CN111718443B - Random copolymer, preparation method and application thereof, and drilling fluid - Google Patents

Random copolymer, preparation method and application thereof, and drilling fluid Download PDF

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CN111718443B
CN111718443B CN201910204682.0A CN201910204682A CN111718443B CN 111718443 B CN111718443 B CN 111718443B CN 201910204682 A CN201910204682 A CN 201910204682A CN 111718443 B CN111718443 B CN 111718443B
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CN111718443A (en
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赵金洲
王琳
杨小华
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China Petroleum and Chemical Corp
Sinopec Research Institute of Petroleum Engineering
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Sinopec Research Institute of Petroleum Engineering
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/52—Amides or imides
    • C08F220/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
    • C08F220/58—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide containing oxygen in addition to the carbonamido oxygen, e.g. N-methylolacrylamide, N-(meth)acryloylmorpholine
    • 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
    • C08F220/38—Esters containing sulfur
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/52—Amides or imides
    • C08F220/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
    • C08F220/56—Acrylamide; Methacrylamide
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    • 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
    • C09K2208/00—Aspects relating to compositions of drilling or well treatment fluids
    • C09K2208/12—Swell inhibition, i.e. using additives to drilling or well treatment fluids for inhibiting clay or shale swelling or disintegrating

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Abstract

The invention relates to the field of reducing the filtration loss of drilling fluid at high calcium and high temperature, and discloses a random copolymer, a preparation method and application thereof, and a drilling fluid and a method for reducing the filtration loss of the drilling fluid. The random copolymer contains a structural unit (A) represented by the formula (1), a structural unit (B) represented by the formula (2), a structural unit (C) represented by the formula (3), and a structural unit (D) represented by the formula (4) or the formula (5),

Description

Random copolymer, preparation method and application thereof, and drilling fluid
Technical Field
The invention relates to the field of filtrate loss reduction of drilling fluid at high calcium and high temperature, in particular to a random copolymer, a preparation method thereof and application of the random copolymer as a calcium-resistant high-temperature-resistant drilling fluid filtrate loss reducer in water-based drilling fluid.
Background
Along with the deep exploration and development, the drilling machine encounters more and more strata such as high temperature, high calcium salt, high pressure and high calcium salt water and the like, the filtration loss and rheological property of the drilling fluid are difficult to maintain in the construction, and the complex conditions such as well wall instability, barite settlement, drill sticking and the like are easily caused. Under the environment of high temperature and high calcium salt, the treating agent for maintaining the performance of the drilling fluid is easy to degrade, crosslink, desorb, dehydrate, flocculate and other chemical and physical changes, so that the filtration loss and rheological property of the drilling fluid are out of control, the speed of drilling operation is seriously influenced, and the safety risk of engineering is greatly increased. For example, in the oil field of Tahe in Xinjiang, the high-salt calcium and high-pressure high-calcium salt water strata in the middle tower, Barmat, Yubei and peripheral exploration areas have wide distribution range, and have large sections of gypsum strata and high-calcium salt water pollution. For example, when the Marbei 1 well drilling tool meets the high-calcium salt water of the martial system, the calcium ion is 26000mg/L, the chloride ion is 179000mg/L, serious overflow occurs, the drilling fluid returning from the well bottom is flocculated and solidified, the fluidity is poor, the medium-pressure filtration loss is up to 70-80mL, the high-calcium salt water continuously seeps, the difficulty in maintaining and treating the drilling fluid is extremely high, and the well is scrapped when the drilling fluid is serious. The high-temperature-resistant high-calcium filtrate reducer becomes one of bottleneck technologies of drilling fluid of deep wells and ultra-deep wells in peripheral exploration areas of Xinjiang.
The filtrate reducer is one of core treating agents of drilling fluid, and has the main functions of promoting the drilling fluid to form a thin and compact filter cake with low permeability on a well wall, further reducing the invasion of filtrate to a stratum, reducing the occurrence probability of hydration and expansion of shale and realizing the stability of the well wall. Most of the existing filtrate reducers comprise natural modified agents and synthetic agents, when Ca is used2+、Mg2+When free high-valence ions exist, irreversible strong interaction with the free high-valence ions occurs, and the interaction is more severe under the high-temperature condition, so that the treatment agent molecules generate radical variation and conformation damage, and even main chain breakage occurs, and the effectiveness of the treatment agent molecules is seriously influenced.
In recent years, a great deal of research is carried out at home and abroad on the high-temperature resistance and salt resistance of the filtrate reducer. The chain structure of the polymer fluid loss additive is adjusted mainly by adopting a monomer containing 2-acrylamide-2-methylpropanesulfonic Acid (AMPS), and the temperature resistance and calcium salt resistance of the product are effectively improved through two methyl substituents on a side group functional group, a sulfonic acid group and the like.
AMPS/AM/AN terpolymer filtrate reducer synthesis and performance (Wangchua, oilfield chemistry, 1995, 12 (4): 367-369), drilling fluid filtrate reducer P (AMPS-IPAM-AM) synthesis and evaluation (Wangchua, drilling fluid and completion fluid, 2010, 27 (2): 10-13) and calcium-resistant drilling fluid filtrate reducer P (AMPS-DEAM) polymer synthesis (Wangchua, fine and special chemicals, 2010, 18 (4): 24-28) respectively disclose AMPS/AM/AN terpolymer, AMPS/IPAM/AM terpolymer and AMPS/DEAM binary copolymer, and have good temperature and filtrate reduction resistance in calcium-containing drilling fluids.
CN201410777862.5 discloses a salt-resistant and calcium-resistant fluid loss additive for drilling fluid copolymerized by AMPS, AA, AM and DMDAAC and a preparation method thereof, wherein the molecular weight is greatly increased, so that the coating property, the inhibition property, the thermal stability and the salt and calcium pollution resistance of the fluid loss additive are greatly improved.
Development and evaluation of high temperature resistant and high calcium resistant filtrate reducer DF-1 (Jiang Cheng et al, oil field chemistry 2015, 32 (1): 1-6) discloses introduction of nano-silica (nano-SiO)2) Synthesizing the drilling fluid filtrate reducer P (AM-AMPS-AA-DMDAAC)/nano-SiO2And has good temperature resistance, salt resistance and calcium resistance.
However, the current domestic filtrate reducer can only be at 150 ℃ and Ca2+The content is 1.4 multiplied by 104The filtration loss is effectively controlled within mg/L, and a filtration loss reducer with higher temperature resistance under higher calcium ion content is lacked; and the relative molecular mass is not controlled sufficiently, so that the static structural force of the drilling fluid is often too strong due to too high relative molecular mass, and the flow pattern control of the high-temperature high-density drilling fluid is not facilitated.
Thus, there is an urgent need for a fluid loss additive for drilling fluids that has calcium resistance and high temperature resistance.
