CN109666095B - Microemulsion profile control and flooding system and application thereof - Google Patents
Microemulsion profile control and flooding system and application thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/52—Amides or imides
- C08F220/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
- C08F220/56—Acrylamide; Methacrylamide
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/12—Polymerisation in non-solvents
- C08F2/16—Aqueous medium
- C08F2/22—Emulsion polymerisation
- C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
- C08F2/26—Emulsion polymerisation with the aid of emulsifying agents anionic
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- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/12—Polymerisation in non-solvents
- C08F2/16—Aqueous medium
- C08F2/22—Emulsion polymerisation
- C08F2/24—Emulsion polymerisation with the aid of emulsifying agents
- C08F2/30—Emulsion polymerisation with the aid of emulsifying agents non-ionic
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- C—CHEMISTRY; METALLURGY
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- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/58—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids
- C09K8/588—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids characterised by the use of specific polymers
Abstract
The invention relates to a micro-emulsion profile control and flooding system and application thereof, and mainly solves the problems of poor temperature resistance and salt resistance and low oil displacement efficiency of profile control and flooding agents in the prior art under the conditions of high-temperature, high-salt and low-permeability reservoirs. The invention adopts a microemulsion profile control and flooding system, which comprises the following components in percentage by weight: (1) 0.01-5.0% of core-shell polymer microspheres; (2)0.01 to 5.0% of an anionic-nonionic surfactant; (3) the technical scheme of 90.0-99.98% of injected water well solves the problem, and can be used for the field application of improving the recovery ratio such as deep profile control, water shutoff, oil displacement and the like for tertiary oil recovery of a high-temperature high-salinity low-permeability reservoir.
Description
Technical Field
The invention relates to a micro-emulsion profile control and flooding system and application thereof in tertiary oil recovery of a high-temperature high-salinity low-permeability reservoir.
Background
With the development of socio-economic, the demand of people for oil is increasing and the reserves of oil are decreasing, and oil is becoming more and more valuable as a non-renewable resource. The problems faced are one: the contradiction between supply and demand is prominent, the demand of petroleum is more and more large, and new oil fields are less and less; II, secondly: a large amount of crude oil remains in the depleted reservoir. 10-25% of underground crude oil can be produced by Primary Oil Recovery (POR), and 15-25% of underground crude oil can be produced by Secondary Oil Recovery (SOR), namely, only 25-50% of underground crude oil is produced by primary oil recovery and secondary oil recovery. In order to ensure the long-term stable supply of oil and meet the requirements of human beings, a technology for improving the oil recovery rate must be researched and developed, and the oil recovery rate of tertiary oil recovery (EOR) can be improved by 6-20% or even more by means of an enhanced oil recovery measure.
The polymer flooding is a main technical method for tertiary oil recovery, the oil displacement mechanism is clear, the process is relatively simple, the technology is mature day by day, and the polymer flooding oil recovery agent is an effective technical measure for improving the recovery ratio. However, in the case of a heterogeneous formation, displacement can only act on a high permeable layer and cannot reach an oil-containing low permeable layer, so that the recovery rate of crude oil is reduced, and the cost is increased. Generally, a water injection well profile control and production well water plugging technology is adopted for a heterogeneous stratum, but the effective range of the technology is limited to a near-wellbore zone, the technology cannot reach deep parts of an oil well, and the purpose of greatly improving the crude oil recovery rate cannot be achieved.
The nanometer-sized cross-linked polymer microsphere is used as a step-by-step deep profile control and displacement material for developing oil reservoirs by water injection, and the use principle of the nanometer-sized cross-linked polymer microsphere is that the nanometer-sized polymer microsphere is utilized, the initial size of the nanometer-sized polymer microsphere is far smaller than the pore throat size of a stratum, the nanometer-sized polymer microsphere can smoothly enter the deep part of the stratum along with injected water and continuously moves forwards in the stratum, and after water absorption and gradual expansion, plugging is formed at the pore throat of a water seepage channel to cause liquid flow redirection, so that the purposes of expanding water waves and volume and improving.
In recent years, researchers at home and abroad have made more researches on the application of the polyacrylamide reverse microemulsion to the oil reservoir deep profile control and flooding materials, and have made better progress and results. Patent CN1903974A synthesizes a terpolymer nano-sized microgel oil displacement material, adopts a low-temperature photoinitiator of a non-redox initiation system, utilizes ultraviolet light to decompose the initiator to generate active free radicals to initiate polymerization, which is beneficial to the stability of reverse microemulsion and the control of particle size, but the content of an emulsifier in the system is up to more than 25 percent, which inevitably causes high production cost. The patent CN101759838A provides a preparation method of a low interfacial tension polyacrylamide nano microsphere profile control and flooding system, and evaluates the tension reduction condition of oil extraction plant piles 106 wells on crude oil in a victory oil field pile, but the expansion performance of polymer microspheres is not expressed, so that the system has no secondary testability on the profile control and flooding capability of an oil reservoir.
Disclosure of Invention
The invention aims to solve the technical problems of poor temperature resistance and salt resistance and low oil displacement efficiency of a profile control agent under the conditions of high temperature, high salt and low permeability in the prior art, and provides a micro-emulsion profile control and flooding system. The system has the characteristics of good temperature resistance and salt resistance and high oil displacement efficiency.
The second technical problem to be solved by the present invention is to provide an application of the microemulsion profile control system in tertiary oil recovery of high-temperature high-salinity low-permeability oil reservoir, which corresponds to the solution of the first technical problem.
In order to solve one of the above technical problems, the technical solution of the present invention is as follows: a micro-emulsion profile control and flooding system comprises the following components in percentage by weight:
(1) 0.01-5.0% of core-shell polymer microspheres;
(2)0.01 to 5.0% of an anionic-nonionic surfactant;
(3) 90.0-99.98% of injected water.
In the technical scheme, the total mineralization degree of the injected water is preferably 80000-180000 mg/L, Ca2++Mg2+Preferably 1000-5000 mg/L.
In the above technical scheme, the preferable molecular general formula of the anionic-nonionic surfactant is RO (CH)2CH2O)nCH2SO3M and R are preferably C10～C25Preferably n is 1 to 20, and M is preferably selected from H, alkali metal or NH4。
In the above technical scheme, R is preferably C12～C18A hydrocarbon group of (1).
In the above-described embodiment, n is preferably 2 to 8.
In the above technical solution, the alkali metal is preferably selected from potassium, sodium or lithium.
In the technical scheme, the core-shell type polymer microsphere is preferably prepared by carrying out polymerization reaction on reversed-phase microemulsion under the action of a redox composite initiator; the reverse microemulsion comprises the following components in parts by weight:
a)50 parts of an oil-soluble solvent;
b) 3-20 parts of an emulsifier;
c) 10-60 parts of a hydrophilic monomer;
d) 0.5-10 parts of a hydrophobic monomer;
e) 10-50 parts of water;
the composite initiator comprises the following components in percentage by weight of all the monomers:
(a) 0.02-1.0% of an oxidant;
(b) 0.02-2.0% of a reducing agent;
(c) 0.03-2.0% of azo compounds;
(d)0.01 to 1.0% of a crosslinking agent;
(e) 0.1-10% of urea and thiourea;
(f) 0.01-0.5% of an aminocarboxylic complexing agent;
(g) 0.5-5% of electrolyte salt.
