阅读说明：本技术 一种耐温抗盐共聚物的制备方法 (Preparation method of temperature-resistant salt-resistant copolymer ) 是由 祝仰文 郭拥军 曹绪龙 窦立霞 徐辉 何冬月 庞雪君 孙秀芝 季岩峰 李海涛 李 于 2019-08-29 设计创作，主要内容包括：本发明属于化学合成领域,涉及一种耐温抗盐共聚物的制备方法。所述包括以下步骤：反应器中依次加入水、添加剂、丙烯酰胺、功能单体、模板物质,加入无机碱调节聚合体系pH值,加入引发剂引发聚合反应,聚合体系置于绝热环境,当聚合体系中心温度升高不变,停止反应,得聚合物胶体；将聚合物胶体粉碎成胶粒,加入水解剂进行水解,干燥、粉碎、筛分,即得；模板物质为聚丙烯酰氧乙基三甲基氯化铵或聚甲基丙烯酰胺丙基三甲基氯化铵,功能单体为含有端烯基的磺酸衍生物及其磺酸盐衍生物；模板物质与功能单体摩尔比为0.1~1:1；功能单体与丙烯酰胺的摩尔比为0.05~0.2:1。本发明各组分相互协同,得到的共聚物耐温抗盐性能显著提升。(The invention belongs to the field of chemical synthesis, and relates to a preparation method of a temperature-resistant salt-resistant copolymer. The method comprises the following steps: sequentially adding water, an additive, acrylamide, a functional monomer and a template substance into a reactor, adding an inorganic base to adjust the pH value of a polymerization system, adding an initiator to initiate polymerization reaction, placing the polymerization system in an adiabatic environment, and stopping the reaction when the central temperature of the polymerization system is not increased to obtain a polymer colloid; crushing polymer colloid into colloidal particles, adding a hydrolytic agent for hydrolysis, drying, crushing and screening to obtain the polymer colloid; the template substance is polyacrylic acyloxy ethyl trimethyl ammonium chloride or polymethacrylamidopropyl trimethyl ammonium chloride, and the functional monomer is a sulfonic acid derivative containing terminal alkenyl and a sulfonate derivative thereof; the molar ratio of the template substance to the functional monomer is 0.1-1: 1; the molar ratio of the functional monomer to the acrylamide is 0.05-0.2: 1. The components of the invention are synergistic, and the temperature resistance and salt resistance of the obtained copolymer are obviously improved.)

1. A preparation method of a temperature-resistant salt-resistant copolymer is characterized by comprising the following steps: sequentially adding water, an additive, acrylamide, a functional monomer and a template substance into a reactor, adding an inorganic base to adjust the pH value of a polymerization system, adding an initiator to initiate polymerization reaction, placing the polymerization system in an adiabatic environment, and stopping the reaction when the central temperature of the polymerization system is not increased to obtain a polymer colloid; crushing polymer colloid into colloidal particles, adding a hydrolytic agent for hydrolysis, drying, crushing and screening to obtain the polymer colloid; the template substance is polyacrylic acyloxy ethyl trimethyl ammonium chloride or polymethacrylamidopropyl trimethyl ammonium chloride, and the functional monomer is a sulfonic acid derivative containing terminal alkenyl and a sulfonate derivative thereof; the molar ratio of the template substance to the functional monomer is 0.1-1: 1; the molar ratio of the functional monomer to the acrylamide is 0.05-0.2: 1.

2. The method according to claim 1, wherein the molecular weight of the poly (acryloyloxyethyl trimethyl ammonium chloride) is 1000 to 20000; the molecular weight of the poly (methyl acrylamide propyl trimethyl ammonium chloride) is 1000-30000.

3. The method according to claim 1, wherein the terminal alkenyl group-containing sulfonic acid derivative and the sulfonate derivative thereof comprise: 2-acrylamido-2-methylpropanesulfonic acid and its sulfonates, vinylsulfonic acid and its sulfonates, and styrenesulfonic acid and its sulfonates.

4. The method of claim 1, wherein the additive comprises EDTA-2Na, urea, and sodium formate, wherein the EDTA-2Na is present in an amount of 0.002 wt% to 0.2 wt% based on the acrylamide concentration, the urea is present in an amount of 0.005 wt% to 10 wt% based on the acrylamide concentration, and the sodium formate is present in an amount of 0.001 wt% to 0.02 wt% based on the acrylamide concentration.

5. The preparation method according to claim 1, wherein the initiator is a redox system composed of an oxidant and a reducing agent, the oxidant is a persulfate, preferably, the persulfate is one selected from potassium persulfate and ammonium persulfate; the reducing agent is sulfite, preferably, the sulfite is selected from one of sodium bisulfite, sodium sulfite and sodium metabisulfite; the mass ratio of the oxidant to the reducer is 1:1, and the addition amount of the oxidant or the reducer is 0.01 wt% -0.2 wt% of the concentration of acrylamide.