Disclosure of Invention
The invention aims to overcome the problems of insufficient calcium content resistance and high temperature resistance of a drilling fluid filtrate reducer in the prior art, and provides a random copolymer, a preparation method and application thereof, and a drilling fluid. The random copolymer can form interaction which is beneficial to fluid loss reduction effect with clay particles in high-calcium drilling fluid by introducing a novel calcium-resistant monomer to regulate and control various functional group structures and proportions on a polymer molecular chain, so that a flexible, thin and compact filter cake with low permeability is formed, the fluid loss of the drilling fluid is effectively reduced, and the temperature resistance of a treating agent is improved.
In order to achieve the above object, a first aspect of the present invention provides a random copolymer comprising a structural unit (A) represented by formula (1), a structural unit (B) represented by formula (2), a structural unit (C) represented by formula (3), and a structural unit (D) represented by formula (4) or formula (5),
Figure BDA0001998595280000031
wherein R is1And R2Each independently is H or C1-C6Alkyl of R3And R4Each independently is H or C1-C3Alkyl groups of (a);
Figure BDA0001998595280000032
wherein R is5is-O-R-or-NH-R-; wherein R is-CmH2m-, and m is 4, 5 or 6; m1Is H, NH4Na or K;
Figure BDA0001998595280000033
wherein R is6Is selected from
Figure BDA0001998595280000034
Figure BDA0001998595280000035
Figure BDA0001998595280000036
M2-M6Each independently is H, NH4Na or K;
Figure BDA0001998595280000041
wherein R is7And R8Each independently is H or C1-C6Alkyl of R9is-CnH2n-, and n is an integer of 2 to 6, R10Is composed of
Figure BDA0001998595280000042
Figure BDA0001998595280000043
X is halogen.
Preferably, an aqueous solution of the random copolymer at a concentration of 1% by weight has an apparent viscosity of 10 to 40 mPas.
Preferably, the random copolymer contains 30 to 50% by weight of the structural unit (A), 40 to 60% by weight of the structural unit (B), 2 to 10% by weight of the structural unit (C) and 1 to 10% by weight of the structural unit (D), based on the total amount of the random copolymer.
Preferably, R in formula (1)1-R4Is H; r in the formula (2)5is-O-C (CH)3)2-CH2-or-NH-C (CH)3)2-CH2-; in the formula (3), R6Is composed of
Figure BDA0001998595280000044
Figure BDA0001998595280000045
R in the formula (4)7And R8Each independently is H or methyl, R9is-CH2CH2-; in the formula (5), X is Cl.
In a second aspect, the present invention provides a method for preparing a random copolymer, comprising:
under the protection of nitrogen and in the presence of an initiator, carrying out free radical copolymerization on a monomer (a) shown in a formula (6), a monomer (b) shown in a formula (7), a monomer (c) shown in a formula (8) and a monomer (d) shown in a formula (9) or a formula (10);
Figure BDA0001998595280000051
wherein R is1And R2Each independently is H or C1-C6Alkyl of R3And R4Each independently is H or C1-C3Alkyl groups of (a);
Figure BDA0001998595280000052
wherein R is5is-O-R-or-NH-R-, wherein R is-CmH2m-, and m is 4, 5 or 6;
Figure BDA0001998595280000053
wherein R is6Is selected from
Figure BDA0001998595280000054
Figure BDA0001998595280000055
Figure BDA0001998595280000061
Wherein R is7And R8Each independently is H or C1-C6Alkyl of R9is-CnH2n-, and n is an integer of 2 to 6, R10Is composed of
Figure BDA0001998595280000062
Figure BDA0001998595280000063
X is halogen.
Preferably, the respective monomer amounts: 20-50 parts by weight of monomer (a), 40-70 parts by weight of monomer (b), 1-10 parts by weight of monomer (c) and 0.5-8 parts by weight of monomer (d).
Preferably, R in formula (6)1-R4Is H; r in the formula (7)5is-O-C (CH)3)2-CH2-or-NH-C (CH)3)2-CH2-; in the formula (8), R6Is composed of
Figure BDA0001998595280000064
Figure BDA0001998595280000065
R in the formula (9)7And R8Each independently of the otherIs H or methyl, R9is-CH2CH2-; in the formula (10), X is Cl.
Preferably, the initiator is selected from the group consisting of oxidation-reduction initiators or azo-type initiators.
Preferably, the total amount of initiator used is from 0.1 to 1.6% by weight based on the total weight of all monomers.
Preferably, the manner of subjecting the monomer (a), the monomer (b), the monomer (c) and the monomer (d) to radical copolymerization includes:
adding the monomer into alkali liquor to be uniformly dissolved, and introducing nitrogen to remove oxygen to obtain a monomer mixed solution; adjusting the temperature of the monomer mixed solution to 40-75 ℃ and the pH value to 5-10; then adding the initiator to initiate the copolymerization reaction for 0.2-4h to obtain a gel-like product; the gel-like product is granulated, dried and pulverized.
Preferably, the total weight concentration of the monomer (a), the monomer (b), the monomer (c), and the monomer (d) in the monomer mixed solution is 20 to 60% by weight.
In a third aspect, the present invention provides a random copolymer produced by the production process of the present invention.
In a fourth aspect, the present invention provides a use of the random copolymer of the invention in a drilling fluid.
Preferably, the random copolymer is added to the drilling fluid slurry as a fluid loss additive in an amount of 0.5 to 4g per 100mL of drilling fluid slurry.
In a fifth aspect, the invention provides a drilling fluid comprising a random copolymer of the invention as a fluid loss additive and a slurry, wherein the amount of the random copolymer is 0.5 to 4g per 100mL of the slurry.
According to the above-mentioned technical means, the monomers contained in the random copolymer are selected and polymerized to obtain a random copolymer containing the structural unit (A), the structural unit (B), the structural unit (C) and the structural unit (D). When the random copolymer is used as a filtrate reducer in water-based drilling fluid, the obtained drilling fluid can play a good role in protecting clay particles under the environment condition of high-concentration calcium ions, can form a flexible, thin and compact filter cake with low permeability, reduces the filtrate loss of the drilling fluid containing high calcium ions, and can be used for a high-calcium salt drilling fluid system at high temperature (150 ℃). In the present invention, the random copolymer is polymerized by selecting a plurality of monomers (a, b, c, d) to be polymerized in cooperation to provide a random copolymer having the above-mentioned structural unit. Furthermore, the monomer (c) and the monomer (d) can also act together to help increase the anti-collapse performance of the polymer, and the obtained fluid loss additive has proper relative molecular mass and is more beneficial to the control of the flow pattern of the drilling fluid under high density.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The first aspect of the present invention provides a random copolymer comprising a structural unit (A) represented by formula (1), a structural unit (B) represented by formula (2), a structural unit (C) represented by formula (3), and a structural unit (D) represented by formula (4) or formula (5),
Figure BDA0001998595280000081
wherein R is1And R2Each independently is H or C1-C6Alkyl of R3And R4Each independently is H or C1-C3Alkyl groups of (a);
Figure BDA0001998595280000082
wherein R is5is-O-R-or-NH-R-; wherein R is-CmH2m-, and m is 4, 5 or 6; m1Is H, NH4Na or K;
Figure BDA0001998595280000083
wherein R is6Is selected from
Figure BDA0001998595280000084
Figure BDA0001998595280000085
Figure BDA0001998595280000086
M2-M6Each independently is H, NH4Na or K;
Figure BDA0001998595280000087
wherein R is7And R8Each independently is H or C1-C6Alkyl of R9is-CnH2n-, and n is an integer of 2 to 6, R10Is composed of
Figure BDA0001998595280000091
Figure BDA0001998595280000092
X is halogen.
