Amide polymer, preparation method and application thereof, and water-based drilling fluid

Abstract

The invention relates to the field of drilling fluids in the petroleum industry, and discloses an amide polymer which contains a structural unit A, a structural unit B, a structural unit C and a structural unit D, the structural unit A is a structural unit with a structure as shown in a formula (1); the structural unit B is a structural unit with a structure as shown in a formula (2); the structural unit C is a structural unit with a structure as shown in a formula (3); the structural unit D is a structural unit with a structure as shown in a formula (4). The amide polymer provided by the invention has excellent temperature-resistant and calcium-resistant effects, and has excellent filtrate loss reduction performance after being applied to the drilling fluid. # imgabs0 #

Description

Technical Field

[0001] The invention relates to the field of oil industry drilling, and in particular to an amide polymer and a preparation method and application thereof, and a water-based drilling fluid. Background Art

[0002] Compared with conventional soil-phase drilling fluids, no / low soil-phase drilling fluids have low solid content, low extreme pressure lubrication coefficient, low circulating pressure loss, large solid capacity, strong resistance to environmental pollution, and the rheology of no / low soil-phase drilling fluids is easy to control under high density conditions.

[0003] However, since the drilling fluid system does not contain clay or the clay content is very low, high molecular polymers must be used as viscosity-enhancing and shear-removing agents to solve the problem of carrying cuttings and suspended cuttings during drilling, so as to improve the rheological properties of the drilling fluid and enhance its rock-carrying capacity, thereby ensuring the cleanliness of the wellbore and providing protection for the safety of drilling operations. Therefore, viscosity-enhancing and shear-removing agents are the core of the entire low / no solid phase drilling fluid treatment agent, and research on them has always been a hot topic.

[0004] At present, the thickening and shearing agents can be divided into modified natural polymer thickening agents, synthetic polymer thickening agents, and nanomaterial thickening and shearing agents. Modified natural polymer thickening agents can be divided into modified biopolymers and modified polysaccharides due to different raw materials, such as guar gum, xanthan gum, welan gum and polysaccharides; synthetic polymer high temperature resistant thickening and shearing agents include polyacrylamide and its related derivatives;

[0005] However, in the face of high temperature and high calcium conditions, the effects of the above-mentioned types of viscosity enhancing and shearing agents are not ideal, so there is an urgent need to develop a temperature-resistant and calcium-resistant viscosity enhancing and shearing agent to meet the current market demand. Summary of the invention

[0006] The purpose of the invention is to solve the problem that the shearing agent in the prior art has poor temperature resistance and calcium resistance.

[0007] In order to achieve the above-mentioned object, the first aspect of the present invention provides an amide polymer, wherein the polymer contains a structural unit A, a structural unit B, a structural unit C and a structural unit D; the molar ratio of the structural unit A, the structural unit B, the structural unit C and the structural unit D is 1:0.125-10:0.0625-5:0.125-0.5;

[0008] The structural unit A is a structural unit having a structure shown in formula (1); the structural unit B is a structural unit having a structure shown in formula (2); the structural unit C is a structural unit having a structure shown in formula (3); and the structural unit D is a structural unit having a structure shown in formula (4);

[0009]

[0010] In formula (1), each R 1 Each independently selected from H, C 1-6 Alkyl; R 2 Selected from C 1-6 Alkylene; R 3 Selected from H, C 1-8 An alkyl group; M1 is selected from H or an alkali metal element;

[0011] In formula (2), each R 4 Each independently selected from H, C 1-6 Alkyl; R 5 Selected from H, C 1-6 The alkyl group;

[0012] In formula (3), each R 6 Each independently selected from H, C 1-6 The alkyl group;

[0013] In formula (4), each R 7 Each independently selected from H, C 1-6 Alkyl; R 8 Selected from H, C 1-6 of alkyl.

[0014] A second aspect of the present invention provides a method for preparing an amide polymer, the method comprising:

[0015] (1) in the presence of a solvent and a protective atmosphere, performing a first mixing of aqueous solutions of monomer D', monomer B, monomer C and monomer A' to obtain a mixture I; the pH value of the aqueous solution of monomer A' in the initial system of the first mixing is 7-8;

[0016] (2) in the presence of an initiator and a surfactant, the mixture I undergoes a polymerization reaction to obtain the amide polymer;

[0017] The monomer A' is selected from monomers having a structure shown in formula (I); the monomer B' is selected from monomers having a structure shown in formula (I I); the monomer C' is selected from monomers having a structure shown in formula (I I I); the monomer D' is selected from monomers having a structure shown in formula (IV);

[0018] The monomer A', the monomer B', the monomer C' and the monomer D' are respectively such that the prepared polymer contains the structural unit A, the structural unit B, the structural unit C and the structural unit D, and the molar ratio of the structural unit A, the structural unit B, the structural unit C and the structural unit D in the prepared polymer is 1:0.125-10:0.0625-5:0.125-0.5;

[0019] The structural unit A is a structural unit having a structure shown in formula (1); the structural unit B is a structural unit having a structure shown in formula (2); the structural unit C is a structural unit having a structure shown in formula (3); and the structural unit D is a structural unit having a structure shown in formula (4);

[0020]

[0021]

[0022] Among them, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 The definition of M1 is the same as that described in the first aspect.

[0023] The third aspect of the present invention provides an amide polymer prepared by the method described in the second aspect.

[0024] The fourth aspect of the present invention provides the use of the amide polymers described in the first aspect and the third aspect as a shear enhancing agent in drilling fluid.