In the above embodiment, the oil-soluble solvent is preferably at least one selected from hydrocarbons and esters. The hydrocarbon can be aliphatic hydrocarbon, aromatic hydrocarbon, petroleum fraction; the aliphatic hydrocarbon is preferably C4～C8Aliphatic hydrocarbons such as cyclohexane, hexane, heptane, octane, isooctane and the like; the aromatic hydrocarbon is preferably C6～C10Aromatic hydrocarbons of (2), such as benzene, toluene, xylene, trimethylbenzene, ethylbenzene, diethylbenzene, isopropylbenzene, etc.; the petroleum fraction is preferably white oil, liquid paraffin, gasoline, kerosene, diesel oil, petroleum ether, etc. The ester is preferably a carboxylic acid ester, and may be more preferably C4～C8Monoesters of (a) such as ethyl acetate, propyl acetate, etc.; still more preferred is C4～C10Diesters of (a) such as dimethyl oxalate, diethyl oxalate, ethyl methyl oxalate and the like; can also be used forMore preferably vegetable oils, preferably selected from peanut oil, soybean oil, sunflower oil and castor oil.
In the technical scheme, the HLB value of the emulsifier is preferably 5-8. The emulsifier is more preferably a nonionic surfactant. The emulsifier is preferably a mixture of nonionic surfactants with HLB of 1-7 and nonionic surfactants with HLB of 8-18. Such nonionic surfactants are, for example, alkoxy adducts of fatty alcohols, alkylphenols, fatty acids, fatty acid esters or amines, such as fatty alcohol polyoxyethylene ethers, alkylphenol ethoxylates, fatty acid polyoxyethylene esters, fatty amine polyoxyethylene ethers, etc., for example, products of partial hydroxyl esterification of polyols, such as sorbitan fatty acid esters, also known as spans, and partial or total hydroxyl ethoxylation of polyols and fatty acid esters, such as tweens.
In the above technical scheme, the emulsifier may further comprise a co-emulsifier. The coemulsifier can be small molecular alcohols. The small molecular alcohol is preferably C3～C12Such as isopropanol, tert-butanol, n-pentanol and the like. The content of the co-emulsifier is preferably 5-30 wt% of the nonionic surfactant in the emulsifier.
In the above technical solution, the hydrophilic monomer is selected from at least one of a nonionic monomer, an anionic monomer and a cationic monomer, more preferably selected from a nonionic monomer, an anionic monomer and a cationic monomer, and most preferably selected from at least one of a nonionic monomer, at least two anionic monomers and at least one cationic monomer, and at this time, the four monomers have a better synergistic effect, and the plugging efficiency is highest; the nonionic hydrophilic monomer is at least one selected from acrylamide, methacrylamide, N-isopropyl acrylamide, N-hydroxymethyl acrylamide, tert-butyl acrylamide, N-vinyl pyrrolidone, N-dimethyl acrylamide and N, N-diethyl acrylamide; the anionic hydrophilic monomer is selected from at least one of acrylic acid, methacrylic acid, itaconic acid, 2-acrylamido-2-methylpropanesulfonic acid, vinylsulfonic acid, vinylbenzenesulfonic acid, allylsulfonic acid, methacrylsulfonic acid, styrenesulfonic acid and/or water-soluble alkali metal, alkaline earth metal and ammonium salts; the cationic hydrophilic monomer is at least one selected from dimethyl diallyl ammonium chloride, acryloyloxyethyl trimethyl ammonium chloride, methacryloyloxyethyl trimethyl ammonium chloride, acryloyloxyethyl dimethyl benzyl ammonium chloride, methacryloyloxyethyl dimethyl benzyl ammonium chloride and methacryloylpropyl trimethyl ammonium chloride.
In the technical scheme, the hydrophobic monomer is selected from at least one of N-phenyl maleimide, maleic anhydride, styrene and derivatives thereof, acrylamide nitrogen alkyl sodium sulfonate with a carbon chain number of 8-18, and alkyl or fluorine substituted alkyl acrylate with a carbon chain number of 8-18.
In the above technical scheme, the oxidant is at least one selected from potassium persulfate, sodium persulfate, ammonium persulfate and benzoyl peroxide; the reducing agent is at least one selected from sodium sulfite, potassium sulfite, sodium bisulfite, potassium bisulfite, sodium thiosulfate and ferrous chloride; the azo compound is selected from azodiisobutyl amidine hydrochloride and 2,2' -azo [2- (2-imidazoline-2-yl) propane]At least one of dihydrochloride, azobisisobutyronitrile, azobisisoheptonitrile; the cross-linking agent is selected from at least one of methylene bisacrylamide, divinyl benzene, polyethylene glycol diacrylate, pentaerythritol triacrylate and N, N' -m-phenylene bismaleimide; the complexone is selected from at least one of ethylenediamine tetraacetic acid and alkali metal salts thereof, diethylenetriamine pentaacetic acid and alkali metal salts thereof; the electrolyte salt is preferably a water-soluble inorganic salt or organic acid salt. The inorganic salt is preferably an alkali metal salt (e.g., sodium chloride, potassium chloride), an alkali metal sulfate (e.g., sodium sulfate, potassium sulfate); the organic acid salt is preferably an alkali metal organic acid salt, more preferably C2～C6Alkali metal salts of carboxylic acids, for example potassium acetate or sodium acetate.
In the above technical solution, the core-shell polymer microsphere is preferably prepared by a method comprising the following steps:
(a) preparing an oil phase: dissolving an emulsifier in an oil-soluble solvent, and uniformly stirring to obtain an oil phase I; dissolving an oil-soluble cross-linking agent and an oil-soluble azo initiator in an oil-soluble solvent, and uniformly stirring to obtain an oil phase II; and dissolving the oil-soluble hydrophobic monomer in the oil-soluble solvent, and uniformly stirring to obtain an oil phase III.
(b) Preparing a water phase: dissolving 40-70 wt% of hydrophilic monomer and water-soluble composite initiator except reducing agent in water, and uniformly stirring to obtain nuclear water phase; dissolving the rest hydrophilic monomer and the water-soluble composite initiator except the reducing agent in water, and uniformly stirring to obtain a shell water phase; dissolving a reducing agent in water to form a reducing agent aqueous solution;
(c) adding the oil phase I into a reactor, adding 40-70 wt% of oil phase II and a nuclear water phase, uniformly stirring, dropwise adding a reducing agent aqueous solution, and reacting at 40-80 ℃ for 1-4 hours to obtain polyacrylamide reverse-phase microemulsion; and when the reaction temperature is reduced to 15-35 ℃, adding the rest oil phase II, oil phase III and shell water phase again, stirring uniformly, dropwise adding a reducing agent aqueous solution, and reacting at 40-80 ℃ for 1-4 hours to finally obtain the core-shell type polyacrylamide reverse microemulsion.
More preferably, the step (c) is as follows:
(c) adding the oil phase I into a reactor, adding 40-70 wt% of oil phase II and a nuclear water phase, uniformly stirring, dropwise adding a reducing agent aqueous solution, and reacting at 50-60 ℃ for 2-3 hours to obtain a polyacrylamide reverse microemulsion; and when the reaction temperature is reduced to 25-30 ℃, adding the rest oil phase II, oil phase III and shell water phase again, stirring uniformly, dropwise adding a reducing agent aqueous solution, and reacting at 50-60 ℃ for 2-3 hours to finally obtain the core-shell type polyacrylamide reverse microemulsion.
