High-temperature-resistant environment-friendly viscosity reducer, preparation method and application thereof

Abstract

The application discloses an anti-high-temperature environment-friendly viscosity reducer, belongs to the technical field of drilling fluid treating agents, and particularly relates to an anti-high-temperature environment-friendly viscosity reducer and a preparation method and application thereof. The anti-high-temperature environment-friendly viscosity reducer is prepared from raw materials including sulfonic acid group-containing raw material I, phenolic hydroxyl group-containing raw material II and carboxyl group-containing monomer A. The carboxyl group-containing monomer A includes monomer A1 shown in formula I and monomer A2 shown in formula II. The anti-high-temperature environment-friendly viscosity reducer is mainly composed of two kinds of natural degradable materials (lignosulfonate and procyanidine) to ensure that the product is non-toxic, easy to degrade, environment-friendly, has excellent viscosity reducing performance in a high-temperature environment and a high-density drilling fluid, has a temperature resistance of 180 DEG C, and has a viscosity reduction rate of more than 70% in a bentonite-based slurry with a density of 2.2 g / cm 3 , a biological toxicity of 100000 mg / L-140000 mg / L and a biological degradation rate BOD5 / COD Cr of 0.22-0.29.

Description

Technical Field

[0001] This invention relates to the field of drilling fluid treatment agents, specifically to a high-temperature resistant, environmentally friendly viscosity reducer, its preparation method, and its application. Background Technology

[0002] In the late 1930s, inorganic phosphates began to be used abroad to control the viscosity of drilling fluids. In the 1940s, tannins were widely used as drilling fluid viscosity reducers. From the 1960s onwards, iron-chromium lignin sulfonate (FCLS) became the main drilling fluid viscosity reducer. After the 1990s, due to the increasing environmental awareness worldwide, the application of FCLS, which is harmful to human health and the environment, was restricted. Researchers abroad began to develop chromium-free lignin sulfonate and tannin-based viscosity reducers. In recent years, international research has focused on anionic polymer viscosity reducers using maleic anhydride (MA), sodium allyl sulfonate (AS), and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) as raw materials, as well as zwitterionic polymer viscosity reducers with cationic groups and organophosphate viscosity reducers.

[0003] In recent years, domestic research on drilling fluid viscosity reducers has also mainly focused on synthetic polymers and the modification of natural polymer materials. In the area of ​​synthetic polymers, Huang Jinjun et al. prepared an amphoteric viscosity reducer, THIN, using acrylic acid, sodium propylene sulfonate, AMPS, and cationic monomers as raw materials. THIN exhibits excellent temperature resistance up to 220℃, good salt and calcium resistance, and a viscosity-reducing effect superior to traditional drilling fluid viscosity reducers XY-27 and FCLS.

[0004] Wang Zhonghua et al. synthesized an AMPS / DMAM / AM copolymer drilling fluid viscosity reducer using AMPS, acrylamide, and NN-dimethylacrylamide as raw materials and an oxidation-reduction initiation system. The viscosity reducer has good viscosity reduction and temperature and salt resistance, with a temperature resistance up to 210℃.

[0005] Hu Caizhi et al. prepared an AA-IPPA copolymer using acrylic acid and isopropylphosphonic acid (IPPA), which exhibited good viscosity-reducing properties and temperature resistance up to 200℃. Long Zhu et al. developed a method for synthesizing drilling fluid viscosity reducers using AMPS, AA, and DMDAAC from alkaline pulping waste liquid as raw materials, with the product achieving temperature resistance up to 150℃.

[0006] Luo Yue et al. synthesized sulfonated styrene-maleic anhydride polymer (SSMA) using toluene and acetone as solvents and styrene and maleic anhydride as main raw materials. The viscosity reduction rate was over 40%, and the temperature resistance was 150℃.

[0007] Liao Jiuming et al. prepared a novel organophosphorus viscosity reducer using poly(1,3-diamino-2-hydroxypropane) and hydroxymethylphosphine as raw materials. Its temperature and salt resistance properties are superior to those of FCLS.

[0008] Shao Hui et al. prepared a non-toxic, easily degradable green viscosity reducer using L-aspartic acid as a raw material, and achieved a good viscosity reduction effect, but the temperature resistance was only 120℃.

[0009] In the field of natural polymer modification, Wang Song et al. prepared a viscosity reducer PNK by graft copolymerization of lignin sulfonate and acrylamide, followed by metal ion complexation and sulfonation treatment, which has a temperature resistance of over 200℃.

[0010] Wei Xiaoming et al. synthesized MGAC-1, a lignin-based viscosity reducer, through a series of modification reactions, including condensation of lignin sulfonate with formaldehyde, graft copolymerization, and metal ion complexation. The MGAC-1 has a temperature resistance of up to 180℃.

[0011] Wang Zhonghua et al. prepared a tannic acid graft copolymer by graft copolymerization of AMPS and AA using tannic acid as raw material. The temperature resistance can reach above 160℃.

