Active polymer, preparation method thereof and profile control agent

Abstract

The invention relates to an active polymer, a preparation method thereof and a profile control agent, and belongs to the technical field of oilfield profile control. The active polymer comprises the following raw materials: a main monomer and a hydrophobic association monomer, wherein the main monomer is used as a basic skeleton structure of the active polymer; wherein in parts by weight, the content of the main body monomer is 20 to 30 parts, and the content of the hydrophobic association monomer is 14 to 23 parts. The main monomer serves as a basic skeleton structure of the active polymer; the main body monomer and the hydrophobic association monomer can be subjected to polymerization reaction to obtain an active polymer with a hydrophobic association effect; the active polymer is associated in an aqueous solution through molecules, and the aqueous solution shows the characteristic of strong tackifying property macroscopically; a hydrophobic group is introduced into a molecular chain of the active polymer, so that a multi-stage complex structure, namely an inverse solution space structure, is formed in a solution through reversible association of weak non-covalent bond force, and the active polymer realizes efficient tackifying of an aqueous solution.

Description

Technical Field

[0001] This application relates to the field of oilfield profile control technology, and in particular to an active polymer and its preparation method, as well as a profile control agent. Background Technology

[0002] Water injection is widely used in the development of light oil, high-pour-point oil, and ordinary heavy oil reservoirs in Liaohe Oilfield. The water-driven reserves have reached 1.019 billion tons, and all have entered the high water-cut stage of the mid-to-late development phase. Affected by water channeling, edge water intrusion, or bottom water coning, the average comprehensive water cut of the main deep-drive blocks has reached 88%. Currently, technologies such as profile control and water shut-off, and deep-drive techniques are used to improve the effectiveness of water-drive development.

[0003] Weak gel deep profile control technology is one of the most researched and applied deep profile control (flooding) fluid diversion technologies. The more mature crosslinking polymers are mainly polyacrylamide and xanthocyanin-based weak gel profile control technologies. Among them, polyacrylamide-based bulk weak gel profile control (flooding) agents are the most widely used in deep profile control fluid diversion treatment in high water-cut oilfields. The partially hydrolyzed polyacrylamide (HPAM) used in polyacrylamide-based bulk weak gel profile control (flooding) agents can experience a viscosity loss rate of up to 70% due to shear chain scission. Increased temperature also leads to HPAM degradation. Furthermore, excessively high formation water salinity results in low polymer viscosity, especially Ca2+. 2+ Mg 2+ The influence of divalent cations can lead to polymer precipitation. To improve the flow ratio, it is necessary to increase the polymer concentration to compensate for the viscosity loss, and the increase in the amount of chemical agent also increases the cost of flow regulation. Summary of the Invention

[0004] This application provides an active polymer and its preparation method, as well as a profile modifier, to solve the following technical problem: how to improve the thickening properties of polymers.

[0005] In a first aspect, this application provides an active polymer, the raw materials of which include:

[0006] The polymer comprises a host monomer and a hydrophobic associating monomer, wherein the host monomer serves as the basic framework structure of the active polymer; wherein, by weight,

[0007] The main monomer is 20 to 30 parts, and the hydrophobic associating monomer is 14 to 23 parts.

[0008] Optionally, the hydrophobic associating monomer includes cationic hydrophobic associating monomers and nonionic hydrophobic associating monomers.

[0009] Optionally, the cationic hydrophobic associating monomer includes at least one of the following: alkyl dimethyl allyl ammonium chloride, hexadecyl dimethyl allyl ammonium chloride; and / or,

[0010] The nonionic hydrophobic associating monomer includes at least one of the following: higher alcohol acrylates, higher alcohol methacrylates, and N-alkylacrylamide.

[0011] Optionally, the weight ratio of the cationic hydrophobic associating monomer to the nonionic hydrophobic associating monomer is (10-15):(4-8).

[0012] Optionally, the main monomer contains acrylamide structural units.

[0013] Optionally, the raw materials for the active polymer may further include monomers containing sulfonic acid groups.

[0014] Optionally, the monomer containing sulfonic acid groups includes at least one of the following: 2-acrylamido-2-methylpropanesulfonic acid, sodium propanesulfonate.

[0015] Optionally, the monomer containing the sulfonic acid group is 5 to 10 parts by weight.

[0016] Secondly, this application provides a method for preparing the active polymer according to any one of the first aspects, the method comprising:

[0017] The raw materials are mixed with the solvent to obtain a mixed solution;

[0018] Under the action of an initiator, the mixed solution undergoes a polymerization reaction to obtain an active polymer; wherein,

[0019] The process parameters for the polymerization reaction include: a reaction pH of 6 to 7 and a reaction temperature of 45°C to 60°C.

[0020] Thirdly, this application provides a profile control agent, the raw materials of which include the active polymer described in any one of the first aspects.