The preparation of the microemulsion profile control and flooding system is not particularly limited, and for example, the preparation method can comprise the following steps: and (3) uniformly mixing the reverse microemulsion containing the core-shell polymer microsphere with required amount, the anionic-nonionic surfactant and the injected water, and stirring for 1-3 hours.
In order to solve the second technical problem, the invention adopts the following technical scheme: the micro-emulsion profile control and flooding system is applied to tertiary oil recovery of a high-temperature high-salinity low-permeability reservoir.
In the above technical scheme, the application is not particularly limited, for example, the microemulsion profile control and flooding system is injected at a formation temperature of more than or equal to 80 ℃ (preferably 85-95 ℃), a total mineralization degree of more than or equal to 80000mg/L (preferably 80000-180000 mg/L), Ca2++Mg2+Not less than 1000mg/L (preferably 1000-5000 mg/L), air permeability of 100-1500 × 10-3μm2(preferably 300 to 1000X 10)-3μm2) Displacing the oil from the reservoir.
According to the core-shell polymer microsphere in the profile control and flooding system, due to the fact that the hydrophobic monomer is introduced into the shell layer, the temperature resistance and salt resistance of the polymer microsphere can be enhanced, the hydration effect of the microsphere can be relieved, and the microsphere can expand controllably under the conditions of high temperature and high salt; once exposed, the cation component in the inner core can generate electrostatic interaction with the negatively charged stratum, so that the gripping force of the microspheres and the pore channels is improved, and the blocking capability of the microspheres is enhanced. Meanwhile, the mode of charging step by step is adopted, so that the polymerization process is controlled stably, more polymerization monomers can be added, the solid content is improved, and the particle size and the distribution of the obtained polymer microspheres are uniform.
By adopting the technical scheme of the invention, the microemulsion profile control system has the total mineralization degree of 18 multiplied by 10 at the temperature of 90 DEG C4mg/L，Ca2++Mg2+: after aging for 30 days under the condition of 5000mg/L saline water, the expansion multiple of the particle size of the microspheres can reach 14.6 times, the microspheres can be used at the formation temperature of 85-95 ℃ and the total mineralization degree of 80000-180000 mg/L, Ca2++Mg2+A total amount of 1000 to 5000mg/L and an air permeability of 300 to 1000X 10-3μm2The crude oil and water in the Putongxi region of the central oil field form the profile control and flooding system by using 0.1-0.2 wt% of polymer microspheres and 0.1-0.3 wt% of fatty alcohol-polyoxyethylene ether sulfonate, and the dynamic interfacial tension value between the aqueous solution of the system and the crude oil in the Putongxi region of the central oil field is measured and can reach 10-2～10-3The low interfacial tension of mN/m is applied to the field application of improving the recovery ratio, so that the effects of well improving the oil washing efficiency and finally improving the recovery ratio can be achieved, and a better technical effect is achieved.
The invention is further illustrated by the following specific examples.
Detailed Description
[ example 1 ]
The polymer microsphere of the embodiment is prepared by the polymerization reaction of reverse microemulsion under the action of a redox composite initiator; the reverse microemulsion comprises the following components in parts by weight:
a)50 parts of an oil-soluble solvent; the oil-soluble solvent is white oil;
b)10 parts of an emulsifier; the emulsifier HLB value is 6.7 (formed by mixing span 60 (namely sorbitan monostearate) HLB value is 4.7, and Tween 80 (polyoxyethylene (20EO) sorbitan monooleate) HLB value is 15);
c)35 parts of hydrophilic monomer: the adhesive consists of 18 parts of acrylamide, 6 parts of sodium acrylate, 6 parts of 2-acrylamide-2-methyl sodium propane sulfonate and 5 parts of dimethyl diallyl ammonium chloride;
d)5 parts of hydrophobic monomer: 2-acrylamido-N-tetradecyl sodium sulfonate;
e)30 parts of water;
the composite initiator comprises the following components in percentage by weight of all the monomers:
(a) 0.5% of a water-soluble oxidizing agent; the water-soluble oxidant is ammonium persulfate
(b) 0.8% of a water-soluble reducing agent; the water-soluble reducing agent is sodium bisulfite
(c) 1% of oil-soluble azo compounds; the oil-soluble azo compound is azobisisobutyronitrile
(d) 0.5% of a water-soluble cross-linking agent; the water-soluble cross-linking agent is N, N' -methylene bisacrylamide
(e) 5% of urea;
(f) 0.3% disodium edetate;
(g) 1% sodium chloride.
The preparation method of the polymer microemulsion comprises the following specific steps:
(a) preparing an oil phase: dissolving the emulsifier consisting of span 60 with HLB of 6.7 (HLB value of 4.7) and Tween 80(HLB value of 15) in 40 parts of white oil, and uniformly stirring to obtain an oil phase I; dissolving azodiisobutyronitrile in 5 parts of the white oil, and uniformly stirring to obtain an oil phase II; and dissolving 2-acrylamide-N-tetradecyl sodium sulfonate in 5 parts of the white oil, and uniformly stirring to obtain an oil phase III.
(b) Preparing a water phase: dissolving 9 parts of acrylamide, 3 parts of sodium acrylate, 3 parts of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 5 parts of dimethyl diallyl ammonium chloride and a half amount of water-soluble composite initiator except sodium bisulfite in 13 parts of water, and uniformly stirring to obtain a nuclear water phase; dissolving the rest hydrophilic monomers and the rest water-soluble composite initiator except the sodium bisulfite into 13 parts of water, and uniformly stirring to obtain a shell water phase; dissolving sodium bisulfite in the balance of water to form a reducing agent aqueous solution;
(c) adding the oil phase I into a reactor, adding half of the oil phase II and all the nuclear water phase, uniformly stirring, dropwise adding half of the reducing agent aqueous solution, and reacting at 50 ℃ for 2 hours to obtain the polyacrylamide reverse microemulsion; and when the reaction temperature is reduced to 30 ℃, adding the rest oil phase II, oil phase III and all shell water phases again, uniformly stirring, dropwise adding the rest reducing agent aqueous solution, and reacting for 2 hours at 50 ℃ to finally obtain the core-shell type polyacrylamide reverse-phase microemulsion.
Characterization of the polymer microemulsion and the polymer microspheres therein:
testing the initial particle size of the microspheres according to the method for measuring the technical conditions of the polymer microsphere deep profile control agent of the enterprise standard Q/SH1020 China petrochemical group Shengli Petroleum administration corporation4mg/L，Ca2++Mg2+: the expansion factor of the particle size of the microspheres after aging for 7 days, 15 days, and 30 days under the condition of 5000mg/L saline water was observed, and the state of the resulting microemulsion system after standing for 3 months was observed, and the results are shown in Table 1.
Mixing 0.15 wt% of the synthesized polymer microsphere and 0.25 wt% of fatty alcohol-polyoxyethylene ether sulfonate (R is C)16N-6) and 99.6 wt% of original pu-westregion were mixed with water for 2 hours to obtain a homogeneous transparent profile control system. The interfacial tension was measured using a rotary drop interfacial tensiometer model TX500, produced by university of Texas, USA, and the body wasThe ultra-low interfacial tension of 0.0016mN/m can be formed between the system and the mixed crude oil in the Puchenxi area, and the application of the ultra-low interfacial tension in the field application for improving the recovery efficiency can play a good role in improving the oil washing efficiency and finally improving the recovery efficiency.
