Polymer microsphere as well as preparation method and application thereof

Abstract

The invention discloses a polymer microsphere and a preparation method and application thereof, the polymer microsphere comprises an acrylamide structure unit and a crosslinking structure unit, and the crosslinking structure unit comprises at least one of the following structures: a triazine ring structure, a silane structure, a siloxane structure and an alcohol ether structure. The polymer microsphere has a better plugging effect and a longer service period in a high-temperature oil reservoir, is beneficial to the improvement of the efficiency of deep profile control in oil field construction, and has important significance for improving the crude oil recovery rate of an old oil field.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polymer microspheres, and particularly relates to a polymer microsphere, a preparation method and application thereof, in particular, application in deep profile control and enhanced oil recovery in high-temperature reservoirs. BACKGROUND

[0002] With long-term water injection development of oilfields, the continuously formed dominant channels consume a large amount of injected liquid, affect sweep efficiency, and further affect effective contact of oil displacement agent with crude oil, which seriously affects further improvement of crude oil recovery.

[0003] Plugging dominant channels is called profile control in practice, but with increasingly harsh conditions of reservoirs, requirements for profile control agents are also continuously improved. For example, in high-temperature reservoirs, the currently commonly used various water-absorbing resin type plugging agents all have effective temperature resistance, and long-term service at high temperature has poor effect, which cannot meet the actual use requirements on site.

[0004] Polymer microspheres are widely used as deep profile control chemical agents due to their simple injection process and excellent injectivity, but the traditional polymer microspheres can effectively plug the formation below 100 DEG C, but if the temperature is higher, they are easily degraded by hydrolysis at high temperature and cannot meet the needs of high-temperature reservoirs. Therefore, a polymer microsphere capable of resisting higher temperature has important value for deep profile control of high-temperature reservoirs. SUMMARY

[0005] In order to overcome the problems in the prior art, the present application provides a polymer microsphere, a preparation method and application thereof, the polymer microsphere has better plugging effect and longer service period in high-temperature reservoirs, which is beneficial to improving the efficiency of deep profile control in oilfield construction and has important significance for improving crude oil recovery in old oilfields.

[0006] One of the purposes of the present application is to provide a polymer microsphere, which comprises an acrylamide structural unit and a crosslinking structural unit, the crosslinking structural unit contains at least one of the following structures: triazine ring structure, silane structure, siloxane structure, alcohol ether structure.

[0007] In a preferred embodiment, the crosslinking structural unit is derived from at least one of a triazine ring compound containing two or more double bond structures, a silane containing two or more double bond structures, a siloxane containing two or more double bond structures, and a polyol polyallyl ether.

[0008] In a further preferred embodiment, the crosslinking structural unit is derived from at least one of the following compounds:

[0009]

[0010] wherein: in formula (1), R1is selected from a double bond-containing group, R2is selected from methylene or carbonyl, and the recurring R1or R2are the same or different; in formula (2), R4is selected from a double bond-containing group, and the recurring R4are the same or different; in formula (3), at least two R5are selected from a double bond-containing group, and the remaining R5are selected from an alkyl group, an aryl group, or hydrogen, and the recurring R5are the same or different; in formula (4), at least two R are selected from a double bond-containing group, and the remaining R are selected from an alkyl group, an aryl group, or hydrogen, and the recurring R are the same or different; in formula (5), R6is selected from a double bond-containing group, p = 0 or 1 and at least two p = 1, and the recurring R6are the same or different, and the recurring p are the same or different; in formula (6), R7is selected from a double bond-containing group, m = 0 or 1 and at least two m = 1, n = 0 to 10, and the recurring R7are the same or different, and the recurring m are the same or different, and the recurring n are the same or different.

[0011] In a further preferred embodiment, the double bond-containing group is selected from an alkenyl group or an alkenyloxy group, preferably from a C2to C10alkenyl group or a C2to C10alkenyloxy group; and / or, the alkyl group is selected from a C1to C20alkyl group, preferably from a C1to C10alkyl group; and / or, the aryl group is selected from a C6to C20aryl group, preferably from a C6to C15aryl group.

[0012] For example, the alkenyl group is a C2to C5alkenyl group, the alkenyloxy group is a C2to C5alkenyloxy group, the alkyl group is a C1to C5alkyl group, and the aryl group is a C6to C10aryl group such as a phenyl group.

[0013] In a preferred embodiment, the crosslinking structural unit is derived from at least one of the following crosslinking agents:

[0014]

[0015]

[0016] In a preferred embodiment, the polymeric microspheres further comprise an optional anionic structural unit, an optional cationic structural unit, and / or an optional non-ionic structural unit.

[0017] In a preferred embodiment, the anionic structural unit is selected from at least one of a carboxylic acid type structural unit and / or an alkali metal salt thereof, a sulfonic acid type structural unit and / or an alkali metal salt thereof.

[0018] In a further preferred embodiment, the anionic structural unit is derived from at least one of the following anionic monomers: acrylic acid, methacrylic acid, p-vinylbenzenesulfonic acid, maleic acid, fumaric acid, vinylbenzenesulfonic acid, allylsulfonic acid, allylbenzenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, and alkali metal salts thereof.

[0019] In a preferred embodiment, the cationic structural unit is selected from at least one of ammonium chloride type structural unit, ammonium bromide type structural unit, ammonium iodide type structural unit.

[0020] In a further preferred embodiment, the cationic structural unit is derived from at least one of the following cationic monomers: methacryloyloxyethyltrimethylammonium chloride, 2-acrylamido-2-methylpropyltrimethylammonium chloride, dimethylethylallylammonium chloride, dimethyldiallylammonium chloride, acryloyloxyethyltrimethylammonium chloride, acryloyloxyethyldimethylbenzylammonium chloride, methacryloyloxyethyldimethylbenzylammonium chloride.

[0021] In a preferred embodiment, the non-ionic structural unit is selected from at least one of substituted acrylamide structural unit, substituted hydroxyalkyl acrylate structural unit, pyrrolidone type structural unit, substituted amino acrylate type structural unit.

[0022] In a further preferred embodiment, the non-ionic structural unit is derived from at least one of the following non-ionic monomers: methacrylamide, dimethylacrylamide, diethylacrylamide, hydroxymethylacrylamide, hydroxyethylacrylamide, dimethylaminopropylmethacrylamide, hydroxymethyl methacrylate, hydroxyethyl methacrylate, dimethylaminoethyl methacrylate, vinyl pyrrolidone, t-butyl acrylamide.

[0023] In a preferred embodiment, the polymer microspheres further contain a co-solvent.

[0024] In a further preferred embodiment, the co-solvent is selected from at least one of C4-C8 alcohol solvent, polyether containing alkyl segment.

[0025] In a still further preferred embodiment, the co-solvent is selected from at least one of butanol, pentanol, alkyl alcohol polyoxyethylene ether (such as carbon number 5-20, specifically isomeric tridecanol, ethylene oxide number 3-12), alkyl polyoxyethylene ether (such as carbon number 5-15, especially 10, ethylene oxide number 3-12), alkyl phenol polyoxyethylene ether (such as carbon number 5-15, especially 10, ethylene oxide number 3-12).