[0012] Zhang Jianyun et al. used tararatanin, an extract from tarara pod powder, which was then sulfonated and Fe... 2+ SMT-T, a viscosity reducer, was prepared by complexation, and its viscosity reduction rate can reach more than 84% at 180℃-1220℃.

[0013] Zhang Liming et al. crosslinked lignin sulfonic acid and tannin extracts with formaldehyde, and the product reacted with Fe... 2+ The complexation process forms FTLS, a drilling fluid viscosity reducer, which has better viscosity reduction performance and temperature and salt resistance compared to traditional FCLS.

[0014] It is evident that existing drilling fluid viscosity reducers, both domestically and internationally, are mainly classified into two categories: synthetic polymers and modified natural polymers. Among them, synthetic polymer viscosity reducers possess excellent temperature resistance but are difficult to degrade, thus lacking environmental friendliness. Modified polymer viscosity reducers, by grafting a large number of acrylamide polymer monomers onto natural polymers such as lignin, improve temperature resistance but also sacrifice some environmental performance.

[0015] Furthermore, due to the extremely high density of solid particles in high-density drilling fluids, a network structure is formed between bentonite and barite particles, making it difficult for existing drilling fluid viscosity reducers to exert their full effect in high-density drilling fluids.

[0016] In summary, current drilling fluid high-temperature viscosity reducers suffer from insufficient environmental friendliness. Synthetic polymer viscosity reducers themselves have high temperature resistance, but poor biodegradability and high cost. Modified natural macromolecular viscosity reducers such as modified lignin and modified humic acid are grafted with a large number of acrylamide polymer monomers to improve temperature resistance, which also results in insufficient environmental friendliness.

[0017] Therefore, the purpose of this invention is to develop a drilling fluid viscosity reducer that is resistant to high temperatures, environmentally friendly, and can perform well in high-density drilling fluids. Summary of the Invention

[0018] This invention addresses the problems of insufficient environmental friendliness and inability to perform well in high-density drilling fluids by existing high-temperature viscosity reducers. It provides a high-temperature resistant and environmentally friendly drilling fluid viscosity reducer that can effectively reduce viscosity in high-density drilling fluids and at high-temperature wellbore environments. This viscosity reducer is non-toxic, easily degradable, and will not harm the environment.

[0019] Through extensive research, the inventors of this invention discovered that by moderately crosslinking lignin sulfonates rich in sulfonic acid groups with proanthocyanidins rich in phenolic hydroxyl groups, and then grafting and chelating a small amount of vinyl monomers containing carboxyl groups, the synthesized product can simultaneously possess temperature resistance, adsorption, dispersibility, and environmental friendliness, making it particularly suitable as a high-temperature resistant and environmentally friendly viscosity reducer for water-based drilling fluids. This led to the completion of this invention.

[0020] To solve the above-mentioned technical problems, the first aspect of the present invention provides a high-temperature resistant and environmentally friendly viscosity reducer, the raw materials for which include raw material I containing sulfonic acid groups, raw material II containing phenolic hydroxyl groups, and monomer A containing carboxyl groups; wherein the monomer A containing carboxyl groups includes monomer A1 represented by formula I and monomer A2 represented by formula II;

[0021]

[0022] In Formula I, R1 and R2 may be the same or different, and are independently selected from hydrogen, C1-C 20 Alkyl group; preferably, R1 and R2 may be the same or different, each independently selected from hydrogen, C1-C2. 10 Alkyl; more preferably, R1 and R2 may be the same or different, each independently selected from hydrogen, C1-C 10 Straight-chain alkyl, C3-C 10 Branched alkyl; more preferably, R1 and R2 may be the same or different, each independently selected from hydrogen, methyl, ethyl, or ethylpropyl;

[0023] In Formula II, R3 and R4 may be the same or different, and each is independently selected from hydrogen, C1-C 20 Alkyl group; preferably, R3 and R4 may be the same or different, each independently selected from hydrogen, C1-C4. 10 Alkyl groups; more preferably, R3 and R4 may be the same or different, each independently selected from hydrogen, C1-C4. 10 Straight-chain alkyl, C3-C 10 Branched alkyl; more preferably, R3 and R4 may be the same or different, each independently selected from hydrogen, methyl, ethyl, and ethylpropyl.

[0024] According to some embodiments of the present invention, the mass ratio of the sulfonic acid-containing raw material I to the phenolic hydroxyl-containing raw material II is 1:(0.25-4), preferably 1:(0.5-2), for example 1:0.25, 1:1, 1:0.4.

[0025] According to some embodiments of the present invention, the mass ratio of the carboxyl-containing monomer A to the total mass of the sulfonic acid-containing raw material I and the phenolic hydroxyl-containing raw material II is 1:(5-10), preferably 1:(6-9), more preferably 1:(7-8); for example 1:5, 1:10.

[0026] According to some embodiments of the present invention, the mass ratio of monomer A1 to monomer A2 is 1:(0.5-1), preferably 1:(0.6-0.9), more preferably 1:(0.7-0.8), for example 1:0.43, 1:1, 1:2.3.