[0025] The fifth aspect of the present invention provides a water-based drilling fluid, wherein the water-based drilling fluid contains an effective amount of the amide polymers described in the first aspect and the third aspect to increase viscosity and improve shear.

[0026] The amide polymer provided by the invention has excellent temperature resistance and calcium resistance effects, and has excellent filtration loss reduction performance after being applied to drilling fluid. DETAILED DESCRIPTION

[0027] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0028] The following provides some exemplary explanations for some groups of the present invention. Unless otherwise specified, the unlisted parts are explained with reference to the following exemplary explanations.

[0029] “C 1-6The term "alkyl" refers to a straight chain alkyl or branched chain alkyl having a total of 1, 2, 3, 4, 5 or 6 carbon atoms. For example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, etc.

[0030] “C 1-6 "Alkylene" means a straight-chain or branched alkyl group having a total of 1, 2, 3, 4, 5 or 6 carbon atoms; for example, -CH2-, -CH2-CH2-, -CH2-CH2-CH2-, -CH(CH3)-CH2-, -CH2-CH(CH3)-, -CH2-(CH2)2-CH2-, -C(CH3)2-CH2-, -CH2-C(CH3)2-, etc.

[0031] As mentioned above, the first aspect of the present invention provides an amide polymer, which contains structural unit A, structural unit B, structural unit C and structural unit D; the molar ratio of the structural unit A, the structural unit B, the structural unit C and the structural unit D is 1: 0.125-10: 0.0625-5: 0.125-0.5;

[0032] The structural unit A is a structural unit having a structure shown in formula (1); the structural unit B is a structural unit having a structure shown in formula (2); the structural unit C is a structural unit having a structure shown in formula (3); and the structural unit D is a structural unit having a structure shown in formula (4);

[0033]

[0034] In formula (1), each R 1 Each independently selected from H, C 1-6 Alkyl; R 2 Selected from C 1-6 Alkylene; R 3 Selected from H, C 1-8 An alkyl group; M1 is selected from H or an alkali metal element;

[0035] In formula (2), each R 4 Each independently selected from H, C 1-6 Alkyl; R 5 Selected from H, C 1-6 The alkyl group;

[0036] In formula (3), each R 6 Each independently selected from H, C 1-6 The alkyl group;

[0037] In formula (4), each R 7 Each independently selected from H, C 1-6 Alkyl; R 8 Selected from H, C1-6 of alkyl.

[0038] Preferably, in formula (1), each R 1 Each is independently selected from H, -CH3, -CH2CH3, -CH2CH2CH3; R 2 is selected from -CH2-, -CH2-CH2-, -CH2-CH2-CH2-; R 3 is selected from H, -CH3, -CH2CH3, -CH2CH2CH3; M1 is selected from H, K, Na;

[0039] In formula (2), each R 4 Each is independently selected from H, -CH3, -CH2CH3, -CH2CH2CH3; R 5 is selected from H, -CH3, -CH2CH3, -CH2CH2CH3;

[0040] In formula (3), each R 6 Each is independently selected from H, -CH3, -CH2CH3, -CH2CH2CH3;

[0041] In formula (4), each R 7 Each is independently selected from H, -CH3, -CH2CH3, -CH2CH2CH3; R 8 Selected from H, -CH3, -CH2CH3, -CH2CH2CH3.

[0042] More preferably, the structural unit A is selected from the structure shown in formula (1-1), the structure shown in formula (1-2), the structure shown in formula (1-3), the structure shown in formula (1-4), the structure shown in formula (1-5), the structure shown in formula (1-6), the structure shown in formula (1-7), the structure shown in formula (1-8), the structure shown in formula (1-9), the structure shown in formula (1-10), the structure shown in formula (1-11), the structure shown in formula (1-12), the structure shown in formula (1-13), the structure shown in 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), the structure shown in formula (1-27), the structure shown in formula (1-28), the structure shown in formula (1-29), the structure shown in formula (1-30), the structure shown in formula (1-31), the structure shown in formula (1-32), the structure shown in formula (1-33), the structure shown in formula (1-34), the structure shown in formula (1-35), the structure shown in formula (1-36), the structure shown in formula (1-37), the structure shown in formula (1-38), the structure shown in formula (1-39), the structure shown in formula (1-40), the structure shown in formula (1-41), the structure shown in formula (1-42), the structure shown in formula (1-43), the structure shown in formula (1-44), the structure shown in formula (1-45), the structure shown in formula (1-46), the structure shown in At least one of the structural units of the structure represented by formula (1-15), the structure represented by formula (1-16), the structure represented by formula (1-17), the structure represented by formula (1-18), the structure represented by formula (1-19), the structure represented by formula (1-20), the structure represented by formula (1-21), the structure represented by formula (1-22), the structure represented by formula (1-23), the structure represented by formula (1-24), the structure represented by formula (1-25), the structure represented by formula (1-26), the structure represented by formula (1-27) and the structure represented by formula (1-28);

[0043] The structural unit B is selected from at least one of the structural units having the structure represented by formula (2-1), the structure represented by formula (2-2), the structure represented by formula (2-3), the structure represented by formula (2-4), the structure represented by formula (2-5), the structure represented by formula (2-6), the structure represented by formula (2-7), the structure represented by formula (2-8), and the structure represented by formula (2-9);

[0044] The structural unit C is selected from at least one of the structural units of the structure represented by formula (3-1), the structure represented by formula (3-2), the structure represented by formula (3-3), the structure represented by formula (3-4), and the structure represented by formula (3-5);