[0021] The technical solutions provided in this application have the following advantages compared with the prior art:

[0022] The active polymer provided in this application embodiment comprises a host monomer and a hydrophobic associating monomer as raw materials. The host monomer serves as the basic skeletal structure of the active polymer. Specifically, by weight, the host monomer comprises 20 to 30 parts, and the hydrophobic associating monomer comprises 14 to 23 parts. The host monomer serves as the basic monomer, thus providing the basic skeletal structure of the active polymer. The host monomer and the hydrophobic associating monomer can undergo a polymerization reaction to obtain an active polymer with hydrophobic association properties. In aqueous solution, this active polymer exhibits strong thickening properties through intermolecular association. Furthermore, due to the introduction of hydrophobic groups into the molecular chain of the active polymer, a multi-level complex structure is formed in solution through reversible association by weak non-covalent bonds, i.e., a reversible solution spatial structure. Therefore, this active polymer achieves highly efficient thickening of aqueous solutions. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic flowchart illustrating a method for preparing an active polymer provided in this application embodiment;

[0026] Figure 2 This is a viscosity curve of an active polymer and different polymers at different concentrations provided in Example 2 of this application;

[0027] Figure 3 Viscosity-time curves of an active polymer and different polymers provided in Example 2 of this application;

[0028] Figure 4 This is a viscosity-time curve of an active polymer and different polymers before and after shearing, provided in Example 2 of this application;

[0029] Figure 5 This is a schematic diagram illustrating the emulsifying properties of an active polymer provided in Example 2 of this application;

[0030] Figure 6 A core simulation experimental device provided in this application embodiment;

[0031] Figure 7This is a test curve of the oil displacement performance of an active polymer provided in Example 2 of this application. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0034] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple. "Weight parts representation" such as parts by weight or parts by mass indicates the proportional relationship between components. In the proportional relationships discussed in this article, parameters that need to be described by proportion should be understood as the first term of the proportion in the order of description, while the proportion number should be understood as the second term. For example, if the weight ratio of substance A, substance B, and substance C is 1:2:3, then substances A, B, and C should correspond one-to-one with the proportion number in the proportion in the order of description, i.e., weight of substance A: weight of substance B: weight of substance C = 1:2:3.

[0035] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0036] In a first aspect, this application provides an active polymer, the raw materials of which include:

[0037] The polymer comprises a host monomer and a hydrophobic associating monomer, wherein the host monomer serves as the basic framework structure of the active polymer; wherein, by weight,

[0038] The main monomer is 20 to 30 parts, and the hydrophobic associating monomer is 14 to 23 parts.

[0039] In the embodiments of this application, the host monomer serves as the basic monomer, thereby serving as the basic skeletal structure of the active polymer; the hydrophobic associating monomer is the basic unit constituting the hydrophobic associating polymer. It is a monomer molecule with a hydrophobic group and usually also contains polymerizable functional groups (such as olefin bonds). Structurally, part of the molecule is an active group that can participate in the polymerization reaction and is used to connect with other monomers to form the polymer backbone; the other part is a hydrophobic group, which is generally a long-chain alkyl, aryl, or other structure with strong hydrophobicity.

[0040] The host monomer and hydrophobically associating monomer can undergo polymerization to obtain an active polymer with hydrophobic association. Hydrophobic association refers to the phenomenon of hydrophobic molecules or hydrophobic groups within molecules agglomerating in aqueous solutions. This active polymer, through intermolecular association in aqueous solutions, exhibits strong thickening properties macroscopically. In other words, the multi-level complex structure formed by the active polymer in aqueous solutions restricts the free movement of molecular chains. When the solution is subjected to external forces (such as stirring or flow), the relative movement between molecular chains is hindered. Compared to traditional polymers, which rely solely on molecular chain entanglement for thickening, this active polymer's network structure formed through hydrophobic association is more effective. Even at relatively low molecular weights, efficient thickening can be achieved due to the interaction between hydrophobic groups. Furthermore, because hydrophobic groups are introduced into the molecular chains of the active polymer, a multi-level complex structure is formed in solution through reversible association by weak non-covalent bonds—a reversible solution spatial structure. Due to this reversible solution spatial structure, when the solution is subjected to changes in external conditions (such as temperature or shear force), this structure can dissociate and recombine. For example, when subjected to shear force, some associated structures will temporarily dissociate, reducing the viscosity of the solution, increasing its fluidity, and making it easier to process or use; when the shear force disappears, the interaction between the hydrophobic groups will cause the molecules to reassociate, and the viscosity of the solution will be restored, allowing it to better exert its thickening effect.

[0041] Therefore, this reversible spatial structure can effectively adjust the interactions between molecular chains under different environmental conditions. Under normal conditions, the multi-level complex structure keeps the molecular chains tightly connected, providing high internal friction and achieving thickening. Moreover, due to the rational distribution of hydrophobic groups (determined by the ratio of host monomer to hydrophobic associating monomer), a sufficient number of physical cross-linking points can be formed through hydrophobic association without increasing the molecular weight excessively, thereby achieving highly efficient thickening of aqueous solutions.

[0042] Furthermore, since hydrophobic association is achieved through weak non-covalent bonds, it exhibits a certain degree of temperature resistance. Although some associated structures may dissociate when the temperature changes, they can reassociate when the temperature recovers. Regarding salt resistance, salt ions have a relatively small impact on hydrophobic association, so the polymer can still maintain good performance within a certain salt concentration range. In terms of shear resistance, its reversible association structure allows the polymer to recover its original properties after being subjected to shear force.

[0043] The main monomer can be 20 to 30 parts, and the hydrophobic associating monomer can be 14 to 23 parts. This ensures that the active polymer forms polymer chains of sufficient length and that the active polymer structure incorporates sufficient hydrophobic associating monomer structures, rationally distributing hydrophobic groups on the polymer molecular chain, thereby generating an effective hydrophobic association effect and better exerting the efficient thickening effect of the active polymer. For example, the main monomer can be 20, 22, 24, 26, 28, or 30 parts, etc.; and the hydrophobic associating monomer can be 14, 16, 18, 20, 22, or 23 parts, etc.

[0044] In some embodiments, the host monomer contains acrylamide structural units.