The present invention provides the above random copolymer, the structural unit (A)
Figure BDA0001998595280000093
In part, -C-C-linkages are linked into the backbone of the random copolymer. Of structural unit (A)
Figure BDA0001998595280000094
(amide group) as a side group of the structural unit (A).
In the present invention, R1And R2Each independently is H or C1-C6Wherein alkyl may be substituted or unsubstituted straight or branched chain alkyl, including but not limited to methyl, ethyl, n-propylIsopropyl, tert-butyl, n-butyl, pentyl or n-hexyl. R3And R4Each independently is H or C1-C3Alkyl group of (1). Wherein alkyl may be substituted or unsubstituted straight or branched chain alkyl including, but not limited to, methyl, ethyl, n-propyl or isopropyl. Preferably, R in formula (1)1And R2Can be H or R1Is methyl, R2Is H; r3And R4Can be H or R4Is methyl, R3Is H. More preferably, R1-R4Is H.
Of structural unit (B)
Figure BDA0001998595280000095
In part, -C-C-linkages are linked into the backbone of the random copolymer. Of structural unit (B)
Figure BDA0001998595280000096
As a side chain of the structural unit (B). R5Oxygen or nitrogen element of (1) and
Figure BDA0001998595280000101
the linkage is formed as an acyloxy or amide group. Preferably, R5Wherein m is 4 and R is-C (CH)3)2-CH2-. Preferably, R in formula (2)5is-O-C (CH)3)2-CH2-or-NH-C (CH)3)2-CH2-. Preferably, the structural unit (B) may be
Figure BDA0001998595280000102
Figure BDA0001998595280000103
M1Is H, NH4Na or K may be a cation which is partially taken in when a polymerization solution is prepared using an alkali solution in the polymerization of the random copolymer.
Of structural unit (C)
Figure BDA0001998595280000104
In part, -C-C-is attached to the backbone of the random copolymer. In the structural unit (C)
Figure BDA0001998595280000105
As a side chain of the structural unit (C). M2Is H, NH4Na or K may be a cation which is partially taken in when a polymerization solution is prepared using an alkali solution in the polymerization of the random copolymer. Preferably, R6Is composed of
Figure BDA0001998595280000106
Figure BDA0001998595280000111
Accordingly, formula (3) is
Figure BDA0001998595280000112
Figure BDA0001998595280000113
Wherein M is2、M3And M5Can be H, NH4Na or K may be a cation which is partially taken in when a polymerization solution is prepared using an alkali solution in the polymerization of the random copolymer.
The structural unit (D) may be selected from the structures of formula (4) or formula (5). In the formula (4), the reaction mixture is,
Figure BDA0001998595280000114
the moiety-C-is linked into the main chain of the random copolymer. In formula (4)
Figure BDA0001998595280000115
As a side chain of the structural unit (D). Preferably, R in formula (4)7And R8Each independently is H or methyl, R9is-CH2CH2-. Accordingly, the structure of formula (4) is
Figure BDA0001998595280000121
Formula (A), (B) and5) in
Figure BDA0001998595280000122
Partially linked into the backbone of the random copolymer. In formula (5)
Figure BDA0001998595280000123
As the side chain of the structural unit (D), it is preferable that X is Cl in the formula (5). Accordingly, the structure of formula (5) is
Figure BDA0001998595280000124
According to the present invention, the random copolymer may contain a randomly linked structural unit (a), structural unit (B), structural unit (C) and structural unit (D). The random copolymer may be obtained by radical polymerization of corresponding monomers capable of providing the structural unit (a), the structural unit (B), the structural unit (C) and the structural unit (D). Preferably, the random copolymer has a structure represented by the following formula:
Figure BDA0001998595280000131
Figure BDA0001998595280000141
a, B, C, D represents a structural unit (A), a structural unit (B), a structural unit (C) and a structural unit (D) contained in the random copolymer, respectively, and these structural units may be randomly linked to form the main chain of the copolymer.
In the present invention, the random copolymer having the above-mentioned structure can be formed by radical polymerization using the monomer (a), the monomer (b), the monomer (c) and the monomer (d) used in the following method, each of which has a terminal vinyl group. In addition, the invention can also be realized by13C-NMR、1H-NMR, elemental analysis, and NMR analysis of the residue from which the polymerization product was isolated to determine the proportion of unpolymerized monomer, whereby the analysis in combination showed that the random copolymer was a copolymerA substance having the above structure.
According to the invention, the relative compound molecular weights can be dimensioned by the apparent viscosity of the random copolymer. Preferably, the random copolymer is formulated to have an apparent viscosity of 10 to 40 mPas in an aqueous solution at a concentration of 1% by weight. The aqueous solution was a solution containing 1% by weight of the random copolymer. The apparent viscosity can be measured by the method specified in ISO 10416:2008 "Recommended Practice for Laboratory Testing of Drilling Fluids".
According to the present invention, the content of each structural unit in the random copolymer may be sufficient for achieving the object of the present invention. Preferably, the random copolymer contains 30 to 50% by weight of the structural unit (A), 40 to 60% by weight of the structural unit (B), 2 to 10% by weight of the structural unit (C) and 1 to 10% by weight of the structural unit (D), based on the total amount of the random copolymer. Preferably, the random copolymer contains 35 to 45% by weight of the structural unit (A), 45 to 55% by weight of the structural unit (B), 3 to 8% by weight of the structural unit (C) and 2 to 6% by weight of the structural unit (D).
More preferably, the random copolymer contains 37 to 41.4% by weight of the structural unit (A), 48.2 to 54.4% by weight of the structural unit (B), 4.1 to 9.9% by weight of the structural unit (C) and 1.8 to 4.8% by weight of the structural unit (D).
In a second aspect, the present invention provides a method for preparing a random copolymer, comprising:
under the protection of nitrogen and in the presence of an initiator, carrying out free radical copolymerization on a monomer (a) shown in a formula (6), a monomer (b) shown in a formula (7), a monomer (c) shown in a formula (8) and a monomer (d) shown in a formula (9) or a formula (10);
Figure BDA0001998595280000151
wherein R is1And R2Each independently is H or C1-C6Alkyl of R3And R4Each independently is H or C1-C3Alkyl groups of (a);
Figure BDA0001998595280000152
wherein R is5is-O-R-or-NH-R-, wherein R is-CmH2m-, and m is 4, 5 or 6;
Figure BDA0001998595280000153
wherein R is6Is selected from
Figure BDA0001998595280000154
Figure BDA0001998595280000155
Figure BDA0001998595280000161
Wherein R is7And R8Each independently is H or C1-C6Alkyl of R9is-CnH2n-, and n is an integer of 2 to 6, R10Is composed of
Figure BDA0001998595280000162
Figure BDA0001998595280000163
X is halogen.