[0027] According to some embodiments of the present invention, the sulfonic acid-containing raw material I is selected from lignin sulfonate; preferably, the lignin sulfonate is selected from at least one of sodium lignin sulfonate, potassium lignin sulfonate, and calcium lignin sulfonate.

[0028] According to some embodiments of the present invention, the phenolic hydroxyl-containing raw material II is selected from proanthocyanidins; preferably, the proanthocyanidins are extracted from at least one of grapes, hawthorn, peanuts, ginkgo, cypress, cliff cypress, blueberries and black beans.

[0029] According to some embodiments of the present invention, the degree of sulfonation of the lignin sulfonate is 0.3 to 1.0, preferably 0.6 to 1.0, more preferably 0.8 to 1.0, for example 0.6 or 0.8.

[0030] According to some embodiments of the present invention, the weight-average molecular weight of the lignin sulfonate is 2000-12000, preferably 4000-10000, more preferably 6000-8000, for example 4000 or 8000.

[0031] According to some embodiments of the present invention, the weight-average molecular weight of the proanthocyanidins is 500-3000, preferably 1000-2000, more preferably 1500-2000, for example 1500 or 3000.

[0032] A second aspect of the present invention provides a method for preparing the above-mentioned high-temperature resistant and environmentally friendly viscosity reducer, comprising the following steps:

[0033] 1) Mix raw material I containing sulfonic acid groups, raw material II containing phenolic hydroxyl groups, and water to obtain a mixed solution. In the presence of a crosslinking agent, carry out the first reaction to obtain the first product.

[0034] 2) In the presence of an initiator, the first product obtained in step 1) is mixed with a carboxyl-containing monomer A to carry out a second reaction to obtain the high-temperature resistant and environmentally friendly viscosity reducer.

[0035] According to some embodiments of the present invention, in step 1), the crosslinking agent is selected from aldehyde crosslinking agents; preferably, the aldehyde crosslinking agent is selected from at least one of formaldehyde, acetaldehyde, and glyoxal.

[0036] According to some embodiments of the present invention, in step 1), the mass ratio of the crosslinking agent to the total weight of raw material I containing sulfonic acid groups and raw material II containing phenolic hydroxyl groups is 1:(10-30), preferably 1:(15-25), and more preferably 1:(18-22).

[0037] According to some embodiments of the present invention, in step 1), the water is selected from tap water, deionized water, or distilled water.

[0038] According to some embodiments of the present invention, in step 1), the total mass concentration of raw material I containing sulfonic acid groups and raw material II containing phenolic hydroxyl groups in the mixed solution is 10% to 40%, preferably 20% to 30%.

[0039] According to some embodiments of the present invention, in step 1), the pH of the mixed solution is adjusted to 3-11, preferably 4-10, more preferably 7-9; preferably, the pH adjuster of the mixed solution is selected from alkali metal hydroxides; more preferably, the alkali metal hydroxide is selected from at least one of sodium hydroxide and potassium hydroxide.

[0040] According to some embodiments of the present invention, in step 1), the conditions of the first reaction include: a temperature of 60°C to 100°C, preferably 70°C to 90°C, more preferably 75°C to 85°C, a time of 2h to 4h, and a stirring rate of 100r / min to 300r / min, preferably 150r / min to 250r / min, for example 200r / min.

[0041] According to some embodiments of the present invention, in step 2), the initiator is selected from at least one of cerium ammonium nitrate, potassium persulfate, and ammonium persulfate.

[0042] According to some embodiments of the present invention, in step 2), the mass ratio of the initiator to the carboxyl-containing monomer A is 1:(100-600), preferably 1:(200-500), more preferably 1:(300-400), for example 1:312.5.

[0043] According to some embodiments of the present invention, in step 2), the conditions of the second reaction include: a reaction temperature of 60°C to 100°C, preferably 70°C to 90°C, more preferably 75°C to 85°C, a time of 4h to 6h, and a stirring rate of 100r / min to 300r / min, preferably 150r / min to 250r / min, for example 200r / min.

[0044] According to some embodiments of the present invention, in step 2), drying and pulverizing are further included after the second reaction; preferably, the drying conditions include: a reaction temperature of 80°C and a time of 24 hours.

[0045] According to some embodiments of the present invention, the biotoxicity of the high-temperature resistant and environmentally friendly viscosity reducer is 100,000 mg / L to 140,000 mg / L, preferably 120,000 to 14,000 mg / L, and the biodegradability rate is BOD5 / COD. Cr The value is 0.22 to 0.29, preferably 0.27 to 0.29.

[0046] A third aspect of the present invention provides the application of the above-mentioned high-temperature resistant and environmentally friendly viscosity reducer in drilling fluid, preferably water-based drilling fluid; preferably, the amount of the high-temperature resistant and environmentally friendly viscosity reducer added to the water-based drilling fluid is 1wt% to 4wt%, with water as 100%.