[0045] In this embodiment, the host monomer may contain acrylamide structural units. When the host monomer contains acrylamide structural units, these units are linked together through a polymerization reaction to form the polymer backbone. The backbone has a certain degree of flexibility, which allows the polymer molecular chains to exhibit different conformations in solution, facilitating interactions between molecular chains and various physicochemical processes in solution. For example, during intermolecular association, the flexible backbone can adjust its shape, making it easier for hydrophobic groups on the molecular chain to approach each other, thereby promoting hydrophobic association. Exemplarily, the host monomer may be one or more combinations of acrylamide and N,N'-methylenebisacrylamide.

[0046] In some embodiments, the hydrophobic associating monomer includes cationic hydrophobic associating monomers and nonionic hydrophobic associating monomers.

[0047] In this embodiment, the hydrophobic associating monomer can be a cationic or nonionic hydrophobic associating monomer. Cationic hydrophobic associating monomers, in addition to having hydrophobic groups, also possess positively charged cationic groups. Introducing cationic hydrophobic associating monomers into the polymer increases the viscosity of the polymer solution through the association of the hydrophobic groups. Simultaneously, due to the electrostatic interaction between the cationic groups and water molecules, the extension of the polymer molecular chains in water may change, and in some cases, the electrostatic repulsion between cationic groups may also increase the distance between molecular chains, thereby altering the interactions between molecular chains and the viscosity of the solution. Nonionic hydrophobic associating monomers mainly consist of hydrophobic groups and nonionic polymerizable groups. Nonionic hydrophobic associating monomers increase the viscosity of the solution by introducing hydrophobic groups onto the polymer molecular chains to form a hydrophobic associating structure.

[0048] In some embodiments, the cationic hydrophobic associating monomer comprises at least one of the following: alkyl dimethyl allyl ammonium chloride, hexadecyl dimethyl allyl ammonium chloride; and / or,

[0049] The nonionic hydrophobic associating monomer includes at least one of the following: higher alcohol acrylates, higher alcohol methacrylates, and N-alkylacrylamide.

[0050] In the embodiments of this application, the cationic hydrophobic associating monomer can be one or more combinations of alkyl dimethyl allyl ammonium chloride and hexadecyl dimethyl allyl ammonium chloride, wherein the structural formula of alkyl dimethyl allyl ammonium chloride can be R n DMAAC, where n can be 12, 14, 16, or 18, is a cationic hydrophobic associating monomer with long side-chain branches and strong steric forces between molecular chains, promoting the association reaction. The nonionic hydrophobic associating monomer can be one or more combinations of higher alcohol acrylates, higher alcohol methacrylates, and N-alkylacrylamides, wherein N in N-alkylacrylamides can be 12, 16, or 18.

[0051] In some embodiments, the weight ratio of the cationic hydrophobic associating monomer to the nonionic hydrophobic associating monomer is (10-15):(4-8).

[0052] In this embodiment, the cationic hydrophobic associating monomer introduces cationic groups that interact electrostatically with water molecules, while its hydrophobic groups also participate in association. The nonionic hydrophobic associating monomer primarily increases viscosity through the association of its hydrophobic groups. The weight ratio of the cationic hydrophobic associating monomer to the nonionic hydrophobic associating monomer can be (10-15):(4-8), thereby their synergistic effect can optimize the viscosity of the polymer solution, ensure the hydrophobic association effect of the polymer, and achieve efficient viscosity enhancement of the aqueous solution, as well as improve the polymer's resistance to temperature, salt, and shear. For example, the weight ratio of the cationic hydrophobic associating monomer to the nonionic hydrophobic associating monomer can be 10:4, 15:8, 13:6, 12:7, etc.

[0053] In some embodiments, the raw materials for the active polymer further include monomers containing sulfonic acid groups.

[0054] In this embodiment, the raw material for the active polymer may further include: a monomer containing a sulfonic acid group, wherein the monomer molecule contains a sulfonic acid group (-SO3H). The sulfonic acid group is a strongly acidic, highly polar, and water-soluble functional group. In aqueous solution, the sulfonic acid group can highly ionize to produce a sulfonate anion (-SO3H). - ) and hydrogen ions (H + This ionization property gives sulfonic acid group monomers good hydrophilicity and allows them to interact electrostatically with other charged substances in solution. Because the electrostatic interaction between sulfonate anions and water molecules, as well as their interaction with other groups, maintains a certain stability under temperature changes, the temperature resistance of the active polymer is improved. The high charge density of sulfonic acid groups makes the anions very stable and less affected by external metal ions. When the salt concentration increases, sulfonate anions can interact with salt ions through ion exchange or shielding, thereby improving the salt resistance of the active polymer. Sulfonic acid groups in the polymer can form strong interactions with surrounding molecules (such as water molecules, other polymer segments, etc.), such as hydrogen bonds. This strong intermolecular interaction makes the polymer molecular chains more tightly connected, and under shear force, the molecular chains are less prone to relative slippage, thus exhibiting good shear resistance.

[0055] In some embodiments, the sulfonic acid-containing monomer includes at least one of the following: 2-acrylamido-2-methylpropanesulfonic acid, sodium propylene sulfonate.

[0056] In the embodiments of this application, the monomer containing the sulfonic acid group can be one or more of 2-acrylamido-2-methylpropanesulfonic acid and sodium propanesulfonate. 2-Acrylamido-2-methylpropanesulfonic acid (AMPS) is a multifunctional water-soluble anionic surfactant monomer with the molecular formula C7H. 13The sulfonic acid groups in the NO4S molecule give it strong anionic properties, hydrophilicity, and salt resistance; the amide groups give it excellent hydrolytic stability, acid and alkali resistance, and thermal stability; the active carbon-carbon double bonds facilitate its homopolymerization or copolymerization with other olefin monomers. Due to the special structure of AMPS monomers, this active polymer has wide applications in water-absorbing and water-retaining materials, oilfield chemicals, and water treatment agents.

