylate, ammonium methacrylate, ammonium vinylsulfonate, ammonium p-vinylbenzenesulfonate, ammonium maleate, ammonium fumarate, ammonium vinylbenzenesulfonate, ammonium allylsulfonate, ammonium allylbenzenesulfonate, ammonium 2-acrylamido-2-methylpropanesulfonate. Wherein the organic ammonium salt can be an ammonium salt formed by acid and ethanolamine and/or triethanolamine. For example, ammonium salts of acrylic acid, ammonium salts formed from acrylic acid and ethanolamine and/or triethanolamine. The ammonium salts of the other substances are similar to the ammonium salts of acrylic acid.

Further preferably, the anionic monomer is acrylic acid and/or sodium 2-acrylamido-2-methylpropanesulfonate.

According to a preferred embodiment of the present invention, the nonionic monomer structural unit is a structural unit derived from a nonionic monomer, wherein the nonionic monomer is selected from one or more of methacrylamide, dimethylacrylamide, diethylacrylamide, methylolacrylamide, hydroxyethylacrylamide, dimethylaminopropyl methacrylamide, methylol methacrylate, hydroxyethyl methacrylate, dimethylaminoethyl methacrylate and vinyl pyrrolidone.

According to a preferred embodiment of the present invention, the cationic monomer building block is a building block derived from a cationic monomer, wherein the cationic monomer is selected from one or more of methacryloyloxyethyl trimethyl ammonium chloride, 2-acrylamido-2-methylpropyl trimethyl ammonium chloride, dimethylethyl allyl ammonium chloride, dimethyldiallyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl dimethyl benzyl ammonium chloride, methacryloyloxyethyl dimethyl benzyl ammonium chloride, epoxypropyl trimethyl ammonium chloride, epoxypropyl benzyl trimethyl ammonium chloride, epoxypropyl ethoxytrimethyl ammonium chloride and epoxypropyl-trimethyl ammonium chloride capped polyethylene glycols.

According to a preferred embodiment of the invention, the weight average molecular weight of the thickener is from 1500 to 2500 ten thousand, preferably from 2000 to 2500 ten thousand.

According to a preferred embodiment of the present invention, the molecular weight distribution of the thickener is 0.2 to 0.8.

b) dissolving an emulsifier in an oil solvent to obtain an oil solution II;

wherein the active monomer I is selected from one or more structures shown in a formula (VI); the active monomer II is selected from one or more structures shown in a formula (VII); the active monomer III is selected from one or more structures shown in a formula (X), and an optional structure shown in a formula (VIII) and a structure shown in a formula (IX),

wherein each R is₁Same or different, each independently selected from hydrogen atom or C₁～C₂₈A hydrocarbon group of (a); each R₂、R₃And R₄Same or different, each independently selected from C₁～C₂₈A hydrocarbon group of (a); r is₅Selected from hydrogen atoms, amino groups, carboxylic acid groups, sulfonic acid groups, sulfuric acid groups, phosphoric acid groups, mercapto groups or halogens; each a and b are the same or different and are respectively 0-40 independently, and the positions of the chain segments of the a and the b can be exchanged; x, Z are respectively and independently selected from ester group, amide group, methylene group, oxygen atom, -CH₂-O-or-NH-; y is selected from ester group, methylene, oxygen atom, -CH₂-O-or-NH-; m is a group of^-Selected from fluoride, chloride, bromide or iodide.

In the present invention, in formula (VII), formula (VIII) and formula (X), it is preferable that a and b are not 0 at the same time. For example, in formula (VII), a and b are not both 0 at the same time.

In the present invention, when the synthesis is carried out using the reactive monomer represented by the formula (VI), the sulfonic acid group in the formula (VI) will become a sodium sulfonate group due to a neutralization process occurring at the time of the synthesis, and therefore the reactive monomer structural unit derived from the structural unit of the formula (VI) formula (I) has a sodium sulfonate group.

According to a more preferred embodiment of the invention, each R is₁Each independently selected from hydrogen atom, C₆～C₁₈Alkyl or C₆～C₁₈An aromatic group of (a); each R₂、R₃And R₄Each independently selected from C₆～C₁₈Alkyl or C₆～C₁₈An aromatic group of (a); a. b is 3-14 independently.

For example, the active monomer I is 2-acrylamido tetradecyl sodium sulfonate (structural formula is formula (1)), 2-acrylate tetradecyl sodium sulfonate (structural formula is formula (2)), and the like.

For example, the reactive monomer II is allyl polyoxyethylene polyoxypropylene ether (EO10PO5, structural formula (3)), allyl polyoxyethylene (EO12, structural formula (4)), or the like.

For example, the reactive monomer III is dodecyl-polyethoxy-polypropoxy-acrylamide (structural formula (5)), dodecyl-polyethoxy-polypropoxy-acrylate (structural formula (6)), or the like, and optionally hexadecyl dimethyl allyl ammonium chloride (structural formula (7)), a compound (ADEKA REASOAP) represented by structural formula (8), or the like,

according to a preferred embodiment of the present invention, the dosage of the acrylamide monomer is 25 to 75 parts by weight, the dosage of the anionic monomer is 0.1 to 25 parts by weight, the dosage of the nonionic monomer is 0.1 to 15 parts by weight, the dosage of the active monomer is 0.001 to 15 parts by weight, the dosage of the cosolvent is 0.1 to 10 parts by weight, the dosage of the solvent is 10 to 70 parts by weight, the dosage of the cationic monomer is 0 to 15 parts by weight, the dosage of the emulsifier is 20 to 70 parts by weight, the dosage of the oil solvent is 50 to 90 parts by weight, the dosage of the oxidant is 0.00005 to 0.001 part by weight, the dosage of the initiator is 0.00001 to 0.001 part by weight, the dosage of the solution containing the reducing agent is 0.000005 to 0.001 part by weight, and the dosage of the phase-changing agent is 10 to 50 parts by weight, wherein the dosage of the reducing agent is calculated by the reducing agent and the solvent is deionized water. Within the above preferred range of the feeding amount of the invention, the obtained thickener has better thickening or drag reduction effect.

More preferably, the feeding amount of the active monomer I is 1-13 parts by weight, the feeding amount of the active monomer II is 1-13 parts by weight, and the feeding amount of the active monomer III is 1-13 parts by weight.

More preferably, the amount of the material to be charged into the structure represented by the formula (X) is 1 to 13 parts by weight, the amount of the material to be charged into the structure represented by the formula (VIII) is 0 to 12 parts by weight, and the amount of the material to be charged into the structure represented by the formula (IX) is 0 to 12 parts by weight.