According to the invention, preferably, the respective monomer is used in an amount of: 20-50 parts by weight of monomer (a), 40-70 parts by weight of monomer (b), 1-10 parts by weight of monomer (c) and 0.5-8 parts by weight of monomer (d). Preferably, the respective monomer amounts: 35-42 parts of monomer (a), 45-55 parts of monomer (b), 3-7 parts of monomer (c) and 1-5 parts of monomer (d). The amount is such that the resulting random copolymer has the desired composition of the respective structural units.
In the present invention, the monomer (a) may preferably define R in the formula (6)1-R4Is H, and can be acrylamide.
In the present invention, the monomer (b) may be preferably usedR in the formula (7)5is-O-C (CH)3)2-CH2-or-NH-C (CH)3)2-CH2-, where m is 4, R is-C (CH)3)2-CH2-. Accordingly, it is preferred that the monomer (b) is 2-acrylamido-2-methylpropanesulfonic acid or 2-acryloyloxy-2-methylpropanesulfonic acid.
In the present invention, the monomer (c) corresponding to the structure of formula (8) may be at least one of N-glucuronyl maleamic acid, N-isopropionyl maleamic acid, N-acetoxy maleamic acid, N-ethanesulfonic maleamic acid, and N-benzenesulfonic maleamic acid. Preferably, in the formula (8), R6Is composed of
Figure BDA0001998595280000164
Preferred monomers of the corresponding structure of the formula (8) are
Figure BDA0001998595280000171
Figure BDA0001998595280000172
Correspondingly, the monomer (c) is at least one of N-glucose hydrochloride maleic amide acid, N-isopropyl maleic amide acid and N-ethanesulfonic maleic amide acid. The monomer (c) can provide a random copolymer with a specific structural unit, so that the random copolymer has good calcium-resistant and temperature-resistant properties. The monomer (c) can be obtained by a synthetic reaction of maleic anhydride with a corresponding compound. The corresponding compound may be glucosamine hydrochloride, alpha-alanine, glycine, taurine or aminobenzenesulfonic acid. The monomer (c) can be prepared by the following method. Preferred structures may be represented as
Figure BDA0001998595280000173
The N-glucose hydrochloride-based maleamic acid of (1) can be prepared by the following method.
Specifically, the preparation method of the N-glucose hydrochloride-based maleamic acid monomer may include:
1) dissolving C mol of glucosamine hydrochloride in a B1mL solvent;
2) mixing A mol of maleic anhydride with B2mL solvent; dropwise adding the solution obtained in the step 1) while stirring;
3) stirring the reaction until white precipitate is generated and the white precipitate is not increased any more;
4) carrying out suction filtration, washing and drying to obtain N-glucose hydrochloride maleic amide acid;
wherein A (B1+ B2) is C (1-1.4) and (40-120) is 1;
the solvent is tetrahydrofuran, glacial acetic acid, propionic acid or dimethylformamide.
In the step 3), the reaction temperature is 25-50 ℃, and the reaction time is 1-6 h; more preferably, the reaction temperature is 30 ℃ and the reaction time is 4 hours.
The reaction equation is as follows:
Figure BDA0001998595280000181
the preparation method of the N-glucose hydrochloride-based maleamic acid can specifically adopt the following steps:
adding A mol of maleic anhydride and B1mL solvent into a dry three-necked bottle, dropwise adding C mol of glucosamine hydrochloride dissolved in the other B2mL solvent under the stirring condition, stirring at 30 ℃ for reacting for 4 hours, performing suction filtration, washing and suction filtration after white precipitates are generated and are not increased any more, and drying to obtain N-glucose hydrochloride-based maleamic acid; wherein, A (B1+ B2) is C (1-1.4) and (40-120) is 1.
The glucosamine hydrochloride structure has a six-membered ring and a polyhydroxy structure, and the structure is introduced into a monomer structure, so that the water solubility of the monomer can be improved; meanwhile, the random copolymer obtained by copolymerizing the monomers can improve the tolerance to small-molecular electrolyte and high temperature.
As for the other monomer(s) which is preferable as the monomer (c), the method for producing N-glucose hydrochloride-based maleamic acid described above may be used, and the glucosamine hydrochloride in the reaction product may be replaced with alpha-alanine or aminoethanesulfonic acid.
In the present invention, when the monomer is used(d) In the case of the compound represented by the formula (9), R in the formula (9) may be preferably defined7And R8Each independently is H or methyl, R9is-CH2CH2-. The structure of formula (9) can be preferably selected from
Figure BDA0001998595280000182
Figure BDA0001998595280000183
Preferably, the monomer (d) satisfying formula (9) may be acryloyloxyethyltrimethylammonium chloride, methyl-acryloyloxyethyltrimethylammonium chloride or N, N-dimethylaminoethyl acrylate, accordingly. When the monomer (d) has a structure represented by formula (10), preferably X is Cl, and the monomer (d) may be dimethyldiallylammonium chloride. In summary, the monomer (d) may be at least one selected from acryloyloxyethyltrimethylammonium chloride, methyl-acryloyloxyethyltrimethylammonium chloride, dimethyldiallylammonium chloride, N-dimethylaminoethyl acrylate.
According to the present invention, the initiator may initiate the radical copolymerization of the above monomers. Preferably, the initiator is selected from the group consisting of redox initiators and/or azo initiators.
Preferably, the redox initiator includes at least one of ammonium persulfate, potassium persulfate, and hydrogen peroxide, and sodium bisulfite, or includes ammonium persulfate and/or potassium persulfate, and an organic amine. The oxidation-reduction initiator may be classified into a main initiator and a sub-initiator, and the main initiator may include at least one of ammonium sulfate, potassium persulfate, and hydrogen peroxide; the coinitiator may comprise sodium bisulfite or an organic amine. The organic amine may be at least one of tetramethylethylenediamine and/or tetramethyl-1, 3-propanediamine, preferably tetramethylethylenediamine. The azo initiator may be a water-soluble azo initiator, preferably azobisisobutylimidazoline hydrochloride and/or azobisisobutylamidine hydrochloride.
