CN102304201A - Hydrophobic association crosslinked polymer coil and preparation method thereof - Google Patents

Abstract

The invention provides a hydrophobic association type cross-linked polymer coil and a preparation method thereof. The preparation method comprises the following steps: (1) dissolving a surfactant and an oil-soluble initiator in a base oil as an oil phase; (2) dissolving a hydrophobic monomer, a water-soluble cross-linking monomer, a conventional water-soluble monomer and a water-soluble Dissolving the initiator in water and preparing an aqueous solution with a total mass percentage of 20%-70% as the water phase; (3) mixing the water phase described in step (2) with the oil phase described in step (1) Carrying out emulsification to form a W/O microemulsion in which the dispersed phase is an aqueous phase and the continuous phase is an oil phase; (4) feeding an inert gas into the W/O microemulsion formed in step (3) to initiate polymerization, The hydrophobic association type cross-linked polymer coils are obtained in the W/O microemulsion. The hydrophobic association type cross-linked polymer coil microemulsion control and flooding agent aqueous system provided by the invention is especially suitable for relatively high permeability reservoirs.

Description

A kind of hydrophobic association type cross-linked polymer coil and its preparation method

technical field

The invention relates to a hydrophobic association type crosslinked polymer coil and a preparation method thereof, belonging to the technical field of petroleum exploitation.

Background technique

At present, the early development of oil fields has gradually entered the middle and late stages of water flooding. How to further improve the volumetric sweep coefficient of injected water and the displacement efficiency within the water sweep volume, and economically and effectively exploit existing oil fields is a major issue to be solved urgently by the petroleum industry. One, in which the development and application of enhanced oil recovery technology has played an important role.

Enhanced oil recovery technology involves many aspects, and the methods based on improving the displacement effect can be divided into two categories: increasing the volumetric sweep coefficient of the injected fluid and improving the oil washing efficiency in the swept volume.

With the deepening of research, the influence of reservoir heterogeneity on the sweep coefficient of water flooding and chemical flooding fluid has attracted increasing attention in the industry. It is recognized that only through deep profile control can it be more economical and effective to adjust and improve The heterogeneity of the reservoir can be improved to improve the volumetric sweep coefficient of the injection fluid, ensure high displacement efficiency of the chemical flooding, and improve the oil recovery of the chemical flooding fluid and the subsequent water flooding stage. Among them, the deep profile control technology represented by cross-linked polymer flow gel, cross-linked polymer solution, and cross-linked polymer microspheres has economic advantages, obvious effects, long-term injection, and environmentally friendly technologies. The research and improvement of this method at a deeper level has very important significance for adjusting and improving the heterogeneity of reservoirs.

The current method for preparing cross-linked polymer coils for tertiary oil recovery is to use a dilute linear partially hydrolyzed polyacrylamide (HPAM) solution (mass fraction below its critical overlap mass fraction) to react with a cross-linking agent to form The water dispersion system of cross-linked polymer coils (that is, cross-linked polymer solution); Another method is to try to form a nano- or micro-scale water dispersion phase, and carry out the cross-linking monomer in the water dispersion phase. The copolymerization reaction of various monomers forms polymer micelles, which swell and dissolve in water to form cross-linked polymer coils of different scales. Theoretically speaking, only the use of cross-linked polymer coils whose particle size matches the formation pore size after injection can effectively retain and block throats, cause deep liquid flow to divert, and truly adjust and improve oil production. The heterogeneity of reservoirs can improve the recovery of crude oil in water flooding development.

The size of the water-soluble cross-linked polymer coils obtained in the preparation method reported in ZL 200410006334.6 is usually several hundred nanometers, and the particle size is relatively small. The size increases to several microns, and the water-soluble cross-linked polymer coils prepared by the above two methods can meet the use requirements of medium and low permeability reservoirs, and the mine test has obtained a good effect of enhancing recovery. However, it is also found in the application of mines that for higher permeability reservoirs (permeability greater than 1000 mD), or medium and low permeability reservoirs with higher permeability bands, in order to obtain better plugging As a result, it is necessary to increase the mass fraction of water-soluble cross-linked polymer coils in the injection solution in the early stage of the test, which reduces the economy of the injection system.

Contents of the invention

The object of the present invention is to provide a hydrophobic association cross-linked polymer coil and a preparation method thereof.

The preparation method of the hydrophobic association type cross-linked polymer coil provided by the invention comprises the following steps:

(1) dissolving the surfactant and the oil-soluble initiator in the base oil as the oil phase, and the boiling point of the base oil is 60°C-300°C;

(2) Hydrophobic monomer, water-soluble cross-linking monomer, conventional water-soluble monomer and water-soluble initiator are dissolved in water, and an aqueous solution with a total mass fraction of 20%-70% is prepared as the water phase; the hydrophobic monomer The body is a water-soluble monomer molecule containing a hydrophobic group in the molecular structure; the water-soluble cross-linking monomer is a monomer molecule containing two or more double bonds and a water-soluble group in the molecular structure; the conventional The water-soluble monomer is a monomer molecule containing only a single double bond and a water-soluble group in the molecular structure;

(3) The water phase described in step (2) is mixed with the oil phase described in step (1) to emulsify to form a W/O microemulsion whose dispersed phase is an aqueous phase and whose continuous phase is an oil phase; the W In the /O type microemulsion, the mass percent content of described base oil, surfactant, oil-soluble initiator, water-soluble initiator, hydrophobic monomer, water-soluble cross-linking monomer and conventional water-soluble monomer is respectively 10.0 %-40.0%, 10.0%-30.0%, 0.01%-5.0‰, 0.01%-30.0‰, 0.1%-50.0%, 0.1%-50.0% and 10.0%-40.0%, the balance is water;

(4) Inert gas is passed into the W/O microemulsion formed in step (3) to initiate a polymerization reaction, and the hydrophobic association type crosslinked polymer strands are obtained in the W/O microemulsion. group.