According to a preferred embodiment of the present invention, the concentration of the reducing agent in the solution containing the reducing agent is 0.5 to 2% by weight. Such as 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, and any value therebetween.

According to a preferred embodiment of the invention, the anionic monomer is selected from acrylic acid, alkali metal salts of acrylic acid, ammonium salts of acrylic acid, methacrylic acid, alkali metal salts of methacrylic acid, ammonium salts of methacrylic acid, vinylsulfonic acid, alkali metal salts of vinylsulfonic acid, ammonium salts of vinylsulfonic acid, p-vinylbenzenesulfonic acid, alkali metal salts of p-vinylbenzenesulfonic acid, ammonium salts of maleic acid, alkali metal salts of maleic acid, ammonium salts of maleic acid, fumaric acid, alkali metal salts of fumaric acid, ammonium salts of fumaric acid, vinylbenzenesulfonic acid, alkali metal salts of vinylbenzenesulfonic acid, ammonium salts of vinylbenzenesulfonic acid, allylsulfonic acid, alkali metal salts of allylsulfonic acid, ammonium salts of allylsulfonic acid, allylbenzenesulfonic acid, alkali metal salts of allylbenzenesulfonic acid, ammonium salts of allylbenzenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, maleic anhydride, maleic acid, salts of maleic acid, salts of maleic acid, salts of maleic acid, salts of maleic acid, salts of maleic acid, salts of, One or more of an alkali metal salt of 2-acrylamido-2-methylpropanesulfonic acid and an ammonium salt of 2-acrylamido-2-methylpropanesulfonic acid.

According to a preferred embodiment of the present invention, in the anionic monomer, the ammonium salt is a salt having an ammonium ion and/or an organic amine salt. Wherein the salt having ammonium ion can be ammonium acrylate, ammonium methacrylate, ammonium vinylsulfonate, ammonium p-vinylbenzenesulfonate, ammonium maleate, ammonium fumarate, ammonium vinylbenzenesulfonate, ammonium allylsulfonate, ammonium allylbenzenesulfonate, or ammonium 2-acrylamido-2-methylpropanesulfonate. Wherein the organic ammonium salt can be an ammonium salt formed by acid and ethanolamine and/or triethanolamine. For example, ammonium salts of acrylic acid, ammonium salts formed from acrylic acid and ethanolamine and/or triethanolamine. The ammonium salts of the other substances are similar to the ammonium salts of acrylic acid.

According to a preferred embodiment of the invention, the non-ionic monomer is selected from one or more of methacrylamide, dimethylacrylamide, diethylacrylamide, methylolacrylamide, hydroxyethylacrylamide, dimethylaminopropyl methacrylamide, methylol methacrylate, hydroxyethyl methacrylate, dimethylaminoethyl methacrylate and vinylpyrrolidone.

According to a preferred embodiment of the invention, the co-solvent is selected from one or more of sodium formate, urea, thiourea and anhydrous sodium sulphate.

According to the embodiment of the present invention, the solvent may be a liquid capable of dissolving the acrylamide monomer, the anionic monomer, the nonionic monomer, the reactive monomer, and the cosolvent, optionally the cationic monomer, and preferably, the solvent is deionized water.

According to a preferred embodiment of the present invention, the cationic monomer is selected from one or more of methacryloyloxyethyl trimethyl ammonium chloride, 2-acrylamido-2-methylpropyl trimethyl ammonium chloride, dimethylethyl allyl ammonium chloride, dimethyldiallyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl dimethyl benzyl ammonium chloride, methacryloyloxyethyl dimethyl benzyl ammonium chloride, epoxypropyl trimethyl ammonium chloride, epoxypropyl benzyl trimethyl ammonium chloride, epoxypropyl ethoxy trimethyl ammonium chloride and epoxypropyl-trimethyl ammonium chloride terminated polyethylene glycol.

According to a preferred embodiment of the present invention, the oil solvent is selected from one or more of aliphatic hydrocarbons, aromatic hydrocarbons, mineral oils and vegetable oils. Preferably, the aliphatic hydrocarbon is selected from one or more of cyclohexane, hexane, heptane, octane and isooctane. Preferably, the aromatic hydrocarbon is selected from one or more of benzene, toluene, ethylbenzene, xylene and cumene. Preferably, the mineral oil is selected from one or more of liquid paraffin, white oil, gasoline, diesel oil and kerosene. Preferably, the vegetable oil is selected from one or more of peanut oil, soybean oil, sunflower oil and castor oil. Preferably, the white oil is a number 5 white oil.

According to an embodiment of the present invention, the oxidizing agent is selected from one or more of persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, benzoyl peroxide, potassium bromate, t-butyl hydroperoxide, lauroyl peroxide, cumene hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, t-butyl peroxybenzoate, t-butyl peroxypivalate, methyl ethyl ketone peroxide, cyclohexanone peroxide, diisopropyl peroxydicarbonate, and dicyclohexyl peroxydicarbonate.

According to a preferred embodiment of the invention, the initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate, azobisisobutyramidine hydrochloride, azobisisobutyrimidazoline hydrochloride and azobisisobutyronitrile formamide.

According to an embodiment of the present invention, the reducing agent is selected from one or more of sodium bisulfite, sodium thiosulfate, sodium dithionite, sodium metabisulfite, tetramethylethylenediamine, ferrous ammonium sulfate, sodium formaldehyde sulfoxylate, N-dimethylaniline, tartaric acid, ferrous sulfate, N-diethylaniline, ferrous pyrophosphate, silver nitrate, mercaptans, ferrous chloride, tetraethyleneimine, glycerol and pentaerythritol.

According to an embodiment of the present invention, the emulsifier and the phase inverter are respectively and independently selected from one or more of fatty alcohol polyoxypropylene polyoxyethylene ether represented by formula (i), aromatic alcohol polyoxypropylene polyoxyethylene ether represented by formula (ii), fatty acid polyoxypropylene polyoxyethylene ester represented by formula (iii), fatty amine polyoxypropylene polyoxyethylene ether represented by formula (iv), sorbitan oleate, sorbitan stearate, sorbitan palmitate and sorbitan laurate,

wherein R is¹、R²And R³Each independently selected from C₁～C₂₈A hydrocarbon group of (a); r is⁴And R⁵From hydrogen atoms or C₁～C₂₈And R is a hydrocarbon group of⁴And R⁵Cannot be simultaneously hydrogen atoms; m is selected from 0-30; n is 1-40;

preferably, R¹、R²And R³Each independently selected from C₆～C₁₄A hydrocarbon group of (a); r is⁴And R⁵From hydrogen atoms or C₆～C₁₄And R is a hydrocarbon group of⁴And R⁵Cannot be simultaneously hydrogen atoms; m is selected from 3-16; n is selected from 3 to 16.