In the invention, the dosage of the initiator can be adjusted according to specific requirements, so that the free radical copolymerization reaction is initiated, and the random copolymer with the required structural unit composition is obtained. Preferably, the total amount of the redox initiator used is from 0.1 to 1.6% by weight, preferably from 0.3 to 1.5% by weight, based on the total weight of all monomers. Wherein the primary initiator may be used in an amount of 0.1 to 0.8 wt%, preferably 0.1 to 0.7 wt%, more preferably 0.3 to 0.7 wt%, based on the total weight of all monomers. The amount of the secondary initiator can be kept in a molar ratio to the amount of the primary initiator of (0.8-1): 1, in the above range. The total amount of azo initiators used is from 0.1 to 1.6% by weight, preferably from 0.3 to 1.5% by weight, based on the total weight of all monomers.
According to the present invention, there is provided a preferable embodiment of the method for producing a random copolymer, wherein the radical copolymerization of the monomer (a), the monomer (b), the monomer (c) and the monomer (d) comprises:
adding the monomer into alkali liquor to be uniformly dissolved, and introducing nitrogen to remove oxygen to obtain a monomer mixed solution; adjusting the temperature of the monomer mixed solution to 40-75 ℃ and the pH value to 5-10; then adding the initiator to initiate the copolymerization reaction for 0.2-4h to obtain a gel-like product; the gel-like product is granulated, dried and pulverized.
Specifically, (i) preparing alkali liquor: adding a certain amount of alkali into deionized water under stirring, and stirring and dissolving uniformly to obtain an alkali solution; the alkali can be at least one of sodium hydroxide, potassium hydroxide and ammonia water; the pH value of the alkali liquor is not lower than 7.
(ii) Adding the monomer (a), the monomer (b), the monomer (c) and the monomer (d) into the alkali liquor in sequence under the stirring condition, introducing nitrogen to remove oxygen (the nitrogen introduction time can be 0.5-2h) after the monomers are dissolved uniformly, and obtaining a monomer mixed solution. The total weight concentration of the monomer (a), the monomer (b), the monomer (c) and the monomer (d) in the monomer mixed solution is 20 to 60% by weight, preferably 30 to 50% by weight; the preferred time for the nitrogen purge is 1-2 hours.
Wherein the order of addition can have a significant impact on product performance. The feeding sequence can effectively avoid the following conditions to influence the product performance, such as partial monomer side reaction caused by high pH value, self-polymerization of partial monomer with low pH value of the system, and the like, thereby ensuring the product performance.
(iii) Adjusting the temperature of the monomer mixed solution to 40-75 ℃, preferably 50-60 ℃, and the pH value to 5-10, preferably 7-9; then adding an initiator, slowing down the stirring speed after the initiator is dissolved, and carrying out polymerization reaction for 0.2-4h, preferably 1-2h to obtain a gel product.
(iv) And (5) granulating, drying and crushing the gel product obtained in the step (iii) to obtain the calcium-resistant high-temperature-resistant drilling fluid filtrate reducer. Wherein the drying temperature is 60-120 deg.C, preferably 70-100 deg.C, and the drying time is 24-36 hr, preferably 24-30 hr.
In a third aspect, the present invention provides a random copolymer produced by the production process of the present invention. May have the structural units (A), (B), (C) and (D). As previously mentioned, are not described in detail.
In a fourth aspect, the present invention provides a use of the random copolymer of the invention in a drilling fluid.
According to the present invention, preferably, the random copolymer is added to the drilling fluid slurry as a fluid loss additive, and the amount of the random copolymer is 0.5 to 4g per 100mL of the drilling fluid slurry.
In a fifth aspect, the invention provides a drilling fluid comprising a random copolymer of the invention as a fluid loss additive and a slurry, wherein the amount of the random copolymer is 0.5 to 4g per 100mL of the slurry.
In the present invention, the drilling fluid may be a water-based drilling fluid. The slurry may contain components conventionally used in the art for water-based drilling fluids, such as, but not limited to, slurrying soils, pH adjusters, flow pattern adjusters, anti-sloughing agents, lubricants, weighting agents, and the like. The amount of the above components in the slurry can be any amount conventionally defined in the art relative to 100mL of water, such as 0.5-3g of slurrying soil, 1-4g of flow pattern regulator, 2-5g of anti-collapse agent, 2-5g of lubricant, and 0-140g of weighting agent (corresponding to a drilling fluid density of 1.0-2.0 g/cm)3Weighted with barite). The pH regulator controls the pH value of the drilling fluid to be 8-10.
The present invention will be described in detail below by way of examples.
The raw materials used in the following examples are as follows:
2-acrylamido-2-methylpropanesulfonic acid: shouguangrude chemical Co., Ltd;
acrylamide: jiangxi Changjiu agricultural chemical Co., Ltd.
Monomer (c):
n-glucose hydrochloride-based maleamic acid: adding 1.4mol of maleic anhydride into a dry three-neck round-bottom flask, dissolving 40mL of glacial acetic acid, slowly dripping the residual 40mL of glacial acetic acid solution dissolved with 1.0mol of glucosamine hydrochloride under the condition of stirring, stirring at 25 ℃ for reaction for 3h, after a white precipitate is generated, carrying out suction filtration-washing-suction filtration, drying to obtain white powder, and carrying out infrared neutralization1And analyzing an H-NMR spectrogram to obtain the N-glucose hydrochloride maleamic acid, and weighing to calculate that the yield is 77%. The product had a melting point of 171 ℃.
N-isopropanomaleamic acid: adding 1.2mol of maleic anhydride into a dry three-neck round-bottom flask, fully dissolving 50mL of glacial acetic acid, slowly dripping the residual 40mL of glacial acetic acid solution dissolved with 1.0mol of alpha-alanine under the stirring condition, slowly stirring at 30 ℃ for reaction for 3h, and gradually generating white precipitate. After the reaction is finished, carrying out suction filtration, washing, suction filtration again and vacuum drying to obtain the N-isopropyl acid maleamic acid, wherein the yield is 80% by weight;
n-ethanesulfonic maleic acid amide: 1.1mol of maleic anhydride is added into a dry three-neck round-bottom flask, 50mL of glacial acetic acid is added to be fully dissolved, and a solution of 1.0mol of aminoethanesulfonic acid dissolved in 35mL of glacial acetic acid is slowly added under stirring. The reaction was stirred at 35 ℃ for 3h and a white precipitate gradually formed. After the reaction is finished, carrying out suction filtration, washing, suction filtration again and vacuum drying to obtain the N-ethanesulfonic maleic acid amide acid, wherein the yield is 70% by weight.
Aqueous acryloyloxyethyltrimethyl ammonium chloride solution: 30% content, Shandong Xuxiang chemical Co., Ltd;
dimethyldiallylammonium chloride: TCI Corp;
ammonium persulfate: chemical agents corporation, national drug group;
sodium bisulfite: chemical agents corporation, national drug group;
sodium hydroxide: chemical agents corporation, national drug group;
ammonia water: chemical agents corporation, national drug group;
calcium chloride: chemical agents corporation, national drug group;
sodium bentonite: bentonite, Xiazijie, Xinjiang, Limited liability company;
calcium bentonite: hongyu Bentonite GmbH, Xuanhua county, Hebei.