[0045] The structural unit D is selected from at least one of the structural units of the structure shown in formula (4-1), the structure shown in formula (4-2), the structure shown in formula (4-3), the structure shown in formula (4-4), the structure shown in formula (4-5), the structure shown in formula (4-6), the structure shown in formula (4-7), the structure shown in formula (4-8), the structure shown in formula (4-9), and the structure shown in formula (4-10);

[0046] Formula (1-1): R 1 Both are H; R 2 -CH2-; R 3 is H; M1 is H;

[0047] Formula (1-2): R 1 Both are H; R 2 -CH2-; R 3 is H; M1 is K;

[0048] Formula (1-3): R 1 Both are H; R 2 -CH2-; R 3 is H; M1 is Na;

[0049] Formula (1-4): R 1 Both are H; R 2 -CH2-; R 3 is -CH3; M1 is H;

[0050] Formula (1-5): R 1 Both are H; R 2 -CH2-; R 3 is -CH3; M1 is K;

[0051] Formula (1-6): R 1 Both are H; R 2 -CH2-; R 3 is -CH3; M1 is Na;

[0052] Formula (1-7): R 1 Both are H; R2 -CH2-; R 3 is -CH2CH3; M1 is H;

[0053] Formula (1-8): R 1 Both are H; R 2 -CH2-; R 3 is -CH2CH3; M1 is K;

[0054] Formula (1-9): R 1 Both are H; R 2 -CH2-; R 3 is -CH2CH3; M1 is Na;

[0055] Formula (1-10): R 1 All are -CH3; R 2 -CH2-; R 3 is H; M1 is H;

[0056] Formula (1-11): R 1 All are -CH3; R 2 -CH2-; R 3 is H; M1 is K;

[0057] Formula (1-12): R 1 All are -CH3; R 2 -CH2-; R 3 is H; M1 is Na;

[0058] Formula (1-13): R 1 All are -CH3; R 2 -CH2-; R 3 is -CH3; M1 is H;

[0059] Formula (1-14): R 1 All are -CH3; R 2 -CH2-; R 3 is -CH3; M1 is K;

[0060] Formula (1-15): R 1 All are -CH3; R 2 -CH2-; R 3 is -CH3; M1 is Na;

[0061] Formula (1-16): R 1 All are -CH3; R 2 -CH2-; R 3 is -CH2CH3; M1 is H;

[0062] Formula (1-17): R 1All are -CH3; R 2 -CH2-; R 3 is -CH2CH3; M1 is K;

[0063] Formula (1-18): R 1 All are -CH3; R 2 -CH2-; R 3 is -CH2CH3; M1 is Na;

[0064] Formula (1-19): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is H; M1 is H;

[0065] Formula (1-20): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is H; M1 is K;

[0066] Formula (1-21): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is H; M1 is Na;

[0067] Formula (1-22): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is -CH3; M1 is H;

[0068] Formula (1-23): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is -CH3; M1 is K;

[0069] Formula (1-24): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is -CH3; M1 is Na; formula (1-25): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is -CH2CH3; M1 is H; formula (1-26): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is -CH2CH3; M1 is K; formula (1-27): R 1 All are -CH2CH3; R 2 -CH2-; R3 is -CH2CH3; M1 is Na; formula (1-28): Formula (2-1): R 4 Both are H; R 5 is H;

[0070] Formula (2-2): R 4 Both are H; R 5 is -CH3;

[0071] Formula (2-3): R 4 Both are H; R 5 is -CH2CH3;

[0072] Formula (2-4): R 4 All are -CH3; R 5 is -CH3;

[0073] Formula (2-5): R 4 All are -CH3; R 5 is -CH2CH3;

[0074] Formula (2-6): R 4 All are -CH2CH3; R 5 is -CH2CH3;

[0075] Formula (2-7): R 4 All are -CH2CH2CH3; R 5 is -CH2CH3;

[0076] Formula (2-8): R 4 All are -CH2CH2CH3; R 5 is -CH2CH2CH3;

[0077] Formula (2-9): Formula (3-1): R 6 All are H;

[0078] Formula (3-2): R 6 All are -CH3;

[0079] Formula (3-3): R 6 All are -CH2CH3;

[0080] Formula (3-4): R 6 All are -CH2CH2CH3;

[0081] Formula (3-5): R 6 All are -CH2CH2CH2CH3;

[0082] Formula (4-1): R 7 Both are H; R7 is H;

[0083] Formula (4-2): R 7 All are -CH3; R 8 is H;

[0084] Formula (4-3): R 7 All are -CH2CH3; R 8 H

[0085] Formula (4-4): R 7 All are -CH2CH2CH3; R 8 H

[0086] Formula (4-5): R 7 All are -CH3; R 8 is -CH3;

[0087] Formula (4-6): R 7 All are -CH2CH3; R 8 is -CH3;

[0088] Formula (4-7): R 7 All are -CH2CH3; R 8 is -CH2CH3;

[0089] Formula (4-8): R 7 All are -CH2CH2CH3; R 8 is -CH2CH3;

[0090] Formula (4-9): R 7 All are -CH2CH2CH3; R 8 is -CH2CH2CH3;

[0091] Formula (4-10):

[0092] Preferably, the molar ratio of the structural unit A, the structural unit B, the structural unit C and the structural unit D is 1: 0.25-5: 0.08-3: 0.125-0.3. The inventors found that under this preferred embodiment, the amide polymer obtained by the present invention has better viscosity-increasing and shear-improving performance, and the fluid loss reduction performance brought about by the viscosity-increasing effect is also better improved, and the drilling fluid has better rheological properties and fluid loss reduction performance.

