WO2024255789A1 - 多元共聚物及其制备方法和应用 - Google Patents

多元共聚物及其制备方法和应用 Download PDF

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Publication number
WO2024255789A1
WO2024255789A1 PCT/CN2024/098940 CN2024098940W WO2024255789A1 WO 2024255789 A1 WO2024255789 A1 WO 2024255789A1 CN 2024098940 W CN2024098940 W CN 2024098940W WO 2024255789 A1 WO2024255789 A1 WO 2024255789A1
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formula
hydrogen
structural unit
alkyl
independently selected
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English (en)
French (fr)
Inventor
王刚
李万军
王岩峰
孔祥吉
黎小刚
景宁
吉飞
刘纪童
仲昭
肖月
叶东庆
李甘璐
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China National Oil And Gas Exploration And Development Co Ltd
China National Petroleum Corp
CNPC Engineering Technology R&D Co Ltd
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China National Oil And Gas Exploration And Development Co Ltd
China National Petroleum Corp
CNPC Engineering Technology R&D Co Ltd
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Publication of WO2024255789A1 publication Critical patent/WO2024255789A1/zh
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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
    • C08F220/10—Esters
    • C08F220/26—Esters containing oxygen in addition to the carboxy oxygen
    • C08F220/30—Esters containing oxygen in addition to the carboxy oxygen containing aromatic rings in the alcohol moiety
    • C08F220/301—Esters containing oxygen in addition to the carboxy oxygen containing aromatic rings in the alcohol moiety and one oxygen in the alcohol moiety
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/02—Well-drilling compositions
    • C09K8/03—Specific additives for general use in well-drilling compositions
    • C09K8/035—Organic additives
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/50—Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls
    • C09K8/504—Compositions based on water or polar solvents
    • C09K8/506—Compositions based on water or polar solvents containing organic compounds
    • C09K8/508—Compositions based on water or polar solvents containing organic compounds macromolecular compounds
    • C09K8/5083—Compositions based on water or polar solvents containing organic compounds macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds

Definitions

  • the invention relates to the technical field of oil drilling, and in particular to a multi-component copolymer and a preparation method and application thereof.
  • Wellbore instability is one of the common underground complex situations encountered in drilling projects, which seriously affects the acquisition of geological data, drilling speed, drilling quality and cost.
  • the target layer cannot be drilled due to wellbore instability, which leads to delays in exploration and development speed and affects economic benefits.
  • the essence of wellbore instability is mechanical instability. When the stress on the wellbore rock exceeds its own strength, wellbore instability will occur.
  • the causes of wellbore instability are complex and can be mainly summarized into three aspects: mechanical factors, physical and chemical factors and engineering technical measures.
  • Wellbore instability is a common problem in the oil and gas industry. It exists in almost all oil and gas field developments, affecting safe drilling and causing significant economic losses. Therefore, improving wellbore stability technology is of great significance to achieving safe, efficient and low-cost drilling goals.
  • various technical measures to stabilize the wellbore have been summarized based on the wellbore instability phenomenon encountered in practice. Among them, optimizing the type and formula of drilling fluid is one of the important measures to improve wellbore instability, improve the inhibition of drilling fluid; use physical and chemical methods to seal the bedding and cracks of the formation to prevent the drilling fluid filtrate from entering the formation; improve the membrane efficiency of the drilling fluid on the formation, and minimize the amount of drilling fluid filtrate entering the formation.
  • Commonly used anti-collapse drilling fluid treatment agents at home and abroad include inorganic salts, asphalt, silicates, polymers, etc.
  • the mechanism of action of inorganic salts such as KCl and NH 4 Cl is mainly to inhibit clay hydration and expansion, but the intensity of action is limited.
  • Asphalt treatment agents are solid when the operating temperature is lower than their softening point, and become soft when approaching their softening point. Under the action of pressure difference, asphalt treatment agents are easily squeezed into the formation bedding cracks and pore throats, forming a plugging zone on the well wall, which can effectively prevent drilling fluid filtrate from entering the formation and prevent well wall collapse.
  • asphalt products usually have fluorescence, which affects geological logging, so their use is limited.
  • Polymer treatment agents mainly inhibit clay hydration and dispersion and prevent shale collapse through adsorption and coating, but polymer treatment agents usually have poor temperature resistance and high cost.
  • polymer treatment agents have their own advantages, they also have obvious shortcomings. Therefore, how to improve the effect of well wall stabilizers has always been a major technical difficulty in the field of drilling fluids.
  • the purpose of the present invention is to overcome the problem of wellbore instability in drilling operations in the prior art, and to provide a multi-polymer and its preparation method and application.
  • the multi-polymer can be used as a wellbore strengthening wellbore stabilizer to inhibit the hydration expansion of formation clay minerals, effectively seal cracks and rocks with developed stratification, and effectively strengthen the wellbore.
  • the first aspect of the present invention provides a multi-component copolymer, wherein the multi-component copolymer comprises a structural unit A, a structural unit B, a structural unit C and a structural unit D; wherein the structural unit A has a structure shown in formula (1); the structural unit B has a structure shown in formula (2); the structural unit C has a structure shown in formula (3); and the structural unit D has a structure shown in formula (4);
  • R1 and R2 are each independently selected from hydrogen or C1 - C6 alkyl; R3 is selected from C1 - C6 alkylene; M is selected from hydrogen or alkali metal;
  • R4 and R5 are each independently selected from hydrogen or C1 - C6 alkyl
  • R 6 and R 7 are each independently selected from hydrogen or a C 1 -C 6 alkyl group
  • R 8 and R 9 are each independently selected from hydrogen or C 1 -C 6 alkyl; and X is selected from halogen.
  • a second aspect of the present invention provides a method for preparing a multi-component copolymer, the preparation method comprising:
  • the polymerizable monomers are subjected to solution polymerization to obtain a multi-polymer; wherein the polymerizable monomers include: a monomer represented by formula (I), a monomer represented by formula (II), a monomer represented by formula (III) and a monomer represented by formula (IV);
  • R1 and R2 are each independently selected from hydrogen or C1 - C6 alkyl; R3 is selected from C1 - C6 alkylene; M1 is selected from hydrogen or alkali metal;
  • R 4 and R 5 are each independently selected from hydrogen or C 1 -C 6 alkyl
  • R 6 and R 7 are each independently selected from hydrogen or C 1 -C 6 alkyl
  • R 8 and R 9 are each independently selected from hydrogen or C 1 -C 6 alkyl; and M 2 is selected from halogen.
  • the third aspect of the present invention provides a multi-polymer obtained by the aforementioned preparation method.
  • a fourth aspect of the present invention provides the use of the aforementioned multi-polymer as a wellbore stabilizer in drilling; preferably, the multi-polymer is used as a wellbore stabilizer in a wellbore reinforcement type wellbore.
  • the fifth aspect of the present invention provides a water-based drilling fluid using the aforementioned multi-polymer as a wellbore stabilizer; preferably, the content of the multi-polymer is 1-6 wt % based on the total weight of the water-based drilling fluid.
  • the multi-component copolymer provided by the present invention has strong linear expansion ability, and can form multiple adsorption points on the well wall, thereby preventing clay from dispersing and playing a role in stabilizing the well wall, thereby reducing the occurrence of underground accidents.
  • the multi-polymer of the present invention can be used as a wellbore stabilizer, especially a wellbore strengthening wellbore stabilizer, which can inhibit the hydration expansion of formation clay minerals, effectively seal cracks and rocks with developed stratification, effectively strengthen the wellbore, maintain the stability of the wellbore, and at the same time has a certain filtration loss reduction effect, thereby improving the development and utilization efficiency of oil and gas resources and the economic benefits of oilfield companies.
  • FIG1 is an infrared spectrum of polymer W1 obtained in Example 1 of the present invention.
  • the first aspect of the present invention provides a multi-component copolymer, the multi-component copolymer comprising a structural unit A, a structural unit B, a structural unit C and a structural unit D; wherein the structural unit A has a structure shown in formula (1); the structural unit B has a structure shown in formula (2); the structural unit C has a structure shown in formula (3); the structural unit D has a structure shown in formula (4);
  • R1 and R2 are each independently selected from hydrogen or C1 - C6 alkyl; R3 is selected from C1 - C6 alkylene; M is selected from hydrogen or alkali metal;
  • R4 and R5 are each independently selected from hydrogen or C1 - C6 alkyl
  • R 6 and R 7 are each independently selected from hydrogen or a C 1 -C 6 alkyl group
  • R 8 and R 9 are each independently selected from hydrogen or C 1 -C 6 alkyl; and X is selected from halogen.
  • the alkyl group or alkylene group in the present invention includes a linear or branched substituted or unsubstituted alkyl group or alkylene group.
  • the multi-component copolymer of the present invention contains aromatic groups, which can enhance the electrostatic interaction of cationic groups so that the copolymer has better adhesion performance.
  • R1 and R2 are each independently selected from hydrogen or C1 - C3 alkyl, preferably hydrogen, methyl or ethyl; R3 is selected from C1 - C3 alkylene, preferably methylene or 1,2-ethylene; M is selected from hydrogen, sodium or potassium.
  • R4 and R5 are each independently selected from hydrogen or C1 - C3 alkyl, preferably hydrogen, methyl, ethyl or propyl.
  • R 6 and R 7 are each independently selected from hydrogen or C 1 -C 3 alkyl, preferably hydrogen, methyl, ethyl or propyl.
  • R8 and R9 are each independently selected from hydrogen or C1 - C3 alkyl, preferably hydrogen, methyl, ethyl or propyl; X is selected from Cl, Br or I.