[0057] In some embodiments, the monomer containing the sulfonic acid group is 5 to 10 parts by weight.

[0058] In the embodiments of this application, the monomer containing sulfonic acid groups can be 5 to 10 parts, thereby achieving excellent temperature resistance, salt resistance, and shear resistance of the active polymer. For example, the monomer containing sulfonic acid groups can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.

[0059] Therefore, through the interaction among the host monomer, cationic hydrophobic associating monomer, nonionic hydrophobic associating monomer, and monomer containing sulfonic acid groups, it is possible to obtain an active polymer with moderate molecular weight, good solubility, and moderate association strength at low cost.

[0060] Secondly, this application provides a method for preparing the active polymer according to any one of the first aspects. Figure 1 A schematic flowchart illustrating a method for preparing an active polymer provided in this application embodiment; please refer to [link / reference]. Figure 1 The method includes:

[0061] S1. Mix the raw materials with the solvent to obtain a mixed solution;

[0062] S2. Under the action of an initiator, the mixed solution undergoes a polymerization reaction to obtain an active polymer; wherein,

[0063] The process parameters for the polymerization reaction include: a reaction pH of 6 to 7 and a reaction temperature of 45°C to 60°C.

[0064] In the embodiments of this application, the pH of the above-mentioned polymerization reaction can be 6-7, and the temperature can be 45℃-60℃, thereby ensuring the smooth progress of the polymerization reaction. For example, the reaction pH can be 6, 6.5, 7, etc.; the reaction temperature can be 45℃, 48℃, 50℃, 55℃, 58℃, 60℃, etc. Furthermore, the polymerization reaction time can be 8h-12h. The initiator can generate an active center, which can initiate the polymerization reaction of monomer molecules, thereby causing the monomers to gradually connect to form a polymer. The initiator can be a combination of NaHSO3-(NH4)2S2O8, with a weight ratio of NaHSO3 to (NH4)2S2O8 of 1:1, and the initiator can be 0.05 parts to 0.1 parts.

[0065] For example, the preparation method of the above-mentioned active polymer specifically includes: adding the main monomer, functional monomer, cationic hydrophobic associating monomer, and nonionic hydrophobic associating monomer to water, stirring and heating to 45℃~60℃, neutralizing the reaction solution with saturated NaOH solution, and adjusting the pH to 6~7. Under nitrogen protection, stirring uniformly, adding NaHSO3-(NH4)2S2O8, and reacting at a constant temperature for 8h~12h. The reaction product is purified with anhydrous ethanol, dried at 40℃, and then pulverized to obtain a white granular polymer product, i.e., the active polymer.

[0066] The preparation method of this active polymer is based on the above-mentioned active polymer. The specific raw materials of the active polymer can be referred to in the above embodiments. Since the preparation method of this active polymer adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0067] Thirdly, this application provides a profile control agent, the raw materials of which include the active polymer described in any one of the first aspects.

[0068] In the embodiments of this application, the preparation method of the above-mentioned modulator is as follows: The high-viscosity active polymer is dissolved in clean water or oilfield reinjection wastewater to obtain a high-viscosity active polymer solution, which is the high-viscosity active polymer solution modulator. The field use weight concentration of this modulator is 0.2% to 0.8% (2000 mg / L to 8000 mg / L); or the high-viscosity active polymer is dissolved in clean water or oilfield reinjection wastewater, and then phenolic resin or organic chromium crosslinking agent is added to obtain a gel modulator.

[0069] The profile control agent is based on the above-mentioned active polymer. The specific raw materials of the active polymer can be referred to in the above embodiments. Since the profile control agent adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0070] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0071] Example 1

[0072] An active polymer, wherein the raw materials for the active polymer, by weight, include:

[0073] Main monomer: Acrylamide, 20 parts;

[0074] Monomer containing sulfonic acid groups: 2-acrylamido-2-methylpropanesulfonic acid, 5 parts;

[0075] Cationic hydrophobic associating monomer: Dodecyl dimethyl allyl ammonium chloride, 10 parts;

[0076] Nonionic hydrophobic associating monomer: Dodecyl acrylate, 4 parts

[0077] NaHSO3-(NH4)2S2O8: The weight ratio of the two is 1:1, 0.05 parts;

[0078] Water: Balance.

[0079] A method for preparing an active polymer: A host monomer, a monomer containing a sulfonic acid group, a cationic hydrophobic associating monomer, and a nonionic hydrophobic associating monomer are added to water. The mixture is stirred and heated to 45°C. The reaction solution is neutralized with saturated NaOH solution, and the pH is adjusted to 6. Under nitrogen protection, the mixture is stirred uniformly, and NaHSO3-(NH4)2S2O8 is added. The reaction is maintained at a constant temperature for 8 hours. The reaction product is purified with anhydrous ethanol, dried at 40°C, and then pulverized to obtain a white granular polymeric product, i.e., the active polymer.

[0080] Example 2

[0081] An active polymer, wherein the raw materials for the active polymer, by weight, include:

[0082] Main monomer: N,N'-methylenebisacrylamide, 30 parts;

[0083] Monomer containing sulfonic acid groups: Sodium allyl sulfonate, 10 parts;

[0084] Cationic hydrophobic associating monomer: octadecyl dimethyl allyl ammonium chloride, 15 parts;

[0085] Nonionic hydrophobic associating monomer: octadecyl methacrylate, 8 parts

[0086] NaHSO3-(NH4)2S2O8: The weight ratio of the two is 1:1, 0.1 parts;

[0087] Water: Balance.