6. The preparation method according to claim 1, wherein the acrylamide concentration is 10 wt% to 30 wt%, the pH value of the polymerization system is 5 to 7, and the initiation temperature is-5 ℃ to 30 ℃.

7. The preparation method according to claim 1, wherein the hydrolysis agent is added according to the degree of hydrolysis, wherein the degree of hydrolysis is 5-25%, and the hydrolysis agent is sodium hydroxide.

8. The preparation method according to claim 1, wherein the hydrolysis temperature is 80-110 ℃, the hydrolysis time is 1.0-4.0 h, the drying temperature is 90-110 ℃, and the drying time is 40 min-3 h.

9. The method of claim 1, wherein the polymer has a viscosity average molecular weight of 1000 to 2500 ten thousand.

10. The temperature-resistant and salt-resistant copolymer prepared by the preparation method of claims 1-8.

Technical Field

The invention belongs to the field of chemical synthesis, and relates to a preparation method of a temperature-resistant salt-resistant copolymer.

Background

With continuous development of oil fields, the conditions for exploiting oil reservoirs are continuously worsened, oil field exploitation gradually enters second-class and third-class oil reservoir blocks with high temperature and high salt content, currently commonly adopted oil displacement agent polyacrylamide has the defect of poor temperature resistance and salt resistance, the application of the oil reservoirs is difficult to meet, and a large number of researchers modify polyacrylamide to obtain a temperature-resistant salt-resistant copolymer with more excellent performance. The introduction of temperature-resistant and salt-resistant monomers into the polymer structure is one of the common methods for improving the performance of the polymer at present, wherein the functional monomers of the sulfonic acid derivative containing terminal alkenyl and the sulfonate derivative thereof are most widely applied. The sulfonic acid group of the monomer is insensitive to the attack of cations, so that the polymer has good salt resistance, the tolerance of the polymer to calcium and magnesium ions can be improved by introducing the functional monomer, the precipitation is not easy to occur, and the viscosity retention rate is improved, so that the temperature resistance and salt resistance of the polymer can be improved by introducing the functional monomer containing the sulfonic acid group into the polymer, and the more complex oil reservoir conditions can be adapted. The introduction of sodium acrylate structural units into the copolymer can improve the solubility of the polymer, and simultaneously, due to the electrostatic repulsion effect between carboxyl groups, the chain molecular conformation of the polymer is more extended, and the viscosity of the polymer is increased under a certain range of conditions. The molecular structure design of the polymer determines that the polymer has good water solubility, viscosity increasing performance, temperature resistance and salt resistance. However, by adopting the traditional solution polymerization mode, the sequence distribution of the anion functional units is random, and the sequence distribution of the functional monomer units on the macromolecular chains is closely related to the solution performance.

The template polymerization method is an effective method for controlling the composition and sequence distribution of the copolymer, and the principle of the template polymerization method is that a polymer (template) which can interact with a monomer or a growing chain through hydrogen bonds, electrostatic bonding, electron transfer interaction, hydrophobic bonding, Van der Waals force and the like is put into a polymerization system in advance, the monomer is pre-assembled on the template, when the macromolecular chain free radical of the polymerization system meets the template, the pre-assembled monomer on the template is initiated to form a section of monomer block structural unit, and the steps are repeated to form the anionic copolymer with a block structure. Meanwhile, the cationic template is contained in the copolymer system synthesized by the method, the polymer has good solubility under the condition of certain molecular weight and cationic template content, physical crosslinking can be formed between the cationic template and macromolecular chain anionic monomer units through ionic bonds, a supermolecular network structure is constructed, and the solution performance of the polymer is greatly improved. Meanwhile, the complicated purification step of removing the template by a template polymerization method is avoided, the cost is saved, and the method has the value of industrial production.

Chinese patent application (CN102060965A) discloses a preparation method of partially hydrolyzed polyacrylamide with improved temperature and salt resistance. According to the method, a polyacrylamide monomer, a functional monomer and a template substance are mixed according to a mass ratio of 100: 1-10: 0.05-5, the polymerization starting temperature is controlled to be 0-15 ℃, the template substance and the functional monomer in the monomer are more obviously acted under the condition of the temperature, and a polyacrylamide product with a block structure is favorably formed. According to the method, a small amount of functional monomers are polymerized with acrylamide monomers under the action of template substances, and can interact with the template substances in the polymerization process, so that the self-competition rate is improved, and a more complete sequence block structure is obtained; the functional monomer is selected from one of acrylic acid, acrylic acid water-soluble derivative monomer, methacrylic acid water-soluble derivative monomer and the like. The obtained product is prepared into the concentration of 1500ppm in the saline water with the total mineralization of 30000ppm, can be well dissolved by stirring for two hours, and the viscosity of the product at 85 ℃ can reach 16.2 cp.