For example, the emulsifier is sorbitan oleate and/or fatty alcohol-polyoxyethylene ether (formula (v), which is formula (i), m is 0, R¹Is C₁₃H₂₇N is 12),

for example, the phase transfer agent is fatty alcohol polyoxypropylene polyoxyethylene ether (the structural formula is formula (vi), which is formula (i), m is 0, R is¹Is C₁₃H₂₇N is 8),

in the preparation method, the phase inversion agent is added, so that the water solubility of the thickening agent is improved, the dissolving time is shortened, and the polymer molecular chain can be fully dissolved in water.

According to a preferred embodiment of the invention, in step a), the pH is adjusted to 6 to 8. For example, the pH is 6, 7, 8, and any value in between. In the present invention, sodium hydroxide, potassium hydroxide, sodium hydrogencarbonate, potassium hydrogencarbonate, sodium carbonate, potassium carbonate and the like can be used for adjusting the pH, and sodium hydroxide is preferred. When the synthesis conditions are too acidic (e.g. pH 4 and below) the viscosity is low because the molecular weight is too low. When the synthesis conditions are too alkaline (for example, pH values of 11 and 11 or more), side reactions during polymerization increase and molecular weight increases, crosslinking during polymerization increases due to the side reactions, dissolution time increases significantly, and viscosity decreases due to the increase in insoluble substances. Therefore, in the preferable pH value range (the pH value is 5-10) of the invention, the synthesis of the thickening agent with better effect is facilitated.

According to a preferred embodiment of the invention, in step b), the temperature of dissolution is not greater than 25 ℃, preferably 0 to 25 ℃. For example, 0 ℃, 5 ℃, 10 ℃, 15 ℃, 20 ℃, 25 ℃, and any value therebetween. The temperature of the solution can be cooled by using a cooling jacket. The thickener of the present invention is preferably synthesized in the preferred temperature range of the present invention.

According to a preferred embodiment of the invention, in step c), the temperature at which the aqueous solution III is mixed with the aqueous solution I obtained in step a) is not more than 25 ℃, preferably 0 to 25 ℃. For example, 0 ℃, 5 ℃, 10 ℃, 15 ℃, 20 ℃, 25 ℃, and any value therebetween. The temperature of the solution can be cooled by using a cooling jacket. The thickener of the present invention is preferably synthesized in the preferred temperature range of the present invention.

According to a preferred embodiment of the invention, in step c), the conditions of emulsification comprise: the rotating speed is 10000-25000 r/min, and the emulsifying time is 2-15 min. In the present invention, the emulsifying apparatus may be a high shear emulsifying machine which is conventional in the art.

According to a preferred embodiment of the invention, in step d), the mixing conditions of the emulsion with the reducing agent comprise: the temperature is 5-15 ℃. In the invention, the equipment for mixing the emulsion and the reducing agent can be a reaction kettle, and the mixing of the emulsion and the reducing agent can be controlled to be 5-15 ℃ by a water bath method. The conditions for mixing the emulsion with the reducing agent may further include: and introducing inert gas under continuous stirring at the stirring speed of 200-500 r/min. The purpose of introducing the inert gas is to remove oxygen in the reaction vessel.

According to a preferred embodiment of the present invention, in step d), the redox reaction conditions include: the temperature is 40-50 ℃, and the time is 1-4 h. For example, at 40 ℃ for 2 h.

According to a preferred embodiment of the present invention, the time for mixing with the phase inversion agent in step d) is 0.5 to 2 hours.

According to a preferred embodiment of the present invention, the process for the preparation of the thickener comprises

b) dissolving an emulsifier in an oil solvent, and controlling the temperature to be not more than 25 ℃ to obtain an oil solution II;

c) mixing an oxidant and an initiator to obtain an aqueous solution III, then adding the aqueous solution III into the aqueous solution I obtained in the step a), then adding the aqueous solution I into the oil solution II obtained in the step b), and emulsifying for 5min at the rotating speed of 10000-25000 r/min under a high-speed shearing emulsifying machine to obtain an emulsion;

d) adding the emulsion into a reaction kettle, setting the stirring speed at 200-500r/min, introducing inert gas for deoxygenation under continuous stirring, then controlling the temperature at 5-15 ℃ through a water bath, slowly dropwise adding a solution containing a reducing agent into the emulsion, slowly heating at the heating rate of 0.05-0.5 ℃/min, maintaining the stirring speed at 200-500r/min until the temperature is raised to 40-50 ℃, carrying out redox reaction for 1-4 h, then slowly dropwise adding a phase transfer agent, and stirring for 0.5-2 h.

According to a preferred embodiment of the invention, the thickener contains acrylamide monomer building blocks, anionic monomer building blocks, nonionic monomer building blocks, reactive monomer building blocks, and optionally cationic monomer building blocks, wherein the reactive monomer building blocks comprise reactive monomer building blocks I, reactive monomer building blocks II, and reactive monomer building blocks III,

wherein each R is₁Same or different, each independently selected from hydrogen atom or C₁～C₂₈A hydrocarbon group of (a); each R₂、R₃And R₄Same or different, each independently selected from C₁～C₂₈A hydrocarbon group of (a); r is₅Selected from hydrogen atoms, amino groups, carboxylic acid groups, sulfonic acid groups, sulfuric acid groups, phosphoric acid groups, mercapto groups or halogens; each a and b are the same or different and are respectively 0-40 independently, and the positions of the chain segments of the a and the b can be exchanged; x, Z are each independently selected from ester group, amide group, methylene group, oxygen atom, -CH₂-O-or-NH-; y is selected from ester group, methylene, oxygen atom, -CH₂-O-or-NH-; m^-Selected from fluoride, chloride, bromide or iodide.

According to a preferred embodiment of the invention, each R₁Each independently selected from hydrogen atom, C₆～C₁₈Alkyl or C₆～C₁₈An aromatic group of (a); each R₂、R₃And R₄Each independently selected from C₆～C₁₈Alkyl or C₆～C₁₈An aromatic group of (a); a. b is independently 3-14.