[0047] Beneficial effects:

[0048] The high-temperature resistant and environmentally friendly viscosity reducer of this invention uses two natural biodegradable materials (lignin sulfonate and proanthocyanidins) as the main structural components of the product, ensuring that the product is non-toxic, easily degradable, and environmentally friendly.

[0049] In this invention, lignin sulfonate is rich in sulfonic acid groups, which can enable the product to form a thick hydration layer on the bentonite surface of the drilling fluid, thereby breaking down the bentonite network structure and reducing the viscosity of the drilling fluid; proanthocyanidins are rich in phenolic hydroxyl groups, which endow the product with strong adsorption on the bentonite surface and make it difficult to desorb at high temperatures; by organically combining these two raw materials, this invention enables the product to have both excellent viscosity reduction and adsorption properties.

[0050] This invention achieves a more robust molecular framework through cross-linking between lignin sulfonate and proanthocyanidin molecules, thereby further improving the product's temperature resistance.

[0051] This invention further improves the temperature and salt resistance and enhances the adsorption performance on the bentonite surface by grafting and copolymerizing two cross-linked natural macromolecules with two vinyl monomers.

[0052] The high-temperature resistant and environmentally friendly viscosity reducer described in this invention exhibits excellent viscosity-reducing performance in high-temperature environments and high-density drilling fluids, with a temperature resistance up to 180℃ and a viscosity of 2.2 g / cm³.3 The density of bentonite-based slurry has a viscosity reduction rate of over 70%, and its biotoxicity ranges from 100,000 mg / L to 140,000 mg / L. Its biodegradability is high, with a BOD5 / COD ratio of [missing information]. Cr The value ranges from 0.22 to 0.29. Detailed Implementation

[0053] The present invention will be further described below with reference to embodiments. However, the present invention is not limited to these embodiments.

[0054] The grape seed extract used in this invention was purchased from Shandong Gushuo Biotechnology Co., Ltd., with a weight-average molecular weight of 1500.

[0055] The hawthorn extract used in this invention was purchased from Shandong Gushuo Biotechnology Co., Ltd., with a weight-average molecular weight of 3000.

[0056] In this invention, sodium lignosulfonate was purchased from Shanghai Wai Dian International Trade Co., Ltd., with a weight-average molecular weight of 4000 and a sulfonation degree of 0.6, or a weight-average molecular weight of 8000 and a sulfonation degree of 0.8.

[0057] In this invention, the formaldehyde was purchased from Tianjin Huakun Chemical Co., Ltd., and its concentration was 36%.

[0058] The acrylic acid used in this invention was purchased from Shandong Mingyue Chemical Co., Ltd., and its purity was 99%.

[0059] The maleic acid used in this invention was purchased from Shandong Huian Chemical Co., Ltd., with a purity of 99%.

[0060] In this invention, the bentonite used for drilling fluid test slurry preparation was purchased from Bohai Drilling Engineering Co., Ltd. of China National Petroleum Corporation, and the specification or model is calcium bentonite for drilling fluid slurry preparation.

[0061] The biotoxicity EC of the high-temperature resistant and environmentally friendly viscosity reducer in this invention 50 The testing was conducted in accordance with SY / T6787-2010 "Technical Requirements for Environmental Protection of Water-Soluble Oilfield Chemical Agents".

[0062] The biodegradability rate (BOD5 / COD) of the high-temperature resistant and environmentally friendly viscosity reducer in this invention is [not specified]. Cr The testing was conducted in accordance with SY / T6787-2010 "Technical Requirements for Environmental Protection of Water-Soluble Oilfield Chemical Agents".

[0063] The six-speed rotational viscometer used in this invention was purchased from Qingdao Haitongda Special Instruments Co., Ltd., and its specification / model is ZNN-D6.

[0064] The roller heating furnace used in this invention was purchased from Qingdao Haitongda Special Instrument Co., Ltd., and its specification / model is XGRL-5.

[0065] Example 1

[0066] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0067] The preparation method is as follows:

[0068] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 12.5 kg of proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0069] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0070] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid, and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A1.

[0071] Biotoxicity EC of sample A1 50 The concentration was 135100 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.28.

[0072] Example 2

[0073] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0074] The preparation method is as follows:

[0075] 1) Add 20 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 5 kg of grape seed proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0076] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0077] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid, and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A2.

[0078] Biotoxicity EC of sample A2 50 The concentration was 124,700 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.27.

[0079] Example 3

[0080] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0081] The preparation method is as follows:

[0082] 1) Add 5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 20 kg of grape seed proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0083] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0084] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A3.

[0085] Biotoxicity EC of sample A3 50 The concentration was 130,400 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.27.

[0086] Example 4

[0087] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0088] The preparation method is as follows:

[0089] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 12.5 kg of grape seed proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0090] 2) Heat the mixed solution from step 1) to 80°C using a constant temperature water bath, then add 6.94g of formaldehyde (36% concentration), and stir the mixture at 200r / min for 2h at 80°C.