[0093] As mentioned above, the second aspect of the present invention provides a method for preparing an amide polymer, the method comprising:

[0094] (1) in the presence of a protective atmosphere, performing a first mixing of aqueous solutions of monomer D', monomer B, monomer C and monomer A' to obtain a mixture I; the pH value of the aqueous solution of monomer A' in the initial system of the first mixing is 7-8;

[0095] (2) in the presence of an initiator and a surfactant, the mixture I undergoes a polymerization reaction to obtain the amide polymer;

[0096] The monomer A' is selected from monomers having a structure shown in formula (I); the monomer B' is selected from monomers having a structure shown in formula (I I); the monomer C' is selected from monomers having a structure shown in formula (I I I); the monomer D' is selected from monomers having a structure shown in formula (IV);

[0097] The monomer A', the monomer B', the monomer C' and the monomer D' are respectively such that the prepared polymer contains the structural unit A, the structural unit B, the structural unit C and the structural unit D, and the molar ratio of the structural unit A, the structural unit B, the structural unit C and the structural unit D in the prepared polymer is 1:0.125-10:0.0625-5:0.125-0.5;

[0098] The structural unit A is a structural unit having a structure shown in formula (1); the structural unit B is a structural unit having a structure shown in formula (2); the structural unit C is a structural unit having a structure shown in formula (3); and the structural unit D is a structural unit having a structure shown in formula (4);

[0099]

[0100]

[0101] Among them, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 The definition of M1 is the same as that described in the first aspect above.

[0102] Preferably, the protective atmosphere is selected from at least one of nitrogen and argon.

[0103] Preferably, in step (1), the first mixing conditions include: temperature of 50°C-70°C, time of 5h-7h, and stirring speed of 300-350rpm.

[0104] Preferably, the polymerization reaction is carried out under stirring conditions, and the polymerization reaction conditions include: stirring speed of 300-500 rpm, temperature of 50-70° C., and time of 5-7 h.

[0105] It should be noted that in the present invention, the pH value of the aqueous solution of the monomer A' in the initial system for the first mixing is 7-8. The pH value can be adjusted by conventional acid-base adjustment methods in the art. The present invention will not be repeated here, and those skilled in the art should not understand it as a limitation of the present invention.

[0106] Preferably, the double bonds of monomer D', monomer B, monomer C and monomer A' all participate in the polymerization reaction, which enables the linear molecules to be linked together to form a cross-linked network structure during the polymerization process, thereby increasing the strength, adjusting the physical properties of the amide polymer and improving the chemical stability.

[0107] In the method described in the second aspect of the present invention, the relevant definitions and substance types of the substituents of the monomer of the structure represented by formula (I), the monomer of the structure represented by formula (II), the monomer of the structure represented by formula (III), and the monomer of the structure represented by formula (IV) are the same as the relevant definitions and substance types of the substituents described above in the present invention, and the present invention will not be elaborated here, and those skilled in the art should not understand it as a limitation on the technical solution of the present invention.

[0108] In the present invention, the monomer A', the monomer B', the monomer C' and the monomer D' can be purchased commercially, or synthesized according to the structural formula provided by the present invention in combination with known methods in the field of organic synthesis.

[0109] In the present invention, it should be noted that the monomer is almost completely converted into the corresponding structural unit contained in the polymer, and the amount of the monomer used can be consistent with the content of the corresponding structural unit contained in the polymer.

[0110] Preferably, the initiator is selected from at least one of alkyl halides, 2-ketoglutaric acid, potassium persulfate, ammonium cerium nitrate, and azobisisobutyramidine hydrochloride.

[0111] More preferably, in the aqueous solution of the monomer A', the amount of water used is 100-150 mL relative to 1 mol of the monomer A'.

[0112] Preferably, based on the total weight of the monomer A', the monomer B', the monomer C' and the monomer D', the amount of the initiator is 0.1-0.2 wt%.

[0113] Preferably, the amount of the surfactant used is 0.00125-0.05 mol per mol of the monomer A'.

[0114] More preferably, the surfactant is selected from at least one of sodium dodecyl sulfate (SDS), sodium dodecylbenzene sulfonate (SDBS), and sodium p-styrene sulfonate (SSS).

[0115] It should be noted that the method for preparing the gel polymer of the present invention also includes conventional post-processing methods, such as drying and crushing to a particle size required for application, which will not be described in detail herein and should not be construed as a limitation to the present invention by those skilled in the art.

[0116] As mentioned above, the third aspect of the present invention provides an amide polymer prepared by the method described in the second aspect.

[0117] Preferably, the number average molecular weight of the amide polymer is 250,000-400,000.

[0118] As mentioned above, the fourth aspect of the present invention provides the use of the amide polymers described in the first aspect and the third aspect as a shear enhancing agent in drilling fluid.

[0119] As mentioned above, the fifth aspect of the present invention provides a water-based drilling fluid, wherein the water-based drilling fluid contains an effective amount of the amide polymer described in the first aspect and the third aspect for increasing viscosity and improving shearing;

[0120] Preferably, the water-based drilling fluid contains water, an amide polymer, a fluid loss reducer, an inhibitor, a pH adjuster, and optionally a weighting agent;

[0121] Among them, relative to 300 parts by weight of water, the content of the amide polymer is 8-12 parts by weight, the content of the filtration loss reducer is 24-30 parts by weight, the content of the inhibitor is 4-8 parts by weight, the content of the weighting agent is 0-20 parts by weight, and the content of the pH adjuster is 0.5-3 parts by weight; the amide polymer is the amide polymer described in the first aspect and the third aspect.