[ COMPARATIVE EXAMPLE 1 ]
The polymer microspheres of the comparative example were prepared by polymerization of inverse microemulsion under the action of redox complex initiator; the reverse microemulsion comprises the following components in parts by weight:
a)50 parts of an oil-soluble solvent; the oil-soluble solvent is white oil;
b)10 parts of an emulsifier; span 40 with emulsifier HLB value of 6.7;
c)35 parts of hydrophilic monomer: the adhesive consists of 18 parts of acrylamide, 6 parts of sodium acrylate, 6 parts of 2-acrylamide-2-methyl sodium propane sulfonate and 5 parts of dimethyl diallyl ammonium chloride;
d)5 parts of hydrophobic monomer: 2-acrylamido-N-tetradecyl sodium sulfonate;
e)30 parts of water;
the composite initiator comprises the following components in percentage by weight of all the monomers:
(a) 0.5% of a water-soluble oxidizing agent; the water-soluble oxidant is ammonium persulfate
(b) 0.8% of a water-soluble reducing agent; the water-soluble reducing agent is sodium bisulfite
(c) 1% of oil-soluble azo compounds; the oil-soluble azo compound is azobisisobutyronitrile
(d) 0.5% of a water-soluble cross-linking agent; the water-soluble cross-linking agent is N, N' -methylene bisacrylamide
(e) 5% of urea;
(f) 0.3% disodium edetate;
(g) 1% sodium chloride.
The preparation method of the polymer microemulsion comprises the following specific steps:
(a) preparing an oil phase: dissolving the emulsifier span 60 with HLB of 6.7 in 40 parts of the white oil, and uniformly stirring to obtain an oil phase I; dissolving azodiisobutyronitrile in 5 parts of the white oil, and uniformly stirring to obtain an oil phase II; and dissolving 2-acrylamide-N-tetradecyl sodium sulfonate in 5 parts of the white oil, and uniformly stirring to obtain an oil phase III.
(b) Preparing a water phase: dissolving 9 parts of acrylamide, 3 parts of sodium acrylate, 3 parts of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 5 parts of dimethyl diallyl ammonium chloride and a half amount of water-soluble composite initiator except sodium bisulfite in 13 parts of water, and uniformly stirring to obtain a nuclear water phase; dissolving the rest hydrophilic monomers and the rest water-soluble composite initiator except the sodium bisulfite into 13 parts of water, and uniformly stirring to obtain a shell water phase; dissolving sodium bisulfite in the balance of water to form a reducing agent aqueous solution;
(c) adding the oil phase I into a reactor, adding half of the oil phase II and all the nuclear water phase, uniformly stirring, dropwise adding half of the reducing agent aqueous solution, and reacting at 50 ℃ for 2 hours to obtain the polyacrylamide reverse microemulsion; and when the reaction temperature is reduced to 30 ℃, adding the rest oil phase II, oil phase III and all shell water phases again, uniformly stirring, dropwise adding the rest reducing agent aqueous solution, and reacting for 2 hours at 50 ℃ to finally obtain the core-shell type polyacrylamide reverse-phase microemulsion.
The polymer microemulsion and the method of characterizing the polymer microspheres therein were the same as in example 1, with the results shown in table 1.
Mixing 0.15 wt% of the synthesized polymer microsphere and 0.25 wt% of fatty alcohol-polyoxyethylene ether sulfonate (R is C)16N-6) and 99.6 wt% of original pu-westregion were mixed with water for 2 hours to obtain a homogeneous transparent profile control system. The interfacial tension is measured by a TX500 type rotary drop interfacial tensiometer produced by American Texas university, the interfacial tension between the system and Puconxi mixed crude oil is 0.1006mN/m, and the system cannot play a good role in improving the oil washing efficiency and finally improving the recovery ratio.
The inventor of the invention finds that the emulsifier used in the invention is preferably a nonionic surfactant mixture with HLB of 5-8 compounded by a nonionic surfactant with HLB of 1-7 and a nonionic surfactant with HLB of 8-18, and the nonionic surfactant with HLB of 1-7 and the nonionic surfactant with HLB of 8-18 in the obtained nonionic surfactant mixture have synergistic effect on improving the stability of the polyacrylamide microemulsion and the expansibility of the polymer microspheres in the polyacrylamide microemulsion. This is visually observed from the data of the same scale in example 1 and comparative example 1.
[ example 2 ]
The polymer microsphere of the embodiment is prepared by the polymerization reaction of reverse microemulsion under the action of a redox composite initiator; the reverse microemulsion comprises the following components in parts by weight:
a)50 parts of an oil-soluble solvent; the oil-soluble solvent is white oil;
b)10 parts of an emulsifier; the emulsifier HLB value is 6.7 (formed by mixing span 60 (namely sorbitan monostearate) HLB value is 4.7, and Tween 80 (polyoxyethylene (20EO) sorbitan monooleate) HLB value is 15);
c)35 parts of hydrophilic monomer: the adhesive consists of 18 parts of acrylamide, 6 parts of sodium acrylate, 6 parts of 2-acrylamide-2-methyl sodium propane sulfonate and 5 parts of dimethyl diallyl ammonium chloride;
d)5 parts of hydrophobic monomer: p-tert-butylstyrene;
e)30 parts of water;
the composite initiator comprises the following components in percentage by weight of all the monomers:
(a) 0.5% of a water-soluble oxidizing agent; the water-soluble oxidant is ammonium persulfate
(b) 0.8% of a water-soluble reducing agent; the water-soluble reducing agent is sodium bisulfite
(c) 1% of water-soluble azo compounds; the water-soluble azo compound is 2,2' -azo [2- (2-imidazoline-2-yl) propane ] dihydrochloride
(d) 0.5% of a water-soluble cross-linking agent; the water-soluble cross-linking agent is N, N' -methylene bisacrylamide
(e) 5% of urea;
(f) 0.3% disodium edetate;
(g) 1% sodium chloride.
The preparation method of the polymer microemulsion comprises the following specific steps:
(a) preparing an oil phase: dissolving an emulsifier consisting of span 60 with HLB of 6.7 (HLB value of 4.7) and Tween 80(HLB value of 15) in 45 parts of white oil, and uniformly stirring to obtain an oil phase I; and dissolving p-tert-butyl styrene in 5 parts of the white oil, and uniformly stirring to obtain an oil phase II.
(b) Preparing a water phase: dissolving 9 parts of acrylamide, 3 parts of sodium acrylate, 3 parts of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 5 parts of dimethyl diallyl ammonium chloride and a half amount of water-soluble composite initiator except sodium bisulfite in 13 parts of water, and uniformly stirring to obtain a nuclear water phase; dissolving the rest hydrophilic monomers and the rest water-soluble composite initiator except the sodium bisulfite into 13 parts of water, and uniformly stirring to obtain a shell water phase; dissolving sodium bisulfite in the balance of water to form a reducing agent aqueous solution;
(c) adding the oil phase I into a reactor, adding all nuclear water phases, uniformly stirring, dropwise adding a half amount of reducing agent aqueous solution, and reacting at 50 ℃ for 3 hours to obtain polyacrylamide reverse microemulsion; and when the reaction temperature is reduced to 30 ℃, adding the oil phase II and all shell water phases again, uniformly stirring, dropwise adding the rest reducing agent aqueous solution, and reacting at 50 ℃ for 3 hours to finally obtain the core-shell type polyacrylamide reverse microemulsion.