The random copolymers obtained in the examples have the following structures13C-NMR、1H-NMR, element analysis, and analysis of the residue after separation of the polymerization product to determine the proportion of the unpolymerized monomer, thereby carrying out comprehensive analysis and determination; the content of each structure in the random copolymer is determined by feeding;
the apparent viscosity of the 1% random copolymer aqueous solution is measured by the method specified in ISO 10416:2008 "Recommended Practice for Laboratory Testing of Drilling Fluids".
Example 1
(1) Dissolving 9.7g of sodium hydroxide in 100g of water to obtain 109.7g of alkali liquor;
(2) 35g of acrylamide, 50g of 2-acrylamido-2-methylpropanesulfonic acid, 6g of N-glucose hydrochloride maleamic acid and 2g of dimethyldiallylammonium chloride are added into the alkali liquor respectively and dissolved uniformly. Introducing nitrogen for 0.5h to remove oxygen to obtain a monomer mixed solution, wherein the pH value is 8;
(3) adding 0.74g of initiator V-044 (azobisisobutyronitrile hydrochloride) into the monomer mixed solution at the temperature of 45 ℃ and under the condition of pH 8 to carry out free radical polymerization reaction for 1h to obtain a gel product;
(4) cutting and granulating the gel product, drying at 65 deg.C for 36h to obtain solid product, and pulverizing.
The obtained solid product was analyzed and determined to be a random copolymer having the following structural composition,
Figure BDA0001998595280000221
wherein M is1And M2Is Na. ComprisesThe apparent viscosity of a 1% by weight aqueous solution of the random copolymer was 30 mPa.s.
Based on the charge calculation, the content of the structural unit (a) was 35.5% by weight, the content of the structural unit (B) was 56.7% by weight, the content of the structural unit (C) was 6.09% by weight, and the content of the structural unit (D) was 2.03% by weight in the random copolymer.
Example 2
(1) Adding 8.7g of sodium hydroxide into 100g of water, stirring and uniformly dissolving to obtain 108.7g of alkali liquor;
(2) respectively adding 42g of acrylamide, 45g of 2-acrylamido-2-methylpropanesulfonic acid, 7g of N-isopropenylmaleamic acid and 5g of dimethyldiallylammonium chloride into the alkali liquor, uniformly dissolving, introducing nitrogen for 0.5h, and removing oxygen to obtain a monomer mixed solution, wherein the pH value is 9;
(3) adding 0.74g of APS (ammonium persulfate) and 0.66g of sodium bisulfite into the monomer mixed solution at the temperature of 50 ℃ and under the condition of pH 7, and carrying out free radical polymerization reaction for 1.5h to obtain a gel-like product;
(4) shearing and granulating the gel product, drying at 70 deg.C for 24 hr to obtain solid product, and pulverizing.
The obtained solid product was analyzed and determined to be a random copolymer having the following structural composition,
Figure BDA0001998595280000231
wherein M is1、M2And M3Is Na. The apparent viscosity of an aqueous solution containing 1% by weight of the random copolymer was 22 mPa.s.
In the random copolymer, the content of the structural unit (a) was 40.4% by weight, the content of the structural unit (B) was 48.1% by weight, the content of the structural unit (C) was 6.7% by weight, and the content of the structural unit (D) was 4.8% by weight.
Example 3
(1) Adding 10.6g of sodium hydroxide into 100g of water, stirring and uniformly dissolving to obtain 110.6g of alkali liquor;
(2) respectively adding 40g of acrylamide, 55g of 2-acryloyloxy-2-methylpropanesulfonic acid, 3g of N-ethanesulfonic maleic acid amide acid and 6.7g of 30 wt% acryloyloxyethyltrimethyl ammonium chloride aqueous solution into the alkali liquor, uniformly dissolving, introducing nitrogen for 0.5h, and removing oxygen to obtain a monomer mixed solution, wherein the pH value is 7;
(3) adding 0.20g of ammonium persulfate and 0.30g of tetramethylethylenediamine into the monomer mixed solution at the temperature of 40 ℃ and the pH value of 7, and carrying out free radical polymerization for 1.5h to obtain a gel-like product;
(4) cutting and granulating the gel product, drying at 105 deg.C for 24 hr to obtain solid product, and pulverizing.
The obtained solid product was analyzed and determined to be a random copolymer having the following structural composition,
Figure BDA0001998595280000241
wherein M is1、M2And M5Is Na. The apparent viscosity of an aqueous solution containing 1% by weight of the random copolymer was 18 mPa.s.
The content of the structural unit (a) was 36.1% by weight, the content of the structural unit (B) was 55.1% by weight, the content of the structural unit (C) was 2.7% by weight, and the content of the structural unit (D) was 6.1% by weight.
Example 4
(1) Adding 11g of potassium hydroxide into 100g of water, stirring and uniformly dissolving to obtain 111g of alkali liquor;
(2) respectively adding 44g of acrylamide, 40g of 2-acrylamido-2-methylpropanesulfonic acid, 2g of N-isopropenylmaleamic acid and 26.7g of 30 wt% of acryloyloxyethyltrimethyl ammonium chloride aqueous solution into alkali liquor, uniformly dissolving, introducing nitrogen for 0.5h, and removing oxygen to obtain a monomer mixed solution, wherein the pH value is 9;
(3) adding 0.5g of initiator V-044 (azobisisobutyrimidazoline hydrochloride) into the monomer mixed solution at the temperature of 50 ℃ and under the condition that the pH value is 9, and carrying out free radical polymerization reaction for 0.5h to obtain a gel product;
(4) shearing and granulating the gel product, drying at 65 ℃ for 30h to obtain a solid product, and crushing.
The obtained solid product was analyzed and determined to have a random structure compositionA copolymer of a monomer and a monomer,
Figure BDA0001998595280000251
wherein M is1、M2And M3Is K. The apparent viscosity of an aqueous solution containing 1% by weight of the random copolymer was 37 mPa.s.
The content of the structural unit (a) was 43.3% by weight, the content of the structural unit (B) was 46.8% by weight, the content of the structural unit (C) was 1.97% by weight, and the content of the structural unit (D) was 7.88% by weight.
Comparative example 1
The procedure of example 1 was followed except that, in step (2), "35 g of acrylamide, 50g of 2-acrylamido-2-methylpropanesulfonic acid, 2g of dimethyldiallylammonium chloride" was added instead of "35 g of acrylamide, 50g of 2-acrylamido-2-methylpropanesulfonic acid, 6g of N-glucuronometallate maleamic acid, 2g of dimethyldiallylammonium chloride". And carrying out free radical polymerization reaction.
The obtained solid product was analyzed to determine that the polymerization reaction product was a random copolymer having the following structure,
Figure BDA0001998595280000252
wherein M is1Is Na. The apparent viscosity of an aqueous solution containing 1% by weight of the random copolymer was 41 mPa.s.
