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

Abstract

The invention discloses a high-temperature-resistant environment-friendly viscosity reducer, belongs to the technical field of drilling fluid treating agents, and particularly relates to the high-temperature-resistant environment-friendly viscosity reducer as well as a preparation method and application thereof. The high-temperature-resistant environment-friendly viscosity reducer is prepared from the following raw materials: a raw material I containing a sulfonic group, a raw material II containing a phenolic hydroxyl group and a monomer A containing a carboxyl group, the carboxyl-containing monomer A comprises a monomer A1 as shown in a formula I and a monomer A2 as shown in a formula II; according to the high-temperature-resistant environment-friendly viscosity reducer, two natural degradable materials (lignosulfonate and procyanidine) serve as the main structure of a product, it is guaranteed that the product is non-toxic, easy to degrade and environmentally friendly, and the high-temperature-resistant environment-friendly viscosity reducer has excellent viscosity reduction performance in a high-temperature environment and a high-density drilling fluid, can resist the temperature of 180 DEG C, and has the good viscosity reduction performance. And the viscosity reduction rate of the bentonite-based slurry with the density of 2.2 g / cm < 3 > reaches 70% or above, the biotoxicity is 100000 mg / L to 140000 mg / L, and the biodegradation rate BOD5 / CODCr is 0.22 to 0.29.

Description

Technical Field

[0001] The invention relates to the technical field of drilling fluid treatment agents, and in particular to a high temperature resistant and environmentally friendly viscosity reducer and a preparation method and application thereof. Background Art

[0002] In the late 1930s, foreign countries began to use inorganic phosphates to control the viscosity of drilling fluids. In the 1940s, tannins were widely used as drilling fluid viscosity reducers. Since the 1960s, iron chromium lignin sulfonate (FCLS) has become the main drilling fluid viscosity reducer. After the 1990s, due to the gradual increase in environmental awareness in countries around the world, the application of FCLS, which is seriously harmful to the human body and the environment, has been restricted. Foreign researchers have begun to develop chromium-free lignin sulfonate and tannin viscosity reducers. In recent years, foreign research has focused on anionic polymer viscosity reducers based on maleic anhydride (MA), sodium allyl sulfonate (AS) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS), as well as zwitterionic polymer viscosity reducers with cationic groups and organic phosphorus viscosity reducers.

[0003] In recent years, the research on drilling fluid viscosity reducers in China has also focused on synthetic polymers and the modification of natural polymer materials. In the field of synthetic polymers, Huang Jinjun et al. prepared a zwitterionic viscosity reducer THIN using acrylic acid, sodium propylene sulfonate, AMPS and cationic monomers as raw materials. The temperature resistance can reach 220°C, and the salt and calcium resistance are good. The viscosity reduction effect is better than the traditional drilling fluid viscosity reducers XY-27 and FCLS.

[0004] Wang Zhonghua et al. used AMPS, acrylamide, and NN-dimethylacrylamide as raw materials and adopted an oxidation-reduction initiation system to synthesize an AMPS / DMAM / AM copolymer drilling fluid viscosity reducer, which has good viscosity reduction and temperature and salt resistance, and can withstand temperatures as high as 210°C.

[0005] Hu Caizhi et al. prepared AA-IPPA copolymer using acrylic acid and isopropylene phosphonic acid (IPPA) with good viscosity reduction performance and temperature resistance up to 200°C. Long Zhu et al. studied a method for synthesizing drilling fluid viscosity reducer using AMPS, AA, and DMDAAC from alkali pulping waste liquid as raw materials, and the product had a temperature resistance of up to 150°C.

[0006] Luo Yue et al. used toluene and acetone as solvents and styrene and maleic anhydride as main raw materials to synthesize sulfonated styrene-maleic anhydride polymer (SSMA), which had a viscosity reduction rate of more than 40% and a temperature resistance of 150°C.

[0007] Liao Jiuming et al. used poly 1,3-diamino-2-hydroxypropane and hydroxymethylphosphine as raw materials to prepare a new type of organic phosphorus viscosity reducer, which has better temperature and salt resistance than FCLS.

[0008] Shao Hui et al. used L-aspartic acid as raw material to prepare a non-toxic, easily degradable green viscosity reducer, which also achieved good viscosity reduction effects, but its temperature resistance was only 120°C.

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

[0010] Wei Xiaoming et al. synthesized the lignin viscosity reducer MGAC-1 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°C.

[0011] Wang Zhonghua et al. used tannic acid as raw material and grafted AMPS and AA to prepare tannic acid grafted copolymers with a temperature resistance of over 160°C.

[0012] Zhang Jianyun et al. used tara tannin extracted from tara pod powder to synthesize 2+ The viscosity reducing agent SMT-T was prepared by complexation, and the viscosity reducing rate can reach more than 84% at 180℃1220℃.

[0013] Zhang Liming et al. used lignin sulfonic acid and tannin extracts to cross-link with formaldehyde, and the product was cross-linked with Fe 2+ The drilling fluid viscosity reducer FTLS is formed by complexation. Compared with the traditional FCLS, it has better viscosity reduction performance and temperature and salt resistance.

[0014] It can be seen that the existing drilling fluid viscosity reducers at home and abroad are mainly divided into two categories: synthetic polymers and modified natural polymers. Among them, synthetic polymer viscosity reducers have excellent temperature resistance, but are difficult to degrade, so they are not environmentally friendly; modified polymer viscosity reducers improve temperature resistance while sacrificing some environmental performance by grafting a large amount of acrylamide polymer monomers on natural polymers such as lignin.