[0088] A method for preparing an active polymer includes: adding a host monomer, a monomer containing a sulfonic acid group, a cationic hydrophobic associating monomer, and a nonionic hydrophobic associating monomer to water; stirring and heating to 60°C; neutralizing the reaction solution with saturated NaOH solution and adjusting the pH to 7; stirring uniformly under nitrogen protection; adding NaHSO3-(NH4)2S2O8; and reacting at a constant temperature for 12 hours; purifying the reaction product with anhydrous ethanol; drying at 40°C; and pulverizing to obtain a white granular polymeric product, i.e., the active polymer.

[0089] Example 3

[0090] An active polymer, wherein the raw materials for the active polymer, by weight, include:

[0091] Main monomer: Acrylamide, 25 parts;

[0092] Monomer containing sulfonic acid groups: 2-acrylamido-2-methylpropanesulfonic acid, 8 parts;

[0093] Cationic hydrophobic associating monomer: hexadecyl dimethyl allyl ammonium chloride, 12 parts;

[0094] Nonionic hydrophobic associating monomer: dodecyl acrylamide, 6 parts

[0095] NaHSO3-(NH4)2S2O8: The weight ratio of the two is 1:1, 0.08 parts;

[0096] Water: Balance.

[0097] A method for preparing an active polymer includes: adding a host monomer, a monomer containing a sulfonic acid group, a cationic hydrophobic associating monomer, and a nonionic hydrophobic associating monomer to water; stirring and heating to 50°C; neutralizing the reaction solution with saturated NaOH solution and adjusting the pH to 6.5; uniformly stirring under nitrogen protection; adding NaHSO3-(NH4)2S2O8; and reacting at a constant temperature for 10 hours; purifying the reaction product with anhydrous ethanol; drying at 40°C; and pulverizing to obtain a white granular polymeric product, i.e., the active polymer.

[0098] Example 4

[0099] An active polymer, wherein the raw materials for the active polymer, by weight, include:

[0100] Main monomer: N,N'-methylenebisacrylamide, 25 parts;

[0101] Monomer containing sulfonic acid groups: Sodium allyl sulfonate, 10 parts;

[0102] Cationic hydrophobic associating monomer: tetradecyl dimethyl allyl ammonium chloride, 15 parts;

[0103] Nonionic hydrophobic associating monomer: hexadecylacrylamide, 5 parts

[0104] NaHSO3-(NH4)2S2O8: The weight ratio of the two is 1:1, 0.06 parts;

[0105] Water: Balance.

[0106] A method for preparing an active polymer includes: adding a host monomer, a monomer containing a sulfonic acid group, a cationic hydrophobic associating monomer, and a nonionic hydrophobic associating monomer to water; stirring and heating to 45°C; neutralizing the reaction solution with saturated NaOH solution and adjusting the pH to 7; stirring uniformly under nitrogen protection; adding NaHSO3-(NH4)2S2O8; and reacting at a constant temperature for 9 hours; purifying the reaction product with anhydrous ethanol; drying at 40°C; and pulverizing to obtain a white granular polymeric product, i.e., the active polymer.

[0107] The emulsification performance of the above-mentioned high-tackifying polymer was tested. The experimental method was as follows: a 5000 mg / L polymer mother liquor was prepared with clean water. An appropriate amount of the mother liquor was then diluted with wastewater to concentrations of 600, 800, 1000, and 1200 mg / L. An oil-to-water ratio of 1:1 was used for emulsification experiments. The mixture was shaken 100 times and placed at 45℃ to observe the emulsification process. The water separation rate after 7 days was calculated. The test results are shown in […]. Figure 4 In the diagram, the red line represents the oil-water boundary, with an oil-water ratio of 1:1.

[0108] Example 5

[0109] An active polymer, wherein the raw materials for the active polymer, by weight, include:

[0110] Main monomer: Acrylamide, 22 parts;

[0111] Monomer containing sulfonic acid groups: 2-acrylamido-2-methylpropanesulfonic acid, 10 parts;

[0112] Cationic hydrophobic associating monomer: octadecyl dimethyl allyl ammonium chloride, 9 parts;

[0113] Nonionic hydrophobic associating monomer: octadecylacrylamide, 8 parts

[0114] NaHSO3-(NH4)2S2O8: The weight ratio of the two is 1:1, 0.06 parts;

[0115] Water: Balance.

[0116] A method for preparing an active polymer includes: adding a host monomer, a monomer containing a sulfonic acid group, a cationic hydrophobic associating monomer, and a nonionic hydrophobic associating monomer to water; stirring and heating to 50°C; neutralizing the reaction solution with saturated NaOH solution and adjusting the pH to 7; stirring uniformly under nitrogen protection; adding NaHSO3-(NH4)2S2O8; and reacting at a constant temperature for 10 hours; purifying the reaction product with anhydrous ethanol; drying at 40°C; and pulverizing to obtain a white granular polymeric product, i.e., the active polymer.

[0117] Example 6

[0118] An active polymer, wherein the raw materials for the active polymer, by weight, include:

[0119] Main monomer: N,N'-methylenebisacrylamide, 25 parts;

[0120] Monomer containing sulfonic acid groups: 2-acrylamido-2-methylpropanesulfonic acid, 8 parts;

[0121] Cationic hydrophobic associating monomer: hexadecyl dimethyl allyl ammonium chloride, 8 parts;

[0122] Nonionic hydrophobic associating monomer: hexadecylacrylamide, 9 parts

[0123] NaHSO3-(NH4)2S2O8: The weight ratio of the two is 1:1, 0.05 parts;

[0124] Water: Balance.