[0026] The co-solvent is used to promote the uniform dissolution of the crosslinking agent in the aqueous solution, which is more conducive to the formation of polymer microspheres and improves its temporary plugging effect.

[0027] In a preferred embodiment, in the polymer microspheres, by weight:

[0028] acrylamide structural unit 2-30 parts;

[0029] anionic structural unit 0-30 parts;

[0030] cationic structural units 0-30 parts;

[0031] nonionic structural units 0-20 parts;

[0032] crosslinking structural units 0.001-1 parts;

[0033] co-solvent 0.005-1 parts.

[0034] In a further preferred embodiment, in the polymer microspheres, by parts by weight:

[0035] acrylamide structural units 5-25 parts, for example 5, 8, 10, 12, 15, 18, 20, 22 or 25 parts;

[0036] anionic structural units 1-25 parts, for example 1, 5, 10, 15, 20 or 25 parts;

[0037] cationic structural units 0-25 parts, for example 0, 5, 10, 15, 20 or 25 parts;

[0038] nonionic structural units 0-10 parts, for example 0, 2, 4, 6, 8 or 10 parts;

[0039] crosslinking structural units 0.001-0.5 parts, for example 0.001, 0.01, 0.05, 0.1, 0.3 or 0.5 parts;

[0040] co-solvent 0.01-0.5 parts, for example 0.01, 0.05, 0.1, 0.2, 0.3, 0.4 or 0.5 parts.

[0041] In a further preferred embodiment, in the polymer microspheres, by parts by weight:

[0042] acrylamide structural units 15-25 parts;

[0043] anionic structural units 5-20 parts;

[0044] cationic structural units 0-7.5 parts;

[0045] nonionic structural units 0-7.5 parts;

[0046] crosslinking structural units 0.01-0.25 parts;

[0047] co-solvent 0.05-0.5 parts.

[0048] In a preferred embodiment, the polymer microspheres are obtained by polymerization of reaction materials comprising acrylamide monomers, crosslinking agents, co-solvents, optionally anionic monomers, optionally cationic monomers, optionally nonionic monomers.

[0049] The technical problem to be solved by the present application is the problem of insufficient long-term aging performance of existing polymer microspheres under high temperature conditions. To this end, the present application introduces a special crosslinking monomer in polymerization to form a crosslinked network with better stability under high temperature to ensure that the network structure of the polymer microspheres does not collapse under high temperature during the long-term service period, thereby ensuring the long-term effectiveness of the deep profile control under high temperature conditions.

[0050] The second object of the present application is to provide a preparation method of polymer microspheres, preferably for preparing the polymer microspheres of the first object of the present application, the preparation method comprising: polymerizing reaction raw materials including acrylamide monomers, crosslinking agents, cosolvents, optional anionic monomers, optional cationic monomers, and optional non-ionic monomers.

[0051] In a preferred embodiment, the crosslinking agent is selected from at least one of a triazine ring compound containing two or more double bond structures, a silane containing two or more double bond structures, a siloxane containing two or more double bond structures, and a polyol polyallyl ether.

[0052] In a further preferred embodiment, the crosslinking agent is selected from at least one of the compounds represented by the following formulae:

[0053]

[0054] In formula (1), R1 is selected from a double bond-containing group, R2 is selected from a methylene group or a carbonyl group, and the repeated R1 or R2 is the same or different; in formula (2), R4 is selected from a double bond-containing group, and the repeated R4 is the same or different; in formula (3), at least two R5 are selected from a double bond-containing group, and the remaining R5 is selected from an alkyl group, an aryl group, or hydrogen, and the repeated R5 is the same or different; in formula (4), at least two R are selected from a double bond-containing group, and the remaining R is selected from an alkyl group, an aryl group, or hydrogen, and the repeated R is the same or different; in formula (5), R6 is selected from a double bond-containing group, p = 0 or 1 and at least two p = 1, and the repeated R6 is the same or different, and the repeated p is the same or different; in formula (6), R7 is selected from a double bond-containing group, m = 0 or 1 and at least two m = 1, n = 0-10, the repeated R7 is the same or different, the repeated m is the same or different, and the repeated n is the same or different.

[0055] In a still further preferred embodiment, the double bond-containing group is selected from an alkenyl group or an alkenyloxy group, preferably a C2-C10 alkenyl group or a C2-C10 alkenyloxy group; and / or, the alkyl group is selected from a C1-C20 alkyl group, preferably a C1-C10 alkyl group; and / or, the aryl group is selected from a C6-C20 aryl group, preferably a C6-C15 aryl group.

[0056] For example, the alkenyl group is a C2-C5 alkenyl group, the alkenyloxy group is a C2-C5 alkenyloxy group, the alkyl group is a C1-C5 alkyl group, and the aryl group is a C6-C10 aryl group such as a phenyl group.

[0057] In a most preferred embodiment, the crosslinking agent is selected from at least one of the compounds represented by the following formulae:

[0058]

[0059]

[0060] In a preferred embodiment, the anionic monomer is selected from at least one of a carboxylic acid-based polymerizable monomer and / or an alkali metal salt thereof, a sulfonic acid-based polymerizable monomer and / or an alkali metal salt thereof.

[0061] In a further preferred embodiment, the anionic monomer is selected from at least one of acrylic acid, methacrylic acid, p-vinylbenzenesulfonic acid, maleic acid, fumaric acid, vinylbenzenesulfonic acid, allylsulfonic acid, allylbenzenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, and an alkali metal salt thereof.

[0062] In a preferred embodiment, the cationic monomer is selected from at least one of an ammonium chloride polymerizable monomer, an ammonium bromide polymerizable monomer, and an ammonium iodide polymerizable monomer.

[0063] In a further preferred embodiment, the cationic monomer is selected from at least one of methacryloyloxyethyltrimethylammonium chloride, 2-acrylamido-2-methylpropyltrimethylammonium chloride, dimethylethylallyl ammonium chloride, dimethyldiallyl ammonium chloride, acryloyloxyethyltrimethylammonium chloride, acryloyloxyethyldimethylbenzylammonium chloride, and methacryloyloxyethyldimethylbenzylammonium chloride.

[0064] In a preferred embodiment, the nonionic monomer is selected from at least one of a substituted acrylamide-based polymerizable monomer, a substituted hydroxyalkyl acrylate-based polymerizable monomer, a pyrrolidone-based polymerizable monomer, and a substituted amino acrylate-based polymerizable monomer, wherein the alkyl group is a C1-C20 alkyl group, preferably a C1-C10 alkyl group.

[0065] In a further preferred embodiment, the nonionic monomer is selected from at least one of methacrylamide, dimethylacrylamide, diethylacrylamide, hydroxymethylacrylamide, hydroxyethylacrylamide, dimethylamino propyl methacrylamide, hydroxymethyl methacrylate, hydroxyethyl methacrylate, dimethylaminoethyl methacrylate, vinyl pyrrolidone, and t-butyl acrylamide.

[0066] In a preferred embodiment, the co-solvent is selected from at least one of an alcohol solvent, a polyether.