  • the structural unit A can be selected from, for example, the structure represented by formula (1-1), the structure represented by formula (1-2), the structure represented by formula (1-3), the structure represented by formula (1-4), the structure represented by formula (1-5), the structure represented by formula (1-6), the structure represented by formula (1-7), the structure represented by formula (1-8), the structure represented by formula (1-9), the structure represented by formula (1-10), the structure represented by formula (1-11), the structure represented by formula (1-12), the structure represented by formula (1-13), the structure represented by formula (1-14) , the structure shown in formula (1-15), the structure shown in formula (1-16), the structure shown in formula (1-17), the structure shown in formula (1-18), the structure shown in formula (1-19), the structure shown in formula (1-20), the structure shown in formula (1-21), the structure shown in formula (1-22), the structure shown in formula (1-23), the structure shown in formula (1-24), the structure shown in formula (1-25), the structure shown in formula (1-26) and the structure shown in formula (1-27) At least one of the structural units; wherein,
  • R 1 is H;
  • R 2 is H;
  • M is H;
  • R 3 is -CH 2 -;
  • R 1 is H;
  • R 2 is H;
  • M is K;
  • R 3 is -CH 2 -;
  • R 1 is H;
  • R 2 is H;
  • M is Na;
  • R 3 is -CH 2 -;
  • R 1 is H;
  • R 2 is -CH 3 ;
  • M is H;
  • R 3 is -CH 2 -;
  • R 1 is H;
  • R 2 is -CH 3 ;
  • M is K;
  • R 3 is -CH 2 -;
  • R 1 is H;
  • R 2 is -CH 3 ;
  • M is Na;
  • R 3 is -CH 2 -;
  • R 1 is H;
  • R 2 is -CH 2 CH 3 ;
  • M is H;
  • R 3 is -CH 2 -;
  • R 1 is H;
  • R 2 is -CH 2 CH 3 ;
  • M is K;
  • R 3 is -CH 2 -;
  • R 1 is H;
  • R 2 is -CH 2 CH 3 ;
  • M is Na;
  • R 3 is -CH 2 -;
  • R 1 is -CH 3 ;
  • R 2 is H;
  • M is H;
  • R 3 is -CH 2 -;
  • R 1 is -CH 3 ;
  • R 2 is H;
  • M is K;
  • R 3 is -CH 2 -;
  • R 1 is -CH 3 ;
  • R 2 is H;
  • M is Na;
  • R 3 is -CH 2 -;
  • R 1 is -CH 3 ;
  • R 2 is -CH 3 ;
  • M is H;
  • R 3 is -CH 2 -;
  • R 1 is -CH 3 ;
  • R 2 is -CH 3 ;
  • M is K;
  • R 3 is -CH 2 -;
  • R 1 is -CH 3 ;
  • R 2 is -CH 3 ;
  • M is Na;
  • R 3 is -CH 2 -;
  • R 1 is -CH 3 ;
  • R 2 is -CH 2 CH 3 ;
  • M is H;
  • R 3 is -CH 2 -;
  • R 1 is -CH 3 ;
  • R 2 is -CH 2 CH 3 ;
  • M is K;
  • R 3 is -CH 2 -;
  • R 1 is -CH 3 ;
  • R 2 is -CH 2 CH 3 ;
  • M is Na;
  • R 3 is -CH 2 -;
  • R 1 is -CH 2 CH 3 ;
  • R 2 is H;
  • M is H;
  • R 3 is -CH 2 -;
  • R 1 is -CH 2 CH 3 ;
  • R 2 is H;
  • M is K;
  • R 3 is -CH 2 -;
  • R 1 is -CH 2 CH 3 ;
  • R 2 is H;
  • M is Na;
  • R 3 is -CH 2 -;
  • R 1 is -CH 2 CH 3 ;
  • R 2 is -CH 3 ;
  • M is H;
  • R 3 is -CH 2 -;
  • R 1 is -CH 2 CH 3 ;
  • R 2 is -CH 3 ;
  • M is K;
  • R 3 is -CH 2 -;
  • R 1 is -CH 2 CH 3 ;
  • R 2 is -CH 3 ;
  • M is Na;
  • R 3 is -CH 2 -;
  • R 1 is -CH 2 CH 3 ;
  • R 2 is -CH 2 CH 3 ;
  • M is H;
  • R 3 is -CH 2 -;
  • R 1 is -CH 2 CH 3 ;
  • R 2 is -CH 2 CH 3 ;
  • M is K;
  • R 3 is -CH 2 -;
  • R 1 is -CH 2 CH 3 ;
  • R 2 is -CH 2 CH 3 ;
  • M is Na;
  • R 3 is -CH 2 -.
  • the structural unit B can be selected from at least one of the structural units represented by formula (2-1), formula (2-2), formula (2-3), formula (2-4), formula (2-5), formula (2-6), formula (2-7), and formula (2-8); wherein,
  • R 4 is H;
  • R 5 is -CH 3 ;
  • R 4 is H;
  • R 5 is -CH 2 CH 3 ;
  • R 4 is -CH 3
  • R 5 is -CH 3 ;
  • R 4 is -CH 3 ;
  • R 5 is -CH 2 CH 3 ;
  • R 4 is -CH 2 CH 3 ;
  • R 5 is -CH 2 CH 3 ;
  • R 4 is -CH 2 CH 2 CH 3 ;
  • R 5 is -CH 2 CH 3 ;
  • R 4 is -CH 2 CH 2 CH 3 ;
  • R 5 is -CH 2 CH 2 CH 3 .
  • the structural unit C can be selected from at least one of the structural units represented by formula (3-1), formula (3-2), formula (3-3), formula (3-4), formula (3-5), formula (3-6), formula (3-7), and formula (3-8); wherein,
  • R 6 is H
  • R 7 is H
  • R 6 is H;
  • R 7 is -CH 3 ;
  • R 6 is H;
  • R 7 is -CH 2 CH 3 ;
  • R 6 is -CH 3
  • R 7 is -CH 3 ;
  • R 6 is -CH 3 ;
  • R 7 is -CH 2 CH 3 ;
  • R 6 is -CH 2 CH 3 ;
  • R 7 is -CH 2 CH 3 ;
  • R 6 is -CH 2 CH 2 CH 3 ;
  • R 8 is -CH 2 CH 3 ;
  • R 6 is -CH 2 CH 2 CH 3 ;
  • R 7 is -CH 2 CH 2 CH 3 .
  • the structural unit D can be, for example, selected from at least one of the structural units represented by formula (4-1), formula (4-2), formula (4-3), formula (4-4), formula (4-5), formula (4-6), formula (4-7), formula (4-8), formula (4-9), formula (4-10), formula (4-11), formula (4-12), formula (4-13), formula (4-14), formula (4-15), formula (4-16), formula (4-17), and formula (4-18); wherein,
  • R 8 is H; R 9 is -CH 3 ; X is Br;
  • R 8 is H; R 9 is -CH 3 ; X is Cl;
  • R 8 is H; R 9 is -CH 3 ; X is I;
  • R 8 is -CH 3 ;
  • R 9 is -CH 3 ;
  • X is Br;
  • R 8 is -CH 3 ;
  • R 9 is -CH 3 ;
  • X is Cl;
  • R 8 is -CH 3 ;
  • R 9 is -CH 3 ;
  • X is I;
  • R 8 is -CH 3 ;
  • R 9 is -CH 2 CH 3 ;
  • X is Br;
  • R 8 is -CH 3 ;
  • R 9 is -CH 2 CH 3 ;
  • X is Cl;
  • R 8 is -CH 3 ;
  • R 9 is -CH 2 CH 3 ;
  • X is I;
  • R 8 is -CH 3 ;
  • R 9 is -CH 2 CH 2 CH 3 ;
  • X is Br;
  • R 8 is -CH 3 ;
  • R 9 is -CH 2 CH 2 CH 3 ;
  • X is Cl;
  • R 8 is -CH 2 CH 3 ;
  • R 9 is -CH 2 CH 2 CH 3 ;
  • X is I;
  • R 8 is -CH 2 CH 3 ;
  • R 9 is -CH 2 CH 3 ;
  • X is Br;
  • R 8 is -CH 2 CH 3 ;
  • R 9 is -CH 2 CH 3 ;
  • X is Cl;
  • the structural unit represented by formula (1) is provided by 2-acrylamide-2-methylpropanesulfonic acid; the structural unit represented by formula (2) is provided by acrylamide; the structure represented by formula (3) is provided by 2-phenoxyethyl acrylate; and the structural unit represented by formula (4) is provided by 2-aminoethyl methacrylate hydrochloride.
  • the structural units contained in the multi-component copolymer are formed by addition polymerization of carbon-carbon double bonds contained in monomers corresponding to the structural units.
  • the molar ratio of the structural unit A, the structural unit B, the structural unit C and the structural unit D is 0.5-2:1.4-1.8:1.5-4.2:0.3-0.8, preferably 1-1.5:1.6-1.7:2-3:0.5-0.7.
  • the average molecular weight of the multi-polymer is 20,000-150,000 g/mol, preferably 30,000-100,000 g/mol, and more preferably 80,000-90,000 g/mol.
  • the intrinsic viscosity of the multi-polymer is 200-500 mL/g, preferably 240-460 mL/g.
  • composition and structure of the multi-polymer can be obtained by infrared analysis or inferred by monomer feeding and reaction.
  • a second aspect of the present invention provides a method for preparing a multi-component copolymer, the preparation method comprising:
  • the polymerizable monomers are subjected to solution polymerization to obtain a multi-polymer; wherein the polymerizable monomers include: a monomer represented by formula (I), a monomer represented by formula (II), a monomer represented by formula (III) and a monomer represented by formula (IV);
  • R1 and R2 are each independently selected from hydrogen or C1 - C6 alkyl; R3 is selected from C1 - C6 alkylene; M1 is selected from hydrogen or alkali metal;
  • R 4 and R 5 are each independently selected from hydrogen or C 1 -C 6 alkyl
  • R 6 and R 7 are each independently selected from hydrogen or C 1 -C 6 alkyl
  • R 8 and R 9 are each independently selected from hydrogen or C 1 -C 6 alkyl; and M 2 is selected from halogen.
  • the present invention prepares a multi-polymer by a free radical polymerization method, adopts solution polymerization, dissolves a polymerization monomer and an initiator (i.e., a free radical initiator) in a suitable solvent, and performs a polymerization reaction in a solution state.
  • the present invention can prepare polymers of different molecular weights by controlling the selection of solvents and initiators, the order and amount of polymerization monomers added, etc.
  • the order of adding the polymerizable monomers can be to add them together and perform solution polymerization in a one-step method. It can also be added in two steps and perform solution polymerization in a two-step method. That is, the monomers represented by formula (III), the monomers represented by formula (IV) and the initiator are first reacted in a solvent in a first step, and then the product of the first step reaction is reacted with the monomers represented by formula (I), the monomers represented by formula (II) and the initiator in a solvent in a second step.