Based on the charge, the content of the structural unit (A) in the random copolymer was 37.8% by weight, the content of the structural unit (B) was 60.02% by weight, and the content of the structural unit (D) was 2.17% by weight.
Comparative example 2
The procedure of example 2 was followed except that in step (2) 42g of acrylamide, 45g of 2-acrylamido-2-methylpropanesulfonic acid, 5g of dimethyldiallylammonium chloride were "added instead" were added 42g of acrylamide, 45g of 2-acrylamido-2-methylpropanesulfonic acid, 7g of N-isopropanoylmaleamic acid, 5g of dimethyldiallylammonium chloride ". And carrying out free radical polymerization reaction.
The obtained solid product was analyzed to confirm that the polymerization reaction product was random having the following structureA copolymer of a monomer and a monomer,
Figure BDA0001998595280000261
wherein M is1Is Na. The apparent viscosity of an aqueous solution containing 1% by weight of the random copolymer was 33 mPa.s.
Based on the charge, the content of the structural unit (A) in the random copolymer was 43.3% by weight, the content of the structural unit (B) was 51.5% by weight, and the content of the structural unit (D) was 5.2% by weight.
Comparative example 3
The procedure of example 3 was followed except that "40 g of acrylamide, 55g of 2-acryloyloxy-2-methylpropanesulfonic acid, 6.7g of a 30% by weight aqueous solution of acryloyloxyethyltrimethylammonium chloride" was added in place of "40 g of acrylamide, 55g of 2-acryloyloxy-2-methylpropanesulfonic acid, 3g of N-ethanesulfonic maleamic acid, 6.7g of a 30% by weight aqueous solution of acryloyloxyethyltrimethylammonium chloride" in step (2). And carrying out free radical polymerization reaction.
The obtained solid product was analyzed to determine that the polymerization reaction product was a random copolymer having the following structure,
Figure BDA0001998595280000271
wherein M is1Is Na. The apparent viscosity of an aqueous solution containing 1% by weight of the random copolymer was 27 mPa.s.
Based on the charge, the content of the structural unit (A) in the random copolymer was 38.8% by weight, the content of the structural unit (B) was 59.24% by weight, and the content of the structural unit (D) was 1.94% by weight.
Comparative example 4
The procedure of example 4 was followed except that in step (2) "44 g of acrylamide, 40g of 2-acrylamido-2-methylpropanesulfonic acid, 26.7g of a 30% by weight aqueous solution of acryloyloxyethyltrimethylammonium chloride" were added instead of "44 g of acrylamide, 40g of 2-acrylamido-2-methylpropanesulfonic acid, 2g of N-isopropanoylmaleamic acid, 26.7g of a 30% by weight aqueous solution of acryloyloxyethyltrimethylammonium chloride". And carrying out free radical polymerization reaction.
The obtained solid product was analyzed to determine that the polymerization reaction product was a random copolymer having the following structure,
Figure BDA0001998595280000272
wherein M is1Is K. The apparent viscosity of an aqueous solution containing 1% by weight of the random copolymer was 39 mPa.s.
Based on the charge calculation, the content of the structural unit (a) was 44.2% by weight, the content of the structural unit (B) was 47.8% by weight, and the content of the structural unit (D) was 8.0% by weight in the random copolymer.
Comparative example 5
The procedure of example 1 was followed except that in step (2) "35 g of acrylamide, 50g of 2-acrylamido-2-methylpropanesulfonic acid, 6g of N-glucuronometallate maleamic acid" was added instead of "35 g of acrylamide, 50g of 2-acrylamido-2-methylpropanesulfonic acid, 6g of N-glucuronometallate maleamic acid, 2g of dimethyldiallylammonium chloride". And carrying out free radical polymerization reaction.
The obtained solid product was analyzed to determine that the polymerization reaction product was a random copolymer having the following structure,
Figure BDA0001998595280000281
wherein M is1And M2Is Na. The apparent viscosity of an aqueous solution containing 1% by weight of the random copolymer was 36 mPa.s.
Based on the charge calculation, the content of the structural unit (A) was 36.3% by weight, the content of the structural unit (B) was 57.5% by weight, and the content of the structural unit (C) was 6.2% by weight in the random copolymer.
Evaluation of drilling fluid Properties
The random copolymers prepared in examples 1 to 4 and comparative examples 1 to 5 were added to different base stocks for evaluation of drilling fluid properties, and the test results are shown in Table 1.
1. Preparing base slurry:
(1) high calcium bentonite brine-based slurry: adding 300mL of tap water into a high-speed stirring cup, adding 9g of sodium bentonite and 1.05g of sodium carbonate under high-speed stirring, and fully stirring for 20min, oftenStanding at warm temperature for hydration for 24h, adding 24g calcium chloride under high speed stirring, further stirring at high speed for 20min, standing for hydration for 4h to obtain high calcium bentonite saline-based slurry (calcium ion content is 2.88 × 10)4mg/L)。
(2) High salinity composite brine-based slurry: 350mL of tap water was added to the high speed stirring cup, and 23.63g of NaCl and 2.63g of CaCl were added with high speed stirring26.9g of MgCl2·6H2O, stirring at high speed for 5min, and adding 3.15g of Na2CO3Mixing with 52.5g of calcium bentonite, stirring at high speed for 20min, standing, and hydrating for 24 hr to obtain highly mineralized composite saline water-based slurry (total mineralized degree 32.64 × 10)4mg/L, wherein the content of calcium ions is 9480 mg/L).
2. And (3) performance testing:
and stirring the pre-hydrated base slurry at a high speed for 20min, loading the mixture into a high-temperature aging tank, performing hot roll aging at 150 ℃ for 16h, and testing readings at 600 revolutions and 300 revolutions and medium-pressure water loss on a six-speed viscometer to obtain the base slurry performance.
0.9 weight percent or 1.2 weight percent of the samples of the examples and the comparative examples are respectively added into the high-calcium bentonite saline-based slurry and the high-salinity composite saline-based slurry which are pre-hydrated, stirred at a high speed for 30min, filled into a high-temperature aging tank after ensuring that the samples are fully dissolved, thermally rolled and aged at 150 ℃ for 16h, and the viscosity and the filtration performance of the samples are measured (the test method of the filtration performance refers to ISO 10416:2008 Recommended Practice for Laboratory Testing of Drilling Fluids).
TABLE 1
Figure BDA0001998595280000291
Experimental results show that the filtrate reducer has excellent calcium-resistant temperature-resistant filtrate-reducing performance, and when the dosage of bentonite brine slurry containing high calcium chloride is 0.9 wt%, the slurry water loss is reduced to within 12mL from 206mL when the filtrate reducer is not added after rolling aging at 150 ℃ for 16 h. When the dosage of the high salinity composite brine slurry is 1.2 weight percent, the slurry water loss is reduced to less than 10mL from 170mL without adding the fluid loss additive after rolling aging at 150 ℃ for 16 h. The calcium-resistant high-temperature-resistant drilling fluid filtrate reducer has a good gel protection effect under the condition of high-concentration calcium ions, can form a filter cake with low permeability, flexibility, thinness and compactness, reduces the filtrate loss of the drilling fluid containing high calcium ions, and can be used for a high-calcium salt drilling fluid system at high temperature (150 ℃).