In the above preparation method, in the W/O microemulsion, the mass percentage of the base oil can be specifically 27.5%; the mass percentage of the surfactant can be specifically 22.5%; the oil The mass percentage of the soluble initiator can be specifically 3.13‰; the mass percentage of the hydrophobic monomer can be specifically 1.2%, 1.4% or 2.0%; the specific mass percentage of the water-soluble crosslinking monomer can be It is 1.7%; the mass percentage content of the conventional water-soluble monomer can be specifically 23.2%.

In the above-mentioned preparation method, the method also includes the steps of adding a precipitating agent to the W/O microemulsion containing the hydrophobic association type crosslinked polymer coils to precipitate, refine and dry; the precipitating agent is Anhydrous ethanol, anhydrous methanol or acetone; Petroleum ether or other low-boiling point hydrocarbons can be used for extraction and refining; the drying temperature can be 40°C-60°C, such as 50°C; the drying time can be 12 Hours - 24 hours, such as 12 hours.

In the above-mentioned preparation method, the HLB value of the surfactant described in step (1) can be 4-10; The surfactant can be at least one of nonionic surfactant, anionic surfactant and cationic surfactant Kinds, such as Span series nonionic surfactants or Tween series nonionic surfactants, specifically can be sorbitan oleate (Span-80) or sorbitan monostearic acid polyethylene oxide (Tween-60 ); the base oil can be at least one of n-paraffin, isoparaffin, cycloalkane and aromatic solvents, such as n-octane, isooctane, methylcyclohexane, xylene, industrial white oil or processed Low-boiling fractions produced by hydroisomerization dewaxing equipment, etc.; the oil-soluble initiator is a thermal decomposition type initiator, specifically azobisisobutyronitrile, azobisisoheptanonitrile or benzoyl peroxide, etc. .

In the above-mentioned preparation method, the hydrophobic monomer described in step (2) can be at least one of anionic monomer, cationic monomer and nonionic monomer; described anionic monomer is shown in formula (1), specifically can be is 2-acrylamido dodecanesulfonic acid, 2-acrylamidotetradecanesulfonic acid, 2-acrylamidohexadecanesulfonic acid or 4(ω-acryloyloxyethoxy)benzoic acid; the The cationic monomer is shown in formula (2) or formula (3), specifically (meth)acryloyloxyethyl dimethyltetradecyl ammonium bromide, (meth)acrylamidopropyl dimethyl Dodecyl ammonium bromide, N, N-dimethyl-N-allyl tetradecyl ammonium chloride or N, N-dimethyl-N-p-vinylbenzyl tetradecyl chloride ammonium chloride, etc.; the nonionic monomer is shown in formula (4), specifically cetyl polyoxyethylene (10) allyl ether, cetyl polyoxyethylene (10) p-phenylene Vinyl benzyl ether, cetyl polyoxyethylene (10) acrylate, alkylphenol polyoxyethylene (10) allyl ether, alkylphenol polyoxyethylene (10) p-styrene benzyl ether Or alkylphenol polyoxyethylene (10) acrylate, etc.;

Formula 1)

Formula (2)

Formula (3)

Formula (4)

In formula (1), n is the natural number of 5-13; In formula (2) and formula (3), R ₁ and R ₂ represent benzyl or have the alkyl or alkoxy group of 1-3 carbon atom; R ₃ represents an alkyl group with 8-22 carbon atoms, or an alkylbenzyl group with a monosubstituted 6-22 carbon atoms; R ₄ represents hydrogen or methyl; A represents an oxygen atom or NH; B represents a group with 2-4 An alkylene or alkyleneoxy group of carbon atoms; M represents methylene or monosubstituted benzyl; X ₁ represents an anion; R ₅ represents hydrogen, an alkyl group with 8-22 carbon atoms, or a single substitution of 6-22 Alkylphenyl of carbon atom; D represents methylene, carbonyl, or monosubstituted benzyl; E represents polyoxyethylene, polyoxypropylene, or polyoxyethylene-polyoxypropylene block chain link; formula (4 ), R ₅ represents hydrogen, an alkyl group with 8-22 carbon atoms, or a monosubstituted alkylphenyl group with 6-22 carbon atoms; D represents methylene, carbonyl, or monosubstituted benzyl; E represents poly Oxyethylene, polyoxypropylene, or polyoxyethylene-polyoxypropylene block chain members.