  • the solution polymerization method of the present invention has the advantages of easy diffusion of polymerization heat, easy control of reaction temperature, low system viscosity, less branching or cross-linking products generated by chain transfer to polymers, easy control of product molecular weight, narrow molecular weight distribution, and direct product preparation in solution. It can be used to prepare polymers that can be used as wellbore strengthening well wall stabilizers and has broad application prospects in wellbore strengthening technology.
  • R1 and R2 are each independently selected from hydrogen or C1- C3 alkyl, preferably hydrogen, methyl or ethyl; R3 is selected from C1 - C3 alkylene, preferably methylene or 1,2 -ethylene; M1 is selected from hydrogen, sodium or potassium.
  • R 4 and R 5 are each independently selected from hydrogen or C 1 -C 3 alkyl, preferably hydrogen, methyl, ethyl or propyl.
  • R 6 and R 7 are each independently selected from hydrogen or C 1 -C 3 alkyl, preferably hydrogen, methyl, ethyl or propyl.
  • R 8 and R 9 are each independently selected from hydrogen or C 1 -C 3 alkyl, preferably hydrogen, methyl, ethyl or propyl; M 2 is selected from Cl, Br or I.
  • the polymerizable monomers in the present invention correspond one-to-one to the structural units in the first aspect, and each substituent is also the same as in the first aspect.
  • each substituent is also the same as in the first aspect.
  • reference may be made to the description of the first aspect, which will not be repeated here.
  • the monomer represented by formula (I) can be selected from 2-acrylamide-2-methylpropanesulfonic acid; the monomer represented by formula (II) can be selected from acrylamide; the monomer represented by formula (III) can be selected from 2-phenoxyethyl acrylate; the monomer represented by formula (IV) can be selected from 2-aminoethyl methacrylate hydrochloride.
  • the molar ratio of the monomer represented by formula (I), the monomer represented by formula (II), the monomer represented by formula (III) and the monomer represented by formula (IV) is 0.5-2:1.4-1.8:1.5-4.2:0.3-0.8, preferably 1-1.5:1.6-1.7:2-3:0.5-0.7.
  • the conditions for solution polymerization include: temperature of 30-100° C., preferably 40-70° C.; time of 4-8 h, preferably 6-7 h.
  • the reaction time in the present invention refers to the total time required for the reaction of four monomers.
  • the total time of the first step reaction and the second step reaction is 4-8 hours, preferably 6-7 hours; the reaction time of the first step reaction and the second step reaction is independently selected from 2-6 hours, preferably 3-3.5 hours.
  • the air in the reaction system may be replaced by ventilation, and the introduced gas may be a gas selected from nitrogen, helium, neon and other substantially reaction inert gases.
  • the initiator is selected from one of alkyl halides, azobisisobutyronitrile (AIBN), 2-ketoglutaric acid, potassium persulfate, cerium ammonium nitrate and azobisisobutyramidine hydrochloride (V50); preferably potassium persulfate.
  • AIBN azobisisobutyronitrile
  • 2-ketoglutaric acid 2-ketoglutaric acid
  • potassium persulfate potassium persulfate
  • cerium ammonium nitrate and azobisisobutyramidine hydrochloride (V50); preferably potassium persulfate.
  • the amount of the initiator (by mass) is preferably 0.5-5 wt %, more preferably 1-2 wt % of the total weight of the polymerized monomers.
  • the amount of the initiator used for the four monomers is based on the total weight of the polymerized monomers.
  • the amount of the initiator used in each step of the reaction is 0.25-2.5wt% of the total weight of the polymerized monomers, preferably 0.5-1wt%.
  • the solution polymerization is carried out in a solvent.
  • the solvent is selected from one of deionized water, ethanol, methanol and dimethyl sulfoxide; preferably deionized water.
  • the amount of the solvent used is such that the total concentration of the polymerizable monomers in the solvent is 0.01-5 mol/L, preferably 0.1-1 mol/L.
  • the present invention when a one-step method is adopted, four monomers are added to a solvent together.
  • the present invention does not specifically limit the concentration of the monomers shown in formula (III) and the monomers shown in formula (IV) in the solvent in the first step reaction, and the conventional operation in the art can be carried out.
  • the total concentration of the polymerized monomers in the solvent refers to the total concentration of the monomers shown in formula (I), the monomers shown in formula (II), the monomers shown in formula (III) and the monomers shown in formula (IV) in the second step solvent in the second step reaction, based on the amount of feed, of 0.01-5 mol/L, preferably 0.1-1 mol/L.
  • the synthesis steps of the multi-polymer using a two-step solution polymerization method are as follows:
  • the third aspect of the present invention provides a multi-polymer obtained by the aforementioned preparation method.
  • the multi-polymer can achieve excellent well wall stability at a relatively low dosage.
  • the fifth aspect of the present invention provides a water-based drilling fluid using the aforementioned multi-polymer as a wellbore stabilizer.
  • the content of the multi-polymer is 1-6 wt %.
  • the water-based drilling fluid may also contain other additives conventionally used in the art, such as bentonite, thickeners, anti-collapse agents, lubricants, weighting agents, alkaline regulators, etc.
  • additives conventionally used in the art, such as bentonite, thickeners, anti-collapse agents, lubricants, weighting agents, alkaline regulators, etc.
  • the types and contents of these additives may be the types and contents conventionally used in the art, and the present invention has no particular limitation on this.
  • the multi-polymer of the present invention can be used as a wellbore stabilizer for drilling fluid, can inhibit the hydration expansion of formation clay minerals, effectively seal cracks and rocks with developed stratification, effectively strengthen the wellbore, maintain the stability of the wellbore, and at the same time has a certain filtration loss reduction effect, thereby improving the development and utilization efficiency of oil and gas resources and the economic benefits of oilfield companies.
  • the drilling fluid is a water-based drilling fluid
  • the synthesis of the polymer in the drilling fluid is studied and evaluated from multiple angles such as different additives, polymer structure and polymer action mechanism.
  • the aforementioned additives may be commercially available products, or may be prepared according to methods known in the art, which will not be described in detail in the present invention.
  • the preparation method of the drilling fluid polymer adopts a free radical solution polymerization preparation method well known to those skilled in the art, which will not be described in detail herein.
  • the present invention lists specific operations in the following text, which should not be understood by those skilled in the art as limiting the present invention.
  • the monomer represented by formula (I) (2-acrylamide-2-methylpropanesulfonic acid): Anaiji Chemical Technology (Shanghai) Co., Ltd.;
  • ME104/02 constant temperature magnetic stirrer (T09-1S), digital display constant temperature water bath (XMTD203), electric stirrer (HD2004W), variable frequency high-speed stirrer (GJSS-B12K), 1103 six-speed rotation viscometer (MK-03), variable frequency high-temperature roller heating furnace (GW300) were all purchased from Qingdao Tongchun Petroleum Instrument Co., Ltd.
  • the molecular weight and molecular weight distribution of the polymer were determined by gel permeation chromatography (three-detector gel permeation chromatography, Wyatt Company, USA). Tetrahydrofuran was used as the mobile phase, the flow rate was 1.0 mL/min, narrow distribution polystyrene was used as the standard sample, the differential refractive index detector was used as the basic detector, and the column temperature and detection temperature were 35°C.
  • the purified sample was prepared into a solution of a certain concentration by adding an appropriate amount of tetrahydrofuran, and the insoluble impurities were filtered out with a filter head before being sent for inspection.
  • the intrinsic viscosity of the polymer was measured using an Ubbelohde viscometer (1836-A, Tianjin Hongyang Machinery Equipment Co., Ltd.). Anhydrous methanol was used as the solvent to prepare a 2 g/mL polymer solution, which was then diluted to 2/3, 1/2, 1/3, and 1/2 of the original concentration. 1/4, the test temperature is 35°C, the elution time of solvent methanol and polymer solutions of different concentrations are measured, and the intrinsic viscosity of the polymer is obtained by extrapolating the elution time against the concentration.
  • the reference data of rheological properties of drilling fluid include apparent viscosity, plastic viscosity and dynamic shear force. After the water-based drilling fluid is stirred at a high-frequency speed of 12000rpm for 20min, the values of ⁇ 600 and ⁇ 300 are measured by a six-speed rotary viscometer according to the standard GB/T 16782-1997, and the apparent viscosity (AV), plastic viscosity (PV) and dynamic shear force (YP) of the water-based drilling fluid are calculated by the following formula.
  • AV apparent viscosity
  • PV plastic viscosity
  • YP dynamic shear force
  • the inhibitory performance of the treatment agent is evaluated through a linear expansion test. Using a dual-channel shale expansion meter, the difference in swelling height of bentonite in different treatment agent solutions and deionized water is measured to intuitively measure the effect and ability of the treatment solution in inhibiting clay hydration expansion.
  • the specific process is as follows:
  • the inhibition performance of the treatment agent was evaluated by core immersion experiments.
  • the appearance and morphological integrity of the cores were measured after being immersed in different wellbore stabilizer solutions for 24 hours.
  • a method for preparing a multi-component copolymer comprises the following steps:
  • Step 1 dissolving 2-phenoxyethyl acrylate and 2-aminoethyl methacrylate hydrochloride in deionized water at a molar ratio of 2:0.5, pouring the solution into a three-necked flask, stirring at 300-400 rpm, and passing nitrogen for 10-20 minutes to remove oxygen in the container, uniformly adding 1 wt% (i.e., 1% of the total mass of the polymerizable monomer) of the initiator potassium persulfate, heating to 70°C, and reacting for 3 hours;
  • 1 wt% i.e., 1% of the total mass of the polymerizable monomer
  • Step 2 Pour the product and the solution into a rotary evaporator to remove the solvent, and place the remaining product in an oven to dry;
  • Step 3 Heat and dissolve the dried product with deionized water, then add 2-acrylamide-2-methylpropanesulfonic acid and acrylamide in a molar ratio of 1:1.6, pour the solution into a three-necked flask, stir at a speed of 300-400 rpm, pass nitrogen for 10-20 min, remove oxygen in the container, uniformly add 1 wt% potassium persulfate initiator (i.e., 1% of the total mass of the polymerized monomers), heat to 70°C, and react for 3 hours;
  • Step 4 The entire reaction process was carried out in a constant temperature water bath to ensure a stable nitrogen environment and temperature.
  • step 3 the total concentration of the polymerized monomers in the three-necked flask was 0.1 mol/L.
  • the synthesized product was polymer W 1 .
  • Table 1 The test results are shown in Table 1.