[0122] More preferably, the fluid loss reducer is selected from at least one of carboxymethyl cellulose, potassium humate, sulfonated phenolic resin and carboxymethyl starch; the pH adjuster is NaOH; the inhibitor is selected from at least one of potassium chloride and sodium humate; the weighting agent is selected from at least one of calcium chloride and calcium carbonate.

[0123] In the present invention, there is no particular limitation on the preparation method of the drilling fluid, and a preparation method known to those skilled in the art may be used, which will not be described in detail herein. In addition, the present invention lists a specific operation hereinafter, which should not be construed as a limitation on the present invention by those skilled in the art.

[0124] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, all the raw materials and reagents used are commercially available.

[0125] Example 1

[0126] Monomer A': is a structure represented by formula (I), and the structural formula is: Among them, M1 is H, CAS number is: 15214-89-8, purchased from Beijing Inokai Technology Co., Ltd.;

[0127] Monomer B': has a structure represented by formula (II), and the structural formula is: CAS number: 7398-69-8, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0128] Monomer C': is a structure represented by formula (III), and the structural formula is: CAS number: 88-12-0, purchased from Shanghai Titan Technology Co., Ltd.;

[0129] Monomer D': is a structure represented by formula (IV), and the structural formula is: CAS number is 2680-03-7, purchased from Beijing Xinbaohai Chemical Technology Co., Ltd.;

[0130] (1) dissolving 1 mol of monomer A' in 100 mL of water, and adjusting the pH value to 7 with NaOH; then, under the protection of nitrogen, mixing the aqueous solutions of monomer D', monomer B, monomer C and monomer A' for the first time to obtain a mixture I; the conditions of the first mixing are: temperature of 70° C., time of 7 h, and stirring speed of 350 rpm;

[0131] (2) subjecting the mixture I to a polymerization reaction with an initiator (potassium persulfate) and 0.00125 mol of a surfactant (sodium dodecyl sulfate), and the resulting product is dried and crushed in sequence to obtain an amide polymer S1; the polymerization reaction conditions are: a stirring speed of 350 rpm, a temperature of 70° C., and a time of 7 h;

[0132] Based on the total weight of the monomer A', the monomer B', the monomer C' and the monomer D', the amount of the initiator is 0.1 wt%;

[0133] The molar ratio of the monomer A', the monomer B', the monomer C' and the monomer D' is 1:0.25:0.08:0.125;

[0134] The number average molecular weight of the amide polymer S1 is 400,000;

[0135] Example 2

[0136] Monomer A': same as in Example 1;

[0137] Monomer B': same as in Example 1;

[0138] Monomer C': same as in Example 1;

[0139] Monomer D': CAS number is 79-06-1, purchased from Beijing Xinbaohai Chemical Technology Co., Ltd.;

[0140] (1) dissolving 1 mol of monomer A' in 150 mL of water, and adjusting the pH value to 8 with NaOH; then, under the protection of nitrogen, mixing the aqueous solutions of monomer D', monomer B, monomer C and monomer A' for the first time to obtain a mixture I; the conditions of the first mixing are: temperature of 50° C., time of 5 h, and stirring speed of 300 rpm;

[0141] (2) subjecting the mixture I to a polymerization reaction with an initiator (potassium persulfate) and 0.05 mol of a surfactant (sodium dodecylbenzene sulfonate), and the resulting product is dried and crushed in sequence to obtain an amide polymer S2; the polymerization reaction conditions are: a stirring speed of 400 rpm, a temperature of 65° C., and a time of 5 h;

[0142] Based on the total weight of the monomer A', the monomer B', the monomer C' and the monomer D', the amount of the initiator is 0.2 wt%;

[0143] The molar ratio of the monomer A', the monomer B', the monomer C' and the monomer D' is 1:5:3:0.3;

[0144] The number average molecular weight of the amide polymer S2 is 320,000.

[0145] Example 3

[0146] This example is carried out using a process similar to that of Example 1, except that in this example, the amount of monomer A' is controlled to be the same as that of Example 1, but the molar ratio of monomer A', monomer B', monomer C' and monomer D' is 1:8:0.08:0.125.

[0147] The rest are the same as in Example 1.

[0148] The prepared amide polymer S3 had a number average molecular weight of 300,000.

[0149] Example 4

[0150] This embodiment adopts a process similar to that of Embodiment 1, except that, in this embodiment, the amount of monomer A' is controlled to be the same as that of Embodiment 1, but the molar ratio of monomer A', monomer B', monomer C' and monomer D' is 1:0.25:5:0.125.

[0151] The rest are the same as in Example 1.

[0152] The amide polymer S4 was prepared, and the number average molecular weight was 350,000.

[0153] Example 5

[0154] This example is carried out using a process similar to that of Example 1, except that in this example, the types of monomers used are different, specifically:

[0155] Monomer A': same as in Example 1;

[0156] Monomer B': The product number is 20241125, purchased from Shandong Xiya Chemical Co., Ltd.;

[0157] Monomer C': same as in Example 1;

[0158] Monomer D': same as in Example 2.

[0159] The rest are the same as in Example 1.

[0160] The amide polymer S5 was prepared, and the number average molecular weight was 200,000.

[0161] Comparative Example 1

[0162] This comparative example was carried out using a process similar to that of Example 1, except that monomer A' was not added in this comparative example.

[0163] The rest are the same as in Example 1.

[0164] The polymer DS1 was prepared.

[0165] Comparative Example 2

[0166] This comparative example was carried out using a process similar to that of Example 1, except that monomer B' was not added in this comparative example.

[0167] The rest are the same as in Example 1.