In the above-mentioned preparation method, the water-soluble cross-linking monomer described in step (2) can be N, N'-methylenebisacrylamide, polyethylene glycol diacrylate, polyethylene glycol diallyl ether, N,N-diallyldimethylammonium chloride, N,N'-diallyl-N,N,N',N'-tetramethylhexammonium chloride, N,N'-di p-vinylbenzyl-N,N,N',N'-tetramethylhexamethylene dichloride, (propyl)trimethyl triacrylate or pentaerythritol triallyl ether; the conventional water-soluble mono The body is acrylamide, methacrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, N,N-dimethylacrylamide, acrylonitrile, diacetoneacrylamide, (form ) 2-hydroxyethyl acrylate acrylamide, acryl alcohol, (meth)acrylic acid, itaconic acid, maleic acid, 2-acrylamide-2-methylpropanesulfonic acid, vinylsulfonic acid and other monomers salt, (meth)acryloyloxyethyltrimethylammonium chloride, (meth)acryloyloxyethyldiethylmethylammonium chloride, (meth)acryloyloxyethyldimethylbenzyl At least one of ammonium chloride, (meth)acryloyloxyethyl diethylbenzyl ammonium chloride and dimethyl diallyl ammonium chloride; the water-soluble initiator is 2,2'-even Azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane} dihydrochloride, 2,2'-azobis(2-amidinopropane) dihydrochloride Salt (V50 azo initiator of Wako Deutschland in Germany), 2,2'-azobis [2-(2-imidazolin-2-yl) propane) dihydrochloride (V44 azo initiator of Wako Deutschland in Germany ) or 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane) dihydrochloride.

In the above preparation method, the temperature of the polymerization reaction in step (4) can be 5°C-85°C, specifically 10°C, 15°C, 20°C or 25°C; the time of the polymerization reaction can be 4 hours- 12 hours, specifically 12 hours.

In the above-mentioned preparation method, the aqueous phase described in step (2) also includes at least one of an oxidative initiator, a thermal decomposition initiator, a chelating agent, a pH regulator and a cosolvent; the oxidative initiator can be Ammonium persulfate, the addition of the oxidizing initiator accounts for 0.001%-0.01% of the mass percentage of the W/O microemulsion, specifically 0.006%; the thermal decomposition initiator can be 2,2'-Azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane} dihydrochloride, 2,2'-Azobis(2-amidine propane) dihydrochloride (V50 azo initiator from Wako Deutschland, Germany), 2,2'-azobis[2-(2-imidazolin-2-yl) propane) dihydrochloride (Wako Deutschland, Germany V44 azo initiator) or 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane) dihydrochloride; the chelating agent can be ethylenediamine Disodium tetraacetate, the addition of the chelating agent accounts for 0.001%-0.01% of the mass percentage of the W/O microemulsion, specifically 0.0075%; the pH regulator can be anhydrous acetic acid Sodium, the added amount of the pH regulator accounts for 1%-10% of the mass percentage of the W/O microemulsion, specifically 1%; the co-solvent can be urea, and the co-solvent The added amount of the W/O microemulsion is 0.001%-0.01%, specifically 0.005%.

In the above-mentioned preparation method, the inert gas described in the step (4) is high-purity nitrogen or argon; the step of feeding a reducing gas is also included in the polymerization reaction, which combines with the oxidizing initiator to form an oxidation- The composite initiation system is reduced to fully carry out the polymerization reaction; wherein the reducing gas is preferably sulfur dioxide gas.

The hydrophobic association type cross-linked polymer coil provided by the present invention exists in the W/O microemulsion, and this microemulsion regulating and displacing agent containing the hydrophobic association type cross-linked polymer coil can be used directly; The hydrophobic association type crosslinked polymer coil powder with a relatively high mass fraction swells and dissolves in water to form an aqueous solution of the hydrophobic association type crosslinked polymer coil. In the profile control treatment of oil reservoirs, through the hydrophobic association type cross-linked polymer coils and their aggregates at higher permeability (permeability greater than 1000 mD), or where there is a higher permeability band Mechanical retention and plugging of larger throats in medium and low permeability reservoirs can cause deep liquid flow redirection, which can adjust and improve the heterogeneity of reservoirs, and seal the advantages of long-term water injection in deep reservoirs water channel. The hydrophobic association type cross-linked polymer coil microemulsion regulating and displacing agent aqueous system provided by the present invention is particularly suitable for higher permeability reservoirs (permeability is greater than 1000 mD), or there is a higher permeability band It can be used in medium and low permeability reservoirs to improve the recovery of crude oil in the middle and later stages of water flooding development.

Detailed ways

The experimental methods used in the following examples are conventional methods unless otherwise specified.

The materials and reagents used in the following examples can be obtained from commercial sources unless otherwise specified.

In order to further illustrate the beneficial effects of the present invention, the following examples are used to illustrate the superior plugging and profile control performance of the novel hydrophobic association type crosslinked polymer coils obtained by W/O type microemulsion polymerization and aggregates thereof:

Plugging profile modification performance and oil displacement efficiency of an artificial core with a gas permeability of 2.0 ^μm2 using a definite volume of aqueous solution of hydrophobic association crosslinked polymer coils, simulating aqueous solution of hydrophobic association crosslinked polymer coils The plugging profile control performance of hydrophobic association cross-linked polymer coils is evaluated by plugging reservoir formation pores.