  • the obtained polymer W 1 was subjected to rotary evaporation drying treatment, and the polymer W 1 was detected by infrared spectrum analysis method, and an infrared spectrum as shown in FIG1 was obtained. As can be seen from FIG1 , a block copolymer containing NH, C ⁇ O, and sulfonic acid structural units was obtained.
  • Step 1 dissolving 2-phenoxyethyl acrylate and 2-aminoethyl methacrylate hydrochloride in deionized water at a molar ratio of 2:0.5, pouring the solution into a three-necked flask, stirring at 300-400 rpm, and passing nitrogen for 10-20 minutes to remove oxygen in the container, uniformly adding 1 wt% (i.e., 1% of the total mass of the polymerizable monomer) of the initiator potassium persulfate, heating to 70°C, and reacting for 3 hours;
  • 1 wt% i.e., 1% of the total mass of the polymerizable monomer
  • Step 2 Pour the product and the solution into a rotary evaporator to remove the solvent, and place the remaining product in an oven to dry;
  • Step 3 Heat and dissolve the dried product with deionized water, then add 2-acrylamide-2-methylpropanesulfonic acid and acrylamide in a molar ratio of 1:1.6, pour the solution into a three-necked flask, stir at a speed of 300-400 rpm, pass nitrogen for 10-20 min, remove oxygen in the container, uniformly add 1 wt% potassium persulfate initiator (i.e., 1% of the total mass of the polymerized monomers), heat to 70°C, and react for 3 hours;
  • Step 4 The entire reaction process was carried out in a constant temperature water bath to ensure a stable nitrogen environment and temperature.
  • step 3 the total concentration of the polymerized monomers in the three-necked flask was 0.5 mol/L.
  • the synthesized product was polymer W 2 .
  • Table 1 The test results are shown in Table 1.
  • Step 1 dissolving 2-phenoxyethyl acrylate methacrylate 2-aminoethyl ester hydrochloride in deionized water at a molar ratio of 2:0.5, pouring the solution into a three-necked flask, stirring at 300-400 rpm, and passing nitrogen for 10-20 minutes to remove oxygen in the container, uniformly adding 1wt% (i.e., 1% of the total mass of the polymerized monomer) of the initiator potassium persulfate, heating to 70°C, and reacting for 3 hours;
  • 1wt% i.e., 1% of the total mass of the polymerized monomer
  • Step 2 Pour the product and the solution into a rotary evaporator to remove the solvent, and place the remaining product in an oven to dry;
  • Step 3 Heat and dissolve the dried product with deionized water, then add 2-acrylamide-2-methylpropanesulfonic acid and acrylamide in a molar ratio of 1:1.6, pour the solution into a three-necked flask, stir at a speed of 300-400 rpm, pass nitrogen for 10-20 min, remove oxygen in the container, uniformly add 1 wt% potassium persulfate initiator (i.e., 1% of the total mass of the polymerized monomers), heat to 70°C, and react for 3 hours;
  • Step 4 The entire reaction process was carried out in a constant temperature water bath to ensure a stable nitrogen environment and temperature.
  • the total concentration of the polymerized monomers in the three-necked flask was 1.0 mol/L.
  • the synthesized product was polymer W 3 .
  • the test results are shown in Table 1.
  • Example 1 The method described in Example 1 is different in that the amounts of the four monomers are based on 2-acrylamide-2-methylpropanesulfonic acid: The molar ratio of acrylamide:2-phenoxyethyl acrylate:2-aminoethyl methacrylate hydrochloride is 1.2:1.65:2.5:0.6, and the total monomer concentration is kept unchanged. After the whole process, polymer W 7 is finally obtained. The test results are shown in Table 1.
  • Example 1 The method described in Example 1 is different in that an equal amount (ie, equal volume) of ethanol is used as a solvent instead of deionized water. After the whole process, polymer W 10 is finally obtained. The test results are shown in Table 1.
  • Example 1 The method described in Example 1 is different in that an equal amount of ammonium cerium nitrate is used as an initiator instead of potassium persulfate, and the polymer W 11 is finally obtained after the whole process.
  • the test results are shown in Table 1.
  • Example 1 The method described in Example 1 is different in that an equal molar amount of sodium styrene sulfonate is used instead of 2-acrylamide-2-methylpropane sulfonic acid, and the polymer D 1 is finally obtained through the whole process.
  • the test results are shown in Table 1.
  • Example 1 The method described in Example 1 is different in that ammonium persulfate is used as the initiator, and the polymer D 2 is finally obtained after the whole process.
  • the test results are shown in Table 1.
  • the prepared well wall stabilizer polymers W1 , W2 , W3 , W4 , W5 , W6 , W7 , W8 , W9 , W10 , W11 , D1 , and D2 were respectively prepared into aqueous solutions with a mass fraction concentration of 1%, and the single-dose performance of the well wall stabilizer was tested.