According to a preferred embodiment of the invention, the anionic monomer building block is a building block derived from an anionic monomer selected from the group consisting of acrylic acid, alkali metal salts of acrylic acid, ammonium salts of acrylic acid, methacrylic acid, alkali metal salts of methacrylic acid, ammonium salts of methacrylic acid, vinylsulfonic acid, alkali metal salts of vinylsulfonic acid, ammonium salts of vinylsulfonic acid, p-vinylbenzenesulfonic acid, alkali metal salts of p-vinylbenzenesulfonic acid, ammonium salts of p-vinylbenzenesulfonic acid, maleic acid, alkali metal salts of maleic acid, ammonium salts of maleic acid, fumaric acid, alkali metal salts of fumaric acid, vinylbenzenesulfonic acid, alkali metal salts of vinylbenzenesulfonic acid, ammonium salts of vinylbenzenesulfonic acid, allylsulfonic acid, alkali metal salts of allylsulfonic acid, ammonium salts of allylsulfonic acid, allylbenzenesulfonic acid, allylsulfonic acid, and mixtures thereof, One or more of an alkali metal salt of allylbenzenesulfonic acid, an ammonium salt of allylbenzenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, an alkali metal salt of 2-acrylamido-2-methylpropanesulfonic acid, and an ammonium salt of 2-acrylamido-2-methylpropanesulfonic acid.

According to a preferred embodiment of the present invention, in the anionic monomer, the alkali metal salt is selected from one or more of lithium salt, sodium salt and potassium salt. For example, the sodium salt may be sodium acrylate, sodium methacrylate, sodium vinylsulfonate, sodium p-vinylbenzenesulfonate, sodium maleate, sodium fumarate, sodium vinylbenzenesulfonate, sodium allylsulfonate, sodium allylbenzenesulfonate, sodium 2-acrylamido-2-methylpropanesulfonate. Lithium and potassium salts are analogous to sodium salts.

According to a preferred embodiment of the present invention, the nonionic monomer structural unit is a structural unit derived from a nonionic monomer, wherein the nonionic monomer is selected from one or more of methacrylamide, dimethylacrylamide, diethylacrylamide, methylolacrylamide, hydroxyethylacrylamide, dimethylaminopropyl methacrylamide, methylolmethacrylate, hydroxyethyl methacrylate, dimethylaminoethyl methacrylate and vinylpyrrolidone.

According to a preferred embodiment of the present invention, the cationic monomer building block is a building block derived from a cationic monomer, wherein the cationic monomer is selected from one or more of methacryloyloxyethyl trimethyl ammonium chloride, 2-acrylamido-2-methylpropyl trimethyl ammonium chloride, dimethylethyl allyl ammonium chloride, dimethyldiallyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl dimethyl benzyl ammonium chloride, methacryloyloxyethyl dimethyl benzyl ammonium chloride, epoxypropyl trimethyl ammonium chloride, epoxypropyl benzyl trimethyl ammonium chloride, epoxypropyl ethoxytrimethyl ammonium chloride, and epoxypropyl-trimethyl ammonium chloride terminated polyethylene glycol.

According to a preferred embodiment of the invention, the thickener according to the invention is used as thickener in the case of a concentration of more than 0.3% by weight; more preferably, the thickener of the present invention is used in a concentration of 0.3 to 6% by weight.

The key point of the invention is that composite active monomers (active monomer I, active monomer II and active monomer III) are introduced into emulsion polyacrylamide to form multiple composite association micelles, so that the influence of a large amount of emulsifying agents and oil solvents on association structures can be eliminated, and the emulsion hydrophobic association polyacrylamide with strong tackifying capability is obtained and used as a thickening agent for fracturing fluid with excellent temperature resistance and salt resistance and instant dissolving capability.

[ example 1 ]

This example illustrates the preparation of a thickener according to the invention.

a) Adding 45 parts by weight of acrylamide, 5 parts by weight of acrylic acid, 10 parts by weight of sodium 2-acrylamido-2-methylpropanesulfonate, 3 parts by weight of vinyl pyrrolidone, 1 part by weight of sodium 2-acrylamidotetradecyl sulfonate, 1 part by weight of allyl polyoxyethylene polyoxypropylene ether (EO10PO5), 2 parts by weight of dodecyl-polyethoxy-polypropoxy-acrylamide and 0.5 part by weight of urea into 60 parts by weight of deionized water, and adjusting the pH value to 7 by using sodium hydroxide to obtain an aqueous solution I;

b) dissolving 60 parts by weight of sorbitan oleate and 4 parts by weight of fatty alcohol-polyoxyethylene ether in 50 parts of No. 5 white oil, and controlling the temperature to be 25 ℃ to obtain an oil solution II;

c) mixing 0.0009 part by weight of potassium bromate with 0.0001 part by weight of azobisisobutyronitrile to obtain an aqueous solution III, adding the aqueous solution III into the aqueous solution I obtained in the step a), and uniformly stirring the mixture at a controlled temperature of 25 ℃. Then adding the mixture into the oil solution II obtained in the step b), and emulsifying for 5min at a rotating speed of 25000r/min under a high-speed shearing emulsifying machine to obtain emulsion;

d) adding the emulsion into a reaction kettle, introducing inert gas to remove oxygen for 30min at a stirring speed of 500r/min, then controlling the temperature to be 15 ℃ through a water bath, slowly dropwise adding 0.008 part by weight of aqueous solution containing sodium metabisulfite (the concentration of the sodium metabisulfite is 1 wt%) into the emulsion, slowly heating at a heating rate of 0.1 ℃/min, maintaining the stirring rate at 300r/min until the temperature is raised to 45 ℃, carrying out redox for 2h, slowly dropwise adding 32 parts by weight of fatty alcohol polyoxypropylene polyoxyethylene ether, and stirring for 1 h to obtain a thickening agent;

the weight average molecular weight of the thickener was determined to be 2100 ten thousand with a molecular weight distribution of 0.27. (the weight average molecular weight was measured by a static light scattering method (the same below); and the molecular weight distribution was measured by a static light scattering method (the same below)).