[0125] A method for preparing an active polymer includes: adding a host monomer, a monomer containing a sulfonic acid group, a cationic hydrophobic associating monomer, and a nonionic hydrophobic associating monomer to water; stirring and heating to 60°C; neutralizing the reaction solution with saturated NaOH solution and adjusting the pH to 7; stirring uniformly under nitrogen protection; adding NaHSO3-(NH4)2S2O8; and reacting at a constant temperature for 10 hours; purifying the reaction product with anhydrous ethanol; drying at 40°C; and pulverizing to obtain a white granular polymeric product, i.e., the active polymer.

[0126] Example 7

[0127] An active polymer, wherein the raw materials for the active polymer, by weight, include:

[0128] Main monomer: Acrylamide, 24 parts;

[0129] Monomer containing sulfonic acid groups: 2-acrylamido-2-methylpropanesulfonic acid, 10 parts;

[0130] Cationic hydrophobic associating monomer: hexadecyl dimethyl allyl ammonium chloride, 10 parts;

[0131] Nonionic hydrophobic associating monomer: dodecyl acrylamide, 7 parts

[0132] NaHSO3-(NH4)2S2O8: The weight ratio of the two is 1:1, 0.06 parts;

[0133] Water: Balance.

[0134] A method for preparing an active polymer includes: adding a host monomer, a monomer containing a sulfonic acid group, a cationic hydrophobic associating monomer, and a nonionic hydrophobic associating monomer to water; stirring and heating to 50°C; neutralizing the reaction solution with saturated NaOH solution and adjusting the pH to 6.5; uniformly stirring under nitrogen protection; adding NaHSO3-(NH4)2S2O8; and reacting at a constant temperature for 10 hours; purifying the reaction product with anhydrous ethanol; drying at 40°C; and pulverizing to obtain a white granular polymeric product, i.e., the active polymer.

[0135] Example 8

[0136] An active polymer.

[0137] The raw materials for this active polymer, by weight, include:

[0138] Main monomer: N,N'-methylenebisacrylamide, 20 parts;

[0139] Monomer containing sulfonic acid groups: 2-acrylamido-2-methylpropanesulfonic acid, 8 parts;

[0140] Cationic hydrophobic associating monomer: octadecyl dimethyl allyl ammonium chloride, 8 parts;

[0141] Nonionic hydrophobic associating monomer: dodecyl acrylamide, 8 parts

[0142] NaHSO3-(NH4)2S2O8: The weight ratio of the two is 1:1, 0.08 parts;

[0143] Water: Balance.

[0144] A method for preparing an active polymer includes: adding a host monomer, a monomer containing a sulfonic acid group, a cationic hydrophobic associating monomer, and a nonionic hydrophobic associating monomer to water; stirring and heating to 50°C; neutralizing the reaction solution with saturated NaOH solution and adjusting the pH to 6.5; uniformly stirring under nitrogen protection; adding NaHSO3-(NH4)2S2O8; and reacting at a constant temperature for 10 hours; purifying the reaction product with anhydrous ethanol; drying at 40°C; and pulverizing to obtain a white granular polymeric product, i.e., the active polymer.

[0145] Experimental test:

[0146] The thickening properties of the active polymers obtained in Examples 1-8 were tested, specifically according to the following steps: The experimental water was wastewater reinjected from the Naiman Oilfield. Solutions of the same product (similar product 1 - polyacrylamide with a molecular weight of 5 million, similar product 2 - polyacrylamide with a molecular weight of 20 million) and the active polymers from Examples 1-8 were prepared using the wastewater at concentrations of 500 mg / L, 1000 mg / L, 1500 mg / L, and 2000 mg / L, respectively. The differences in the concentration-viscosity relationship between the different polymers were analyzed by comparing and contrasting the concentration-viscosity curves. The testing standard was SYT5590-2004, the performance evaluation method for profile control agents. Please refer to Table 1 for the viscosity of the active polymers at different concentrations.

[0147] Table 1. Viscosities (mPa·s) of active polymers and different polymers at different concentrations

[0148] Serial Number 500mg / L 1000mg / L 1500mg / L 2000mg / L Example 1 72 125 189 242 Example 2 84 147 218 289 Example 3 76 131 204 267 Example 4 75 156 198 284 Example 5 72 149 188 256 Example 6 79 152 192 248 Example 7 81 164 202 257 Example 8 83 166 208 264 Similar product 1 69 83 122 146 2 similar products 54 68 98 127

[0149] Figure 2 This is a viscosity curve of an active polymer and different polymers at different concentrations provided in Example 2 of this application; please refer to [link / reference]. Figure 2 In conjunction with Table 1, it is shown that the active polymers provided in Examples 1-8 have better thickening properties than similar products and can be applied to tertiary oil recovery such as chemical flooding and polymer flooding.

[0150] The viscosity stability of the active polymers obtained in Examples 1-8 was tested, specifically by preparing 2000 mg / L solutions of the same product and the active polymers from Examples 1-8 using wastewater. Please refer to Table 2 for the viscosity stability data of the active polymers.

[0151] Table 2. Viscosity stability data (mPa·s) of the active polymer and different polymers

[0152]

[0153]

[0154] Figure 3 Viscosity-time curves of an active polymer and different polymers provided in Example 2 of this application; please refer to Figure 3 In conjunction with Table 2, it is shown that the high-tackifying active polymers provided in Examples 1 to 8 have better tackifying properties than similar products and can maintain high viscosity over time.

[0155] The shear resistance of the active polymers obtained in Examples 1-8 was tested, specifically according to the following steps: 2000 mg / L solutions of the same product and the high-viscosity active polymers from Examples 1-8 were prepared using wastewater, and then sheared using a soymilk maker. Please refer to Table 3 for the maximum viscosity of the active polymers and different polymers before and after shearing.