[0168] The polymer DS2 was prepared.

[0169] Comparative Example 3

[0170] This comparative example was carried out using a process similar to that of Example 1, except that monomer C' was not added in this comparative example.

[0171] The rest are the same as in Example 1.

[0172] The polymer DS3 was prepared.

[0173] Comparative Example 4

[0174] This comparative example was carried out using a process similar to that of Example 1, except that the monomer D' was not added in this comparative example.

[0175] The rest are the same as in Example 1.

[0176] Polymer DS4 was prepared.

[0177] Comparative Example 5

[0178] This comparative example is carried out using a process similar to that of Example 1, except that in this comparative example, the amount of monomer A' is controlled to be the same as that of Example 1, but the molar ratio of monomer A', monomer B', monomer C' and monomer D' is 1:0.1:6:0.6.

[0179] The rest are the same as in Example 1.

[0180] Polymer DS5 was prepared.

[0181] Test Case

[0182] This test example is used to illustrate the rheological properties of the amide polymer prepared in the above example before and after aging at 180°C.

[0183] Test method: 9 g of the amide polymer prepared in the above examples and comparative examples was stirred with 300 g of deionized water at 5000 rpm for 20 min, and the changes in rheological properties were measured before and after aging at 180°C.

[0184] The test instrument is a six-speed viscometer (model: ZNN-D6B; manufacturer: Qingdao Tongchun Petroleum Instrument Co., Ltd., the maximum test range is 300), and the test standard is: GB / T29170-2012;

[0185] The test items include: apparent viscosity (AV (mPa·S)), plastic viscosity (PV (mPa·S)), dynamic shear force (YP (Pa)), dynamic plastic ratio. The greater the viscosity and dynamic shear force, the better the rock carrying effect. The test results are shown in Table 1.

[0186] Table 1

[0187]

[0188] It can be seen from the results in Table 1 that the amide polymer provided by the present invention has better rheological properties before and after aging at 180°C.

[0189] Test Example 2

[0190] This test example is used to exemplarily illustrate the viscosity changes of the amide polymer S1 provided in Example 1 of the present invention, the amide polymer S4 provided in Example 4, and the polymer DS1 provided in Comparative Example 1 before and after aging at 180°C at different calcium addition amounts.

[0191] Test method: Take 9g of the polymer obtained in the above example and 300g of deionized water and stir them at 5000rpm for 15min; then add CaCl2 (the amount added in different test systems is different, see Table 2 for details), change the speed to 1000r / min, and measure the changes in its rheological properties before and after aging at 180℃ after 5min; the test items and test standards are the same as those in Test Example 1, and the test results are shown in Table 2.

[0192] Table 2

[0193]

[0194] Table 2 (Continued)

[0195]

[0196] Table 2 (Continued)

[0197]

[0198] It can be seen from Table 2 that the amide polymers provided by the present invention have better viscosity-increasing and shear-increasing properties, and also better temperature and calcium resistance.

[0199] Test Example 3

[0200] This test example is used to illustrate the change in viscosity and shearing ability of the amide polymer S1 provided in Example 1 of the present invention before and after aging at 180°C, 150°C, 120°C, and 100°C for 16 hours. The test method and test items are the same as those in Test Example 1; the test results are shown in Table 3.

[0201] Table 3

[0202]

[0203] It can be seen from Table 3 that the amide polymer S1 has good temperature resistance. After aging at different temperatures, its six-speed data readings are all over the range, and the viscosity exceeds 150 mPa·S， This indicates that it has good viscosity-increasing ability after aging.

[0204] Test Example 3

[0205] This test example is used to illustrate the viscosity-enhancing, shear-increasing and filtration-loss-reducing performance tests of the amide polymer S1 provided in Example 1 of the present invention after being applied to water-based drilling fluid.

[0206] Test method:

[0207] System 1: 300 g of water + 9 g of amide polymer S1 + 27 g of fluid loss reducer (sulfonated phenolic resin) + 6 g of inhibitor (potassium chloride) + 12 g of weighting agent (1000 mesh CaCO3) + 1.2 g of pH adjuster (NaOH).

[0208] System 2: 300 g of water + 27 g of fluid loss reducer (sulfonated phenolic resin) + 6 g of inhibitor (potassium chloride) + 12 g of weighting agent (1000 mesh CaCO3) + 1.2 g of pH adjuster (NaOH).

[0209] The viscosity increasing, shear increasing and filtration loss reducing performance of the above-mentioned system 1 and system 2 were tested according to the test standard GB / T29170-2012. The test results are shown in Table 4.

[0210] Table 4

[0211] AV(mPa·S) PV (mPa·S) YP(Pa) Dynamic plastic ratio API(ml) <![CDATA[FL HTHP (ml)]]> System 1 75 55 20.4 0.37 2.8 9.5 System 2 20 15 5.1 0.34 10 55

[0212] It can be seen from Table 4 that the amide polymer provided by the present invention can improve the rheological and fluid loss reduction performance of the system after being applied to the drilling fluid.

[0213] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. An amide polymer, characterized in that: The polymer contains structural unit A, structural unit B, structural unit C and structural unit D; the molar ratio of the structural unit A, the structural unit B, the structural unit C and the structural unit D is 1:0.125-10:0.0625-5:0.125-0.5; The structural unit A is a structural unit having a structure shown in formula (1); the structural unit B is a structural unit having a structure shown in formula (2); the structural unit C is a structural unit having a structure shown in formula (3); and the structural unit D is a structural unit having a structure shown in formula (4); In formula (1), each R 1 Each independently selected from H, C 1-6 Alkyl; R 2 Selected from C 1-6 Alkylene; R 3 Selected from H, C 1-8 An alkyl group; M1 is selected from H or an alkali metal element; In formula (2), each R 4 Each independently selected from H, C 1-6 Alkyl; R 5 Selected from H, C 1-6 The alkyl group; In formula (3), each R 6 Each independently selected from H, C 1-6 The alkyl group; In formula (4), each R 7 Each independently selected from H, C 1-6 Alkyl; R 8 Selected from H, C 1-6 of alkyl.