[ example 2 ]

a) Adding 45 parts by weight of acrylamide, 5 parts by weight of acrylic acid, 10 parts by weight of sodium 2-acrylamido-2-methylpropanesulfonate, 3 parts by weight of vinylpyrrolidone, 1 part by weight of sodium 2-acrylamidotetradecyl sulfonate, 1 part by weight of allyl polyoxyethylene polyoxypropylene ether (EO10PO5), 2 parts by weight of dodecyl-polyethoxy-polypropoxy-acrylamide, 3 parts by weight of hexadecyldimethylallylammonium chloride and 0.5 part by weight of urea into 60 parts by weight of deionized water, and adjusting the pH value to 6 by using sodium hydroxide to obtain an aqueous solution I;

c) mixing 0.0009 part by weight of potassium bromate and 0.0001 part by weight of azobisisobutyronitrile to obtain an aqueous solution III, adding the aqueous solution III into the aqueous solution I obtained in the step a), and uniformly stirring at a controlled temperature of 25 ℃. Then adding the mixture into the oil solution II obtained in the step b), and emulsifying for 5min at a rotating speed of 25000r/min under a high-speed shearing emulsifying machine to obtain emulsion;

d) adding the emulsion into a reaction kettle, introducing inert gas to remove oxygen for 30min at a stirring speed of 500r/min, then controlling the temperature to be 15 ℃ through a water bath, slowly dropwise adding 0.008 part by weight of aqueous solution containing sodium metabisulfite (the concentration of the sodium metabisulfite is 1 wt%) into the emulsion, slowly heating at a heating rate of 0.1 ℃/min, maintaining the stirring rate at 300r/min until the temperature is raised to 45 ℃, carrying out redox for 2h, slowly dropwise adding 32 parts by weight of fatty alcohol polyoxypropylene polyoxyethylene ether, and stirring for 1 h to obtain the thickening agent.

The weight average molecular weight of the thickening agent is 2200 ten thousand and the molecular weight distribution is 0.31.

[ example 3 ]

This example illustrates the preparation of the thickener of the present invention.

a) Adding 45 parts by weight of acrylamide, 5 parts by weight of acrylic acid, 10 parts by weight of sodium 2-acrylamido-2-methylpropanesulfonate, 3 parts by weight of vinylpyrrolidone, 1 part by weight of sodium 2-acrylamidotetradecylsulfonate, 1 part by weight of allylpolyoxyethylenepolyoxypropylene ether (EO10PO5), 5 parts by weight of dodecyl-polyethoxy-polypropoxy-acrylamide, 2 parts by weight of a compound represented by the formula (8) (ADEKA REASOAP), and 0.5 part by weight of urea to 60 parts by weight of deionized water, and adjusting the pH value to 8 with sodium hydroxide to obtain an aqueous solution I;

The weight average molecular weight of the thickening agent is 2200 ten thousand and the molecular weight distribution is 0.19.

[ example 4 ] A method for producing a polycarbonate

a) Adding 25 parts by weight of acrylamide, 0.1 part by weight of vinyl benzenesulfonic acid, 0.1 part by weight of dimethyldiallylammonium chloride, 0.0003 part by weight of sodium 2-acrylamidotetradecyl sulfonate, 0.0003 part by weight of allylpolyoxyethylenepolyoxypropylene ether (EO10PO5), 0.0004 part by weight of dodecyl-polyethoxy-polypropoxy-acrylamide and 0.1 part by weight of thiourea into 70 parts by weight of deionized water, and adjusting the pH value to 5 with sodium hydroxide to obtain an aqueous solution I;

b) dissolving 10 parts by weight of sorbitan palmitate and 10 parts by weight of sorbitan laurate in 50 parts of peanut oil, and controlling the temperature to be 5 ℃ to obtain an oil solution II;

c) mixing 0.00005 weight part of tert-butyl hydroperoxide and 0.00001 weight part of azobisisoheptonitrile to obtain an aqueous solution III, adding into the aqueous solution I obtained in the step a), and stirring uniformly at the controlled temperature of 5 ℃. Then adding the mixture into the oil solution II obtained in the step b), and emulsifying for 5min at a rotating speed of 25000r/min under a high-speed shearing emulsifying machine to obtain emulsion;

d) adding the emulsion into a reaction kettle, introducing inert gas to remove oxygen for 30min at a stirring speed of 500r/min, then controlling the temperature to be 15 ℃ through a water bath, slowly dropwise adding 0.01 part by weight of aqueous solution containing ammonium ferrous sulfate (the concentration of the ammonium ferrous sulfate is 0.5 wt%) into the emulsion, slowly heating up at a heating rate of 0.01 ℃/min, maintaining the stirring speed of 300r/min until the temperature is raised to 40 ℃, carrying out redox for 2h, slowly dropwise adding 10 parts by weight of sorbitan laurate, and stirring for 1 h to obtain the thickening agent.

The weight average molecular weight of the thickening agent is 2100 ten thousand, and the molecular weight distribution is 0.18.

[ example 5 ]

a) Adding 75 parts by weight of acrylamide, 25 parts by weight of maleic acid, 15 parts by weight of methacryloyloxyethyl trimethyl ammonium chloride, 15 parts by weight of sodium 2-acrylate tetradecyl sulfonate, 3 parts by weight of allyl polyoxyethylene (EO12), 2 parts by weight of dodecyl-polyethoxy-polypropoxy-acrylate, 2 parts by weight of the compound represented by formula (8) (ADEKA REASOAP), 2 parts by weight of hexadecyldimethylallyl ammonium chloride, 10 parts by weight of anhydrous sodium sulfate to 10 parts by weight of deionized water, and adjusting the pH to 5 with sodium hydroxide to obtain an aqueous solution I;

b) dissolving 70 parts by weight of sorbitan palmitate in 90 parts by weight of benzene, and controlling the temperature to be 20 ℃ to obtain an oil solution II;

c) 0.001 part by weight of sodium persulfate was mixed with 0.001 part by weight of dimethyl azodiisobutyrate to give an aqueous solution III, which was then added to the aqueous solution I obtained in step a) with stirring to homogeneity and at a controlled temperature of 20 ℃. Then adding the mixture into the oil solution II obtained in the step b), and emulsifying for 5min at a rotating speed of 25000r/min under a high-speed shearing emulsifying machine to obtain emulsion;

d) adding the emulsion into a reaction kettle, introducing inert gas to remove oxygen for 30min at a stirring speed of 500r/min, then controlling the temperature to be 15 ℃ through a water bath, slowly dropwise adding 0.5 part by weight of aqueous solution containing glycerol (the concentration of the glycerol is 2 wt%) into the emulsion, slowly heating up at a heating rate of 0.5 ℃/min, maintaining the stirring speed at 300r/min until the temperature is raised to 50 ℃, carrying out redox for 2h, slowly dropwise adding 50 parts by weight of sorbitan oleate, and stirring for 1 h to obtain the thickening agent.

The weight average molecular weight of the thickening agent is 1900 ten thousand and the molecular weight distribution is 0.27.