Disclosure of Invention

The invention mainly aims to provide a preparation method of a copolymer with higher temperature resistance and salt resistance.

In order to achieve the purpose, the invention adopts the following technical scheme:

One of the purposes of the invention is to provide a preparation method of a temperature-resistant and salt-resistant copolymer, which comprises the following steps: sequentially adding water, an additive, acrylamide, a functional monomer and a template substance into a reactor, adding an inorganic base to adjust the pH value of a polymerization system, adding an initiator to initiate polymerization reaction, placing the polymerization system in an adiabatic environment, and stopping the reaction when the central temperature of the polymerization system is not increased to obtain a polymer colloid; crushing polymer colloid into colloidal particles, adding a hydrolytic agent for hydrolysis, drying, crushing and screening to obtain the polymer colloid; the template substance is polyacrylic acyloxy ethyl trimethyl ammonium chloride or polymethacrylamidopropyl trimethyl ammonium chloride, and the functional monomer is a sulfonic acid derivative containing terminal alkenyl and a sulfonate derivative thereof; the molar ratio of the template substance to the functional monomer is (0.1-1) to 1; the molar ratio of the functional monomer to the acrylamide is 0.05-0.2: 1.

In the method, preferably, the molecular weight of the poly (acryloyloxyethyl trimethyl ammonium chloride) is 1000-20000; the molecular weight of the poly (methyl acrylamide propyl trimethyl ammonium chloride) is 1000-30000.

In the above method, preferably, the terminal alkenyl group-containing sulfonic acid derivative and sulfonate derivative thereof include: 2-acrylamido-2-methylpropanesulfonic acid and its sulfonates, vinylsulfonic acid and its sulfonates, and styrenesulfonic acid and its sulfonates.

In the above method, preferably, the additive is composed of EDTA-2Na, urea and sodium formate, the EDTA-2Na content is 0.002 wt% to 0.2 wt% of the acrylamide concentration, the urea content is 0.005 wt% to 10 wt% of the acrylamide concentration, and the sodium formate content is 0.001 wt% to 0.02 wt% of the acrylamide concentration.

In the above method, preferably, the initiator is a redox system composed of an oxidizing agent and a reducing agent, the oxidizing agent is a persulfate, and preferably, the persulfate is selected from one of potassium persulfate and ammonium persulfate; the reducing agent is sulfite, preferably, the sulfite is selected from one of sodium bisulfite, sodium sulfite and sodium metabisulfite; the mass ratio of the oxidant to the reducer is 1:1, and the addition amount of the oxidant or the reducer is 0.01 wt% -0.2 wt% of the concentration of acrylamide. In the scheme of the invention, the initiator is completely composed of the inorganic salt oxidant and the inorganic salt reducing agent, and the initiator is not only cheap but also high in initiating efficiency.

In the method, preferably, the concentration of the acrylamide is 10 wt% to 30 wt%, the pH value of the polymerization system is 5 to 7, and the initiation temperature is-5 ℃ to 30 ℃.

In the method, preferably, the hydrolyzing agent is added according to the hydrolysis degree, the hydrolysis degree is 5-25%, and the hydrolyzing agent is sodium hydroxide.

In the method, preferably, the hydrolysis temperature is 80-110 ℃, the hydrolysis time is 1.0-4.0 h, the drying temperature is 90-110 ℃, and the drying time is 40 min-3 h.

The second object of the present invention is to provide a temperature-resistant and salt-resistant copolymer prepared by the above preparation method.

Preferably, the copolymer has a viscosity average molecular weight of 1000 to 2500 ten thousand.

The monomer contains sulfonic acid groups and can show insensitivity to attack of cations, so that the polymer has good salt resistance, but only randomly distributed polymers can be obtained by a common polymerization method at present, and the influence of the block distribution of sulfonic functional monomers on the performance of the copolymer is rarely reported. According to the invention, poly (acryloyloxyethyl trimethyl ammonium chloride) or poly (methacrylamide) propyl trimethyl ammonium chloride is used as a template substance, a sulfonic acid derivative containing terminal alkenyl and a sulfonate derivative thereof are used as functional monomers to perform a polymerization reaction with acrylamide, and then the post-hydrolysis is performed, so that the obtained copolymer has good temperature and salt resistance, and further research shows that in the reaction process, the temperature and salt resistance of the obtained copolymer can be obviously influenced by the proportion of the template substance to the sulfonic acid derivative containing terminal alkenyl and the sulfonate derivative thereof, and the temperature and salt resistance of the obtained copolymer is optimal when the molar ratio of the template substance to the functional monomers is 0.1-1: 1. In addition, all the components of the invention are synergistic, and the temperature resistance and salt resistance of the prepared copolymer are obviously improved.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, and/or combinations thereof, unless the context clearly indicates otherwise.

In order to make the technical solutions of the present invention more clearly understood by those skilled in the art, the technical solutions of the present invention will be described in detail below with reference to specific embodiments.