2. The amide polymer according to claim 1, characterized in that In formula (1), each R 1 Each is independently selected from H, -CH3, -CH2CH3, -CH2CH2CH3; R 2 is selected from -CH2-, -CH2-CH2-, -CH2-CH2-CH2-; R 3 is selected from H, -CH3, -CH2CH3, -CH2CH2CH3; M1 is selected from H, K, Na; In formula (2), each R 4 Each is independently selected from H, -CH3, -CH2CH3, -CH2CH2CH3; R 5 is selected from H, -CH3, -CH2CH3, -CH2CH2CH3; In formula (3), each R 6 Each is independently selected from H, -CH3, -CH2CH3, -CH2CH2CH3; In formula (4), each R 7 Each is independently selected from H, -CH3, -CH2CH3, -CH2CH2CH3; R 8 Selected from H, -CH3, -CH2CH3, -CH2CH2CH3.

3. The amide polymer according to claim 1 or 2, characterized in that: The structural unit A is selected from the structure shown in formula (1-1), the structure shown in formula (1-2), the structure shown in formula (1-3), the structure shown in formula (1-4), the structure shown in formula (1-5), the structure shown in formula (1-6), the structure shown in formula (1-7), the structure shown in formula (1-8), the structure shown in formula (1-9), the structure shown in formula (1-10), the structure shown in formula (1-11), the structure shown in formula (1-12), the structure shown in formula (1-13), the structure shown in 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), the structure shown in formula (1-27), the structure shown in formula (1-28), the structure shown in formula (1-29), the structure shown in formula (1-30), the structure shown in formula (1-31), the structure shown in formula (1-32), the structure shown in formula (1-33), the structure shown in formula (1-34), the structure shown in formula (1-35), the structure shown in formula (1-36), the structure shown in formula (1-37), the structure shown in formula (1-38), the structure shown in formula (1-39), the structure shown in formula (1-40), the structure shown in formula (1-41), the structure shown in formula (1-42), the structure shown in formula (1-43), the structure shown in formula (1-44), the structure shown in formula (1-45), the structure shown in formula (1-46), 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), the structure shown in formula (1-27) and the structure shown in formula (1-28); The structural unit B is selected from at least one of the structural units having the structure represented by formula (2-1), the structure represented by formula (2-2), the structure represented by formula (2-3), the structure represented by formula (2-4), the structure represented by formula (2-5), the structure represented by formula (2-6), the structure represented by formula (2-7), the structure represented by formula (2-8), and the structure represented by formula (2-9); The structural unit C is selected from at least one of the structural units of the structure represented by formula (3-1), the structure represented by formula (3-2), the structure represented by formula (3-3), the structure represented by formula (3-4), and the structure represented by formula (3-5); The structural unit D is selected from at least one of the structural units of the structure shown in formula (4-1), the structure shown in formula (4-2), the structure shown in formula (4-3), the structure shown in formula (4-4), the structure shown in formula (4-5), the structure shown in formula (4-6), the structure shown in formula (4-7), the structure shown in formula (4-8), the structure shown in formula (4-9), and the structure shown in formula (4-10); Formula (1-1): R 1 Both are H; R 2 -CH2-; R 3 is H; M1 is H; Formula (1-2): R 1 Both are H; R 2 -CH2-; R 3 is H; M1 is K; Formula (1-3): R 1 Both are H; R 2 -CH2-; R 3 is H; M1 is Na; Formula (1-4): R 1 Both are H; R 2 -CH2-; R 3 is -CH3; M1 is H; Formula (1-5): R 1 Both are H; R 2 -CH2-; R 3 is -CH3; M1 is K; Formula (1-6): R 1 Both are H; R 2 -CH2-; R 3 is -CH3; M1 is Na; Formula (1-7): R 1 Both are H; R 2 -CH2-; R 3 is -CH2CH3; M1 is H; Formula (1-8): R 1 Both are H; R 2 -CH2-; R 3 is -CH2CH3; M1 is K; Formula (1-9): R 1 Both are H; R 2 -CH2-; R 3 is -CH2CH3; M1 is Na; Formula (1-10): R 1 All are -CH3; R 2 -CH2-; R 3 is H; M1 is H; Formula (1-11): R 1 All are -CH3; R 2 -CH2-; R 3 is H; M1 is K; Formula (1-12): R 1 All are -CH3; R 2 -CH2-; R 3 is H; M1 is Na; Formula (1-13): R 1 All are -CH3; R 2 -CH2-; R 3 is -CH3; M1 is H; Formula (1-14): R 1 All are -CH3; R 2 -CH2-; R 3 is -CH3; M1 is K; Formula (1-15): R 1 All are -CH3; R 2 -CH2-; R 3 is -CH3; M1 is Na; Formula (1-16): R 1 All are -CH3; R 2 -CH2-; R 3 is -CH2CH3; M1 is H; Formula (1-17): R 1 All are -CH3; R 2 -CH2-; R 3 is -CH2CH3; M1 is K; Formula (1-18): R 1 All are -CH3; R 2 -CH2-; R 3 is -CH2CH3; M1 is Na; formula (1-19): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is H; M1 is H; Formula (1-20): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is H; M1 is K; Formula (1-21): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is H; M1 is Na; Formula (1-22): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is -CH3; M1 is H; Formula (1-23): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is -CH3; M1 is K; Formula (1-24): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is -CH3; M1 is Na; formula (1-25): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is -CH2CH3; M1 is H; formula (1-26): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is -CH2CH3; M1 is K; formula (1-27): R 1 All are -CH2CH3; R 2 -CH2-; R 3 is -CH2CH3; M1 is Na; formula (1-28): Formula (2-1): R 4 Both are H; R 5 is H; Formula (2-2): R 4 Both are H; R 5 is -CH3; Formula (2-3): R 4 Both are H; R 5 is -CH2CH3; Formula (2-4): R 4 All are -CH3; R 5 is -CH3; Formula (2-5): R 4 All are -CH3; R 5 is -CH2CH3; Formula (2-6): R 4 All are -CH2CH3; R 5 is -CH2CH3; Formula (2-7): R 4 All are -CH2CH2CH3; R 5 is -CH2CH3; Formula (2-8): R 4 All are -CH2CH2CH3; R 5 -CH2CH2CH3; Formula (2-9): Formula (3-1): R 6 All are H; Formula (3-2): R 6 All are -CH3; Formula (3-3): R 6 All are -CH2CH3; Formula (3-4): R 6 All are -CH2CH2CH3; Formula (3-5): R 6 All are -CH2CH2CH2CH3; Formula (4-1): R 7 Both are H; R 7 is H; Formula (4-2): R 7 All are -CH3; R 8 is H; Formula (4-3): R 7 All are -CH2CH3; R 8 H Formula (4-4): R 7 All are -CH2CH2CH3; R 8 H Formula (4-5): R 7 All are -CH3; R 8 is -CH3; Formula (4-6): R 7 All are -CH2CH3; R 8 is -CH3; Formula (4-7): R 7 All are -CH2CH3; R 8 is -CH2CH3; Formula (4-8): R 7 All are -CH2CH2CH3; R 8 is -CH2CH3; Formula (4-9): R 7 All are -CH2CH2CH3; R 8 is -CH2CH2CH3; Formula (4-10):