[0156] Table 3. Maximum viscosity (mPa·s) of active polymers and different polymers before and after shear.

[0157] Serial Number Highest viscosity before shearing Highest viscosity after shearing Example 1 242 196 Example 2 289 246 Example 3 267 216 Example 4 284 230 Example 5 256 207 Example 6 248 201 Example 7 257 208 Example 8 264 214 Similar product 1 146 118 2 similar products 127 103

[0158] Figure 4 This is a viscosity-time curve of an active polymer before and after shearing, provided in Example 2 of this application, and different polymers; please refer to [link / reference]. Figure 4 In conjunction with Table 3, the active polymers provided in Examples 1-8 exhibit significant adhesion-enhancing effects after shearing, demonstrating stronger resistance to mechanical shearing compared to similar products.

[0159] The emulsification performance of the active polymer provided in Example 2 was tested. The experimental method was as follows: a 5000 mg / L polymer mother liquor was prepared with clean water. An appropriate amount of the mother liquor was then diluted with wastewater to concentrations of 600, 800, 1000, and 1200 mg / L. An oil-to-water ratio of 1:1 was used for emulsification experiments. The mixture was shaken 100 times and placed at 45°C to observe the emulsification process. The emulsification water separation rate was calculated after 7 days. The test results are shown in […]. Figure 4 In the diagram, the red line represents the oil-water boundary, with an oil-water ratio of 1:1. Figure 5 This is a schematic diagram illustrating the emulsifying properties of an active polymer provided in Example 2 of this application; please refer to [link / reference]. Figure 5 This indicates that the active polymer provided in Example 2 has emulsifying capabilities that are not found in similar products, and also exhibits good emulsification stability.

[0160] The oil displacement performance of the active polymer provided in Example 2 was tested. Experimental method: The above-mentioned high-viscosity active polymer solution and a polymer solution of a similar product were prepared at a concentration of 3000 mg / L. A physical simulation displacement experiment using an artificial core with a size of 30 cm and a permeability of 300 mD was conducted. 0.5 PV of the prepared high-viscosity active polymer solution was injected. Figure 6 A core simulation experimental apparatus provided in this application embodiment; please refer to Figure 6 ;as well as Figure 7 This is a test curve of the oil displacement performance of an active polymer provided in Example 2 of this application; please refer to... Figure 7This indicates that after the injection of the active polymer solution, the pressure at pressure points 1 and 2 increased. Under the high viscosity and emulsification effect of the active polymer solution, the recovery rate increased and the water cut decreased. In the subsequent water drive stage, the active polymer solution penetrated deep into the core, and the pressure at pressure points 3 and 4 increased, with an overall recovery rate of 11%.

[0161] The reservoir permeability control test was conducted on the active polymer provided in Example 2. Experimental method: The above-mentioned active polymer solution and a polymer solution of a similar product were prepared at a concentration of 3000 mg / L. A polymer flooding physical simulation displacement experiment was conducted using an artificial core with a size of 30 cm and a permeability of 300 mD. 0.5 PV of the prepared active polymer solution was injected. The test results are shown in Table 4, which compares the permeability control capabilities of the active polymer. The results indicate that the active polymer solution provided in Example 2 has a larger resistance coefficient and residual resistance coefficient compared to similar products, suggesting a greater reduction in reservoir permeability.

[0162] Table 4 Comparison of percolation control capabilities of active polymers

[0163] sample Core number drag coefficient Residual drag coefficient Highly viscous polymers 2024-1 Seamless 21.5 6.9 Similar product 1 2024-2 Seamless 13.3 3.2 Highly viscous polymers 2024-3 with seams 18.6 5.8 2 similar products 2024-4 with seams 10.8 3.0

[0164] A gel profile control agent was formulated using the active polymer provided in Example 2 for plugging strength testing. The experimental method was as follows: 2000 mg / L solutions of the same product and the high-viscosity active polymer solution from Example 2 were prepared separately with water. 4000 mg / L of phenolic resin crosslinking agent was added, and the gel profile control agent was obtained after gelation. A core physics simulation experiment was then conducted using a 30 cm artificial core with a permeability of 300 mD to test the permeability and maximum breakthrough pressure before and after plugging. The plugging strength of the obtained profile control agent was examined. Please refer to Table 5 for the plugging performance of the active polymer profile control agent. The plugging strength of the gel can be described by the breakthrough pressure. The testing method is as follows: ① Saturate the core with water; ② Inject a certain amount of plugging agent at a certain flow rate, following a conventional procedure with external pressure and a constant temperature water bath; ③ Place the core with the plugging agent in a sealed container and place it in a constant temperature water bath at a set temperature for a period of time; ④ Under the conditions of a set temperature of 25℃ and the same external pressure of 0.5 MPa, inject water at a certain flow rate until the first drop of liquid flows out of the core holder outlet and liquid continues to flow out thereafter. At this point, the reading of the pressure gauge at the inlet end is the maximum breakthrough pressure of the plugging agent. As shown in Table 5, the profile control agent formulated with the active polymer provided in Example 7 has a more significant plugging effect and stronger plugging ability compared to similar products.