Comparative example 1, the preparation of cross-linked polymer coils

According to ZL 200410006334.6, in the preparation method of a kind of cross-linked polymer coils disclosed in ZL 200410006334.6, the W/O microemulsion of water-soluble cross-linked polymer coils is prepared in Example 1, and the specific steps are as follows:

(1) Prepare the oil phase: Weigh 48 grams of base oil isoparaffin (viscosity 10.85cP), add it to a stirred 250 ml three-necked flask, add 19.2 grams of sorbitan monooleate (Span -80) and 12.8 grams of polyoxyethylene sorbitan monostearate (20) ether (Tween-60) two kinds of nonionic surfactants, mix as oil phase after;

(2) Prepare the water phase: Weigh 21.8 grams of conventional water-soluble monomer acrylamide, 6.9 grams of sodium acrylate, water-soluble cross-linking monomer N, N'-diallyl-N, N, N', N' - 0.62 grams of tetramethylhexammonium chloride, its molecular structure contains two double bonds, 1.33 grams of anhydrous sodium acetate, 0.98 milligrams of chelating agent disodium edetate, 1.31 milligrams of cosolvent urea, oxidative initiator 0.88 milligrams of ammonium persulfate, the above various ingredients are dissolved in 34.4 grams of deionized water (conductivity ≤ 4μS/cm) as the water phase stand-by;

(3) Stirring is started, and the above water phase is slowly added to the above oil phase, and the two are mixed evenly to form a stable W/O microemulsion (conductivity≤0.15 μS/cm);

(4) Set 25°C as the initiation temperature, firstly inject inert gas and high-purity nitrogen into the above-mentioned stable W/O microemulsion to drive oxygen, reduce the oxygen content in the system (≤0.3μg/g) to initiate the polymerization reaction , and then pass through the reducing gas sulfur dioxide and ammonium persulfate in the water phase to form an oxidation-reduction initiation system, so that the polymerization reaction can be fully carried out, and a W/O microemulsion containing cross-linked polymer coils is obtained;

(5) Add absolute ethanol to the above-mentioned W/O microemulsion containing cross-linked polymer coils as a precipitant to precipitate cross-linked polymer coils, extract and dry to make cross-linked polymer coils Powder.

The cross-linked polymer coils with a mass fraction of 400 mg/kg were matured in the simulated water of Bohai SZ36-1 oilfield at 60°C for ⁹⁶ hours to obtain an aqueous solution of cross-linked polymer coils. The displacement experiment of the simulated oil in the -1 oil field shows that the simulated oil recovery can be increased by 12.6% under the experimental conditions.

Embodiment 1, the preparation of hydrophobic association type cross-linked polymer coil

(1) Preparation of the oil phase: Weigh 110.0 grams of base oil isoparaffins (produced by the isomerization dewaxing unit of Daqing Refining and Chemical Company) (viscosity 10.85cP, flash point 178°C), and add it to a stirring 250 In the milliliter three-necked flask, add 57.4 gram sorbitan monooleate (Span-80, HLB value 4.3) and 32.6 gram sorbitan monostearate polyoxyethylene (20) ethers (Tween-60, The HLB value is 14.9) two kinds of non-ionic surfactants, mixed uniformly as the oil phase;

(2) Prepare the water phase: Weigh 58.9 grams of conventional water-soluble monomer acrylamide, 33.8 grams of sodium acrylate, water-soluble cross-linking monomer N, N'-diallyl-N, N, N', N' -Tetramethylhexammonium chloride 6.8 grams, its molecular structure contains two double bonds, hydrophobic monomer N, N '-dimethyl-N-p-vinyl benzyl octadecyl ammonium chloride 5.4 grams, Its molecular structure contains long-chain alkyl groups, 4.0 grams of anhydrous sodium acetate, 3.0 mg of disodium edetate as a chelating agent, 2.0 mg of cosolvent urea, 2.5 mg of oxidizing initiator ammonium persulfate, and 2 mg of thermal decomposition initiator , 12.5 mg of 2'-azobis(2-amidinopropane) dihydrochloride, each of the above ingredients was added to a stirred 250-milliliter three-port container with 91.1 grams of deionized water (conductivity≤4μS/cm) added. In the flask, it is used as the water phase after dissolving, and in the water phase, the total mass percentage of each component is 100%;

(3) Add the above-mentioned oil phase into a 500 ml jacketed reactor equipped with a gas inlet pipe, a thermometer, and a constant-speed stirrer, start stirring, and slowly add the above-mentioned water phase into the oil phase, and the two are mixed evenly to form Stable W/O type microemulsion (conductivity≤0.15μS/cm), in this W/O type microemulsion, the mass percentage of base oil is 27.5%, the mass percentage of surfactant is 22.5%, The mass percentage of the conventional water-soluble monomer is 23.2%, the mass percentage of the water-soluble crosslinking monomer is 1.7%, the mass percentage of the hydrophobic monomer is 1.4%, and the mass percentage of the pH value regulator 1.0%, the mass content of chelating agent is 0.0075%, the mass content of cosolvent is 0.005%, the mass content of oxidative initiator is 0.0063%, and the mass content of thermal decomposition type initiator is 0.00313%;

(4) Set 15°C as the initiation temperature, firstly inject inert gas and high-purity nitrogen into the above-mentioned stable W/O microemulsion to drive oxygen, reduce the oxygen content in the system (≤0.3μg/g) to initiate the polymerization reaction , and then pass through the reducing gas sulfur dioxide and ammonium persulfate in the water phase to form an oxidation-reduction initiation system, so that the polymerization reaction can be fully carried out. After 12 hours of reaction, a W/O type microstructure containing hydrophobic association type cross-linked polymer coils is obtained. Lotion;

(5) Add absolute ethanol to the above-mentioned W/O microemulsion containing hydrophobic association type crosslinked polymer coils as a precipitating agent to precipitate hydrophobic association type crosslinked polymer coils, extract through petroleum ether, and dry (The drying temperature is 50° C.; the drying time is 12 hours) to make a hydrophobic association type crosslinked polymer coil powder.