[ COMPARATIVE EXAMPLE 1 ]

a) Adding 45 parts by weight of acrylamide, 5 parts by weight of acrylic acid, 10 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 3 parts by weight of vinyl pyrrolidone, 4 parts by weight of 2-acrylamido tetradecyl sulfonic acid sodium salt and 0.5 part by weight of urea into 60 parts by weight of deionized water, and adjusting the pH value to 7 by using sodium hydroxide to obtain an aqueous solution I;

The thickener had a weight average molecular weight of 1950 ten thousand and a molecular weight distribution of 0.32.

[ COMPARATIVE EXAMPLE 2 ]

a) Adding 45 parts by weight of acrylamide, 5 parts by weight of acrylic acid, 10 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 3 parts by weight of vinyl pyrrolidone, 4 parts by weight of hexadecyl dimethyl allyl ammonium chloride and 0.5 part by weight of urea into 60 parts by weight of deionized water, and adjusting the pH value to 7 by using sodium hydroxide to obtain an aqueous solution I;

The weight average molecular weight of the thickening agent is determined to be 1980 ten thousand, and the molecular weight distribution is 0.35.

[ COMPARATIVE EXAMPLE 3 ]

a) Adding 45 parts by weight of acrylamide, 5 parts by weight of acrylic acid, 10 parts by weight of sodium 2-acrylamido-2-methylpropanesulfonate, 3 parts by weight of vinyl pyrrolidone, 4 parts by weight of allyl polyoxyethylene polyoxypropylene ether (EO10PO5) and 0.5 part by weight of urea into 60 parts by weight of deionized water, and adjusting the pH value to 7 by using sodium hydroxide to obtain an aqueous solution I;

[ COMPARATIVE EXAMPLE 4 ]

a) Adding 45 parts by weight of acrylamide, 5 parts by weight of acrylic acid, 10 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 3 parts by weight of vinyl pyrrolidone and 0.5 part by weight of urea into 60 parts by weight of deionized water, and adjusting the pH value to 7 by using sodium hydroxide to obtain an aqueous solution I;

[ COMPARATIVE EXAMPLE 5 ]

a) Adding 45 parts by weight of acrylamide, 5 parts by weight of acrylic acid, 10 parts by weight of 2-acrylamido-2-methylpropanesulfonic acid sodium salt and 0.5 part by weight of urea into 60 parts by weight of deionized water, and adjusting the pH value to 7 by using sodium hydroxide to obtain an aqueous solution I;

The weight average molecular weight of the thickening agent is 2400 ten thousand, and the molecular weight distribution is 0.18.

[ COMPARATIVE EXAMPLE 6 ]

a) Adding 45 parts by weight of acrylamide, 5 parts by weight of acrylic acid and 0.5 part by weight of urea into 60 parts by weight of deionized water, and adjusting the pH value to 7 by using sodium hydroxide to obtain an aqueous solution I;

The weight average molecular weight of the thickening agent is 2200 ten thousand and the molecular weight distribution is 0.21.

[ test examples ]

The dissolution time of the thickeners of examples 1 to 5 and comparative examples 1 to 6 and the shear viscosity in 6000mg/L saline were measured, respectively, and the results are shown in Table 1.

(1) The measurement of the dissolution time specifically comprises: 300g of deionized water is weighed in a beaker, the thickening agent is slowly dripped into the beaker at the speed of 500r/min, and the time for which the aqueous solution can be drawn by contacting through a stirring rod is recorded as the dissolution time.

(2) The measurement of the shear viscosity in 6000mg/L saline specifically comprises the following steps:

the thickener was added to 6000mg/L saline, the concentration of the thickener being 0.6% by weight. The shear viscosity was measured at 30 ℃ and a shear rate of 1701/s using a Haake rheometer coaxial cylinder model.

TABLE 1

Numbering	Dissolution time (min)	Shear viscosity (mPa. multidot.s) in 6000mg/L saline
			Example 1	1.5	47
Example 2	1	52
			Example 3	2	58
Example 4	1.5	59
			Example 5	3	48
Comparative example 1	4	11.1
			Comparative example 2	7.5	5.7
Comparative example 3	2.9	9.2
			Comparative example 4	5.4	2.1
Comparative example 5	5.2	1.9
			Comparative example 6	4.8	2.3

As can be seen from the examples and comparative examples, and the results in table 1, the emulsion type thickener of the present invention has excellent thickening ability and temperature and salt resistance, and has a fast dissolution rate.

In addition, compared with the embodiment 1, the active monomer in the embodiment 2 is introduced and has a special structure between double bonds, so that the active monomer can be more effectively arranged on the interface of the associated micelle to form a stronger associated network structure, and the viscosity performance is higher.

Compared with the examples 1 and 2, the acrylamide derivative is selected for two of the active monomers in the example 3, so that the influence of insufficient double bond activity on the molecular weight can be reduced, a polymer product with higher molecular weight can be obtained, and higher viscosity performance is realized, but the dissolution is slightly influenced due to higher molecular weight, and the dissolution time is slightly longer.

In comparative examples 1 to 3, only one reactive monomer had insufficient association strength and thus had a lower viscosity than in example 1.

In comparative examples 4 to 6, the molecular weight was higher than that of examples 1, 2 and 3 because no reactive monomer was added, but the viscosity was lower because no group capable of generating an association structure was present.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.

Claims

1. A thickening agent comprises an acrylamide monomer structural unit, an anionic monomer structural unit, a nonionic monomer structural unit, an active monomer structural unit and an optional cationic monomer structural unit, wherein the active monomer structural unit comprises an active monomer structural unit I, an active monomer structural unit II and an active monomer structural unit III,

wherein each R is₁Same or different, each independently selected from hydrogen atom or C₁～C₂₈A hydrocarbon group of (a); each R₂、R₃And R₄Same or different, each independently selected from C₁～C₂₈A hydrocarbon group of (a); r is₅Selected from hydrogen atoms; each a and b are the same or different and are respectively 0-40 independently, the positions of the chain segments of the a and the b can be changed, and the a and the b are not 0; x, Z are each independently selected from ester group, amide group, methylene group, oxygen atom, -CH₂-O-or-NH-; y is selected from estersRadical, methylene, oxygen atom, -CH₂-O-or-NH-; m is a group of^-Selected from fluoride, chloride, bromide or iodide;