  • the bentonite block was pressed into a linear expansion instrument, and deionized water and the polymer well wall stabilizer prepared in Examples 1-6 were added respectively. After soaking for 16 hours, the final expansion height on the linear expansion instrument was read. The test results of the linear expansion experiment are shown in Table 2.
  • the wellbore strengthening wellbore stabilizer polymer provided by the present invention has a certain inhibitory effect on the hydration expansion of bentonite, and the prepared polymer can significantly reduce the expansion height of the bentonite block and effectively enhance the wellbore stability of the formation.
  • the cores were placed in 1% concentration of wellbore stabilizer polymer W1 , W2 , W3 , W4 , W5 , W6 , W7 , W8 , W9 , W10 , W11 , D1 , and D2 solutions, respectively, and immersed for 24 hours. The integrity of the cores was observed. The test results are shown in Table 3.
  • the wellbore strengthening wellbore stabilizer provided by the present invention has a certain degree of cementing effect on clay particles, thereby playing a role in stabilizing the wellbore and strengthening the wellbore.
  • the wellbore stabilizer prepared by the present invention is formulated into a water-based drilling fluid system, wherein the polymer addition amount is 1%, and the basic properties such as filtration loss and rheology of each water-based drilling fluid containing the synthesized wellbore stabilizer are tested.
  • the results of the apparent viscosity (AV/mPa ⁇ s), plastic viscosity (PV/mPa ⁇ s), dynamic shear force (YP/Pa), dynamic plastic ratio (YP/PV (Pa/mPa ⁇ s)), and medium pressure filtration loss (API/mL) of the above-mentioned drilling fluid are shown in Table 4.
  • the wellbore strengthening wellbore stabilizer provided by the present invention can improve the viscosity of the drilling fluid, effectively reduce the filtration loss, reduce the loss of drilling fluid during drilling work, and play a role in stabilizing the wellbore wall.
  • the polymer synthesized by the solution polymerization method provided by the present invention is applied to water-based drilling fluid, and the preparation of wellbore strengthening wellbore stabilizer has a very obvious effect, which can greatly improve the rheological properties and filtration loss of the drilling fluid, and the preparation method is simple and the cost is low. Therefore, the present invention has a very broad application prospect, can effectively solve the wellbore instability problem existing in drilling work, improve the inhibition performance of drilling fluid on the hydration expansion of formation clay, reduce the occurrence of complex accidents underground, and bring about the improvement of economic benefits.

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Abstract

本发明涉及石油钻井技术领域，具体公开了多元共聚物及其制备方法和应用。该多元共聚物含有结构单元A、结构单元B、结构单元C和结构单元D；其中，所述结构单元A具有式（1）所示结构；所述结构单元B具有式（2）所示结构；所述结构单元C具有式（3）所示结构。本发明的多元共聚物可用作井壁稳定剂，尤其是井眼强化型井壁稳定剂，可抑制地层粘土矿物水化膨胀，对裂缝和层理发育的岩石进行有效封堵，有效强化井眼，维持井壁稳定，同时具有一定的降滤失作用，提高油气资源开发利用效率和油田公司的经济效益。

Description

多元共聚物及其制备方法和应用
相关申请的交叉引用
本申请要求2023年06月13日提交的中国专利申请202310702169.0的权益，该申请的内容通过引用被合并于本文。
技术领域
本发明涉及石油钻井技术领域，具体涉及多元共聚物及其制备方法和应用。
背景技术
井壁失稳是钻井工程中常遇到的井下复杂情况之一，严重影响地质资料的录取、钻井速度、钻井质量及成本。对于部分新探区还会因井壁失稳而无法钻达目的层，进而导致延误勘探与开发速度，影响经济效益。井壁失稳的实质是力学不稳定。当井壁岩石所受到的应力超过其本身的强度时，就会发生井壁失稳。井壁失稳的原因复杂，主要可归纳为力学因素、物理化学因素和工程技术措施等三个方面，钻井过程中所钻遇的地层，如泥页岩、砂质或粉砂质泥岩、流岩、砂岩、泥质砂岩或粉砂岩、岩浆岩等均可能发生井壁失稳。
井壁失稳作为油气行业的普遍性难题，几乎在所有油气田开发中均存在，影响安全钻进，造成重大经济损失。因此，提高井壁稳定性技术，对实现安全、高效、低成本钻进目标具有重要意义。目前根据实践中所遇到的井壁失稳现象，总结出各种稳定井壁的技术措施，其中优选钻井液类型与配方是改善井壁失稳的重要措施之一，提高钻井液的抑制性；采用物理化学方法封堵地层的层理和裂隙，阻止钻井液滤液进入地层；提高钻井液对地层的膜效率，尽量减少钻井液滤液进入地层的量等。国内外常用的防塌钻井液处理剂有无机盐、沥青类、硅酸盐类、聚合物类等。无机盐如KCl、NH4Cl，其作用机理主要是抑制粘土水化及膨胀，但是作用强度有限。沥青类处理剂的使用温度低于其软化点时呈固态，接近其软化点时变软，在压差作用下，沥青类处理剂容易被挤入地层层理裂缝和孔喉中，在井壁形成一个封堵带，可有效阻止钻井液滤液进入地层，防止井壁坍塌，但是沥青类产品通常带有荧光，影响地质录井，因而其使用受到限制。聚合物类处理剂主要通过吸附和包被来抑制黏土水化分散、防止泥页岩坍塌，但聚合物类处理剂通常抗温性差、成本较高。上述的处理剂虽然各有优点，但是同时存在明显的不足。因此，如何提高井壁稳定剂作用效果一直以来都是钻井液领域的重大技术难点。
发明内容
本发明的目的是为了克服现有技术存在的钻井作业中的井壁失稳问题，提供多元共聚物及其制备方法和应用，该多元共聚物可作为井眼强化型井壁稳定剂，抑制地层粘土矿物水化膨胀，对裂缝和层理发育的岩石进行有效封堵，有效强化井眼。
为了实现上述目的，本发明第一方面提供一种多元共聚物，所述多元共聚物含有结构单元A、结构单元B、结构单元C和结构单元D；其中，所述结构单元A具有式(1)所示结构；所述结构单元B具有式(2)所示结构；所述结构单元C具有式(3)所示结构；所述结构单元D具有式(4)所示结构；
式(1)中，R1和R2各自独立地选自氢或C1-C6的烷基；R3选自C1-C6的亚烷基；M选自氢或碱金属；
式(2)中，R4和R5各自独立地选自氢或C1-C6的烷基；
式(3)中，R6和R7各自独立地选自氢或C1-C6的烷基；
式(4)中，R8和R9各自独立地选自氢或C1-C6的烷基；X选自卤素。
本发明第二方面提供一种多元共聚物的制备方法，所述制备方法包括：
在引发剂存在下，将聚合单体进行溶液聚合，得到多元共聚物；其中，所述聚合单体包括：式(I)所示单体、式(II)所示单体、式(III)所示单体和式(IV)所示单体；
式(I)中，R1和R2各自独立地选自氢或C1-C6的烷基；R3选自C1-C6的亚烷基；M1选自氢或碱金属；
式(II)中，R4和R5各自独立地选自氢或C1-C6的烷基；
式(III)中，R6和R7各自独立地选自氢或C1-C6的烷基；
式(IV)中，R8和R9各自独立地选自氢或C1-C6的烷基；M2选自卤素。
本发明第三方面提供前述的制备方法制得的多元共聚物。
本发明第四方面提供前述的多元共聚物作为井壁稳定剂在钻井中的应用；优选地，所述多元共聚物作为井壁稳定剂在井眼强化型井壁中的应用。
本发明第五方面提供前述的多元共聚物作为井壁稳定剂的水基钻井液；优选地，以所述水基钻井液的总重量为基准，所述多元共聚物的含量为1-6wt％。
通过上述技术方案，本发明所取得的有益技术效果如下：