The above-mentioned hydrophobic association type crosslinked polymer coils with a mass fraction of 400mg/kg were aged in the simulated water of Bohai SZ36-1 oilfield at 60°C for 96 hours to obtain an aqueous solution of hydrophobic association type crosslinked polymer coils. The 2.0μm ² artificial core was used to carry out the displacement experiment of simulated oil in Bohai SZ36-1 Oilfield, and it was measured that the simulated oil recovery could be increased by 18.6% under the experimental conditions.

Embodiment 2, preparation of hydrophobic association type cross-linked polymer coils

(1) Preparation of the oil phase: Weigh 110.0 grams of base oil isoparaffins (produced by the isomerization dewaxing unit of Daqing Refining and Chemical Company) (viscosity 10.85cP, flash point 178°C), and add it to a stirring 250 In the milliliter three-necked flask, add 57.4 gram sorbitan monooleate (Span-80, HLB value 4.3) and 32.6 gram sorbitan monostearate polyoxyethylene (20) ethers (Tween-60, HLB value is 14.9) two kinds of nonionic surfactants, 12.5 milligrams of pyrolysis type initiator azobisisoheptanonitrile, after mixing homogeneously as oil phase;

(2) Prepare the water phase: Weigh 58.9 grams of conventional water-soluble monomer acrylamide, 33.3 grams of sodium acrylate, water-soluble cross-linking monomer N, N'-diallyl-N, N, N', N' -Tetramethylhexammonium chloride 6.8 grams, its molecular structure contains two double bonds, hydrophobic monomer N, N '-dimethyl-N to vinyl benzyl octadecyl ammonium chloride 8.1 grams, its The molecular structure contains long-chain alkyl groups, 4.0 grams of anhydrous sodium acetate, 3.0 mg of disodium edetate as a chelating agent, 2.0 mg of cosolvent urea, and 2.5 mg of ammonium persulfate as an oxidizing initiator. 88.4 grams of deionized water (conductivity ≤ 4 μS/cm) has been added to a stirred 250 ml three-necked flask, and after being dissolved, it will be used as an aqueous phase. In this aqueous phase, the total mass percentage of each component is 100%;

(3) Add the above-mentioned oil phase into a 500 ml jacketed reactor equipped with a gas inlet pipe, a thermometer, and a constant-speed stirrer, start stirring, and slowly add the above-mentioned water phase into the oil phase, and the two are mixed evenly to form Stable W/O type microemulsion (conductivity≤0.15μS/cm), in this W/O type microemulsion, the mass percentage of base oil is 27.5%, the mass percentage of surfactant is 22.5%, The mass percentage of the conventional water-soluble monomer is 23.2%, the mass percentage of the water-soluble crosslinking monomer is 1.7%, the mass percentage of the hydrophobic monomer is 2.0%, and the mass percentage of the pH regulator 1.0%, the mass content of chelating agent is 0.0075%, the mass content of cosolvent is 0.005%, the mass content of oxidative initiator is 0.0063%, and the mass content of thermal decomposition type initiator is 0.00313%;

(4) Set 25°C as the initiation temperature, firstly inject inert gas and high-purity nitrogen into the above-mentioned stable W/O microemulsion to drive oxygen, reduce the oxygen content in the system (≤0.3μg/g) to initiate the polymerization reaction , and then pass through the reducing gas sulfur dioxide and ammonium persulfate in the water phase to form an oxidation-reduction initiation system, so that the polymerization reaction can be fully carried out. After 12 hours of reaction, a W/O type microstructure containing hydrophobic association type cross-linked polymer coils is obtained. Lotion;

(5) Add absolute ethanol to the above-mentioned W/O microemulsion containing hydrophobic association type crosslinked polymer coils as a precipitating agent to precipitate hydrophobic association type crosslinked polymer coils, extract through petroleum ether, and dry (The drying temperature is 50° C.; the drying time is 12 hours) to make a hydrophobic association type crosslinked polymer coil powder.

The above-mentioned hydrophobic association type crosslinked polymer coils with a mass fraction of 400mg/kg were aged in the simulated water of Bohai SZ36-1 oilfield at 60°C for 96 hours to obtain an aqueous solution of hydrophobic association type crosslinked polymer coils. The 2.0μm ² artificial core was used for the displacement experiment of simulated oil in Bohai SZ36-1 oilfield, and it was measured that the simulated oil recovery could be increased by 17.2% under the experimental conditions.