4. The amide polymer according to any one of claims 1 to 3, characterized in that The molar ratio of the structural unit A, the structural unit B, the structural unit C and the structural unit D is 1:0.25-5:0.08-3:0.125-0.

3.

5. A method for preparing an amide polymer, characterized in that: The method includes: (1) in the presence of a protective atmosphere, performing a first mixing of aqueous solutions of monomer D', monomer B, monomer C and monomer A' to obtain a mixture I; the pH value of the aqueous solution of monomer A' in the initial system of the first mixing is 7-8; (2) in the presence of an initiator and a surfactant, the mixture I undergoes a polymerization reaction to obtain the amide polymer; The monomer A' is selected from monomers having a structure shown in formula (I); the monomer B' is selected from monomers having a structure shown in formula (I I); the monomer C' is selected from monomers having a structure shown in formula (I I I); the monomer D' is selected from monomers having a structure shown in formula (IV); The monomer A', the monomer B', the monomer C' and the monomer D' are respectively such that the prepared polymer contains the structural unit A, the structural unit B, the structural unit C and the structural unit D, and the molar ratio of the structural unit A, the structural unit B, the structural unit C and the structural unit D in the prepared polymer is 1:0.125-10:0.0625-5:0.125-0.5; The structural unit A is a structural unit having a structure shown in formula (1); the structural unit B is a structural unit having a structure shown in formula (2); the structural unit C is a structural unit having a structure shown in formula (3); and the structural unit D is a structural unit having a structure shown in formula (4); Among them, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 The definition of M1 corresponds to the same as that in any one of claims 1 to 4.

6. The method according to claim 5, characterized in that The polymerization reaction is carried out under stirring conditions, and the conditions of the polymerization reaction include: stirring speed of 300-500 rpm, temperature of 50-70° C., and time of 5-7 h; And / or, the initiator is selected from at least one of alkyl halides, 2-ketoglutaric acid, potassium persulfate, ammonium cerium nitrate, and azobisisobutyramidine hydrochloride.

7. The method according to claim 5 or 6, characterized in that: The solvent is selected from at least one of water, ethanol, methanol and dimethyl sulfoxide; And / or, based on the total weight of the monomer A', the monomer B', the monomer C' and the monomer D', the amount of the initiator is 0.1-0.2 wt%; And / or, the amount of the surfactant used is 0.00125-0.05 mol per mol of the monomer A'.

8. An amide polymer prepared by the method according to any one of claims 5 to 7.

9. Use of the amide polymer according to any one of claims 1 to 4 and 8 as a viscosity increasing and shear improving agent in drilling fluid.

10. A water-based drilling fluid, characterized in that: The water-based drilling fluid contains an effective amount of the amide polymer described in any one of claims 1 to 4 and 8 to increase viscosity and reduce shear strength; Preferably, the water-based drilling fluid contains water, an amide polymer, a fluid loss reducer, an inhibitor, a pH adjuster, and optionally a weighting agent; Wherein, relative to 300 parts by weight of water, the content of the amide polymer is 8-12 parts by weight, the content of the filtration reducer is 24-30 parts by weight, the content of the inhibitor is 4-8 parts by weight, the content of the weighting agent is 0-20 parts by weight, and the content of the pH adjuster is 0.5-3 parts by weight; the amide polymer is the amide polymer described in any one of claims 1-4 and 8.

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