The polymer microemulsion and the method of characterizing the polymer microspheres therein were the same as in example 1, with the results shown in table 1.
Mixing 0.15 wt% of the synthesized polymer microsphere and 0.25 wt% of fatty alcohol-polyoxyethylene ether sulfonate (R is C)16N-6) and 99.6 wt% of original pu-westregion were mixed with water for 2 hours to obtain a homogeneous transparent profile control system. The interfacial tension is measured by a TX500 type rotary drop interfacial tensiometer produced by American Texas university, and the system and Puconxi mixed crude oil can form an ultralow interfacial tension of 0.0028mN/m, so that the system can play a good role in improving the oil washing efficiency and finally improving the recovery ratio when being applied to field application of improving the recovery ratio.
[ example 3 ]
The polymer microsphere of the embodiment is prepared by the polymerization reaction of reverse microemulsion under the action of a redox composite initiator; the reverse microemulsion comprises the following components in parts by weight:
a)50 parts of an oil-soluble solvent; the oil-soluble solvent is white oil;
b)10 parts of an emulsifier; the emulsifier HLB value is 6.7 (formed by mixing span 60 (namely sorbitan monostearate) HLB value is 4.7, and Tween 80 (polyoxyethylene (20EO) sorbitan monooleate) HLB value is 15);
c)35 parts of hydrophilic monomer: the adhesive consists of 18 parts of acrylamide, 6 parts of sodium acrylate, 6 parts of 2-acrylamide-2-methyl sodium propane sulfonate and 5 parts of dimethyl diallyl ammonium chloride;
d)5 parts of hydrophobic monomer: stearyl methacrylate;
e)30 parts of water;
the composite initiator comprises the following components in percentage by weight of all the monomers:
(a) 0.5% of a water-soluble oxidizing agent; the water-soluble oxidant is ammonium persulfate
(b) 0.8% of a water-soluble reducing agent; the water-soluble reducing agent is sodium bisulfite
(c) 1% of oil-soluble azo compounds; the oil-soluble azo compound is azobisisobutyronitrile
(d) 0.5% of a water-soluble cross-linking agent; the water-soluble cross-linking agent is N, N' -methylene bisacrylamide
(e) 5% of urea;
(f) 0.3% disodium edetate;
(g) 1% sodium chloride.
The preparation method of the polymer microemulsion comprises the following specific steps:
(a) preparing an oil phase: dissolving the emulsifier consisting of span 60 with HLB of 6.7 (HLB value of 4.7) and Tween 80(HLB value of 15) in 40 parts of white oil, and uniformly stirring to obtain an oil phase I; dissolving azodiisobutyronitrile in 5 parts of the white oil, and uniformly stirring to obtain an oil phase II; and dissolving stearyl methacrylate in 5 parts of the white oil, and uniformly stirring to obtain an oil phase III.
(b) Preparing a water phase: dissolving 9 parts of acrylamide, 3 parts of sodium acrylate, 3 parts of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 5 parts of dimethyl diallyl ammonium chloride and a half amount of water-soluble composite initiator except sodium bisulfite in 13 parts of water, and uniformly stirring to obtain a nuclear water phase; dissolving the rest hydrophilic monomers and the rest water-soluble composite initiator except the sodium bisulfite into 13 parts of water, and uniformly stirring to obtain a shell water phase; dissolving sodium bisulfite in the balance of water to form a reducing agent aqueous solution;
(c) adding the oil phase I into a reactor, adding half of the oil phase II and all the nuclear water phase, uniformly stirring, dropwise adding half of the reducing agent aqueous solution, and reacting at 60 ℃ for 2 hours to obtain the polyacrylamide reverse microemulsion; and when the reaction temperature is reduced to 30 ℃, adding the rest oil phase II, oil phase III and all shell water phases again, uniformly stirring, dropwise adding the rest reducing agent aqueous solution, and reacting for 2 hours at 60 ℃ to finally obtain the core-shell type polyacrylamide reverse-phase microemulsion.
The polymer microemulsion and the method of characterizing the polymer microspheres therein were the same as in example 1, with the results shown in table 1.
Mixing 0.15 wt% of the synthesized polymer microsphere and 0.25 wt% of fatty alcohol-polyoxyethylene ether sulfonate (R is C)16N-6) and 99.6 wt% of original pu-westregion were mixed with water for 2 hours to obtain a homogeneous transparent profile control system. The interfacial tension is measured by a TX500 type rotary drop interfacial tensiometer produced by American Texas university, and the system and Puconxi mixed crude oil can form an ultralow interfacial tension of 0.0023mN/m, so that the system can play a good role in improving the oil washing efficiency and finally improving the recovery ratio when being applied to field application of improving the recovery ratio.
[ example 4 ]
The polymer microsphere of the embodiment is prepared by the polymerization reaction of reverse microemulsion under the action of a redox composite initiator; the reverse microemulsion comprises the following components in parts by weight:
a)50 parts of an oil-soluble solvent; the oil-soluble solvent is white oil;
b)10 parts of an emulsifier having an HLB value of 6.7 (defined by span 60 (i.e., sorbitan monostearate) HLB value 4.7; tween 80 (polyoxyethylene (20EO) sorbitan monooleate) with an HLB value of 15;
c)35 parts of hydrophilic monomer: the adhesive consists of 18 parts of acrylamide, 6 parts of sodium acrylate, 6 parts of 2-acrylamide-2-methyl sodium propane sulfonate and 5 parts of dimethyl diallyl ammonium chloride;
d)5 parts of hydrophobic monomer: n-phenylmaleimide;
e)30 parts of water;
the composite initiator comprises the following components in percentage by weight of all the monomers:
(a) 0.5% of a water-soluble oxidizing agent; the water-soluble oxidant is ammonium persulfate
(b) 0.8% of a water-soluble reducing agent; the water-soluble reducing agent is sodium bisulfite
(c) 1% of water-soluble azo compounds; the water-soluble azo compound is 2,2' -azo [2- (2-imidazoline-2-yl) propane ] dihydrochloride
(d) 0.5% of a water-soluble cross-linking agent; the water-soluble cross-linking agent is N, N' -methylene bisacrylamide
(e) 5% of urea;
(f) 0.3% disodium edetate;
(g) 1% sodium chloride.
The preparation method of the polymer microemulsion comprises the following specific steps:
(a) preparing an oil phase: dissolving an emulsifier consisting of span 60 with HLB of 6.7 (HLB value of 4.7) and Tween 80(HLB value of 15) in 45 parts of white oil, and uniformly stirring to obtain an oil phase I; and dissolving N-phenylmaleimide in 5 parts of the white oil, and uniformly stirring to obtain an oil phase II.