[0165] Table 5. Blocking performance of active polymer profile control agents

[0166]

[0167] A gel profile control agent was prepared using the active polymer provided in Example 2, and its temperature and salt resistance performance was tested. Experimental method: 2000 mg / L solutions of the same product and the active polymer solution in Example 2 were prepared using reinjection wastewater with different mineralization. 4000 mg / L of phenolic resin crosslinking agent was added, and the gel profile control agent was obtained after gelation. The profile control agent was placed in a constant temperature chamber, and the viscosity at different temperatures and mineralization was observed to examine the temperature and salt resistance performance of the obtained profile control agent. Please refer to Table 6 for the gelation salt resistance stability performance of the profile control agent and Table 7 for the gelation temperature stability performance of the profile control agent. Stability evaluation method: A certain weight of temporary plugging agent was weighed M1, sealed, and placed in a pressure-resistant glass bottle. The bottle was placed in an oven at a set temperature for continuous constant temperature. Samples were periodically taken out to observe the free water and weighed M2 to calculate the dehydration rate. The dehydration rate was calculated using the following formula (1). The stability was judged based on the dehydration rate. A dehydration rate ≤20% is considered unbroken; 20% < dehydration rate ≤50% is considered partially broken; 50% < dehydration rate ≤80% is considered basically broken; and 80% < dehydration rate ≤100% is considered completely broken. Testing instrument: High-temperature constant temperature chamber.

[0168] Formula (1): Dehydration rate = (M1-M2) / M1 × 100%

[0169] Table 6. Gelation and Salt Resistance Properties of Different Profile Modifiers

[0170]

[0171] Note: Maintained a constant temperature of 80℃ for one month.

[0172] As shown in Table 6, the profile control agent formulated with the active polymer provided in Example 2 has better salt resistance (mineralization) than similar products, with a maximum of 200,000 mg / L.

[0173] Table 7. Gelation temperature stability of different profile modifiers

[0174]

[0175] Note: Continuous constant temperature for 30 days

[0176] As shown in Table 7, the profile control agent formulated with the active polymer provided in Example 2 has superior long-term temperature resistance compared to similar products, with a maximum temperature resistance of up to 120°C.

[0177] One or more technical solutions in the embodiments of this application have at least the following technical effects or advantages:

[0178] (1) The high viscosity-enhancing polymer provided in this application has good temperature resistance, good salt resistance, and a wide range of adaptability to oil reservoir types. Compared with similar products, it has the following characteristics:

[0179] ① High viscoelasticity: Its viscosity is 10-20 times higher than that of conventional polyacrylamide, and it can be used for oil displacement, profile control, and fracturing fluid proppant transport, etc.

[0180] ② Delayed viscosity increase is beneficial for injection: The viscosity reaches its peak value at room temperature in 3 to 5 days, and it can maintain a high viscosity as time goes on;

[0181] ③ Strong adsorption and retention capacity: It can significantly reduce the permeability of the core, with the resistance coefficient and residual resistance coefficient reaching 20 and 5, respectively;

[0182] ④ Good shear resistance: It has better shear resistance and can continue to associate and thicken after shearing;

[0183] ⑤ The polymer molecular chain contains hydrophobic groups and surface-active groups, thus combining the properties of hydrophobic associative polymers and surfactants, and has certain emulsifying and viscosity-reducing properties for crude oil.

[0184] ⑥ Due to the sulfonic acid group in the molecular chain, it has strong anionicity, water solubility, and good salt resistance; the amide group gives it good hydrolytic stability, acid and alkali resistance, and thermal stability. The formulated profile control agent can withstand temperatures up to 120℃, mineralization resistance up to 20000mg / L, and a blocking rate of over 90%.

[0185] ⑦ The on-site raw material usage is low, the cost is low, it is non-flammable, the operation is safe, it is suitable for industrial production, it is not demanding in terms of water quality, and it is non-toxic and non-volatile when used on-site, thus avoiding the health hazards to workers caused by traditional chemical products.

[0186] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An active polymer, wherein the raw materials for the active polymer include: The polymer comprises a host monomer and a hydrophobic associating monomer, wherein the host monomer serves as the basic framework structure of the active polymer; wherein, by weight, The main monomer is 20 to 30 parts, and the hydrophobic associating monomer is 14 to 23 parts.

2. The active polymer according to claim 1, characterized in that, The hydrophobic associating monomers include cationic hydrophobic associating monomers and nonionic hydrophobic associating monomers.

3. The active polymer according to claim 2, characterized in that, The cationic hydrophobic associating monomer includes at least one of the following: alkyl dimethyl allyl ammonium chloride, hexadecyl dimethyl allyl ammonium chloride; and / or, The nonionic hydrophobic associating monomer includes at least one of the following: higher alcohol acrylates, higher alcohol methacrylates, and N-alkylacrylamide.

4. The active polymer according to claim 2 or 3, characterized in that, The weight ratio of the cationic hydrophobic associating monomer to the nonionic hydrophobic associating monomer is (10-15):(4-8).

5. The active polymer according to claim 1, characterized in that, The main monomer contains acrylamide structural units.

6. The active polymer according to claim 1, characterized in that, The raw materials for the active polymer also include monomers containing sulfonic acid groups.

7. The active polymer according to claim 6, characterized in that, The monomer containing sulfonic acid groups includes at least one of the following: 2-acrylamide-2-methylpropanesulfonic acid and sodium propylene sulfonate.

8. The active polymer according to claim 6 or 7, characterized in that, The sulfonic acid group-containing monomer is 5 to 10 parts by weight.

9. A method for preparing the active polymer according to any one of claims 1 to 8, the method comprising: The raw materials are mixed with the solvent to obtain a mixed solution; Under the action of an initiator, the mixed solution undergoes a polymerization reaction to obtain an active polymer; wherein, The process parameters for the polymerization reaction include: a reaction pH of 6 to 7 and a reaction temperature of 45°C to 60°C.

10. A profile control agent, wherein the raw material of the profile control agent comprises the active polymer according to any one of claims 1 to 8.

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