本发明提供的多元共聚物具有较强的线形展开能力，它可以在井壁形成多个吸附点，阻止粘土分散起到稳定井壁的作用，进而减少井下事故的发生。
本发明的多元共聚物可用作井壁稳定剂，尤其是井眼强化型井壁稳定剂，可抑制地层粘土矿物水化膨胀，对裂缝和层理发育的岩石进行有效封堵，有效强化井眼，维持井壁稳定，同时具有一定的降滤失作用，提高油气资源开发利用效率和油田公司的经济效益。
附图说明
图1是本发明实施例1得到的聚合物W1的红外光谱图。
具体实施方式
在本文中所披露的范围的端点和任何值都不限于该精确的范围或值，这些范围或值应当理解为包含接近这些范围或值的值。对于数值范围来说，各个范围的端点值之间、各个范围的端点值和单独的点值之间，以及单独的点值之间可以彼此组合而得到一个或多个新的数值范围，这些数值范围应被视为在本文中具体公开。
本发明第一方面提供一种多元共聚物，所述多元共聚物含有结构单元A、结构单元B、结构单元C和结构单元D；其中，所述结构单元A具有式(1)所示结构；所述结构单元B具有式(2)所示结构；所述结构单元C具有式(3)所示结构；所述结构单元D具有式(4)所示结构；
式(1)中，R1和R2各自独立地选自氢或C1-C6的烷基；R3选自C1-C6的亚烷基；M选自氢或碱金属；
式(2)中，R4和R5各自独立地选自氢或C1-C6的烷基；
式(3)中，R6和R7各自独立地选自氢或C1-C6的烷基；
式(4)中，R8和R9各自独立地选自氢或C1-C6的烷基；X选自卤素。
本发明中的烷基或亚烷基包括直链或支链的取代或未被取代的烷基或亚烷基。
本发明的多元共聚物含有芳香基团，可以增强阳离子基团静电相互作用使得共聚物具有更好的粘附的性能。
在本发明的一些实施方式中，式(1)中，R1和R2各自独立地选自氢或C1-C3的烷基，优选为氢、甲基或乙基；R3选自C1-C3的亚烷基，优选为亚甲基或1,2-亚乙基；M选自氢、钠或钾。
在本发明的一些实施方式中，式(2)中，R4和R5各自独立地选自氢或C1-C3的烷基，优选为氢、甲基、乙基或丙基。
在本发明的一些实施方式中，式(3)中，R6和R7各自独立地选自氢或C1-C3的烷基，优选为氢、甲基、乙基或丙基。
在本发明的一些实施方式中，式(4)中，R8和R9各自独立地选自氢或C1-C3的烷基，优选为氢、甲基、乙基或丙基；X选自Cl、Br或I。
所述结构单元A例如可以选自式(1-1)所示结构、式(1-2)所示结构、式(1-3)所示结构、式(1-4)所示结构、式(1-5)所示结构、式(1-6)所示结构、式(1-7)所示结构、式(1-8)所示结构、式(1-9)所示结构、式(1-10)所示结构、式(1-11)所示结构、式(1-12)所示结构、式(1-13)所示结构、式(1-14)所示结构、式(1-15)所示结构、式(1-16)所示结构、式(1-17)所示结构、式(1-18)所示结构、式(1-19)所示结构、式(1-20)所示结构、式(1-21)所示结构、式(1-22)所示结构、式(1-23)所示结构、式(1-24)所示结构、式(1-25)所示结构、式(1-26)所示结构和式(1-27)所示结构的结构单元中的至少一种；其中，
式(1-1)：R1为H；R2为H；M为H；R3为-CH2-；
式(1-2)：R1为H；R2为H；M为K；R3为-CH2-；
式(1-3)：R1为H；R2为H；M为Na；R3为-CH2-；
式(1-4)：R1为H；R2为-CH3；M为H；R3为-CH2-；
式(1-5)：R1为H；R2为-CH3；M为K；R3为-CH2-；
式(1-6)：R1为H；R2为-CH3；M为Na；R3为-CH2-；
式(1-7)：R1为H；R2为-CH2CH3；M为H；R3为-CH2-；
式(1-8)：R1为H；R2为-CH2CH3；M为K；R3为-CH2-；
式(1-9)：R1为H；R2为-CH2CH3；M为Na；R3为-CH2-；
式(1-10)：R1为-CH3；R2为H；M为H；R3为-CH2-；
式(1-11)：R1为-CH3；R2为H；M为K；R3为-CH2-；
式(1-12)：R1为-CH3；R2为H；M为Na；R3为-CH2-；
式(1-13)：R1为-CH3；R2为-CH3；M为H；R3为-CH2-；
式(1-14)：R1为-CH3；R2为-CH3；M为K；R3为-CH2-；
式(1-15)：R1为-CH3；R2为-CH3；M为Na；R3为-CH2-；
式(1-16)：R1为-CH3；R2为-CH2CH3；M为H；R3为-CH2-；
式(1-17)：R1为-CH3；R2为-CH2CH3；M为K；R3为-CH2-；
式(1-18)：R1为-CH3；R2为-CH2CH3；M为Na；R3为-CH2-；
式(1-19)：R1为-CH2CH3；R2为H；M为H；R3为-CH2-；
式(1-20)：R1为-CH2CH3；R2为H；M为K；R3为-CH2-；
式(1-21)：R1为-CH2CH3；R2为H；M为Na；R3为-CH2-；
式(1-22)：R1为-CH2CH3；R2为-CH3；M为H；R3为-CH2-；
式(1-23)：R1为-CH2CH3；R2为-CH3；M为K；R3为-CH2-；
式(1-24)：R1为-CH2CH3；R2为-CH3；M为Na；R3为-CH2-；
式(1-25)：R1为-CH2CH3；R2为-CH2CH3；M为H；R3为-CH2-；
式(1-26)：R1为-CH2CH3；R2为-CH2CH3；M为K；R3为-CH2-；
式(1-27)：R1为-CH2CH3；R2为-CH2CH3；M为Na；R3为-CH2-。
所述结构单元B例如可以选自式(2-1)所示结构、式(2-2)所示结构、式(2-3)所示结构和式(2-4)所示结构、(2-5)所示结构、式(2-6)所示结构、式(2-7)所示结构和式(2-8)所示结构的结构单元中的至少一种；其中，
式(2-1)：R4为H；R5为H；
式(2-2)：R4为H；R5为-CH3；
式(2-3)：R4为H；R5为-CH2CH3；
式(2-4)：R4为-CH3；R5为-CH3；
式(2-5)：R4为-CH3；R5为-CH2CH3；
式(2-6)：R4为-CH2CH3；R5为-CH2CH3；
式(2-7)：R4为-CH2CH2CH3；R5为-CH2CH3；
式(2-8)：R4为-CH2CH2CH3；R5为-CH2CH2CH3。
所述结构单元C例如可以选自式(3-1)所示结构、式(3-2)所示结构、式(3-3)所示结构、式(3-4)所示结构、式(3-5)所示结构、式(3-6)所示结构、式(3-7)所示结构、式(3-8)所示结构的结构单元中的至少一种；其中，
式(3-1)：R6为H；R7为H；
式(3-2)：R6为H；R7为-CH3；
式(3-3)：R6为H；R7为-CH2CH3；
式(3-4)：R6为-CH3；R7为-CH3；
式(3-5)：R6为-CH3；R7为-CH2CH3；
式(3-6)：R6为-CH2CH3；R7为-CH2CH3；
式(3-7)：R6为-CH2CH2CH3；R8为-CH2CH3；
式(3-8)：R6为-CH2CH2CH3；R7为-CH2CH2CH3。
所述结构单元D例如可以选自式(4-1)所示结构、式(4-2)所示结构、式(4-3)所示结构、式(4-4)所示结构、式(4-5)所示结构、式(4-6)所示结构、式(4-7)所示结构、式(4-8)所示结构、式(4-9)所示结构、式(4-10)所示结构、式(4-11)所示结构、式(4-12)所示结构、式(4-13)所示结构、式(4-14)所示结构、式(4-15)所示结构、式(4-16)所示结构、式(4-17)所示结构、式(4-18)所示结构的结构单元中的至少一种；其中，
式(4-1)：R8为H；R9为H；X为Br；
式(4-2)：R8为H；R9为H；X为Cl；
式(4-3)：R8为H；R9为H；X为I；
式(4-4)：R8为H；R9为-CH3；X为Br；
式(4-5)：R8为H；R9为-CH3；X为Cl；
式(4-6)：R8为H；R9为-CH3；X为I；
式(4-7)：R8为-CH3；R9为-CH3；X为Br；
式(4-8)：R8为-CH3；R9为-CH3；X为Cl；
式(4-9)：R8为-CH3；R9为-CH3；X为I；
式(4-10)：R8为-CH3；R9为-CH2CH3；X为Br；
式(4-11)：R8为-CH3；R9为-CH2CH3；X为Cl；
式(4-12)：R8为-CH3；R9为-CH2CH3；X为I；
式(4-13)：R8为-CH3；R9为-CH2CH2CH3；X为Br；
式(4-14)：R8为-CH3；R9为-CH2CH2CH3；X为Cl；
式(4-15)：R8为-CH2CH3；R9为-CH2CH2CH3；X为I；
式(4-16)：R8为-CH2CH3；R9为-CH2CH3；X为Br；
式(4-17)：R8为-CH2CH3；R9为-CH2CH3；X为Cl；
式(4-18)：R8为-CH3；R9为-CH2CH3；X为I。
优选地，式(1)所示的结构单元由2-丙烯酰胺-2-甲基丙磺酸提供；式(2)所示的结构单元由丙烯酰胺提供；式(3)所示的结构由2-苯氧基乙基丙烯酸酯提供；式(4)所示的结构单元由甲基丙烯酸2-氨基乙基酯盐酸盐提供。
本发明中，所述多元共聚物含有的上述结构单元为上述结构单元各自分别对应的单体所含的碳碳双键通过加聚反应而形成。
在本发明的一些实施方式中，所述结构单元A、结构单元B、结构单元C和结构单元D的摩尔比为0.5-2:1.4-1.8:1.5-4.2:0.3-0.8，优选为1-1.5:1.6-1.7:2-3:0.5-0.7。
在本发明的一些实施方式中，所述多元共聚物的平均分子量为2万-15万g/mol，优选为3万-10万g/mol，更优选为8万-9万g/mol。
所述多元共聚物的特性粘度为200-500mL/g，优选为240-460mL/g。
本发明中，所述多元共聚物的上述组成和结构可以通过红外的分析测定获得，也可以通过单体投料和反应推断而得。
本发明第二方面提供一种多元共聚物的制备方法，所述制备方法包括：
在引发剂存在下，将聚合单体进行溶液聚合，得到多元共聚物；其中，所述聚合单体包括：式(I)所示单体、式(II)所示单体、式(III)所示单体和式(IV)所示单体；
式(I)中，R1和R2各自独立地选自氢或C1-C6的烷基；R3选自C1-C6的亚烷基；M1选自氢或碱金属；
式(II)中，R4和R5各自独立地选自氢或C1-C6的烷基；
式(III)中，R6和R7各自独立地选自氢或C1-C6的烷基；
式(IV)中，R8和R9各自独立地选自氢或C1-C6的烷基；M2选自卤素。
本发明通过自由基聚合方法制备多元共聚物，采用溶液聚合，将聚合单体和引发剂(也即自由基引发剂)溶于适当溶剂中，在溶液状态下进行聚合反应。本发明可以通过控制溶剂与引发剂的选择、聚合单体加入顺序和加入量等制备不同分子量的聚合物。
其中，在本发明中，聚合单体的加入顺序可以是一起加入，采用一步法进行溶液聚合。也可以分两步加入，采用两步法进行溶液聚合。也即，先将式(III)所示单体、式(IV)所示单体和引发剂在溶剂中进行第一步反应，然后再将第一步反应的产物与式(I)所示单体、式(II)所示单体和引发剂在溶剂中进行第二步反应。
本发明的溶液聚合法具有聚合热易扩散，反应温度易控制，体系粘度低，向高分子的链转移生成支化或交联产物较少，产物分子量易控制，分子量分布较窄，可以溶液方式直接成品等优点，能够应用于制备可作为井眼强化型井壁稳定剂的聚合物，在井眼强化技术有着广阔的应用前景。