[0091] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid, and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A4.

[0092] Biotoxicity EC of sample A4 50 The concentration was 125,500 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.28.

[0093] Example 5

[0094] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0095] The preparation method is as follows:

[0096] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 12.5 kg of grape seed proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0097] 2) Heat the mixed solution from step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (36% concentration), and stir the mixture at 200r / min for 2h at 80°C.

[0098] 3) Add 1.25 kg of acrylic acid, 1.25 kg of maleic acid, and 0.008 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A5.

[0099] Biotoxicity EC of sample A550 The concentration was 132,880 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.29.

[0100] Example 6

[0101] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0102] The preparation method is as follows:

[0103] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 12.5 kg of grape seed proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0104] 2) Heat the mixed solution in step 1) to 98°C using a constant temperature water bath, then add 2.78g of formaldehyde (concentration 36%), and stir the mixture at 200r / min for 2h at a temperature of 98°C.

[0105] 3) Add 3.0 kg of acrylic acid, 1.5 kg of maleic acid and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A6.

[0106] Biotoxicity EC of sample A6 50 The concentration was 125,900 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.28.

[0107] Example 7

[0108] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0109] The preparation method is as follows:

[0110] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 12.5 kg of grape seed proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0111] 2) Heat the mixed solution from step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (36% concentration), and stir the mixture at 200r / min for 4h at 80°C.

[0112] 3) Add 1.5 kg of acrylic acid, 3.5 kg of maleic acid, and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C, then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A7.

[0113] Biotoxicity EC of sample A7 50 The concentration was 133,100 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.27.

[0114] Example 8

[0115] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0116] The preparation method is as follows:

[0117] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 12.5 kg of grape seed proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 7 with NaOH.

[0118] 2) Heat the mixed solution from step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (36% concentration), and stir the mixture at 200r / min for 4h at 80°C.

[0119] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid, and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A8.

[0120] Biotoxicity EC of sample A8 50 The concentration was 129,300 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.29.

[0121] Example 9

[0122] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0123] The preparation method is as follows:

[0124] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 4000, sulfonation degree 0.6), 12.5 kg of proanthocyanidins (hawthorn extract, weight average molecular weight 3000) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0125] 2) Heat the mixed solution from step 1) to 80°C using a constant temperature water bath, then add 2.78g of glyoxal (36% concentration), and stir the mixture at 200r / min for 2h at 80°C.

[0126] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid, and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C, then dry at 80 °C for 24 h and pulverize to obtain anti-high viscosity reducing agent A9.

[0127] Biotoxicity EC of sample A9 50 The concentration was 134,640 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.29.

[0128] Example 10

[0129] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0130] The preparation method is as follows:

[0131] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 6.25 kg of proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0132] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0133] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid, and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A10.

[0134] Biotoxicity EC of sample A10 50 The concentration was 114450 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.28.

[0135] Example 11

[0136] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0137] The preparation method is as follows:

[0138] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 25 kg of proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and a stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0139] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0140] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid, and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A11.

[0141] Biotoxicity EC of sample A11 50 The concentration was 135100 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.29.

[0142] Example 12

[0143] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0144] The preparation method is as follows:

[0145] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 62.5 kg of proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0146] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0147] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A12.

[0148] Biotoxicity EC of sample A12 50 The concentration was 119910 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.26.

[0149] Example 13

[0150] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0151] The preparation method is as follows:

[0152] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 1.875 kg of proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0153] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0154] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid, and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A13.

[0155] Biotoxicity EC of sample A13 50 The concentration was 92510 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.24.

[0156] Example 14

[0157] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0158] The preparation method is as follows:

[0159] 1) Add 17.5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 17.5 kg of proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and a stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0160] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0161] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid, and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A14.

[0162] Biotoxicity EC of sample A14 50 The concentration was 127,800 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.28.

[0163] Example 15

[0164] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0165] The preparation method is as follows:

[0166] 1) Add 20 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 20 kg of proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0167] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0168] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A15.

[0169] Biotoxicity EC of sample A15 50 The concentration was 112,400 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.30.

[0170] Example 16

[0171] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0172] The preparation method is as follows:

[0173] 1) Add 10 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 10 kg of proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0174] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0175] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid, and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A16.

[0176] Biotoxicity EC of sample A16 50 The concentration was 91900 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.22.

[0177] Example 17

[0178] This embodiment provides a high-temperature resistant, environmentally friendly viscosity reducer.

[0179] The preparation method is as follows:

[0180] 1) Add 30 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 30 kg of proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0181] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0182] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid, and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C, then dry at 80 °C for 24 h and pulverize to obtain high-temperature resistant environmentally friendly viscosity reducer A17.

[0183] Biotoxicity EC of sample A17 50 The concentration was 166,400 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.35.

[0184] Comparative Example 1

[0185] This comparative example provides a viscosity reducer.