Embodiment 3, the preparation of hydrophobic association type cross-linked polymer coil

(1) Preparation of the oil phase: Weigh 110.0 grams of base oil isoparaffins (produced by the isomerization dewaxing unit of Daqing Refining and Chemical Company) (viscosity 10.85cP, flash point 178°C), and add it to a stirring 250 In the milliliter three-necked flask, add 57.4 gram sorbitan monooleate (Span-80, HLB value 4.3) and 32.6 gram sorbitan monostearate polyoxyethylene (20) ethers (Tween-60, The HLB value is 14.9) two kinds of non-ionic surfactants, mixed uniformly as the oil phase;

(2) Prepare the water phase: Weigh 58.9 grams of conventional water-soluble monomer acrylamide, 33.8 grams of sodium acrylate, water-soluble cross-linking monomer N, N'-diallyl-N, N, N', N' - 6.8 grams of tetramethylhexammonium chloride, its molecular structure contains two double bonds, 4.8 grams of hydrophobic monomer 2-acrylamido hexadecyl sodium sulfonate, its molecular structure contains long chain alkyl, anhydrous 4.0 grams of sodium acetate, 3.0 mg of disodium edetate as a chelating agent, 2.0 mg of cosolvent urea, 2.5 mg of ammonium persulfate as an oxidative initiator, and 2,2'-azobis(2-amidine Propane) dihydrochloride 12.5 milligrams, above-mentioned various compositions join respectively in the 250 milliliters of three-neck flasks with stirring that has added 91.7 gram deionized water (conductivity≤4 μ S/cm), after dissolving, stand-by as water phase, In the aqueous phase, the total mass percentage of each component is 100%;

(3) Add the above-mentioned oil phase into a 500 ml jacketed reactor equipped with a gas inlet pipe, a thermometer, and a constant-speed stirrer, start stirring, and slowly add the above-mentioned water phase into the oil phase, and the two are mixed evenly to form Stable W/O type microemulsion (conductivity≤0.15μS/cm), in this W/O type microemulsion, the mass percentage of base oil is 27.5%, the mass percentage of surfactant is 22.5%, The mass percentage of the conventional water-soluble monomer is 23.2%, the mass percentage of the water-soluble crosslinking monomer is 1.7%, the mass percentage of the hydrophobic monomer is 1.2%, and the mass percentage of the pH value regulator 1.0%, the mass content of chelating agent is 0.0075%, the mass content of cosolvent is 0.005%, the mass content of oxidative initiator is 0.0063%, and the mass content of thermal decomposition type initiator is 0.00313%;

(4) Set 10°C as the initiation temperature, firstly inject inert gas and high-purity nitrogen into the above-mentioned stable W/O microemulsion to drive oxygen, reduce the oxygen content in the system (≤0.3μg/g) to initiate the polymerization reaction , and then pass through the reducing gas sulfur dioxide and ammonium persulfate in the water phase to form an oxidation-reduction initiation system, so that the polymerization reaction can be fully carried out. After 12 hours of reaction, a W/O type microstructure containing hydrophobic association type cross-linked polymer coils is obtained. Lotion;

(5) Add absolute ethanol to the above-mentioned W/O microemulsion containing hydrophobic association type crosslinked polymer coils as a precipitating agent to precipitate hydrophobic association type crosslinked polymer coils, extract through petroleum ether, and dry (the drying temperature is 50°C; the drying time is 12 hours), and the hydrophobic association type crosslinked polymer coil powder is made.

The above-mentioned hydrophobic association type crosslinked polymer coils with a mass fraction of 400mg/kg were aged in the simulated water of Bohai SZ36-1 oilfield at 60°C for 96 hours to obtain an aqueous solution of hydrophobic association type crosslinked polymer coils. The 2.0μm ² artificial core was used for the displacement experiment of simulated oil in Bohai SZ36-1 oilfield, and it was measured that the simulated oil recovery could be increased by 17.8% under the experimental conditions.

Embodiment 4, preparation of hydrophobic association type cross-linked polymer coils

(1) Preparation of oil phase: Weigh 110.0 grams of No. 10 industrial white oil (viscosity 10.35cP, flash point 156°C), add it to a stirred 250 ml three-neck flask, add 57.4 grams of sorbitol anhydride Monooleate (Span-80, HLB value is 4.3) and 32.6 grams of polyoxyethylene (20) sorbitan monostearate (Tween-60, HLB value is 14.9) two kinds of nonionic surfactants, After mixing evenly, it is used as the oil phase;

(2) Prepare the water phase: Weigh 59.0 grams of conventional water-soluble monomer acrylamide, 33.8 grams of sodium acrylate, water-soluble cross-linking monomer N, N'-diallyl-N, N, N', N' - 6.8 grams of tetramethylhexammonium chloride, its molecular structure contains two double bonds, 7.8 grams of hydrophobic monomer hexadecyl polyoxyethylene (10) p-styrene benzyl ether, its molecular structure contains long chain Alkyl, 4.0 g of anhydrous sodium acetate, 3.0 mg of disodium edetate as a chelating agent, 2.0 mg of cosolvent urea, 2.5 mg of ammonium persulfate as an oxidative initiator, and 2,2'-azobis 12.5 mg of (2-amidinopropane) dihydrochloride, the above ingredients were added to the 250 ml three-necked flask with stirring that had added 88.7 g of deionized water (conductivity ≤ 4 μS/cm), dissolved as water For use, in the aqueous phase, the total mass percentage of each component is 100%;