(b) Preparing a water phase: dissolving 9 parts of acrylamide, 3 parts of sodium acrylate, 3 parts of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 5 parts of dimethyl diallyl ammonium chloride and a half amount of water-soluble composite initiator except sodium bisulfite in 13 parts of water, and uniformly stirring to obtain a nuclear water phase; dissolving the rest hydrophilic monomers and the rest water-soluble composite initiator except the sodium bisulfite into 13 parts of water, and uniformly stirring to obtain a shell water phase; dissolving sodium bisulfite in the balance of water to form a reducing agent aqueous solution;
(c) adding the oil phase I into a reactor, adding all nuclear water phases, uniformly stirring, dropwise adding a half amount of reducing agent aqueous solution, and reacting at 50 ℃ for 3 hours to obtain polyacrylamide reverse microemulsion; and when the reaction temperature is reduced to 30 ℃, adding the oil phase II and all shell water phases again, uniformly stirring, dropwise adding the rest reducing agent aqueous solution, and reacting at 50 ℃ for 3 hours to finally obtain the core-shell type polyacrylamide reverse microemulsion.
The polymer microemulsion and the method of characterizing the polymer microspheres therein were the same as in example 1, with the results shown in table 1.
Mixing 0.15 wt% of the synthesized polymer microsphere and 0.25 wt% of fatty alcohol-polyoxyethylene ether sulfonate (R is C)16N-6) and 99.6 wt% of original pu-westregion were mixed with water for 2 hours to obtain a homogeneous transparent profile control system. The interfacial tension is measured by adopting a TX500 type rotary drop interfacial tensiometer produced by American Texas university, and the system and Puconxi mixed crude oil can form an ultralow interfacial tension of 0.0045mN/m, so that the system can play a good role in improving the oil washing efficiency and finally improving the recovery ratio when being applied to field application of improving the recovery ratio.
[ example 5 ]
The polymer microsphere of the embodiment is prepared by the polymerization reaction of reverse microemulsion under the action of a redox composite initiator; the reverse microemulsion comprises the following components in parts by weight:
a)50 parts of an oil-soluble solvent; the oil-soluble solvent is white oil;
b)10 parts of an emulsifier; the emulsifier HLB value is 6.7 (formed by mixing span 60 (namely sorbitan monostearate) HLB value is 4.7, and Tween 80 (polyoxyethylene (20EO) sorbitan monooleate) HLB value is 15);
c)35 parts of hydrophilic monomer: the adhesive consists of 18 parts of acrylamide, 6 parts of sodium acrylate, 6 parts of 2-acrylamide-2-methyl sodium propane sulfonate and 5 parts of acryloyloxyethyl trimethyl ammonium chloride;
d)5 parts of hydrophobic monomer: maleic anhydride
e)30 parts of water;
the composite initiator comprises the following components in percentage by weight of all the monomers:
(a) 0.5% of a water-soluble oxidizing agent; the water-soluble oxidant is ammonium persulfate
(b) 0.8% of a water-soluble reducing agent; the water-soluble reducing agent is sodium bisulfite
(c) 1% of water-soluble azo compounds; the water-soluble azo compound is 2,2' -azo [2- (2-imidazoline-2-yl) propane ] dihydrochloride
(d) 0.5% of a water-soluble cross-linking agent; the water-soluble cross-linking agent is N, N' -methylene bisacrylamide
(e) 5% of urea;
(f) 0.3% disodium edetate;
(g) 1% sodium chloride.
The preparation method of the polymer microemulsion comprises the following specific steps:
(a) preparing an oil phase: dissolving an emulsifier consisting of span 60 with HLB of 6.7 (HLB value of 4.7) and Tween 80(HLB value of 15) in 45 parts of white oil, and uniformly stirring to obtain an oil phase I; and dissolving maleic anhydride in 5 parts of the white oil, and uniformly stirring to obtain an oil phase II.
(b) Preparing a water phase: dissolving 9 parts of acrylamide, 3 parts of sodium acrylate, 3 parts of 2-acrylamido-2-methylpropanesulfonic acid sodium salt, 5 parts of acryloyloxyethyl trimethyl ammonium chloride and a half amount of water-soluble composite initiator except sodium bisulfite in 13 parts of water, and uniformly stirring to obtain a nuclear water phase; dissolving the rest hydrophilic monomers and the rest water-soluble composite initiator except the sodium bisulfite into 13 parts of water, and uniformly stirring to obtain a shell water phase; dissolving sodium bisulfite in the balance of water to form a reducing agent aqueous solution;
(c) adding the oil phase I into a reactor, adding all nuclear water phases, uniformly stirring, dropwise adding a half amount of reducing agent aqueous solution, and reacting at 50 ℃ for 2 hours to obtain polyacrylamide reverse microemulsion; and when the reaction temperature is reduced to 30 ℃, adding the oil phase II and all shell water phases again, stirring uniformly, dropwise adding the rest reducing agent aqueous solution, and reacting at 50 ℃ for 2 hours to finally obtain the core-shell type polyacrylamide reverse microemulsion.
The polymer microemulsion and the method of characterizing the polymer microspheres therein were the same as in example 1, with the results shown in table 1.
Mixing 0.15 wt% of the synthesized polymer microsphere and 0.25 wt% of fatty alcohol-polyoxyethylene ether sulfonate (R is C)16N-6) and 99.6 wt% of original pu-westregion were mixed with water for 2 hours to obtain a homogeneous transparent profile control system. The interfacial tension is measured by adopting a TX500 type rotary drop interfacial tension meter produced by American Texas university, and the ultra-low interfacial tension of 0.0064mN/m can be formed between the system and Pucixi mixed crude oil, so that the system can play a good role in improving the oil washing efficiency and finally improving the recovery ratio when being applied to field application for improving the recovery ratio.
[ COMPARATIVE EXAMPLE 2 ]
The polymer microspheres of the comparative example were prepared by polymerization of inverse microemulsion under the action of redox complex initiator; the reverse microemulsion comprises the following components in parts by weight:
a)50 parts of an oil-soluble solvent; the oil-soluble solvent is white oil;
b)10 parts of an emulsifier; the emulsifier HLB value is 6.7 (formed by mixing span 60 (namely sorbitan monostearate) HLB value is 4.7, and Tween 80 (polyoxyethylene (20EO) sorbitan monooleate) HLB value is 15);
c)35 parts of hydrophilic monomer: the adhesive consists of 18 parts of acrylamide, 6 parts of sodium acrylate, 6 parts of 2-acrylamide-2-methyl sodium propane sulfonate and 5 parts of dimethyl diallyl ammonium chloride;
d)5 parts of hydrophobic monomer: 2-acrylamido-N-tetradecyl sodium sulfonate;
e)30 parts of water;
the composite initiator comprises the following components in percentage by weight of all the monomers:
(a) 0.5% of a water-soluble oxidizing agent; the water-soluble oxidant is ammonium persulfate
(b) 0.8% of a water-soluble reducing agent; the water-soluble reducing agent is sodium bisulfite
(c) 1% of oil-soluble azo compounds; the oil-soluble azo compound is azobisisobutyronitrile
(d) 0.5% of a water-soluble cross-linking agent; the water-soluble cross-linking agent is N, N' -methylene bisacrylamide
(e) 5% of urea;
(f) 0.3% disodium edetate;
(g) 1% sodium chloride.
The preparation method of the polymer microemulsion comprises the following specific steps:
(a) preparing an oil phase: dissolving the emulsifier consisting of span 60 with HLB of 6.7 (HLB value of 4.7) and Tween 80(HLB value of 15) in 40 parts of white oil, and uniformly stirring to obtain an oil phase I; and dissolving azodiisobutyronitrile and 2-acrylamide-N-tetradecyl sodium sulfonate in 10 parts of the white oil, and uniformly stirring to obtain an oil phase II.