[0186] The procedure is carried out according to the method described in Example 1, except that proanthocyanidins are not added in step 1), as follows:

[0187] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 8000, degree of sulfonation 0.8) and 100 g of deionized water to a three-necked flask equipped with a thermometer and a stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0188] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0189] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain viscosity reducer D1.

[0190] Biotoxicity EC of sample D1 50The concentration was 124,000 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.26.

[0191] Comparative Example 2

[0192] This comparative example provides a viscosity reducer.

[0193] The procedure is carried out according to the method described in Example 1, except that sodium lignosulfonate is not added in step 1), as follows:

[0194] 1) Add 12.5 kg of proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and a stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0195] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0196] 3) Add 2.5 kg of acrylic acid, 2.5 kg of maleic acid and 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2). Continue stirring at 200 r / min for 4 h at 80 °C. Then dry at 80 °C for 24 h and pulverize to obtain viscosity reducer D2.

[0197] Biotoxicity EC of sample D2 50 The concentration was 147,300 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.29.

[0198] Comparative Example 3

[0199] This comparative example provides a viscosity reducer.

[0200] The method described in Example 1 is followed, except that acrylic acid and maleic acid are not added in step 1), as follows:

[0201] 1) Add 12.5 kg of sodium lignosulfonate (weight average molecular weight 8000, sulfonation degree 0.8), 12.5 kg of proanthocyanidins (grape seed extract, weight average molecular weight 1500) and 100 g of deionized water to a three-necked flask equipped with a thermometer and stirrer. Stir until completely dissolved to obtain a mixed solution. Then adjust the pH of the mixed solution to 9 with NaOH.

[0202] 2) Heat the mixed solution in step 1) to 80°C using a constant temperature water bath, then add 2.78g of formaldehyde (mass concentration 36%), and stir the mixture at 200r / min for 2h at 80°C.

[0203] 3) Add 0.016g of ammonium persulfate to the mixed solution after the reaction in step 2), continue stirring at 200r / min for 4h at 80℃, dry at 80℃ for 24h, and pulverize to obtain viscosity reducer D3.

[0204] Biotoxicity EC of sample D3 50 The concentration was 153200 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.32.

[0205] Comparative Example 4

[0206] This comparative example provides a viscosity reducer.

[0207] Sodium iron-chromium lignin sulfonate produced by Hubei Xinrunde Chemical Co., Ltd. was used as viscosity reducer D4.

[0208] Biotoxicity EC of sample D4 50 The concentration was 12400 mg / L, and the biodegradability rate was BOD5 / COD. Cr It is 0.12.

[0209] Test case

[0210] 1) Measure 300 mL of distilled water into a cup, add 0.42 g of anhydrous sodium carbonate (weighed to 0.01 g) and 12.0 g of bentonite for drilling fluid test slurry preparation (weighed to 0.01 g), and stir at 120 r / min for 20 min, stopping at least twice to scrape off the bentonite adhering to the container wall. After curing in a sealed container at (25±3)℃ for 24 h, add 756 g of barite powder (weighed to 0.1 g) while stirring at 1000 r / min, stopping at least twice to scrape off the barite adhering to the container wall, and stir at 1000 r / min for 10 min to obtain a fresh water-weighted base slurry; then measure the base slurry using a six-speed rotational viscometer. Take readings and determine the density of the base slurry according to GB / T16783.1-2014. The density of the freshwater weighted base slurry should be (2.20±0.05) g / cm³. 3 Within the range, The reading should be within the range of 155 to 185. If it is not within this range, the amount of bentonite and / or barite added can be adjusted accordingly.

[0211] 2) Take two portions of the freshwater weighted base slurry prepared in step 1). Stir one portion of the base slurry at 1000 r / min for 10 min, then place it in a roller furnace and roll it at 120℃ for 16 h. After cooling to (25±3)℃, stir it at 1000 r / min for 5 min and measure the reading at 100 rpm. The second batch of base slurry, with 10g (weighed to 0.01g) of sample added under glass rod stirring, was stirred at 1000r / min for 10min and then placed in a roller heating furnace. It was rolled at 180℃ for 16h, cooled to (25±3)℃, and stirred at 1000r / min for 5min. The reading at 100 revolutions was measured.

[0212] The viscosity reduction rate of the sample under the condition of 180℃ / 16h is calculated according to formula (1).

[0213]

[0214] In formula (1):

[0215] Y – Viscosity reduction rate, %;

[0216] —Reading value of base slurry at 100r / min;

[0217] —Reading value at 100r / min for sample slurry.

[0218] 3) Determine the viscosity reduction rate of the high-temperature resistant and environmentally friendly viscosity reducers A1-A17 prepared in Examples 1-17 of the present invention and the viscosity reducers D1-D4 prepared in Comparative Examples 1-4 according to steps 1) and 2).