在本发明的一些实施方式中，式(I)中，R1和R2各自独立地选自氢或C1-C3的烷基，优选为氢、甲基或乙基；R3选自C1-C3的亚烷基，优选为亚甲基或1,2-亚乙基；M1选自氢、钠或钾。
在本发明的一些实施方式中，式(II)中，R4和R5各自独立地选自氢或C1-C3的烷基，优选为氢、甲基、乙基或丙基。
在本发明的一些实施方式中，式(III)中，R6和R7各自独立地选自氢或C1-C3的烷基，优选为氢、甲基、乙基或丙基。
在本发明的一些实施方式中，式(IV)中，R8和R9各自独立地选自氢或C1-C3的烷基，优选为氢、甲基、乙基或丙基；M2选自Cl、Br或I。
本发明中的聚合单体与第一方面中的结构单元一一对应，各取代基也与前述第一方面相同，具体选择可参考第一方面的描述，在此不再赘述。
优选地，式(I)所示单体可选自2-丙烯酰胺-2-甲基丙磺酸；式(II)所示单体可选自丙烯酰胺；式(III)所示单体可选自2-苯氧基乙基丙烯酸酯；式(IV)所示单体可选自甲基丙烯酸2-氨基乙基酯盐酸盐。
在本发明的一些实施方式中，式(I)所示单体、式(II)所示单体、式(III)所示单体和式(IV)所示单体的摩尔比为0.5-2:1.4-1.8:1.5-4.2:0.3-0.8，优选为1-1.5:1.6-1.7:2-3:0.5-0.7。
在本发明的一些实施方式中，所述溶液聚合的条件包括：温度为30-100℃，优选为40-70℃；时间为4-8h，优选为6-7h。
其中，本发明中的反应时间指的是四个单体反应所需的总时间。采用两步法进行溶液聚合时，第一步反应和第二步反应的总时长为4-8h，优选为6-7h；第一步反应和第二步反应的反应时间各自独立地选自2-6h，优选3-3.5h。
为了使得引发反应可以顺利进行，还可以通气置换反应体系中的空气，通入的气体可以是选自氮气、氦气、氖气等基本反应惰性的气体。
在本发明的一些实施方式中，所述引发剂选自卤代烷、偶氮二异丁腈(AIBN)、2-酮戊二酸、过硫酸钾、硝酸铈铵和偶氮二异丁脒盐酸盐(V50)中的一种；优选为过硫酸钾。
以聚合单体的总重量为基准，该引发剂的用量(以质量计)优选为聚合单体总重量的0.5-5wt％，更优选为1-2wt％。
其中，在本发明中，四个单体，不论是采用一步法，还是两步法进行溶液聚合，引发剂的用量均以聚合单体的总重量为基准。当采用两步法时，以聚合单体的总重量为基准，每一步反应中引发剂的用量各自独自为聚合单体总重量的0.25-2.5wt％，优选为0.5-1wt％。
在本发明的一些实施方式中，所述溶液聚合在溶剂中进行。
在本发明的一些实施方式中，所述溶剂选自去离子水、乙醇、甲醇和二甲基亚砜中的一种；优选为去离子水。
在本发明的一些实施方式中，所述溶剂的用量使得所述聚合单体在溶剂中的总浓度为0.01-5mol/L，优选为0.1-1mol/L。
其中，在本发明中，当采用一步法时，四个单体一起加入到溶剂中。当采用两步法时，本发明对第一步反应中式(III)所示单体和式(IV)所示单体在溶剂中的浓度不做特殊限定，按照本领域的常规操作进行即可。聚合单体在溶剂中的总浓度指的是在第二步反应中，以投料量计，式(I)所示单体、式(II)所示单体、式(III)所示单体和式(IV)所示单体在第二步溶剂中的总浓度为0.01-5mol/L，优选为0.1-1mol/L。
具体地，该多元共聚物采用两步法进行溶液聚合的合成步骤如下：
①将式(III)所示单体和式(IV)所示单体溶解于溶剂中后倒入三口烧瓶，以300-400rpm转速搅拌，并通氮气10-20min，排除容器中的氧气，匀速加入引发剂，升温至40-70℃，例如70℃，反应2-6h，例如3h；其中，式(III)所示单体和式(IV)所示单体的摩尔比为1.5-4.2:0.3-0.8，优选为2-3:0.5-0.7；以聚合单体的总质量(也即式(I)所示单体、式(II)所示单体、式(III)所示单体和式(IV)所示单体的总重量)为基准， 步骤②中引发剂的用量(以质量计)为聚合单体总质量的0.25-2.5wt％，优选为0.5-1wt％；
②将产物与溶液倒入旋转蒸发仪，除去溶剂，将剩余产物置于烘箱内烘干；
③用去离子水将烘干后的产物全部溶解，可升高温度以加速溶解，随后加入式(I)所示单体和式(II)所示单体，再将上述溶液倒入三口烧瓶中，以300-400rmp转速搅拌，通氮气10-20mim，排除容器中的氧气，匀速加入引发剂，升温至40-70℃，例如70℃，反应2-6h，例如3h；其中，式(I)所示单体和式(II)所示单体的摩尔比为0.5-2:1.4-1.8，优选为1-1.5:1.6-1.7；以聚合单体的总重量(也即式(I)所示单体、式(II)所示单体、式(III)所示单体和式(IV)所示单体的总重量)为基准，步骤③中引发剂的用量(以质量计)为聚合单体总质量的0.25-2.5wt％，优选为0.5-1wt％；所述步骤③中溶剂的用量使得聚合单体在步骤③的溶剂中的总浓度为0.01-5mol/L，优选为0.1-1mol/L；
④全部反应过程在恒温水浴锅下，确保氮气环境及温度稳定，得到多元共聚物。
本发明第三方面提供前述的制备方法制得的多元共聚物。
本发明第四方面提供前述的多元共聚物作为井壁稳定剂在钻井中的应用。
在本发明的一些实施方式中，所述多元共聚物作为井壁稳定剂在井眼强化型井壁中的应用。
根据本发明，所述多元共聚物可以在较低用量下即可获得优异的井壁稳定性能。
本发明第五方面提供前述的多元共聚物作为井壁稳定剂的水基钻井液。
在本发明的一些实施方式中，以所述水基钻井液的总重量为基准，所述多元共聚物的含量为1-6wt％。
本发明的多元共聚物可作为钻井液用井壁稳定剂，用于制备含有该多元共聚物作为井壁稳定剂的水基钻井液。该水基钻井液可应用于油气钻井中。
根据本发明，所述水基钻井液还可以含有本领域常规采用的其他添加剂，例如膨润土、增粘剂、防塌剂、润滑剂、加重剂、碱性调节剂等，这些添加剂的种类和含量都可以为本领域常规采用的种类和含量，本发明对此并无特别的限定。
本发明的多元共聚物可作为钻井液用井壁稳定剂，可以抑制地层粘土矿物水化膨胀，对裂缝和层理发育的岩石进行有效封堵，有效强化井眼，维持井壁稳定，同时具有一定的降滤失作用，提高油气资源开发利用效率和油田公司的经济效益。
以下将通过实施例对本发明进行详细描述。应当理解的是，此处所描述的具体实施方式仅用于说明和解释本发明，并不用于限制本发明。
本发明中，所述钻井液为水基钻井液，对所述钻井液中的所述聚合物的合成，从不同添加剂、聚合物结构以及聚合物作用机理等多角度进行聚合物性能他探究与评价。
本发明中，前述添加剂可以为市售品，也可以根据本领域已知的方法制得，本发明不再赘述。
本发明中，对所述钻井液聚合物的制备方法采用本领域技术人员所熟知的自由基溶液聚合制备方法，本发明在此不再赘述，并且本发明在后文中列举了具体的操作，本领域技术人员不应理解为对本发明的限制。
下述实施例中的实验方法，如无特殊说明，均为常规方法。
下述实施例中所用的材料、试剂等，如无特殊说明，均可从商业途径得到。
1、实验原料：
式(I)所示单体(2-丙烯酰胺-2-甲基丙磺酸)：安耐吉化学技术(上海)有限公司；
式(II)所示单体(丙烯酰胺)：安耐吉化学技术(上海)有限公司；
式(III)所示单体(2-苯氧基乙基丙烯酸酯)：安耐吉化学技术(上海)有限公司；
式(IV)所示单体(甲基丙烯酸2-氨基乙基酯盐酸盐)：安耐吉化学技术(上海)有限公司。
2、实验仪器：
电子天平(ME104/02)、恒温磁力搅拌器(T09-1S)、数显恒温水浴锅(XMTD203)、电动搅拌机(HD2004W)、变频高速搅拌机(GJSS-B12K)、1103型六速旋转粘度计(MK-03)、变频高温滚子加热炉(GW300)，均购于青岛同春石油仪器有限公司。
以下实例中，涉及到的性能的测试方法如下：
1、聚合物的性能测试：
(1)平均分子量：
通过凝胶渗透色谱(三检测器凝胶色谱仪，美国Wyatt公司)测定聚合物分子量及分子量分布。以四氢呋喃为流动相，流速为1.0mL/min，以窄分布聚苯乙烯为标准样，示差折光检测器为基本检测器，柱温及检测温度为35℃。纯化后的样品通过适量四氢呋喃配置成一定浓度的溶液，用滤头滤去不溶的杂质后送检。
(2)特性粘度：
使用乌氏粘度计(1836-A，天津泓阳机械设备有限公司)测定聚合物的特性粘度。使用无水甲醇作为溶剂配置2g/mL的聚合物溶液，然后分别稀释至原浓度的2/3、1/2、1/3、 1/4，测试温度为35℃，测定溶剂甲醇及不同浓度聚合物溶液的流出时间，流出时间对浓度作图外推得到聚合物的特性粘度。
2、水基钻井液滤失性能的评价：采用中压滤失仪测定含有溶液方法制备的聚合物井壁稳定剂水基钻井液的滤失体积，具体过程如下：
将150mL配制好的钻井液倒入中压滤失仪中，放好垫圈及专用滤纸，盖上盖子拧紧密封，在输出压力为0.7MPa下记录30min时间内滤液体积，即为钻井液中压API滤失量，单位为mL。
3、水基钻井液流变性能的评价：钻井液流变性参考数据包括表观粘度、塑性粘度和动切力。将水基钻井液以12000rpm的高频转速搅拌20min后，参照标准GB/T 16782-1997，采用六速旋转粘度计测定Φ600和Φ300的数值，并采用以下公式计算水基钻井液的表观粘度(AV)、塑性粘度(PV)和动切力(YP)。
(1)、表观粘度AV(单位mPa·s)＝1/2*Φ600；
(2)、塑性粘度PV(单位mPa·s)＝Φ600-Φ300；
(3)、动切力(单位Pa)YP＝AV-PV。
4、水基钻井液抑制性能的评价：
通过线性膨胀实验评价处理剂抑制性能。采用双通道泥页岩膨胀仪，对比测量膨润土在不同处理剂溶液与去离子水下的溶胀高度的差异，可以直观地测量出处理溶液抑制粘土水化膨胀的作用和能力。具体过程如下：
(1)裁切合适大小的圆形滤纸放在压力罐底部，称取5g膨润土，将其倒入压力罐中，再放置一张圆形滤纸，用液压器在10MPa的压力下压5分钟，制成岩块。(放置第二张滤纸片的目的是防治加入溶液后压好的膨润土膨胀程度不均匀)。
(2)启动计算机中线性膨胀测量软件，将装有压紧的膨润土岩块的压力罐装在双通道泥页岩膨胀仪的测量通道上，压力罐的边缘卡住槽内，将膨胀仪的初始值清零。
(3)使用滴管沿压力罐内壁缓慢添加待测溶液直至压力罐上方出现凸出的液面，点击开始按钮，开始记录膨润土块膨胀高度随时间的变化。
(4)记录16h后的膨胀高度，并将软件测量的所有数据导出到表格以进行存储和处理。
通过岩心浸泡实验评价处理剂抑制性能。将岩心分别置于不同井壁稳定剂溶液中浸泡24h后的样貌和形态完整性。
以下实施例用于示例性地说明本发明的多元共聚物及其制备方法。
实施例1
一种多元共聚物的制备方法，具体包括以下步骤：
步骤①：将2-苯氧基乙基丙烯酸酯和甲基丙烯酸2-氨基乙基酯盐酸盐按照摩尔比为2：0.5的比例溶解在去离子水中，将溶液倒入三口烧瓶，以300-400rpm转速搅拌，并通氮气10-20min，排除容器中的氧气，匀速加入引发剂过硫酸钾1wt％(也即聚合单体总质量的1％)，升温至70℃，反应3h；
步骤②：将产物与溶液倒入旋转蒸发仪，除去溶剂，将剩余产物置于烘箱内烘干；
步骤③：用去离子水将烘干后的产物全部加热溶解，随后按照摩尔比为1：1.6的比例加入2-丙烯酰胺-2-甲基丙磺酸和丙烯酰胺，再将溶液倒入三口烧瓶中，以300-400rmp转速搅拌，通氮气10-20mim，排除容器中的氧气，匀速加入引发剂过硫酸钾1wt％(也即聚合单体总质量的1％)，升温至70℃，反应3h；
步骤④：全部反应过程在恒温水浴锅下，确保氮气环境及温度稳定，在步骤③中，三口烧瓶内聚合单体总浓度为0.1mol/L。所合成的产物即为聚合物W1。测试结果如表1所示。