[0067] In a further preferred embodiment, the co-solvent is selected from at least one of a C4 to C8 alcohol solvent, a polyether containing alkyl segments.

[0068] In a still further preferred embodiment, the co-solvent is selected from at least one of butanol, pentanol, an alkyl alcohol polyoxyethylene ether (e.g. carbon number 5 to 20, in particular isomeric tridecanols, ethoxy number 3 to 12), an alkyl polyoxyethylene ether (e.g. carbon number 5 to 15, in particular 10, ethoxy number 3 to 12), an alkyl phenol polyoxyethylene ether (e.g. carbon number 5 to 15, in particular 10, ethoxy number 3 to 12).

[0069] In a preferred embodiment, in the raw material, by parts by weight:

[0070] acrylamide monomer 2 to 30 parts;

[0071] anionic monomer 0 to 30 parts;

[0072] cationic monomer 0 to 30 parts;

[0073] non-ionic monomer 0 to 20 parts;

[0074] cross-linking agent 0.001 to 1 part;

[0075] co-solvent 0.005 to 1 part.

[0076] In a further preferred embodiment, in the raw material, by parts by weight:

[0077] acrylamide monomer 5 to 25 parts, for example 5, 8, 10, 12, 15, 18, 20, 22 or 25 parts;

[0078] anionic monomer 1 to 25 parts, for example 1, 5, 10, 15, 20 or 25 parts;

[0079] cationic monomer 0 to 25 parts, for example 0, 5, 10, 15, 20 or 25 parts;

[0080] non-ionic monomer 0 to 10 parts, for example 0, 2, 4, 6, 8 or 10 parts;

[0081] cross-linking agent 0.001 to 0.5 parts, for example 0.001, 0.01, 0.05, 0.1, 0.3 or 0.5 parts;

[0082] co-solvent 0.01 to 0.5 parts, for example 0.01, 0.05, 0.1, 0.2, 0.3, 0.4 or 0.5 parts.

[0083] In a further preferred embodiment, in the raw material, by weight parts:

[0084] acrylamide monomer 15-25 parts;

[0085] anionic monomer 5-20 parts;

[0086] cationic monomer 0-7.5 parts;

[0087] nonionic monomer 0-7.5 parts;

[0088] crosslinking agent 0.01-0.25 parts;

[0089] co-solvent 0.05-0.5 parts.

[0090] In a preferred embodiment, the reaction raw material further comprises an initiation system, water, a chelating agent, an oil solvent, an emulsifier.

[0091] In a further preferred embodiment, by weight parts:

[0092] initiation system 0.001-0.06 parts, preferably 0.005-0.025 parts;

[0093] water 10-100 parts, preferably 25-50 parts;

[0094] chelating agent 0.001-1 parts, preferably 0.005-0.1 parts;

[0095] oil solvent 40-100 parts, preferably 50-75 parts;

[0096] emulsifier 2-10 parts, preferably 2.5-8 parts.

[0097] For example, by weight parts: initiation system 0.001 parts, 0.005 parts, 0.01 parts, 0.02 parts, 0.04 parts or 0.06 parts, water 10 parts, 20 parts, 40 parts, 60 parts, 80 parts or 100 parts, chelating agent 0.001 parts, 0.005 parts, 0.01 parts, 0.05 parts, 0.1 parts, 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts or 1 parts, oil solvent 40 parts, 60 parts, 80 parts or 100 parts, emulsifier 2 parts, 4 parts, 6 parts, 8 parts or 10 parts.

[0098] In a preferred embodiment, the initiation system comprises an oxidizing agent, a reducing agent, an azo initiator.

[0099] In a further preferred embodiment, the oxidizing agent is selected from at least one of the group consisting of persulfate (e.g. potassium persulfate, sodium persulfate), hydrogen peroxide, benzoyl peroxide, potassium bromate, tert-butyl hydroperoxide, lauryl peroxide, cumene hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, tert-butyl benzene peroxide, tert-butyl peroxypivalate, methyl ethyl ketone peroxide, cyclohexanone peroxide, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate; and / or, the reducing agent is selected from at least one of the group consisting of sodium bisulfite, sodium thiosulfate, sodium hyposulfite, sodium metabisulfite, tetramethylethylenediamine, ferrous ammonium sulfate, sodium formaldehyde sulfoxylate, N,N-dimethylaniline, tartaric acid, ferrous sulfate, N,N-diethylaniline, ferrous pyrophosphate, silver nitrate, mercaptans, ferrous chloride, tetraethylenepentamine, glycerol, pentaerythritol; and / or, the azo initiator is selected from at least one of the group consisting of azobis isobutyronitrile, azobis isopentyl nitrile, azobis isohexyl nitrile, dimethyl azobis isobutyrate, azobis isobutyl amide hydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, azobis(2,5-dimethyl-6-carboxy)hexyl nitrile, 4,4'-azobis(4-cyanopentanoic acid).

[0100] In a further preferred embodiment, by weight parts:

[0101] oxidizing agent 0.0001-0.005 parts; preferably 0.0002-0.003 parts;

[0102] reducing agent 0.0001-0.005 parts; preferably 0.0002-0.003 parts;

[0103] azo initiator 0.001-0.05 parts; preferably 0.005-0.02 parts.

[0104] In a preferred embodiment, the chelating agent is selected from at least one of the group consisting of disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, penta-sodium diethylenetriaminepentaacetate.

[0105] In a preferred embodiment, the oil solvent is selected from at least one of the group consisting of aliphatic hydrocarbon, aromatic hydrocarbon, mineral oil.

[0106] In a further preferred embodiment, the aliphatic hydrocarbon is selected from at least one of the group consisting of cyclohexane, hexane, heptane, octane, and / or, the aromatic hydrocarbon is selected from at least one of the group consisting of benzene, toluene, ethylbenzene, xylene, and / or, the mineral oil is selected from at least one of the group consisting of liquid paraffin, white oil, gasoline, diesel, kerosene.

[0107] In a preferred embodiment, the emulsifier is selected from at least one of fatty alcohol polyoxypropylene polyoxyethylene ether (Formula 11), aromatic alcohol polyoxypropylene polyoxyethylene ether (Formula 12), fatty acid polyoxypropylene polyoxyethylene ester (Formula 13), fatty amine polyoxypropylene polyoxyethylene ether (Formula 14), sorbitan oleate, sorbitan stearate, sorbitan palmitate, sorbitan laurate:

[0108]

[0109]

[0110] wherein R1', R2' and R3' are each independently selected from C1-C20 hydrocarbon groups; R4' and R5' are each independently selected from a hydrogen atom or a C1-C20 hydrocarbon group, and R4' and R5' cannot be hydrogen atoms at the same time; m is 0-20; and n is 2-30.

[0111] In a preferred embodiment, the preparation method comprises:

[0112] 1) dissolving acrylamide, optional anionic monomer, optional nonionic monomer, crosslinking agent, optional cationic monomer, chelating agent, and cosolvent in water to obtain a reaction solution, and dissolving emulsifier in oil solvent to obtain an oil phase solution;

[0113] 2) adding the reaction solution into the oil phase solution, and stirring to react;

[0114] 3) continuously stirring under protective gas, adding an aqueous solution containing azo initiator, then adding an aqueous solution containing oxidant, and finally, slowly adding an aqueous solution containing reducing agent until the reaction system is warmed up.