(3) Add the above-mentioned oil phase into a 500 ml jacketed reactor equipped with a gas inlet pipe, a thermometer, and a constant-speed stirrer, start stirring, and slowly add the above-mentioned water phase into the oil phase, and the two are mixed evenly to form Stable W/O type microemulsion (conductivity≤0.15μS/cm), in this W/O type microemulsion, the mass percentage of base oil is 27.5%, the mass percentage of surfactant is 22.5%, The mass percentage of the conventional water-soluble monomer is 23.2%, the mass percentage of the water-soluble crosslinking monomer is 1.7%, the mass percentage of the hydrophobic monomer is 2.0%, and the mass percentage of the pH regulator 1.0%, the mass content of chelating agent is 0.0075% g, the mass content of cosolvent is 0.005%, the mass content of oxidative initiator is 0.0063%, and the mass content of water-soluble initiator is 0.00313%;

(4) Set 20°C as the initiation temperature, firstly inject inert gas and high-purity nitrogen into the above-mentioned stable W/O microemulsion to drive oxygen, reduce the oxygen content in the system (≤0.3μg/g) to initiate the polymerization reaction , and then pass through the reducing gas sulfur dioxide and ammonium persulfate in the water phase to form an oxidation-reduction initiation system, so that the polymerization reaction can be fully carried out. After 12 hours of reaction, a W/O type microstructure containing hydrophobic association type cross-linked polymer coils is obtained. Lotion;

(5) Add absolute ethanol to the above-mentioned W/O microemulsion containing hydrophobic association type crosslinked polymer coils as a precipitating agent to precipitate hydrophobic association type crosslinked polymer coils, extract through petroleum ether, and dry (The drying temperature is 50° C.; the drying time is 12 hours) to make a hydrophobic association type crosslinked polymer coil powder.

The above-mentioned hydrophobic association type crosslinked polymer coils with a mass fraction of 400mg/kg were aged in the simulated water of Bohai SZ36-1 oilfield at 60°C for 96 hours to obtain an aqueous solution of hydrophobic association type crosslinked polymer coils. The 2.0μm ² artificial core was used for the displacement experiment of simulated oil in Bohai SZ36-1 oilfield, and it was measured that the simulated oil recovery could be increased by 18.2% under the experimental conditions.

The results of each embodiment are comprehensively listed in Table 1.

Table 1 Comparative example 1 and embodiment 1-4 preparation cross-linked polymer coil enhanced oil recovery comparison

Comparing Examples 1 and 2, it can be seen that the plugging and profile modification effects of hydrophobic association cross-linked polymer coils containing different mass fractions of hydrophobic monomers on artificial cores ^of 2.0 μm are slightly different, which means that hydrophobic The problem of controlling the crosslinking degree of associative crosslinked polymer coils needs to be realized by adjusting the mass fraction of hydrophobic monomers in the hydrophobic associative crosslinked polymer coils.

Comparing Examples 1, 3 and 4, it can be seen that the ability to enhance oil recovery of the hydrophobic association type crosslinked polymer coils can be adjusted by adjusting the molecular structure and preparation method of the hydrophobic monomer.

The above examples and comparative results only suggest the effect that the preparation method of the present invention can achieve, that is, different hydrophobic association type crosslinked polymer coils can be prepared adaptively according to the reservoir characteristics and recovery degree.

On the other hand, comparing the comparative examples with the four specific examples, it can be seen that the aqueous solution of the profile control agent used for plugging and profile control obtained under the conditions of the same mass fraction, the same salinity, the same temperature, and the same aging time, When carrying out oil displacement experiments on rock cores with the same gas permeability, the aqueous solution of hydrophobic association crosslinked polymer coils obtained by this method can better improve the recovery of simulated oil, indicating that the hydrophobicity obtained by this method The aqueous solution of associative cross-linked polymer coils has the same or better plugging ability than conventional cross-linked polymer coils obtained by emulsion polymerization for porous media with higher permeability.

Claims (10)

1. a hydrophobic association type cross-linked polymer clew preparation method comprises the steps:

(1) tensio-active agent and oil-soluble initiator are dissolved in base oil as oil phase, the boiling point of said base oil is 60 ℃-300 ℃;

(2) hydrophobic monomer, water-soluble cross-linked monomer, conventional water-soluble monomer and water soluble starter are dissolved in the water, the aqueous solution that is made into the total mass percentage composition and is 20%-70% is as water; Said hydrophobic monomer is the water-soluble monomer molecule that contains hydrophobic grouping in the molecular structure; Said water-soluble cross-linked monomer is the monomer molecule that contains two or more pairs key and water soluble group in the molecular structure; The water-soluble monomer of said routine is the monomer molecule that only contains single pair of key and water soluble group in the molecular structure;

(3) the described water of step (2) is mixed with the described oil phase of step (1) carry out emulsification, the formation disperse phase is that water, external phase are the w/o type microemulsion of oil phase; In the said w/o type microemulsion; The quality percentage composition of the water-soluble monomer of said base oil, tensio-active agent, oil-soluble initiator, water soluble starter, hydrophobic monomer, water-soluble cross-linked monomer and routine is respectively 10.0%-40.0%, 10.0%-30.0%, 0.01%-5.0 ‰, 0.01%-30.0 ‰, 0.1%-50.0%, 0.1%-50.0% and 10.0%-40.0%, and surplus is a water;

(4) in the said w/o type microemulsion that step (3) forms, feed the rare gas element initiated polymerization, in said w/o type microemulsion, promptly get said hydrophobic association type linked polymer coil.