将得到的聚合物W1进行旋蒸干燥处理，采用红外光谱图分析方法检测聚合物W1，得到如图1所示的红外光谱图，从图1可见，得到了含有N-H、C＝O、磺酸基结构单元的嵌段共聚。
实施例2
步骤①：将2-苯氧基乙基丙烯酸酯和甲基丙烯酸2-氨基乙基酯盐酸盐按照摩尔比为2：0.5的比例溶解在去离子水中，将溶液倒入三口烧瓶，以300-400rpm转速搅拌，并通氮气10-20min，排除容器中的氧气，匀速加入引发剂过硫酸钾1wt％(也即聚合单体总质量的1％)，升温至70℃，反应3h；
步骤②：将产物与溶液倒入旋转蒸发仪，除去溶剂，将剩余产物置于烘箱内烘干；
步骤③：用去离子水将烘干后的产物全部加热溶解，随后按照摩尔比为1：1.6的比例加入2-丙烯酰胺-2-甲基丙磺酸和丙烯酰胺，再将溶液倒入三口烧瓶中，以300-400rmp转速搅拌，通氮气10-20mim，排除容器中的氧气，匀速加入引发剂过硫酸钾1wt％(也即聚合单体总质量的1％)，升温至70℃，反应3h；
步骤④：全部反应过程在恒温水浴锅下，确保氮气环境及温度稳定，在步骤③中，三口烧瓶内聚合单体总浓度为0.5mol/L。所合成的产物即为聚合物W2。测试结果如表1所示。
实施例3
步骤①：将2-苯氧基乙基丙烯酸酯甲基丙烯酸2-氨基乙基酯盐酸盐按照摩尔比为2：0.5的比例溶解在去离子水中，将溶液倒入三口烧瓶，以300-400rpm转速搅拌，并通氮气10-20min，排除容器中的氧气，匀速加入引发剂过硫酸钾1wt％(也即聚合单体总质量的1％)，升温至70℃，反应3h；
步骤②：将产物与溶液倒入旋转蒸发仪，除去溶剂，将剩余产物置于烘箱内烘干；
步骤③：用去离子水将烘干后的产物全部加热溶解，随后按照摩尔比为1：1.6的比例加入2-丙烯酰胺-2-甲基丙磺酸和丙烯酰胺，再将溶液倒入三口烧瓶中，以300-400rmp转速搅拌，通氮气10-20mim，排除容器中的氧气，匀速加入引发剂过硫酸钾1wt％(也即聚合单体总质量的1％)，升温至70℃，反应3h；
步骤④：全部反应过程在恒温水浴锅下，确保氮气环境及温度稳定，在步骤③中，三口烧瓶内聚合单体总浓度为1.0mol/L。所合成的产物即为聚合物W3。测试结果如表1所示。
实施例4
根据实施例1所述的方法，不同的是，四种单体的用量按2-丙烯酰胺-2-甲基丙磺酸：丙烯酰胺：2-苯氧基乙基丙烯酸酯：甲基丙烯酸2-氨基乙基酯盐酸盐＝1.5:1.7:3:0.7的摩尔比，并保持总的单体浓度不变，经过整个过程最终得到聚合物W4。测试结果如表1所示。
实施例5
根据实施例2所述的方法，不同的是，四种单体的用量按2-丙烯酰胺-2-甲基丙磺酸：丙烯酰胺：2-苯氧基乙基丙烯酸酯：甲基丙烯酸2-氨基乙基酯盐酸盐＝1.5:1.7:3:0.7的摩尔比，并保持总的单体浓度不变，经过整个过程最终得到聚合物W5。测试结果如表1所示。
实施例6
根据实施例3所述的方法，不同的是，四种单体的用量按2-丙烯酰胺-2-甲基丙磺酸：丙烯酰胺：2-苯氧基乙基丙烯酸酯：甲基丙烯酸2-氨基乙基酯盐酸盐＝1.5:1.7:3:0.7的摩尔比，并保持总的单体浓度不变，经过整个过程最终得到聚合物W6。测试结果如表1所示。
实施例7
根据实施例1所述的方法，不同的是，四种单体的用量按2-丙烯酰胺-2-甲基丙磺酸： 丙烯酰胺：2-苯氧基乙基丙烯酸酯：甲基丙烯酸2-氨基乙基酯盐酸盐＝1.2:1.65:2.5:0.6的摩尔比，并保持总的单体浓度不变，经过整个过程最终得到聚合物W7。测试结果如表1所示。
实施例8
根据实施例2所述的方法，不同的是，四种单体的用量按2-丙烯酰胺-2-甲基丙磺酸：丙烯酰胺：2-苯氧基乙基丙烯酸酯：甲基丙烯酸2-氨基乙基酯盐酸盐＝1.2:1.65:2.5:0.6的摩尔比，并保持总的单体浓度不变，经过整个过程最终得到聚合物W8。测试结果如表1所示。
实施例9
根据实施例3所述的方法，不同的是，四种单体的用量按2-丙烯酰胺-2-甲基丙磺酸：丙烯酰胺：2-苯氧基乙基丙烯酸酯：甲基丙烯酸2-氨基乙基酯盐酸盐＝1.2:1.65:2.5:0.6的摩尔比，并保持总的单体浓度不变，经过整个过程最终得到聚合物W9。测试结果如表1所示。
实施例10
根据实施例1所述的方法，不同的是，采用等量(也即等体积)的乙醇代替去离子水作溶剂，经过整个过程最终得到聚合物W10。测试结果如表1所示。
实施例11
根据实施例1所述的方法，不同的是，采用等量的硝酸铈铵代替过硫酸钾作引发剂，经过整个过程最终得到聚合物W11。测试结果如表1所示。
对比例1
根据实施例1所述的方法，不同的是，采用等摩尔量的苯乙烯磺酸钠代替2-丙烯酰胺-2-甲基丙磺酸，经过整个过程最终得到聚合物D1。测试结果如表1所示。
对比例2
根据实施例1所述的方法，不同的是，引发剂采用过硫酸铵，经过整个过程最终得到聚合物D2。测试结果如表1所示。
表1聚合物的性能
测试例
性能测试
按照上述方法，分别将制得的井壁稳定剂聚合物W1、W2、W3、W4、W5、W6、W7、W8、W9、W10、W11、D1、D2配制成质量分数浓度为1％的水溶液，进行井壁稳定剂的单剂性能测试。
将膨润土岩块压入线性膨胀仪，分别加入去离子水及实施例1-6制备的聚合物井壁稳定剂，浸泡16h后读取线性膨胀仪上的最终膨胀高度，线性膨胀实验测试结果如表2所示。
表2聚合物对膨润土块的线性膨胀
通过表2中的实施例1-11与去离子水的线性膨胀高度结果比较可知，本发明提供的井眼强化型井壁稳定剂聚合物对膨润土水化膨胀具有一定抑制作用，制备的聚合物能够显著降低膨润土块的膨胀高度，有效增强地层的井壁稳定性。
将岩心分别置于浓度为1％的井壁稳定剂聚合物W1、W2、W3、W4、W5、W6、W7、W8、W9、W10、W11、D1、D2溶液中，浸泡24h，观察岩心的完整性，测试结果表3所示。
表3岩心在不同井壁稳定剂聚合物中浸泡24h后的状态
通过表3的结果可以看出，本发明提供的井眼强化型井壁稳定剂具有一定程度的胶结粘土颗粒的效果，进而起到稳定井壁、强化井眼的作用。
将本发明制备的井壁稳定剂配成水基钻井液体系，其中，聚合物加量均为1％，测试各含有所合成的井壁稳定剂的水基钻井液的滤失量以及流变等基础性能。上述钻井液的表观粘度(AV/mPa·s)、塑性粘度(PV/mPa·s)、动切力(YP/Pa)、动塑比(YP/PV(Pa/mPa·s))、中压滤失量(API/mL)结果见表4。
表4聚合物对钻井液性能的影响

从表4数据可以看出，测试结果表明，本发明提供的水基钻井液井壁稳定剂对钻井液基础性能具有一定的影响，能够对钻井液的流变性起到调节作用，制备的不同结构的聚合物对钻井液具有不同程度的影响。
综合表2-4的数据结果可以比较得出，本发明提供的井眼强化型井壁稳定剂能够改善钻井液的粘度，有效降低滤失量，可以减少钻井液在钻进工作中的漏失，发挥稳定井壁的作用。
综上所述，本发明提供的溶液聚合法合成的聚合物应用于水基钻井液，制备井眼强化型井壁稳定剂有着非常明显的效果，能大大改善钻井液流体的流变性能及滤失量，并且制备方法简单，成本较低，因此本发明有着非常广阔的应用前景，能够有效解决钻井工作中存在的井壁失稳问题，提高钻井液对地层粘土水化膨胀的抑制性能，减少井下复杂事故的发生，带来经济效益的提高。
以上详细描述了本发明的优选实施方式，但是，本发明并不限于此。在本发明的技术构思范围内，可以对本发明的技术方案进行多种简单变型，包括各个技术特征以任何其它的合适方式进行组合，这些简单变型和组合同样应当视为本发明所公开的内容，均属于本发明的保护范围。

Claims (15)

  1. 一种多元共聚物，其特征在于，所述多元共聚物含有结构单元A、结构单元B、结构单元C和结构单元D；其中，所述结构单元A具有式(1)所示结构；所述结构单元B具有式(2)所示结构；所述结构单元C具有式(3)所示结构；所述结构单元D具有式(4)所示结构；
    式(1)中，R1和R2各自独立地选自氢或C1-C6的烷基；R3选自C1-C6的亚烷基；M选自氢或碱金属；
    式(2)中，R4和R5各自独立地选自氢或C1-C6的烷基；
    式(3)中，R6和R7各自独立地选自氢或C1-C6的烷基；
    式(4)中，R8和R9各自独立地选自氢或C1-C6的烷基；X选自卤素。
  2. 根据权利要求1所述的多元共聚物，其中，式(1)中，R1和R2各自独立地选自氢或C1-C3的烷基；R3选自C1-C3的亚烷基；M选自氢、钠或钾；
    和/或，式(2)中，R4和R5各自独立地选自氢或C1-C3的烷基；
    和/或，式(3)中，R6和R7各自独立地选自氢或C1-C3的烷基；
    和/或，式(4)中，R8和R9各自独立地选自氢或C1-C3的烷基。
  3. 根据权利要求2所述的多元共聚物，其中，式(1)中，R1和R2各自独立地为氢、甲基或乙基；R3为亚甲基或1,2-亚乙基；
    和/或，式(2)中，R4和R5各自独立地为氢、甲基、乙基或丙基；
    和/或，式(3)中，R6和R7各自独立地为氢、甲基、乙基或丙基；
    和/或，式(4)中，R8和R9各自独立地为氢、甲基、乙基或丙基。
  4. 根据权利要求1或2所述的多元共聚物，其中，所述结构单元A、结构单元B、结构单元C和结构单元D的摩尔比为0.5-2:1.4-1.8:1.5-4.2:0.3-0.8。
  5. 根据权利要求1所述的多元共聚物，其中，所述多元共聚物的平均分子量为2万-15万g/mol。
  6. 一种多元共聚物的制备方法，其特征在于，所述制备方法包括：
    在引发剂存在下，将聚合单体进行溶液聚合，得到多元共聚物；其中，所述聚合单体包括：式(I)所示单体、式(II)所示单体、式(III)所示单体和式(IV)所示单体；
    式(I)中，R1和R2各自独立地选自氢或C1-C6的烷基；R3选自C1-C6的亚烷基；M1选自氢或碱金属；
    式(II)中，R4和R5各自独立地选自氢或C1-C6的烷基；
    式(III)中，R6和R7各自独立地选自氢或C1-C6的烷基；
    式(IV)中，R8和R9各自独立地选自氢或C1-C6的烷基；M2选自卤素。
  7. 根据权利要求6所述的制备方法，其中，式(I)所示单体、式(II)所示单体、式(III)所示单体和式(IV)所示单体的摩尔比为0.5-2:1.4-1.8:1.5-4.2:0.3-0.8。
  8. 根据权利要求6或7所述的制备方法，其中，所述溶液聚合的条件包括：温度为30-100℃；时间为4-8h。
  9. 根据权利要求6所述的制备方法，其中，所述引发剂选自卤代烷、偶氮二异丁腈、2-酮戊二酸、过硫酸钾、硝酸铈铵和偶氮二异丁脒盐酸盐中的一种。
  10. 根据权利要求5所述的制备方法，其中，所述溶液聚合在溶剂中进行；
    其中，所述溶剂选自去离子水、乙醇、甲醇和二甲基亚砜中的一种。
  11. 权利要求6-10中任意一项所述的制备方法制得的多元共聚物。
  12. 权利要求1-5和11中任意一项所述的多元共聚物作为井壁稳定剂在钻井中的应用。
  13. 根据权利要求12所述的应用，其中，所述多元共聚物作为井壁稳定剂在井眼强化型井壁中的应用。
  14. 含有权利要求1-5和11中任意一项所述的多元共聚物作为井壁稳定剂的水基钻井液。
  15. 根据权利要求14所述的水基钻井液，其中，以所述水基钻井液的总重量为基准，所述多元共聚物的含量为1-6wt％。
PCT/CN2024/098940 2023-06-13 2024-06-13 多元共聚物及其制备方法和应用 Ceased WO2024255789A1 (zh)

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