[0115] In a preferred embodiment, in step 1), the pH value of the reaction solution is adjusted to 5-10, for example, 5, 6, 7, 8, 9 or 10.

[0116] In a preferred embodiment, in step 3), the protective gas is selected from at least one of nitrogen and inert gas.

[0117] In a further preferred embodiment, in step 3), the concentration of the aqueous solution containing azo initiator, the aqueous solution containing oxidant, and the aqueous solution containing reducing agent is independently 0.1-10 wt%, preferably 0.2-5 wt%, for example, 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 4 wt%, 6 wt%, 8 wt% or 10 wt%.

[0118] In a preferred embodiment, in step 3), after bubbling the protective gas for 10-50 min under stirring, the water solution containing azo initiator is added, the water solution containing oxidant is added after 0.5-15 min, the water solution containing reducing agent is slowly added after 0.5-15 min, and the reaction is ended after the reaction system is warmed up.

[0119] In a further preferred embodiment, the warming speed is controlled to be no higher than 2.5℃ / min by adjusting the adding speed of the water solution containing reducing agent.

[0120] A third object of the present application is to provide the use of the polymer microspheres of the first object of the present application or the polymer microspheres obtained by the preparation method of the second object of the present application in enhanced oil recovery, especially for plugging agents or profile control agents.

[0121] The endpoints of the ranges and any numerical values disclosed herein are not limited to the precise values recited as exact measurements between the endpoints are not to be expected. The ranges and values are approximations that are already adequately described above. Any numerical value, however, can be expressed as approximately the value, and it is intended that the approximation be encompassed by the value. In the following text, the technical solutions of various aspects can be combined with each other to obtain new technical solutions in principle, which should also be considered as being specifically disclosed herein.

[0122] Compared with the prior art, the present application has the following beneficial effects: the polymer microspheres obtained by the technical solutions of the present application have a plugging capacity of more than 90% to the core after being aged at 110℃ for 6 months in 30000mg / L salinity brine (calcium and magnesium ion content of 1500ppm each), and a plugging capacity of more than 85% to the core after being aged at 120℃ for 6 months. Compared with ordinary polymer microspheres, the polymer microspheres have outstanding long-term high-temperature resistance. DETAILED DESCRIPTION

[0123] The following specific embodiments are used to further illustrate the present application, and it is necessary to point out that the following embodiments are only used to further illustrate the present application, and cannot be understood as limiting the protection scope of the present application. Some non-essential improvements and adjustments to the present application made by those skilled in the art based on the content of the present application are still within the protection scope of the present application.

[0124] In addition, it should be noted that the various specific technical features described in the following specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present application will not further describe various possible combinations.

[0125] Moreover, the various embodiments of the present application can be combined in any manner, as long as the idea of the present application is not violated, and the technical solutions thus formed are part of the original disclosure of the present specification and fall within the protection scope of the present application.

[0126] The raw materials used in the examples and comparative examples, if not specifically limited, are disclosed in the prior art, for example, can be directly purchased or prepared according to the preparation method disclosed in the prior art.

[0127] Example 1

[0128] Dissolve 5.5 parts of emulsifier sorbitan monooleate (Span 80) and 0.5 parts of fatty alcohol polyoxyethylene ether (model AEO7) in 60 parts of 5# white oil to form a uniform oil phase solution, and add to a reaction kettle. Dissolve 25 parts of acrylamide, 5 parts of acrylic acid, 0.08 parts of cosolvent isotridecyl alcohol polyoxyethylene ether (EO5) (model TO-5), and 0.0075 parts of chelating agent disodium ethylenediaminetetraacetate in 30 parts of deionized water, and stir to form a solution. Add 0.175 parts of crosslinking agent represented by formula (a) (1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione) to the solution and stir to dissolve to form a reaction solution. Adjust the pH of the reaction solution to 7.0 with a 32 wt% sodium hydroxide solution, and then add to the reaction kettle. Stir at a speed of 700 rpm for 1 hour. After continuously stirring, pass nitrogen gas for 30 min. Add 1 wt% concentration of an aqueous solution of an azo initiator (containing 0.0075 parts of azobisdimethylaminoformamidine hydrochloride), and after 5 min, add 1 wt% concentration of an aqueous solution of an oxidizing agent (containing 0.0006 parts of potassium persulfate). After 5 min, slowly drop 1 wt% concentration of an aqueous solution of a reducing agent (containing 0.00075 parts of sodium thiosulfate) until the reaction system is warmed up. The product is obtained.

[0129] Example 2

[0130] The emulsifier sorbitan laurate 6.3 parts, fatty alcohol polyoxyethylene ether (type AEO7) 0.7 parts were dissolved in 55 parts of 10# white oil to form a uniform oil phase solution, and were added to the reaction kettle. 23 parts of acrylamide, 2-acrylamido-2-methylpropane sulfonic acid 7.5 parts, 0.05 parts of cosolvent butanol, 0.02 parts of chelating agent ethylenediaminetetraacetic acid tetrasodium were added to 35 parts of deionized water, stirred uniformly to form a solution, and 0.25 parts of crosslinking agent (1,3,5-triacryloylhexahydro-1,3,5-triazine) shown in formula (c) was added to the solution and stirred to dissolve to obtain a reaction solution. After adjusting the pH value of the reaction solution to 7.0 with 32 wt% sodium hydroxide solution, it was added to the reaction kettle and stirred at 700 rpm for 1 hour. After continuously stirring for 30 min, 1 wt% concentration of azo initiator aqueous solution (containing 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, i.e. azobis imidazolyl propane dihydrochloride 0.012 parts) was added, 5 min later, 1 wt% concentration of oxidizing agent aqueous solution (containing sodium persulfate 0.00075 parts) was added, 5 min later, 1 wt% concentration of reducing agent aqueous solution (containing sodium bisulfite 0.0009 parts) was slowly added until the reaction system was warmed up. The product was obtained.

[0131]

Example 3

[0132] The emulsifier sorbitan laurate 6.3 parts, fatty alcohol polyoxyethylene ether (type AEO7) 0.7 parts were dissolved in 55 parts of 10# white oil to form a uniform oil phase solution, and were added to the reaction kettle. 23 parts of acrylamide, 2-acrylamido-2-methylpropane sulfonic acid 7.5 parts, 0.05 parts of cosolvent butanol, 0.02 parts of chelating agent ethylenediaminetetraacetic acid tetrasodium were added to 35 parts of deionized water, stirred uniformly to form a solution, and 0.25 parts of crosslinking agent (1,3,5-triacryloylhexahydro-1,3,5-triazine) shown in formula (c) was added to the solution and stirred to dissolve to obtain a reaction solution. After adjusting the pH value of the reaction solution to 7.0 with 32 wt% sodium hydroxide solution, it was added to the reaction kettle and stirred at 700 rpm for 1 hour. After continuously stirring for 30 min, 1 wt% concentration of azo initiator aqueous solution (containing 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, i.e. azobis imidazolyl propane dihydrochloride 0.012 parts) was added, 5 min later, 1 wt% concentration of oxidizing agent aqueous solution (containing sodium persulfate 0.00075 parts) was added, 5 min later, 1 wt% concentration of reducing agent aqueous solution (containing sodium bisulfite 0.0009 parts) was slowly added until the reaction system was warmed up. The product was obtained.