[0219] Table 1 Results of viscosity reduction rate determination

[0220] Sample to be tested Viscosity reduction rate / % Freshwater weighted base slurry / A1 76 A2 71 A3 70 A4 72 A5 75 A6 71 A7 74 A8 70 A9 73 A10 71 A11 72 A12 67 A13 61 A14 71 A15 70 A16 69 A17 66 D1 54 D2 43 D3 58 D4 48

[0221] In Table 1, “ / ” indicates that the sample to be tested has no viscosity reduction rate.

[0222] The experimental results in Table 1 show that, at a density of 2.2 g / cm³, 3When the high-temperature resistant and environmentally friendly viscosity reducers A1-A17 prepared in Examples 1-17 of this invention are added to freshwater weighted bentonite-based slurry and aged at 180°C for 16 hours, the viscosity reduction rate of the high-temperature resistant and environmentally friendly viscosity reducers A1-A17 prepared in Examples 1-17 of this invention can reach 70%-76%, which is far superior to the commonly used iron-chromium lignin sulfonate (Comparative Example 4) and viscosity reducers D1-D3 prepared in Comparative Examples 1-3. This indicates that the high-temperature resistant and environmentally friendly viscosity reducers A1-A17 prepared in Examples 1-17 of this invention have good viscosity reduction and temperature resistance, and can effectively improve the rheological properties of water-based drilling fluids, especially high-density water-based drilling fluids, under high-temperature environments.

[0223] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A high-temperature resistant and environmentally friendly viscosity reducer, characterized in that, The raw materials for preparing the high-temperature resistant and environmentally friendly viscosity reducer include raw material I containing sulfonic acid groups, raw material II containing phenolic hydroxyl groups, and monomer A containing carboxyl groups; the monomer A containing carboxyl groups includes monomer A1 shown in Formula I and monomer A2 shown in Formula II. Equation I Formula II In Formula I, R1 and R2 may be the same or different, and are independently selected from hydrogen, C1-C 20 alkyl; In Formula II, R3 and R4 may be the same or different, and each is independently selected from hydrogen, C1-C 20 alkyl; The sulfonic acid-containing raw material I is selected from lignin sulfonate; The phenolic hydroxyl-containing raw material II is selected from proanthocyanidins; The mass ratio of raw material I containing sulfonic acid groups to raw material II containing phenolic hydroxyl groups is 1:(0.25~4). The mass ratio of the carboxyl-containing monomer A to the total mass of the sulfonic acid-containing raw material I and the phenolic hydroxyl-containing raw material II is 1:(5-10).

2. The high-temperature resistant and environmentally friendly viscosity reducer according to claim 1, characterized in that, The mass ratio of the sulfonic acid-containing raw material I to the phenolic hydroxyl-containing raw material II is 1:(0.5-2); the mass ratio of the carboxyl-containing monomer A to the total mass of the sulfonic acid-containing raw material I and the phenolic hydroxyl-containing raw material II is 1:(6-9). And / or, the mass ratio of monomer A1 to monomer A2 is 1:(0.5~1).

3. The high-temperature resistant and environmentally friendly viscosity reducer according to claim 2, characterized in that, The mass ratio of the carboxyl-containing monomer A to the total mass of the sulfonic acid-containing raw material I and the phenolic hydroxyl-containing raw material II is 1:(7-8). And / or, the mass ratio of monomer A1 to monomer A2 is 1:(0.6 to 0.9).

4. The high-temperature resistant and environmentally friendly viscosity reducer according to claim 3, characterized in that, The mass ratio of monomer A1 to monomer A2 is 1:(0.7 to 0.8).

5. The high-temperature resistant and environmentally friendly viscosity reducer according to any one of claims 1-4, characterized in that, The lignin sulfonate is selected from at least one of sodium lignin sulfonate, potassium lignin sulfonate, and calcium lignin sulfonate. And / or, the proanthocyanidins are extracted from at least one of grapes, hawthorn, peanuts, ginkgo, cypress, cliff cypress, blueberries and black beans; And / or, in Formula I, R1 and R2 may be the same or different, and each is independently selected from hydrogen, C1-C 10 Straight-chain alkyl, C3-C 10 Branched alkyl groups; And / or, in Formula II, R3 and R4 may be the same or different, and each is independently selected from hydrogen, C1-C 10 Straight-chain alkyl, C3-C 10 Branched alkyl groups.

6. The high-temperature resistant and environmentally friendly viscosity reducer according to any one of claims 1-4, characterized in that, The degree of sulfonation of the lignin sulfonate is 0.3 to 1.0; And / or, the weight-average molecular weight of the lignin sulfonate is 2000 to 12000; And / or, the weight-average molecular weight of the proanthocyanidins is 500 to 3000.

7. The high-temperature resistant and environmentally friendly viscosity reducer according to claim 6, characterized in that, The degree of sulfonation of the lignin sulfonate is 0.6 to 1.0; And / or, the weight-average molecular weight of the lignin sulfonate is 4000 to 10000; And / or, the weight-average molecular weight of the proanthocyanidins is 1000 to 2000.