the anionic monomer structural unit is a structural unit derived from an anionic monomer, wherein the anionic monomer is selected from acrylic acid, alkali metal salts of acrylic acid, ammonium salts of acrylic acid, methacrylic acid, alkali metal salts of methacrylic acid, ammonium salts of methacrylic acid, vinylsulfonic acid, alkali metal salts of vinylsulfonic acid, ammonium salts of vinylsulfonic acid, p-vinylbenzenesulfonic acid, alkali metal salts of p-vinylbenzenesulfonic acid, ammonium salts of p-vinylbenzenesulfonic acid, maleic acid, alkali metal salts of maleic acid, ammonium salts of maleic acid, fumaric acid, alkali metal salts of fumaric acid, ammonium salts of fumaric acid, vinylbenzenesulfonic acid, alkali metal salts of vinylbenzenesulfonic acid, ammonium salts of vinylbenzenesulfonic acid, allylsulfonic acid, alkali metal salts of allylsulfonic acid, ammonium salts of allylsulfonic acid, allylbenzenesulfonic acid, alkali metal salts of allylbenzenesulfonic acid, ammonium salts of allylsulfonic acid, and the like, One or more of 2-acrylamido-2-methylpropanesulfonic acid, an alkali metal salt of 2-acrylamido-2-methylpropanesulfonic acid, and an ammonium salt of 2-acrylamido-2-methylpropanesulfonic acid;

the cationic monomer structural unit is derived from a cationic monomer, wherein the cationic monomer is selected from one or more of methacryloyloxyethyl trimethyl ammonium chloride, 2-acrylamide-2-methylpropyl trimethyl ammonium chloride, dimethyl ethyl allyl ammonium chloride, dimethyl diallyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl dimethyl benzyl ammonium chloride and methacryloyloxyethyl dimethyl benzyl ammonium chloride;

the nonionic monomer structural unit is a structural unit derived from a nonionic monomer, wherein the nonionic monomer is selected from one or more of methacrylamide, dimethylacrylamide, diethylacrylamide, methylolacrylamide, hydroxyethylacrylamide, dimethylaminopropyl methacrylamide, methylol methacrylate, hydroxyethyl methacrylate, dimethylaminoethyl methacrylate and vinyl pyrrolidone.

2. The thickener of claim 1, wherein each R is₁Each independently selected from hydrogen atom, C₆～C₁₈Alkyl or C of₆～C₁₈An aromatic group of (a); each R₂、R₃And R₄Each independently selected from C₆～C₁₈Alkyl or C₆～C₁₈An aromatic group of (a); a. b is independently 3-14.

3. The thickener according to claim 1 or 2, wherein the content of the acrylamide monomer structural unit is 25 to 75 parts by weight, the content of the anionic monomer structural unit is 0.1 to 25 parts by weight, the content of the nonionic monomer structural unit is 0.1 to 15 parts by weight, the content of the reactive monomer structural unit is 0.001 to 15 parts by weight, and the content of the cationic monomer structural unit is 0 to 15 parts by weight.

4. The thickening agent according to claim 3, wherein the content of the reactive monomer structural unit I is 1 to 13 parts by weight, the content of the reactive monomer structural unit II is 1 to 13 parts by weight, and the content of the reactive monomer structural unit III is 1 to 13 parts by weight.

5. The thickener according to claim 3, wherein the content of the structural unit represented by formula (V) is 1 to 13 parts by weight, the content of the structural unit represented by formula (III) is 0 to 12 parts by weight, and the content of the structural unit represented by formula (IV) is 0 to 12 parts by weight.

6. The thickener according to claim 1 or 2, wherein the thickener has a weight average molecular weight of 1500 to 2500 ten thousand; the molecular weight distribution is 0.2-0.8.

7. The thickener according to claim 6, wherein the thickener has a weight average molecular weight of 2000 to 2500 ten thousand.

8. A method of making a thickener comprising:

b) dissolving an emulsifier in an oil solvent to obtain an oil solution II;

wherein each R is₁Same or different, each independently selected from hydrogen atom or C₁～C₂₈A hydrocarbon group of (a); each R₂、R₃And R₄Same or different, each independently selected from C₁～C₂₈A hydrocarbon group of (a); r₅Selected from hydrogen atoms; each a and b are the same or different and are respectively 0-40 independently, the positions of the chain segments of the a and the b can be changed, and the a and the b are not 0; x, Z are individually independentSelected from ester group, amide group, methylene group, oxygen atom, -CH₂-O-or-NH-; y is selected from ester group, methylene, oxygen atom, -CH₂-O-or-NH-; m^-Selected from fluoride, chloride, bromide or iodide;

the anionic monomer is selected from the group consisting of acrylic acid, alkali metal salts of acrylic acid, ammonium salts of acrylic acid, methacrylic acid, alkali metal salts of methacrylic acid, ammonium salts of methacrylic acid, vinylsulfonic acid, alkali metal salts of vinylsulfonic acid, ammonium salts of vinylsulfonic acid, p-vinylbenzenesulfonic acid, alkali metal salts of p-vinylbenzenesulfonic acid, ammonium salts of p-vinylbenzenesulfonic acid, maleic acid, alkali metal salts of maleic acid, ammonium salts of maleic acid, fumaric acid, alkali metal salts of fumaric acid, ammonium salts of fumaric acid, vinylbenzenesulfonic acid, alkali metal salts of vinylbenzenesulfonic acid, ammonium salts of vinylbenzenesulfonic acid, allylsulfonic acid, alkali metal salts of allylsulfonic acid, ammonium salts of allylsulfonic acid, allylbenzenesulfonic acid, alkali metal salts of allylbenzenesulfonic acid, ammonium salts of allylbenzenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, methacrylic acid, maleic anhydride, or a sulfonic acid, or a salt, a, One or more of an alkali metal salt of 2-acrylamido-2-methylpropanesulfonic acid and an ammonium salt of 2-acrylamido-2-methylpropanesulfonic acid;

the cationic monomer is selected from one or more of methacryloyloxyethyl trimethyl ammonium chloride, 2-acrylamide-2-methylpropyl trimethyl ammonium chloride, dimethyl ethyl allyl ammonium chloride, dimethyl diallyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl dimethyl benzyl ammonium chloride and methacryloyloxyethyl dimethyl benzyl ammonium chloride;

the non-ionic monomer is selected from one or more of methacrylamide, dimethylacrylamide, diethylacrylamide, hydroxymethyl acrylamide, hydroxyethyl acrylamide, dimethylaminopropyl methacrylamide, hydroxymethyl methacrylate, hydroxyethyl methacrylate, dimethylaminoethyl methacrylate and vinyl pyrrolidone.