[0133]

Example 4

[0134] The emulsifier sorbitan monooleate 6.5 parts, fatty amine polyoxyethylene ether (dodecylamine polyoxyethylene (08) ether, Solvay Fentacare 1208, CAS: 1541-67-9) 0.7 parts are dissolved in 60 parts of 5# white oil to form a uniform oil phase solution, and then added to the reaction kettle. 22 parts of acrylamide, 5 parts of vinyl pyrrolidone, 0.075 parts of cosolvent amyl alcohol, 0.03 parts of chelating agent diethylenetriamine pentaacetic acid penta sodium are added to 40 parts of deionized water, stirred uniformly to form a solution, 0.1 parts of crosslinking agent (pentaerythritol tetraallyl ether) represented by formula (i) is added and stirred to dissolve to obtain a reaction solution, and then the reaction solution is adjusted to a pH value of 7.0 with a 32 wt% sodium hydroxide solution and then added to the reaction kettle. Stir at 700 rpm for 1 hour. After continuously stirring for 30 min, 1 wt% concentration of azo initiator aqueous solution (containing azo bis(2,5-dimethyl-6-carboxyl) hexane cyanide 0.01 parts) is added, 5 min later, 1 wt% concentration of oxidizing agent aqueous solution (containing tert-butyl hydroperoxide 0.0025 parts) is added, 5 min later, 1 wt% concentration of reducing agent aqueous solution (containing ferrous ammonium sulfate 0.003 parts) is slowly added, until the reaction system is warmed up. The product is obtained.

[0135]

Example 5

[0136] The emulsifier sorbitan monooleate (Span 80) 5.5 parts, fatty alcohol polyoxyethylene ether (model AEO7) 0.5 parts are dissolved in 60 parts of 5# white oil to form a uniform oil phase solution, and then added to the reaction kettle. 15 parts of acrylamide, 20 parts of acrylic acid, 0.08 parts of cosolvent isomeric tridecanol polyoxyethylene ether (EO5) (model TO-5), 0.0075 parts of chelating agent ethylenediaminetetraacetic acid disodium are added to 30 parts of deionized water, stirred uniformly to form a solution, 0.175 parts of crosslinking agent (1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione) represented by formula (a) is added and stirred to dissolve to obtain a reaction solution, and then the reaction solution is adjusted to a pH value of 7.0 with a 32 wt% sodium hydroxide solution and then added to the reaction kettle. Stir at 700 rpm for 1 hour. After continuously stirring for 30 min, 1 wt% concentration of azo initiator aqueous solution (containing azo diisobutyl amidine hydrochloride 0.0075 parts) is added, 5 min later, 1 wt% concentration of oxidizing agent aqueous solution (containing potassium persulfate 0.0006 parts) is added, 5 min later, 1 wt% concentration of reducing agent aqueous solution (containing sodium thiosulfate 0.00075 parts) is slowly added, until the reaction system is warmed up. The product is obtained.

[0137]

Example 6

[0138] The emulsifier sorbitan laurate 6.3 parts, fatty alcohol polyoxyethylene ether (type AEO7) 0.7 parts were dissolved in 55 parts of 10# white oil to form a uniform oil phase solution, and were added to the reaction kettle. 18 parts of acrylamide, 2-acrylamido-2-methylpropane sulfonic acid 17.5 parts, 0.05 parts of cosolvent butanol, 0.02 parts of chelating agent ethylenediaminetetraacetic acid tetrasodium were added to 35 parts of deionized water, stirred uniformly to form a solution, and 0.25 parts of crosslinking agent (1,3,5-triacryloylhexahydro-1,3,5-triazine) shown in formula (c) was added to the solution and stirred to dissolve to obtain a reaction solution. After adjusting the pH value of the reaction solution to 7.0 with 32 wt% sodium hydroxide solution, it was added to the reaction kettle and stirred at 700 rpm for 1 hour. After continuously stirring for 30 min, 1 wt% concentration of azo initiator aqueous solution (containing 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, i.e. azobis imidazolyl propane dihydrochloride 0.012 parts) was added, 5 min later, 1 wt% concentration of oxidizing agent aqueous solution (containing sodium persulfate 0.00075 parts) was added, 5 min later, 1 wt% concentration of reducing agent aqueous solution (containing sodium bisulfite 0.0009 parts) was slowly added until the reaction system was warmed up. The product was obtained.

[0139]

Example 7

[0140] The emulsifier sorbitan laurate 6.3 parts, fatty alcohol polyoxyethylene ether (type AEO7) 0.7 parts were dissolved in 55 parts of 10# white oil to form a uniform oil phase solution, and were added to the reaction kettle. 18 parts of acrylamide, 2-acrylamido-2-methylpropane sulfonic acid 17.5 parts, 0.05 parts of cosolvent butanol, 0.02 parts of chelating agent ethylenediaminetetraacetic acid tetrasodium were added to 35 parts of deionized water, stirred uniformly to form a solution, and 0.25 parts of crosslinking agent (1,3,5-triacryloylhexahydro-1,3,5-triazine) shown in formula (c) was added to the solution and stirred to dissolve to obtain a reaction solution. After adjusting the pH value of the reaction solution to 7.0 with 32 wt% sodium hydroxide solution, it was added to the reaction kettle and stirred at 700 rpm for 1 hour. After continuously stirring for 30 min, 1 wt% concentration of azo initiator aqueous solution (containing 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, i.e. azobis imidazolyl propane dihydrochloride 0.012 parts) was added, 5 min later, 1 wt% concentration of oxidizing agent aqueous solution (containing sodium persulfate 0.00075 parts) was added, 5 min later, 1 wt% concentration of reducing agent aqueous solution (containing sodium bisulfite 0.0009 parts) was slowly added until the reaction system was warmed up. The product was obtained.

[0141]

Example 8

[0142] The emulsifier sorbitan monoleate 6.5 parts, fatty amine polyoxyethylene ether (dodecylamine polyoxyethylene (08) ether, Solvay Fentacare 1208, CAS: 1541-67-9) 0.7 parts are dissolved in 60 parts of 5# white oil to form a uniform oil phase solution, and then added to the reaction kettle. 22 parts of acrylamide, 7.5 parts of vinyl pyrrolidone, 0.075 parts of cosolvent amyl alcohol, 0.03 parts of chelating agent diethylenetriamine pentaacetic acid pentasodium are added to 40 parts of deionized water, stirred uniformly to form a solution, and then 0.1 parts of the crosslinking agent shown in formula (i) (pentaerythritol tetraallyl ether) is added and stirred to dissolve to obtain a reaction solution. After adjusting the pH value of the reaction solution to 7.0 with 32wt% sodium hydroxide solution, it is added to the reaction kettle and stirred at 700 rpm for 1 hour. After continuously stirring for 30 minutes, 1wt% concentration of azo initiator aqueous solution (containing azo bis(2,5-dimethyl-6-carboxyl) hexane cyanide 0.01 parts) is added, 5 minutes later, 1wt% concentration of oxidizing agent aqueous solution (containing tert-butyl hydroperoxide 0.0025 parts) is added, 5 minutes later, 1wt% concentration of reducing agent aqueous solution (containing ferrous ammonium sulfate 0.003 parts) is slowly added, until the reaction system is warmed up. The product is obtained.