8. The high-temperature resistant and environmentally friendly viscosity reducer according to claim 7, characterized in that, The degree of sulfonation of the lignin sulfonate is 0.8 to 1.0; And / or, the weight-average molecular weight of the lignin sulfonate is 6000 to 8000; And / or, the weight-average molecular weight of the proanthocyanidins is 1500 to 2000.

9. A method for preparing a high-temperature resistant, environmentally friendly viscosity reducer as described in any one of claims 1-8, characterized in that, Includes the following steps: 1) Mix raw material I containing sulfonic acid groups, raw material II containing phenolic hydroxyl groups, and water to obtain a mixed solution. In the presence of a crosslinking agent, carry out the first reaction to obtain the first product. 2) In the presence of an initiator, the first product obtained in step 1) is mixed with a carboxyl-containing monomer A to carry out a second reaction to obtain the high-temperature resistant and environmentally friendly viscosity reducer.

10. The preparation method according to claim 9, characterized in that, In step 1), the crosslinking agent is selected from aldehyde crosslinking agents; And / or, the mass ratio of the crosslinking agent to the total weight of raw material I containing sulfonic acid groups and raw material II containing phenolic hydroxyl groups is 1:(10-30). Or, the water is selected from any one of tap water, deionized water, or distilled water; And / or, in the mixed solution, the total mass concentration of raw material I containing sulfonic acid groups and raw material II containing phenolic hydroxyl groups is 10% to 40%; And / or, the pH of the mixed solution is adjusted to 3–11; And / or, the conditions for the first reaction include: a temperature of 60℃ to 100℃, a time of 2h to 4h, and a stirring rate of 100r / min to 300r / min.

11. The preparation method according to claim 10, characterized in that, In step 1), the aldehyde crosslinking agent is selected from at least one of formaldehyde, acetaldehyde, and glyoxal; And / or, the mass ratio of the crosslinking agent to the total weight of raw material I containing sulfonic acid groups and raw material II containing phenolic hydroxyl groups is 1:(15-25). And / or, in the mixed solution, the total mass concentration of raw material I containing sulfonic acid groups and raw material II containing phenolic hydroxyl groups is 20% to 30%; And / or, the pH of the mixed solution is adjusted to 4–10; And / or, the conditions for the first reaction include: a temperature of 70°C to 90°C and a stirring rate of 150 r / min to 250 r / min.

12. The preparation method according to claim 11, characterized in that, In step 1), the mass ratio of the crosslinking agent to the total weight of raw material I containing sulfonic acid groups and raw material II containing phenolic hydroxyl groups is 1:(18-22). And / or, the pH of the mixed solution is adjusted to 7–9; And / or, the conditions for the first reaction include: a temperature of 75°C to 85°C.

13. The preparation method according to claim 10, characterized in that, The pH adjuster for the mixed solution is selected from alkali metal hydroxides.

14. The preparation method according to claim 13, characterized in that, The alkali metal hydroxide is selected from at least one of sodium hydroxide and potassium hydroxide.

15. The preparation method according to any one of claims 9-14, characterized in that, In step 2), the initiator is selected from at least one of cerium ammonium nitrate, potassium persulfate, and ammonium persulfate; And / or, the mass ratio of the initiator to the carboxyl-containing monomer A is 1:(100-600); And / or, the conditions for the second reaction include: a reaction temperature of 60℃ to 100℃, a reaction time of 4h to 6h, and a stirring rate of 100r / min to 300r / min.

16. The preparation method according to claim 15, characterized in that, In step 2), the mass ratio of the initiator to the carboxyl-containing monomer A is 1:(200-500). And / or, the conditions for the second reaction include: a reaction temperature of 70°C to 90°C and a stirring rate of 150 r / min to 250 r / min.

17. The preparation method according to claim 16, characterized in that, In step 2), the conditions for the second reaction include: a reaction temperature of 75℃~85℃.

18. The preparation method according to any one of claims 9-14, characterized in that, The second reaction is followed by drying and pulverizing.

19. The preparation method according to claim 18, characterized in that, The drying conditions include a reaction temperature of 80°C and a time of 24 hours.

20. The preparation method according to any one of claims 9-14, characterized in that, The biotoxicity of the high-temperature resistant and environmentally friendly viscosity reducer is 100,000 mg / L to 140,000 mg / L; its biodegradability is BOD5 / COD. Cr The value ranges from 0.22 to 0.

29.

21. The application of a high-temperature resistant environmentally friendly viscosity reducer according to any one of claims 1-8 or a high-temperature resistant environmentally friendly viscosity reducer prepared by any one of claims 9-20 in drilling fluid.

22. The application of a high-temperature resistant environmentally friendly viscosity reducer according to any one of claims 1-8 or a high-temperature resistant environmentally friendly viscosity reducer prepared by any one of claims 9-20 in water-based drilling fluid.

23. In the application according to claim 22, the amount of the high-temperature resistant environmentally friendly viscosity reducer added to the water-based drilling fluid is 1wt% to 4wt%, with water as 100%.

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