9. The method of claim 8, wherein each R is₁Each independently selected from hydrogen atoms、C₆～C₁₈Alkyl or C₆～C₁₈An aromatic group of (a); each R₂、R₃And R₄Each independently selected from C₆～C₁₈Alkyl or C₆～C₁₈An aromatic group of (a); a. b is independently 3-14.

10. The method according to claim 8 or 9, wherein the charge amount of the acrylamide monomer is 25 to 75 parts by weight, the charge amount of the anionic monomer is 0.1 to 25 parts by weight, the charge amount of the nonionic monomer is 0.1 to 15 parts by weight, the charge amount of the reactive monomer is 0.001 to 15 parts by weight, the charge amount of the cosolvent is 0.1 to 10 parts by weight, the charge amount of the solvent is 10 to 70 parts by weight, and the charge amount of the cationic monomer is 0 to 15 parts by weight, the feeding amount of the emulsifier is 20-70 parts by weight, the feeding amount of the oil solvent is 50-90 parts by weight, the feeding amount of the oxidant is 0.00005-0.001 part by weight, the feeding amount of the initiator is 0.00001-0.001 part by weight, the feeding amount of the solution containing the reducing agent is 0.000005-0.001 part by weight, and the feeding amount of the phase inversion agent is 10-50 parts by weight, wherein the solution containing the reducing agent is calculated by the reducing agent, and the solvent is calculated by deionized water.

11. The method according to claim 10, wherein the amount of the reactive monomer I is 1 to 13 parts by weight, the amount of the reactive monomer II is 1 to 13 parts by weight, and the amount of the reactive monomer III is 1 to 13 parts by weight.

12. The method according to claim 10, wherein the amount of the feed material for the structure represented by formula (X) is 1 to 13 parts by weight, the amount of the feed material for the structure represented by formula (VIII) is 0 to 12 parts by weight, and the amount of the feed material for the structure represented by formula (IX) is 0 to 12 parts by weight.

13. The method according to claim 8 or 9, wherein the concentration of the reducing agent in the solution containing the reducing agent is 0.5 to 2% by weight.

14. The method according to claim 8 or 9, wherein the co-solvent is selected from one or more of sodium formate, urea, thiourea and anhydrous sodium sulfate.

15. The method of claim 8 or 9, wherein the solvent is deionized water.

16. The method according to claim 8 or 9, wherein the oil solvent is selected from one or more of aliphatic hydrocarbons, aromatic hydrocarbons, mineral oils and vegetable oils.

17. The method of claim 16, wherein the aliphatic hydrocarbon is selected from one or more of cyclohexane, hexane, heptane, octane, and isooctane.

18. The method of claim 16, wherein the aromatic hydrocarbon is selected from one or more of benzene, toluene, xylene, and cumene.

19. The method of claim 16, wherein the mineral oil is selected from one or more of liquid paraffin, white oil, gasoline, diesel, and kerosene.

20. The method of claim 16, wherein the vegetable oil is selected from one or more of peanut oil, soybean oil, sunflower oil, and castor oil.

21. The method according to claim 8 or 9, wherein the oxidizing agent is selected from one or more of persulfates, hydrogen peroxide, benzoyl peroxide, potassium bromate, t-butyl hydroperoxide, lauroyl peroxide, cumene hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, t-butyl peroxybenzoate, t-butyl peroxypivalate, methyl ethyl ketone peroxide, cyclohexanone peroxide, diisopropyl peroxydicarbonate, and dicyclohexyl peroxydicarbonate.

22. The method according to claim 8 or 9, wherein the oxidizing agent is selected from potassium persulfate or sodium persulfate.

23. A process according to claim 8 or 9, characterised in that the initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate, azobisisobutyramidine hydrochloride, azobisisobutyrimidazoline hydrochloride and azobisisobutyronitrile formamide.

24. The method of claim 8 or 9, wherein the reducing agent is selected from one or more of sodium bisulfite, sodium thiosulfate, sodium dithionite, sodium metabisulfite, tetramethylethylenediamine, ferrous ammonium sulfate, sodium formaldehyde sulfoxylate, N-dimethylaniline, tartaric acid, ferrous sulfate, N-diethylaniline, ferrous pyrophosphate, silver nitrate, mercaptans, ferrous chloride, tetraethylene imine, glycerol and pentaerythritol.

25. The method according to claim 8 or 9, wherein the emulsifier and the phase inverter are each independently selected from one or more of fatty alcohol polyoxypropylene polyoxyethylene ether represented by formula (i), aromatic alcohol polyoxypropylene polyoxyethylene ether represented by formula (ii), fatty acid polyoxypropylene polyoxyethylene ester represented by formula (iii), fatty amine polyoxypropylene polyoxyethylene ether represented by formula (iv), sorbitan oleate, sorbitan stearate, sorbitan palmitate and sorbitan laurate,

wherein R is¹、R²And R³Each independently selected from C₁～C₂₈A hydrocarbon group of (a); r⁴And R⁵From hydrogen atoms or C₁～C₂₈And R is a hydrocarbon group of⁴And R⁵Cannot be simultaneously hydrogen atoms; m is selected from 0-30, and m is not 0; n is 1-40.

26. The method of claim 25, wherein R is¹、R²And R³Each independently selected from C₆～C₁₄A hydrocarbon group of (a); r⁴And R⁵From hydrogen atoms or C₆～C₁₄And R is a hydrocarbon group of⁴And R⁵Cannot be simultaneously hydrogen atoms; m is selected from 3-16; n is selected from 3 to 16.

27. The method according to claim 8 or 9, wherein in step a), the pH is adjusted to 6-8.

28. The process according to claim 8 or 9, characterized in that in step b) the temperature of dissolution is not more than 25 ℃.

29. The method according to claim 8 or 9, wherein in step b), the temperature of the dissolution is 0 to 25 ℃.

30. The process according to claim 8 or 9, characterized in that in step c) the conditions of emulsification comprise: the rotating speed is 10000-25000 r/min, and the emulsifying time is 2-15 min.

31. The method according to claim 8 or 9, wherein in step d) the mixing conditions of the emulsion with the reducing agent comprise: the temperature is 5-15 ℃.

32. The method according to claim 8 or 9, wherein in step d) the redox reaction conditions comprise: the temperature is 40-50 ℃, and the time is 1-4 h.

33. A thickener prepared by the process of any of claims 8-32.

34. Use of a viscosifying agent according to any one of claims 1-7 and/or a viscosifying agent prepared according to the method of any one of claims 8-32 in a fracturing process.