2. preparation method according to claim 1 is characterized in that: said method also is included in the w/o type microemulsion that contains said hydrophobic association type linked polymer coil and adds precipitation agent and precipitate and the exsiccant step.

3. preparation method according to claim 2 is characterized in that: said precipitation agent is dehydrated alcohol, anhydrous methanol or acetone.

4. according to arbitrary described preparation method among the claim 1-3, it is characterized in that: the HLB value of tensio-active agent described in the step (1) is 4-10; Said tensio-active agent is at least a in nonionogenic tenside, anion surfactant and the cats product; Said base oil is at least a in normal paraffin, isoparaffin, naphthenic hydrocarbon and the aromatic hydrocarbon solvent; Said oil-soluble initiator is a thermolysis type initiator.

5. according to arbitrary described preparation method among the claim 1-4, it is characterized in that: hydrophobic monomer is at least a in anionic monomer, cationic monomer and the non-ionic monomer described in the step (2); Said anionic monomer is suc as formula shown in (1); Said cationic monomer is suc as formula shown in (2) or the formula (3); Said non-ionic monomer is suc as formula shown in (4);

Formula (1)

Formula (2)

Formula (3)

Formula (4)

In the formula (1), n is the natural number of 5-13; In formula (2) and the formula (3), R ₁And R ₂Represent benzyl or have the alkyl or the alkoxyl group of 1-3 carbon atom; R ₃Representative has alkyl or single alkyl benzyl that replaces 6-22 carbon atom of 8-22 carbon atom; R ₄Represent hydrogen or methyl; A represention oxygen atom or NH; The B representative has the alkylidene group or the alkylene oxide group of 2-4 carbon atom; M represents methylene radical or single substituted benzyl; X ₁Represent negatively charged ion; , R ₅Represent alkyl or single alkyl phenyl that replaces 6-22 carbon atom of hydrogen, a 8-22 carbon atom; D represents methylene radical, carbonyl or single substituted benzyl; E represents polyoxyethylene groups, polyoxypropylene base or polyoxyethylene-polyoxypropylene block chain link; In the formula (4), R ₅Represent alkyl or single alkyl phenyl that replaces 6-22 carbon atom of hydrogen, a 8-22 carbon atom; D represents methylene radical, carbonyl or single substituted benzyl; E represents polyoxyethylene groups, polyoxypropylene base or polyoxyethylene-polyoxypropylene block chain link.

6. according to arbitrary described preparation method among the claim 1-5; It is characterized in that: water-soluble cross-linked monomer is N described in the step (2); N '-methylene-bisacrylamide, polyethyleneglycol diacrylate, polyoxyethylene glycol diallyl ether, N; N-diallyl dimethyl chlorination amine, N; N '-diallyl-N; N; N '; The own dichloride ammonium of N '-tetramethyl-, N; N '-two couple vinyl benzyl-N; N, N ', the own dichloride amine of N '-tetramethyl-, three vinylformic acid-(propyl group) trimethyl or pentaerythritol triallyl ether; The water-soluble monomer of said routine is an acrylamide; Methacrylamide; The N-vinyl formamide; The N-vinyl acetamide; The N-vinyl pyrrolidone; N,N-DMAA; Vinyl cyanide; Diacetone acrylamide; (first) vinylformic acid 2-hydroxyethyl ester acrylamide; Vinylcarbinol; (methyl) vinylformic acid; Itaconicacid; Toxilic acid; 2-acrylamide-2-methyl propane sulfonic acid; The corresponding salt of vinyl sulfonic acid monomer; (methyl) acrylyl oxy-ethyl-trimethyl salmiac; (methyl) acrylyl oxy-ethyl diethylmethyl ammonium chloride; (methyl) acrylyl oxy-ethyl dimethyl benzyl ammonium chloride; At least a in (methyl) acrylyl oxy-ethyl diethyl benzyl ammonium chloride and the dimethyl diallyl ammonium chloride; Said water soluble starter is 2; 2 '-azo two 2-[1-(2-hydroxyethyl)-2-tetrahydroglyoxaline-2-yl] and propane } dihydrochloride, 2; 2 '-azo two (2-amidine propane) dihydrochloride, 2; 2 '-azo two [2-(2-tetrahydroglyoxaline-2-yl) propane) dihydrochloride or 2,2 '-azo two [2-(5-methyl-2-tetrahydroglyoxaline-2-yl) propane) dihydrochloride.

7. according to arbitrary described preparation method among the claim 1-6, it is characterized in that: the temperature of the said polyreaction of step (4) can be 5 ℃-85 ℃; The time of said polyreaction can be 4 hours-12 hours.

8. according to arbitrary described preparation method among the claim 1-7, it is characterized in that: the said aqueous phase of step (2) also comprises in oxidative initiator, thermolysis type initiator, sequestrant, pH value conditioning agent and the solubility promoter at least a.

9. according to arbitrary described preparation method among the claim 1-8, it is characterized in that: rare gas element is nitrogen or argon gas described in the step (4); Also comprise the step that feeds reducing gas in the said polyreaction; Said reducing gas is a sulfurous gas.

10. the hydrophobic association type linked polymer coil of arbitrary said method preparation among the claim 1-9.