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims (21)

1. A random copolymer comprising a structural unit (A) represented by the formula (1), a structural unit (B) represented by the formula (2), a structural unit (C) represented by the formula (3), and a structural unit (D) represented by the formula (4) and/or the formula (5),
Figure FDA0003495581090000011
wherein R is1And R2Each independently is H or C1-C6Alkyl of R3And R4Each independently is H or C1-C3Alkyl groups of (a);
Figure FDA0003495581090000012
wherein R is5is-O-R-or-NH-R-, wherein R is-CmH2m-, and M is 4, 5 or 6, M1Is H, NH4Na or K;
Figure FDA0003495581090000013
wherein R is6Is selected from
Figure FDA0003495581090000014
Figure FDA0003495581090000015
M2-M6Each independently is H, NH4Na or K;
Figure FDA0003495581090000021
wherein R is7And R8Each independently is H or C1-C6Alkyl of R9is-CnH2n-, and n is an integer of 2 to 6, R10Is composed of
Figure FDA0003495581090000022
Figure FDA0003495581090000023
X is halogen;
wherein an aqueous solution of the random copolymer having a concentration of 1% by weight has an apparent viscosity of 10 to 40 mPas.
2. The random copolymer according to claim 1, wherein the random copolymer comprises 30 to 50% by weight of the structural unit (A), 40 to 60% by weight of the structural unit (B), 2 to 10% by weight of the structural unit (C) and 1 to 10% by weight of the structural unit (D), based on the total amount of the random copolymer.
3. The random copolymer according to claim 2, wherein the random copolymer comprises 35 to 45% by weight of the structural unit (A), 45 to 55% by weight of the structural unit (B), 3 to 8% by weight of the structural unit (C) and 2 to 6% by weight of the structural unit (D).
4. The random copolymer according to any one of claims 1 to 3,
r in the formula (1)1-R4Is H; r in the formula (2)5is-O-C (CH)3)2-CH2-or-NH-C(CH3)2-CH2-；
In the formula (3), R6Is composed of
Figure FDA0003495581090000031
R in the formula (4)7And R8Each independently is H or methyl, R9is-CH2CH2-; in the formula (5), X is Cl.
5. A method of making a random copolymer comprising:
carrying out free radical copolymerization on a monomer (a) shown in a formula (6), a monomer (b) shown in a formula (7), a monomer (c) shown in a formula (8) and a monomer (d) shown in a formula (9) and/or a formula (10) under the protection of nitrogen and in the presence of an initiator;
Figure FDA0003495581090000032
wherein R is1And R2Each independently is H or C1-C6Alkyl of R3And R4Each independently is H or C1-C3Alkyl groups of (a);
Figure FDA0003495581090000033
wherein R is5is-O-R-or-NH-R-, wherein R is-CmH2m-, and m is 4, 5 or 6;
Figure FDA0003495581090000034
wherein R is6Is selected from
Figure FDA0003495581090000035
Figure FDA0003495581090000041
Figure FDA0003495581090000042
Wherein R is7And R8Each independently is H or C1-C6Alkyl of R9is-CnH2n-, and n is an integer of 2 to 6, R10Is composed of
Figure FDA0003495581090000043
Figure FDA0003495581090000044
X is halogen.
6. The production method according to claim 5, wherein each monomer is used in an amount of: 20-50 parts by weight of monomer (a), 40-70 parts by weight of monomer (b), 1-10 parts by weight of monomer (c) and 0.5-8 parts by weight of monomer (d).
7. The production method according to claim 6, wherein each monomer is used in an amount of: 35-42 parts of monomer (a), 45-55 parts of monomer (b), 3-7 parts of monomer (c) and 1-5 parts of monomer (d).
8. The process according to claim 7, wherein R in the formula (6)1-R4Is H; r in the formula (7)5is-O-C (CH)3)2-CH2-or-NH-C (CH)3)2-CH2-; in the formula (8), R6Is composed of
Figure FDA0003495581090000051
R in the formula (9)7And R8Each independently is H or methyl, R9is-CH2CH2-; in the formula (10), X is Cl.
9. The production method according to any one of claims 5 to 8, wherein the initiator is selected from an oxidation-reduction initiator and/or an azo-type initiator.
10. The production method according to claim 9, wherein the oxidation-reduction initiator includes at least one of ammonium persulfate, potassium persulfate, and hydrogen peroxide, and sodium hydrogen sulfite, or includes ammonium persulfate and/or potassium persulfate, and an organic amine; the organic amine is tetramethyl ethylene diamine and/or tetramethyl-1, 3-propane diamine;
the azo initiator is a water-soluble azo initiator.
11. The production method according to claim 10, wherein the azo-type initiator is azobisisobutyrimidazoline hydrochloride or azobisisobutyramidine hydrochloride.
12. The method according to any one of claims 5 to 8, wherein the initiator is used in a total amount of 0.1 to 1.6% by weight based on the total weight of all monomers.
13. The method of claim 12, wherein the total amount of the initiator is 0.3 to 1.5 wt% based on the total weight of all the monomers.
14. The production method according to any one of claims 5 to 8, wherein the manner of subjecting the monomer (a), the monomer (b), the monomer (c), and the monomer (d) to radical copolymerization includes:
adding the monomer into alkali liquor to be uniformly dissolved, and introducing nitrogen to remove oxygen to obtain a monomer mixed solution;
adjusting the temperature of the monomer mixed solution to 40-75 ℃ and the pH value to 5-10; then adding the initiator to initiate the copolymerization reaction for 0.2-4h to obtain a gel-like product;
the gel-like product is granulated, dried and pulverized.
15. The production method according to claim 14, wherein the total weight concentration of the monomer (a), the monomer (b), the monomer (c), and the monomer (d) in the monomer mixed solution is 20 to 60% by weight.
16. The production method according to claim 15, wherein the total weight concentration of the monomer (a), the monomer (b), the monomer (c), and the monomer (d) in the monomer mixed solution is 30 to 50% by weight.
17. The method of claim 14, wherein the drying temperature is 60-120 ℃; the drying time is 24-36 h.
18. The method of claim 17, wherein the drying temperature is 70-100 ℃; the drying time is 24-30 h.
19. Use of a random copolymer according to any one of claims 1 to 4 in a drilling fluid.
20. Use according to claim 19, wherein the random copolymer is added to a drilling fluid slurry as a fluid loss additive, in an amount of from 0.5 to 4g per 100mL of drilling fluid slurry.
21. A drilling fluid comprising the random copolymer according to any one of claims 1 to 4 as a fluid loss additive and a slurry, wherein the amount of the random copolymer is 0.5 to 4g per 100mL of the slurry.
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