[0143]

Example 9

[0144] The emulsifier sorbitan monoleate 5.8 parts, fatty acid polyoxyethylene ester (as shown in formula 13, carbon number 12, ethylene n is 9, m is 0, lauryl polyoxyethylene ester, type LAE-9, Xingtaixianglansheng Technology Co., Ltd. in Xingtai City, Hebei Province) 1.2 parts are dissolved in 65 parts of 110# solvent oil to form a uniform oil phase solution, and then added to the reaction kettle. 25 parts of acrylamide, dimethyl diallyl ammonium chloride 0.5 parts, 0.25 parts of cosolvent alkyl polyoxyethylene ether (C13-EO5, code TO5, Yangba Petrochemical Co., Ltd.), 0.05 parts of chelating agent ethylenediaminetetraacetic acid tetrasodium are added to 30 parts of deionized water, stirred uniformly to form a solution, and then 0.15 parts of the crosslinking agent shown in formula (f) (tetraallylsilane) is added and stirred to dissolve to obtain a reaction solution. After adjusting the pH value of the reaction solution to 7.0 with 32wt% sodium hydroxide solution, it is added to the reaction kettle and stirred at 700 rpm for 1 hour. After continuously stirring for 30 minutes, 1wt% concentration of azo initiator aqueous solution (containing 4,4'-azo bis(4-cyanopentanoic acid) 0.015 parts) is added, 5 minutes later, 1wt% concentration of oxidizing agent aqueous solution (containing potassium bromate 0.002 parts) is added, 5 minutes later, 1wt% concentration of reducing agent aqueous solution (containing sodium pyrosulfite 0.0025 parts) is slowly added, until the reaction system is warmed up. The product is obtained.

[0145]

Example 10

[0146] The emulsifier sorbitan monoleate 6.5 parts, fatty amine polyoxyethylene ether (dodecylamine polyoxyethylene (08) ether, Solvay Fentacare 1208, CAS: 1541-67-9) 0.7 parts are dissolved in 60 parts of 5# white oil to form a uniform oil phase solution, and then added to the reaction kettle. 22 parts of acrylamide, 0.5 parts of vinyl pyrrolidone, 0.075 parts of cosolvent amyl alcohol, 0.03 parts of chelating agent diethylenetriamine pentaacetic acid pentasodium are added to 40 parts of deionized water, stirred uniformly to form a solution, and then 0.1 parts of the crosslinking agent shown in formula (i) (pentaerythritol tetraallyl ether) is added and stirred to dissolve to obtain a reaction solution. After adjusting the pH value of the reaction solution to 7.0 with 32wt% sodium hydroxide solution, it is added to the reaction kettle and stirred at 700 rpm for 1 hour. After continuously stirring for 30 minutes, 1wt% concentration of azo initiator aqueous solution (containing azobis (2, 5-dimethyl-6-carboxyl) hexane cyanide 0.01 parts) is added, 5 minutes later, 1wt% concentration of oxidizing agent aqueous solution (containing tert-butyl hydroperoxide 0.0025 parts) is added, 5 minutes later, 1wt% concentration of reducing agent aqueous solution (containing ferrous ammonium sulfate 0.003 parts) is slowly added, until the reaction system is warmed up. The product is obtained.

[0147]

Comparative Example 1

[0148] The emulsifier sorbitan monoleate 5.5 parts, fatty alcohol polyoxyethylene ether (model AEO7) 0.5 parts are dissolved in 60 parts of 5# white oil to form a uniform oil phase solution, and then added to the reaction kettle. 25 parts of acrylamide, 5 parts of acrylic acid, 0.08 parts of cosolvent isomeric tridecanol polyoxyethylene ether (EO5) (model TO5), 0.0075 parts of chelating agent ethylenediaminetetraacetic acid disodium are added to 30 parts of deionized water, stirred uniformly to form a solution, and then 0.175 parts of crosslinking agent methylene bisacrylamide is added and stirred to dissolve to obtain a reaction solution. After adjusting the pH value of the reaction solution to 7.0 with 32wt% sodium hydroxide solution, it is added to the reaction kettle and stirred at 700 rpm for 1 hour. After continuously stirring for 30 minutes, 1wt% concentration of azo initiator aqueous solution (containing azobis (2, 5-dimethyl-6-carboxyl) hexane cyanide 0.0075 parts) is added, 5 minutes later, 1wt% concentration of oxidizing agent aqueous solution (containing potassium persulfate 0.0006 parts) is added, 5 minutes later, 1wt% concentration of reducing agent aqueous solution (containing sodium thiosulfate 0.00075 parts) is slowly added, until the reaction system is warmed up. The product is obtained.

[0149]

Comparative Example 2

[0150] The emulsifier sorbitan laurate 6.3 parts, fatty alcohol polyoxyethylene ether (type AEO7) 0.7 parts were dissolved in 55 parts of 10# white oil to form a uniform oil phase solution, and were added into the reaction kettle. 23 parts of acrylamide, 2-acrylamido-2-methylpropane sulfonic acid 7.5 parts, 0.05 parts of cosolvent butanol, 0.02 parts of chelating agent ethylenediaminetetraacetic acid tetrasodium were added into 35 parts of deionized water, stirred uniformly to form a solution, 0.25 parts of crosslinking agent ethylene glycol bisacrylate (purchased from Aldrich) was added and stirred to dissolve to obtain a reaction solution, the reaction solution was adjusted to pH 7.0 with 32 wt% sodium hydroxide solution, and then added into the reaction kettle, and stirred at 700 rpm for 1 hour. After continuously stirring, nitrogen was introduced for 30 min, then 1 wt% concentration of azo initiator aqueous solution (containing 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride 0.012 parts) was added, 5 min later, 1 wt% concentration of oxidizing agent aqueous solution (containing sodium persulfate 0.00075 parts) was added, 5 min later, 1 wt% concentration of reducing agent aqueous solution (containing sodium bisulfite 0.0009 parts) was slowly added until the reaction system was warmed up. The product was obtained.