(b) Preparing a water phase: dissolving acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid sodium salt, dimethyl diallyl ammonium chloride and a water-soluble composite initiator except sodium bisulfite in 26 parts of water, and uniformly stirring to obtain a water phase; dissolving sodium bisulfite in the balance of water to form a reducing agent aqueous solution;
(c) adding the oil phase I into a reactor, adding the oil phase II and all the water phases, uniformly stirring, dropwise adding a reducing agent aqueous solution, and reacting at 50 ℃ for 4 hours to obtain the polyacrylamide reverse microemulsion.
The polymer microemulsion and the method of characterizing the polymer microspheres therein were the same as in example 1, with the results shown in table 1.
Mixing 0.15 wt% of the synthesized polymer microsphere and 0.25 wt% of fatty alcohol-polyoxyethylene ether sulfonate (R is C)16N-6) and 99.6 wt% of original pu-westregion were mixed with water for 2 hours to obtain a homogeneous transparent profile control system. The interface tension is measured by a TX500 type rotary drop interface tensiometer produced by American Texas university, the system and Puconxi mixed crude oil can form an ultralow interface tension of 0.0564mN/m, and the application of the system in the field application of improving the recovery efficiency can improve the oil washing efficiency to a certain extent and finally realize the oil washing efficiencyImproving the recovery efficiency.
[ COMPARATIVE EXAMPLE 3 ]
The polymer microspheres of the comparative example were prepared by polymerization of inverse microemulsion under the action of redox complex initiator; the reverse microemulsion comprises the following components in parts by weight:
a)50 parts of an oil-soluble solvent; the oil-soluble solvent is white oil;
b)10 parts of an emulsifier; the emulsifier HLB value is 6.7 (formed by mixing span 60 (namely sorbitan monostearate) HLB value is 4.7, and Tween 80 (polyoxyethylene (20EO) sorbitan monooleate) HLB value is 15);
c)40 parts of hydrophilic monomer: 20 parts of acrylamide, 10 parts of sodium acrylate and 10 parts of 2-acrylamide-2-methyl sodium propane sulfonate;
d)30 parts of water;
the composite initiator comprises the following components in percentage by weight of all the monomers:
(a) 0.5% of a water-soluble oxidizing agent; the water-soluble oxidant is ammonium persulfate
(b) 0.8% of a water-soluble reducing agent; the water-soluble reducing agent is sodium bisulfite
(c) 1% of water-soluble azo compounds; the water-soluble azo compound is 2,2' -azo [2- (2-imidazoline-2-yl) propane ] dihydrochloride
(d) 0.5% of a water-soluble cross-linking agent; the water-soluble cross-linking agent is N, N' -methylene bisacrylamide
(e) 5% of urea;
(f) 0.3% disodium edetate;
(g) 1% sodium chloride.
The preparation method of the polymer microemulsion comprises the following specific steps:
(a) preparing an oil phase: and (3) dissolving the emulsifier consisting of span 60 with the HLB of 6.7 (the HLB value is 4.7) and Tween 80 (the HLB value is 15) in 50 parts of the white oil, and uniformly stirring to obtain an oil phase.
(b) Preparing a water phase: dissolving acrylamide, sodium acrylate, 2-acrylamido-2-methylpropanesulfonic acid sodium salt and a water-soluble composite initiator except sodium bisulfite in 26 parts of water, and uniformly stirring to obtain a water phase; dissolving sodium bisulfite in the balance of water to form a reducing agent aqueous solution;
(c) adding the oil phase into a reactor, adding half of the aqueous phase solution as a nuclear aqueous phase, uniformly stirring, dropwise adding half of the reducing agent aqueous solution, and reacting at 50 ℃ for 2 hours to obtain the polyacrylamide reverse microemulsion; and (3) when the reaction temperature is reduced to 30 ℃, adding the rest aqueous phase solution as a shell aqueous phase again, uniformly stirring, dropwise adding the rest aqueous solution of the reducing agent, and reacting at 50 ℃ for 2 hours to finally obtain the core-shell type polyacrylamide reverse-phase microemulsion.
The polymer microemulsion and the method of characterizing the polymer microspheres therein were the same as in example 1, with the results shown in table 1.
Mixing 0.15 wt% of the synthesized polymer microsphere and 0.25 wt% of fatty alcohol-polyoxyethylene ether sulfonate (R is C)16N-6) and 99.6 wt% of original pu-westregion were mixed with water for 2 hours to obtain a homogeneous transparent profile control system. The interfacial tension is measured by a TX500 type rotary drop interfacial tensiometer produced by American Texas university, and the system and Puconxi mixed crude oil can form an ultralow interfacial tension of 0.0816mN/m, so that the system can play a certain role in improving the oil washing efficiency and finally improving the recovery ratio when being applied to field application of improving the recovery ratio.
[ example 6 ]
The polymer microsphere of the embodiment is prepared by the polymerization reaction of reverse microemulsion under the action of a redox composite initiator; the reverse microemulsion comprises the following components in parts by weight:
a)50 parts of an oil-soluble solvent; the oil-soluble solvent is white oil;
b)10 parts of an emulsifier; the emulsifier HLB value is 6.7 (formed by mixing span 60 (namely sorbitan monostearate) HLB value is 4.7, and Tween 80 (polyoxyethylene (20EO) sorbitan monooleate) HLB value is 15);
c)35 parts of hydrophilic monomer: the adhesive consists of 18 parts of acrylamide, 12 parts of sodium acrylate and 5 parts of dimethyl diallyl ammonium chloride;
d)5 parts of hydrophobic monomer: 2-acrylamido-N-tetradecyl sodium sulfonate;
e)30 parts of water;
the composite initiator comprises the following components in percentage by weight of all the monomers:
(a) 0.5% of a water-soluble oxidizing agent; the water-soluble oxidant is ammonium persulfate
(b) 0.8% of a water-soluble reducing agent; the water-soluble reducing agent is sodium bisulfite
(c) 1% of oil-soluble azo compounds; the oil-soluble azo compound is azobisisobutyronitrile
(d) 0.5% of a water-soluble cross-linking agent; the water-soluble cross-linking agent is N, N' -methylene bisacrylamide
(e) 5% of urea;
(f) 0.3% disodium edetate;
(g) 1% sodium chloride.
The preparation method of the polymer microemulsion comprises the following specific steps:
(a) preparing an oil phase: dissolving the emulsifier consisting of span 60 with HLB of 6.7 (HLB value of 4.7) and Tween 80(HLB value of 15) in 40 parts of white oil, and uniformly stirring to obtain an oil phase I; dissolving azodiisobutyronitrile in 5 parts of the white oil, and uniformly stirring to obtain an oil phase II; and dissolving 2-acrylamide-N-tetradecyl sodium sulfonate in 5 parts of the white oil, and uniformly stirring to obtain an oil phase III.