[0151]

Comparative Example 3

[0152] The emulsifier sorbitan monooleate 5.8 parts, fatty acid polyoxyethylene ester (as shown in formula 13, carbon number 12, ethylene oxide n is 9, m is 0, lauryl polyoxyethylene ester, type LAE-9, Xingtaixianglansheng Technology, Xingtai City, Hebei Province) 1.2 parts were dissolved in 65 parts of 110# solvent oil to form a uniform oil phase solution, and were added into the reaction kettle. 25 parts of acrylamide, dimethyldiallylammonium chloride 4.5 parts, 0.25 parts of cosolvent alkyl polyoxyethylene ether (C13-EO5, code TO5, Yangba Petrochemical Co., Ltd.), 0.05 parts of chelating agent ethylenediaminetetraacetic acid tetrasodium were added into 30 parts of deionized water, stirred uniformly to form a solution, 0.15 parts of crosslinking agent diethylene glycol bisacrylate was added and stirred to dissolve to obtain a reaction solution, the reaction solution was adjusted to pH 7.0 with 32 wt% sodium hydroxide solution, and then added into the reaction kettle, and stirred at 700 rpm for 1 hour. After continuously stirring, nitrogen was introduced for 30 min, then 1 wt% concentration of azo initiator aqueous solution (4,4'-azobis(4-cyanopentanoic acid) 0.015 parts) was added, 5 min later, 1 wt% concentration of oxidizing agent aqueous solution (containing potassium bromate 0.002 parts) was added, 5 min later, 1 wt% concentration of reducing agent aqueous solution (containing sodium metabisulfite 0.0025 parts) was slowly added until the reaction system was warmed up. The product was obtained.

[0153]

Comparative Example 4

[0154] The emulsifier sorbitan monooleate 6.5 parts, fatty amine polyoxyethylene ether (dodecylamine polyoxyethylene (08) ether, Solvay Fentacare 1208, CAS: 1541-67-9) 0.7 parts are dissolved in 60 parts of 5# white oil to form a uniform oil phase solution, which is added to the reaction kettle. 22 parts of acrylamide, 5 parts of vinyl pyrrolidone, 0.075 parts of cosolvent pentanol, 0.03 parts of chelating agent diethylene triamine pentaacetic acid penta sodium are added to 40 parts of deionized water, stirred uniformly to form a solution, 0.25 parts of crosslinking agent methylene bisacrylamide is added and stirred to dissolve to obtain a reaction solution, the reaction solution is adjusted to a solution pH value of 7.0 with 32 wt% sodium hydroxide solution, and then added to the reaction kettle, stirred at a speed of 700 rpm for 1 hour. After continuously stirring, nitrogen is introduced for 30 min, then 1 wt% concentration of azo initiator aqueous solution (containing azo bis(2,5-dimethyl-6-carboxyl) hexane cyanide 0.01 parts) is added, 5 min later, 1 wt% concentration of oxidizing agent aqueous solution (containing tert-butyl hydroperoxide 0.0025 parts) is added, 5 min later, 1 wt% concentration of reducing agent aqueous solution (containing ferrous ammonium sulfate 0.003 parts) is slowly added, until the reaction system is warmed up. The product is obtained.

[0155]

Evaluation experiment

[0156] The total salinity of the salt water used for evaluation is 30000 mg / L, and the calcium and magnesium ion content is 1500 ppm each, and the rest is sodium ion and chloride ion. The sample obtained in the example or comparative example is added to the salt water under stirring to prepare a solution of polymer microspheres with a weight concentration of 0.5%, and is aged at 110°C and 120°C for 6 months respectively. The plugging performance is tested in a man-made core with a permeability of 500 mD (length 10 cm, diameter 2.5 cm, injection speed 0.5 mL / min), and the plugging rate is calculated as follows:

[0157] Plugging rate = (1-P1 / P2)*100%

[0158] P1 is the equilibrium pressure when water is injected, and P2 is the pressure when 10 PV of microsphere solution is injected.

[0159] The evaluation results are shown in Table 1.

[0160] Table 1: Plugging rate of samples of examples and comparative examples after aging at different temperatures

[0161]

[0162]

[0163] It can be obviously seen that the polymer microspheres obtained by the present application still have a high plugging rate for artificial cores after aging at a high temperature for a long time, while the microspheres obtained by the comparative example can hardly plug the cores, and the plugging rate is not more than 25%. It can be proved that the polymer microspheres of the present application have excellent thermal stability, and play an important role in effectively plugging formation pores of the microspheres in long-term service in high-temperature reservoirs.

[0164] It is worth noting that the inventors found in the experiment that the crosslinking agent used in the present application has poor water solubility, and in the absence of a cosolvent, the crosslinking agent cannot be dissolved in the system, and a uniform solution cannot be obtained for the synthesis reaction, so the synthesis and evaluation of the comparative sample cannot be carried out without adding a cosolvent and only using the crosslinking agent.

[0165] The present application is described in detail above in combination with the specific embodiments and exemplary examples, but these descriptions cannot be understood as limitations of the present application. Those skilled in the art understand that various equivalent replacements, modifications or improvements can be made to the technical solutions and embodiments of the present application without departing from the spirit and scope of the present application, and these all fall within the scope of the present application. The protection scope of the present application is subject to the appended claims.

Claims

1. A polymer microsphere comprising acrylamide structural units and crosslinking structural units, the crosslinking structural units containing at least one of a triazine ring structure, a silane structure, a siloxane structure, an alcohol ether structure.

2. The polymeric microspheres of claim 1, wherein, The crosslinking structural units are derived from at least one of a triazine ring compound containing two or more double bond structures, a silane containing two or more double bond structures, a siloxane containing two or more double bond structures, a polyol polyallyl ether; Preferably, the crosslinking structural units are derived from at least one of the following compounds: wherein: in formula (1), R1 is selected from a double bond-containing group, R2 is selected from a methylene group or a carbonyl group, and the repeated R1 or R2 are the same or different; in formula (2), R4 is selected from a double bond-containing group, and the repeated R4 are the same or different; in formula (3), at least two R5 are selected from a double bond-containing group, and the rest of R5 are selected from an alkyl group, an aryl group or hydrogen, and the repeated R5 are the same or different; in formula (4), at least two R are selected from a double bond-containing group, and the rest of R are selected from an alkyl group, an aryl group or hydrogen, and the repeated R are the same or different; in formula (5), R6 is selected from a double bond-containing group, p = 0 or 1 and at least two p = 1, and the repeated R6 are the same or different, and the repeated p are the same or different; in formula (6), R7 is selected from a double bond-containing group, m = 0 or 1 and at least two m = 1, n = 0-10, and the repeated R7 are the same or different, and the repeated m are the same or different, and the repeated n are the same or different; More preferably, the double bond-containing group is selected from an alkenyl group or an alkenyloxy group, preferably a C2-C10 alkenyl group or a C2-C10 alkenyloxy group; and / or, the alkyl group is selected from a C1-C20 alkyl group, preferably a C1-C10 alkyl group; and / or, the aryl group is selected from a C6-C20 aryl group, preferably a C6-C15 aryl group.

3. The polymeric microspheres of claim 1, wherein, The polymer microsphere further comprises optional anionic structural units, optional cationic structural units, optional nonionic structural units.

4. The polymer microsphere according to claim 3, wherein: the anionic structural units are selected from at least one of carboxylic acid structural units and / or alkali metal salts thereof, sulfonic acid structural units and / or alkali metal salts thereof; and / or, the cationic structural units are selected from at least one of ammonium chloride structural units, ammonium bromide structural units, ammonium iodide structural units; and / or, the nonionic structural units are selected from at least one of substituted acrylamide structural units, substituted hydroxyalkyl acrylate structural units, pyrrolidone structural units, substituted amino acrylate structural units.

5. The polymer microsphere according to claim 4, wherein: the anionic structural units are derived from at least one of the following anionic monomers: acrylic acid, methacrylic acid, p-vinylbenzenesulfonic acid, maleic acid, fumaric acid, vinylbenzenesulfonic acid, allylsulfonic acid, allylbenzenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, and alkali metal salts thereof; and / or, The cationic structural unit is derived from at least one of the following cationic monomers: methacryloyloxyethyl trimethyl ammonium chloride, 2-acrylamido-2-methylpropyl trimethyl ammonium chloride, dimethyl ethyl allyl ammonium chloride, dimethyl diallyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl dimethyl benzyl ammonium chloride, methacryloyloxyethyl dimethyl benzyl ammonium chloride; and / or, The non-ionic structural unit is derived from at least one of the following non-ionic monomers: methacrylamide, dimethyl acrylamide, diethyl acrylamide, hydroxymethyl acrylamide, hydroxyethyl acrylamide, dimethylamino propyl methacrylamide, hydroxymethyl methacrylate, hydroxyethyl methacrylate, dimethylamino ethyl methacrylate, vinyl pyrrolidone, t-butyl acrylamide.

6. The polymeric microspheres according to one of claims 1 to 5, characterized in that The polymer microspheres further contain a co-solvent; preferably, the co-solvent is selected from at least one of alcohol solvents, polyethers; more preferably, the co-solvent is selected from at least one of C4-C8 alcohol solvents, polyethers containing alkyl segments.

7. The polymeric microspheres of claim 6, wherein, In the polymer microspheres, by weight parts: acrylamide structural units 2-30 parts; anionic structural units 0-30 parts; cationic structural units 0-30 parts; non-ionic structural units 0-20 parts; cross-linking structural units 0.001-1 parts; co-solvent 0.005-1 parts; Cross-linking structural units 0.001-1 parts; co-solvent 0.005-1 parts; Preferably, in the polymer microspheres, by weight parts: acrylamide structural units 5-25 parts; anionic structural units 1-25 parts; cationic structural units 0-25 parts; non-ionic structural units 0-10 parts; cross-linking structural units 0.001-0.5 parts; co-solvent 0.01-0.5 parts.

8. A process for the preparation of polymer microspheres, preferably for the preparation of polymer microspheres according to claims 1 to 7, comprising: The reaction raw materials including acrylamide monomers, cross-linking agents, co-solvents, optional anionic monomers, optional cationic monomers, and optional non-ionic monomers are polymerized.

9. The preparation method according to claim 8, characterized in that, The cross-linking agent is selected from at least one of triazine ring compounds containing two or more double bond structures, silanes containing two or more double bond structures, siloxanes containing two or more double bond structures, and polyol polyallyl ethers; and / or, The anionic monomer is selected from at least one of carboxylic acid polymerizable monomers and / or alkali metal salts thereof, sulfonic acid polymerizable monomers and / or alkali metal salts thereof; and / or, The cationic monomer is selected from at least one of ammonium chloride polymerizable monomers, ammonium bromide polymerizable monomers, and ammonium iodide polymerizable monomers; and / or, The non-ionic monomer is selected from at least one of substituted acrylamide polymerizable monomers, substituted hydroxyalkyl acrylate polymerizable monomers, pyrrolidone polymerizable monomers, and substituted acrylamide ester polymerizable monomers, wherein the alkyl group is a C1-C20 alkyl group, preferably a C1-C10 alkyl group; and / or, The co-solvent is selected from at least one of alcohol solvents and polyethers.

10. The preparation method according to claim 9, characterized in that, The cross-linking agent is selected from at least one of the following compounds: wherein: in formula (1), R1 is selected from a double-bond-containing group, R2 is selected from methylene or carbonyl, and the repeated R1 or R2 is the same or different; in formula (2), R4 is selected from a double-bond-containing group, and the repeated R4 is the same or different; in formula (3), at least two R5 are selected from a double-bond-containing group, and the rest of R5 is selected from an alkyl group, an aryl group or hydrogen, and the repeated R5 is the same or different; in formula (4), at least two R are selected from a double-bond-containing group, and the rest of R is selected from an alkyl group, an aryl group or hydrogen, and the repeated R is the same or different; in formula (5), R6 is selected from a double-bond-containing group, p = 0 or 1 and at least two p = 1, and the repeated R6 is the same or different, and the repeated p is the same or different; in formula (6), R7 is selected from a double-bond-containing group, m = 0 or 1 and at least two m = 1, n = 0-10, and the repeated R7 is the same or different, and the repeated m is the same or different, and the repeated n is the same or different; and / or, the anionic monomer is selected from at least one of acrylic acid, methacrylic acid, p-vinylbenzenesulfonic acid, maleic acid, fumaric acid, vinylbenzenesulfonic acid, allylsulfonic acid, allylbenzenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, and alkali metal salts thereof; and / or, the cationic monomer is selected from at least one of methacryloyloxyethyltrimethylammonium chloride, 2-acrylamido-2-methylpropyltrimethylammonium chloride, dimethylethylallyl ammonium chloride, dimethyldiallyl ammonium chloride, acryloyloxyethyltrimethylammonium chloride, acryloyloxyethyldimethylbenzylammonium chloride, methacryloyloxyethyldimethylbenzylammonium chloride; and / or, the nonionic monomer is selected from at least one of methacrylamide, dimethylacrylamide, diethylacrylamide, hydroxymethylacrylamide, hydroxyethylacrylamide, dimethylamino propyl methacrylamide, hydroxymethyl methacrylate, hydroxyethyl methacrylate, dimethylaminoethyl methacrylate, vinylpyrrolidone, t-butyl acrylamide; and / or, the co-solvent is selected from at least one of C4-C8 alcohol solvents, polyether containing alkyl segments.

11. The preparation method according to claim 8, characterized in that, In the raw materials, by weight parts: acrylamide monomer 2-30 parts; anionic monomer 0-30 parts; cationic monomer 0-30 parts; nonionic monomer 0-20 parts; crosslinking agent 0.001-1 part; co-solvent 0.005-1 part; preferably, acrylamide monomer 5-25 parts; anionic monomer 1-25 parts; cationic monomer 0-25 parts; nonionic monomer 0-10 parts; crosslinking agent 0.001-0.5 parts; co-solvent 0.01-0.5 parts.

12. The method of any one of claims 8 to 11, wherein the method further comprises the step of: The reaction raw materials further include an initiation system, water, a chelating agent, an oil solvent, an emulsifier; Preferably, by weight parts: initiation system 0.001-0.06 parts, preferably 0.005-0.025 parts; water 10-100 parts, preferably 25-50 parts; chelating agent 0.001-1 part, preferably 0.005-0.1 part; oil solvent 40-100 parts, preferably 50-75 parts; emulsifier 2-10 parts, preferably 2.5-8 parts.

13. Use of the polymer microspheres according to one of claims 1 to 7 or obtained by the production process according to one of claims 8 to 12 for enhanced oil recovery, in particular for plugging agents or profile control agents.

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