(b) Preparing a water phase: dissolving 9 parts of acrylamide, 6 parts of sodium acrylate, 5 parts of dimethyl diallyl ammonium chloride and half of water-soluble composite initiator except sodium bisulfite in 13 parts of water, and uniformly stirring to obtain a nuclear water phase; dissolving the rest hydrophilic monomers and the rest water-soluble composite initiator except the sodium bisulfite into 13 parts of water, and uniformly stirring to obtain a shell water phase; dissolving sodium bisulfite in the balance of water to form a reducing agent aqueous solution;
(c) adding the oil phase I into a reactor, adding half of the oil phase II and all the nuclear water phase, uniformly stirring, dropwise adding half of the reducing agent aqueous solution, and reacting at 50 ℃ for 2 hours to obtain the polyacrylamide reverse microemulsion; and when the reaction temperature is reduced to 30 ℃, adding the rest oil phase II, oil phase III and all shell water phases again, uniformly stirring, dropwise adding the rest reducing agent aqueous solution, and reacting for 2 hours at 50 ℃ to finally obtain the core-shell type polyacrylamide reverse-phase microemulsion.
Characterization of the polymer microemulsion and the polymer microspheres therein:
testing the initial particle size of the microspheres according to the method for measuring the technical conditions of the polymer microsphere deep profile control agent of the enterprise standard Q/SH1020 China petrochemical group Shengli Petroleum administration corporation4mg/L，Ca2++Mg2+: the expansion factor of the particle size of the microspheres after aging for 7 days, 15 days, and 30 days under the condition of 5000mg/L saline water was observed, and the state of the resulting microemulsion system after standing for 3 months was observed, and the results are shown in Table 1.
Mixing 0.15 wt% of the synthesized polymer microsphere and 0.25 wt% of fatty alcohol-polyoxyethylene ether sulfonate (R is C)16N-6) and 99.6 wt% of original pu-westregion were mixed with water for 2 hours to obtain a homogeneous transparent profile control system. The interfacial tension is measured by adopting a TX500 type rotary drop interfacial tensiometer produced by American Texas university, and the system and Puconxi mixed crude oil can form an ultralow interfacial tension of 0.0016mN/m, so that the system can play a good role in improving the oil washing efficiency and finally improving the recovery ratio when being applied to field application of improving the recovery ratio.
The inventor discovers that a micro-emulsion profile control system formed by the polymer microspheres and the fatty alcohol-polyoxyethylene ether sulfonate prepared by the invention can form ultra-low interfacial tension with crude oil in Puchenxi region of the original oilfield, and when the micro-emulsion profile control system is applied to field application for improving the recovery ratio, the micro-emulsion profile control system can play a good role in improving the oil washing efficiency and finally improving the recovery ratio. Meanwhile, the inverse microemulsion prepared by the invention can well solve the problem that the polymer microspheres in the microemulsion in the prior art have poor expansibility under high-temperature and high-salt conditions, which can be visually seen from the comparative data of the embodiments 1-6 and the comparative examples 2 and 3.
TABLE 1
Claims (9)
1. A micro-emulsion profile control and flooding system comprises the following components in percentage by weight:
(1) 0.01-5.0% of core-shell polymer microspheres;
(2)0.01 to 5.0% of an anionic-nonionic surfactant;
(3) 90.0-99.98% of injected water;
the core-shell polymer microsphere is prepared by carrying out polymerization reaction on reverse microemulsion under the action of a redox composite initiator; the reverse microemulsion comprises the following components in parts by weight:
a)50 parts of an oil-soluble solvent;
b) 3-20 parts of an emulsifier;
c) 10-60 parts of a hydrophilic monomer;
d) 0.5-10 parts of a hydrophobic monomer;
e) 10-50 parts of water;
the composite initiator comprises the following components in percentage by weight of all the monomers:
(a) 0.02-1.0% of an oxidant;
(b) 0.02-2.0% of a reducing agent;
(c) 0.03-2.0% of azo compounds;
(d)0.01 to 1.0% of a crosslinking agent;
(e) 0.1-10% of urea and thiourea;
(f) 0.01-0.5% of an aminocarboxylic complexing agent;
(g) 0.5-5% of electrolyte salt;
the hydrophilic monomers include at least one nonionic monomer, at least two anionic monomers, and at least one cationic monomer;
the core-shell polymer microsphere is prepared by adopting a method comprising the following steps:
(a) preparing an oil phase: dissolving an emulsifier in an oil-soluble solvent, and uniformly stirring to obtain an oil phase I; dissolving an oil-soluble cross-linking agent and an oil-soluble azo initiator in an oil-soluble solvent, and uniformly stirring to obtain an oil phase II; dissolving an oil-soluble hydrophobic monomer in an oil-soluble solvent, and uniformly stirring to obtain an oil phase III;
(b) preparing a water phase: dissolving 40-70 wt% of hydrophilic monomer and water-soluble composite initiator except reducing agent in water, and uniformly stirring to obtain nuclear water phase; dissolving the rest hydrophilic monomer and the water-soluble composite initiator except the reducing agent in water, and uniformly stirring to obtain a shell water phase; dissolving a reducing agent in water to form a reducing agent aqueous solution;
(c) adding the oil phase I into a reactor, adding 40-70 wt% of oil phase II and a nuclear water phase, uniformly stirring, dropwise adding a reducing agent aqueous solution, and reacting at 40-80 ℃ for 1-4 hours to obtain polyacrylamide reverse-phase microemulsion; and when the reaction temperature is reduced to 15-35 ℃, adding the rest oil phase II, oil phase III and shell water phase again, stirring uniformly, dropwise adding a reducing agent aqueous solution, and reacting at 40-80 ℃ for 1-4 hours to finally obtain the core-shell type polyacrylamide reverse microemulsion.
2. The microemulsion profile control and flooding system according to claim 1, characterized in that the total mineralization of the injected water is 80000-180000 mg/L, Ca2++Mg2+1000-5000 mg/L.
3. The microemulsion profile-controlling system as claimed in claim 1, wherein the anionic-nonionic surfactant has a molecular formula of RO (CH)2CH2O)nCH2SO3M, R are C10～C25N is 1-20, M is selected from H, alkali metal or NH4。
4. The microemulsion profile-controlling system as claimed in claim 3, wherein R is C12～C18A hydrocarbon group of (1).
5. The microemulsion profile control and flooding system according to claim 3, characterized in that n is 2-8.
6. The microemulsion profile-controlling and flooding system according to claim 3, characterized in that the alkali metal in the fatty alcohol-polyoxyethylene ether sulfonate is selected from potassium, sodium or lithium.
7. The microemulsion flooding system of claim 1, wherein the oil-soluble solvent is selected from at least one of a hydrocarbon or an ester.
8. The microemulsion profile control and displacement system as claimed in claim 1, wherein the emulsifier has HLB value of 4-9.
9. The microemulsion profile control and flooding system as set forth in any one of claims 1 to 8, is applied to tertiary oil recovery of high-temperature high-salinity low-permeability oil reservoirs.
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| CN106589226A (en) * | 2015-10-20 | 2017-04-26 | 中国石油化工股份有限公司 | Profile controlling and flooding composition and application thereof |
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| BRPI0907314B1 (en) * | 2008-04-21 | 2019-04-24 | Nalco Company | Composition of expandable polymeric microparticle and method for modifying water permeability of an underground formation |
| CN102399345B (en) * | 2010-09-14 | 2013-12-18 | 中国科学院理化技术研究所 | Emulsion deep profile/displacement control agent and preparation method of emulsion deep profile/displacement control agent containing gel microspheres of core shell structure |
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| CN106589226A (en) * | 2015-10-20 | 2017-04-26 | 中国石油化工股份有限公司 | Profile controlling and flooding composition and application thereof |
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