[0015] In addition, due to the extremely high density of solid particles in high-density drilling fluids, a grid structure is formed between bentonite and barite particles, resulting in the drilling fluid viscosity reducers of the prior art often having difficulty in exerting a good effect in high-density drilling fluids.

[0016] In summary, the current drilling fluid high temperature resistant viscosity reducers have the defect of insufficient environmental protection, and 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 amount of acrylamide polymer monomers to improve temperature resistance, which makes them also insufficient in environmental protection.

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

[0018] The present invention aims to solve the problem that the high-temperature resistant viscosity reducers for drilling fluid used in the prior art are not environmentally friendly enough and cannot play a better role in high-density drilling fluid. The present invention provides a drilling fluid viscosity reducer with both temperature resistance and environmental protection. The drilling fluid viscosity reducer can play an excellent viscosity reducing role in high-density drilling fluid and in a high-temperature environment at the bottom of the well, and is non-toxic, easily degradable, and will not cause harm to the environment.

[0019] The inventors of the present invention have found through extensive research that by moderately cross-linking sulfonic acid group-rich lignin sulfonate with phenolic hydroxyl-rich proanthocyanidin, and then grafting and chelating a small amount of carboxyl group-containing vinyl monomer, the synthetic product can have temperature resistance, adsorption, dispersibility, and environmental protection, and is particularly suitable for use as a high-temperature resistant and environmentally friendly viscosity reducer for water-based drilling fluids, thereby completing the present invention.

[0020] In order to solve the above technical problems, the first aspect of the present invention provides a high temperature resistant and environmentally friendly viscosity reducing agent, wherein the raw materials for preparing the agent include a raw material I containing a sulfonic acid group, a raw material II containing a phenolic hydroxyl group, and a monomer A containing a carboxyl group; the carboxyl group-containing monomer A includes a monomer A1 shown in formula I and a monomer A2 shown in formula II;

[0021]

[0022] In Formula I, R1 and R2 are the same or different and are independently selected from hydrogen, C1-C 20 Preferably, R1 and R2 are the same or different and are independently selected from hydrogen, C1-C 10 More preferably, R1 and R2 are the same or different and are independently selected from hydrogen, C1-C 10 Straight chain alkyl, C3-C 10 Branched alkyl; further preferably, R1 and R2 are the same or different, and are independently selected from hydrogen, methyl, ethyl, ethylpropyl;

[0023] In formula II, R3 and R4 are the same or different and are independently selected from hydrogen, C1-C 20 Preferably, R3 and R4 are the same or different and are independently selected from hydrogen, C1-C 10 More preferably, R3 and R4 are the same or different and are independently selected from hydrogen, C1-C 10 Straight chain alkyl, C3-C 10 Branched alkyl; further preferably R3 and R4 are the same or different, and are independently selected from hydrogen, methyl, ethyl, ethylpropyl.

[0024] According to some embodiments of the present invention, the mass ratio of the raw material I containing sulfonic acid groups to the raw material II containing phenolic hydroxyl groups 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 ratio of the mass of the carboxyl-containing monomer A to the total mass of the sulfonic acid group-containing raw material I and the phenolic hydroxyl group-containing raw material II is 1:(5-10), preferably 1:(6-9), and 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 group-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 raw material II containing phenolic hydroxyl groups is selected from proanthocyanidins; preferably, the proanthocyanidins are extracted from at least one of grapes, hawthorn, peanuts, ginkgo, thuja serrata, thuja serrata, blueberries and black beans.

[0029] According to some embodiments of the present invention, the sulfonation degree of the lignin sulfonate is 0.3 to 1.0, preferably 0.6 to 1.0, more preferably 0.8 to 1.0, such as 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, such as 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, 3000.

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

[0033] 1) mixing a sulfonic acid group-containing raw material I, a phenolic hydroxyl group-containing raw material II and water to obtain a mixed solution, and performing a first reaction in the presence of a cross-linking agent to obtain a first product;

[0034] 2) In the presence of an initiator, the first product obtained in step 1) is mixed with the 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 cross-linking agent is selected from aldehyde cross-linking agents; preferably, the aldehyde cross-linking 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 ratio of the mass of the cross-linking agent to the total weight of the raw material I containing sulfonic acid groups and the 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 any one of tap water, deionized water, and distilled water.

[0038] According to some embodiments of the present invention, in step 1), in the mixed solution, the total mass concentration of the raw material I containing sulfonic acid groups and the raw material II containing phenolic hydroxyl groups 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, and more preferably 7-9; preferably, the pH adjuster of the mixed solution is selected from alkali metal hydroxides; further 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: temperature of 60°C to 100°C, preferably 70°C to 90°C, more preferably 75°C to 85°C, time of 2h to 4h, 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 ammonium cerium 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: reaction temperature of 60°C to 100°C, preferably 70°C to 90°C, more preferably 75°C to 85°C, time of 4h to 6h, 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), the second reaction further comprises drying and crushing; preferably, the drying conditions include: reaction temperature of 80° C. and time of 24 h.

[0045] According to some embodiments of the present invention, the biological toxicity of the high temperature resistant and environmentally friendly viscosity reducer is 100000 mg / L to 140000 mg / L, preferably 120000 to 14000 mg / L, and the biodegradation rate BOD5 / COD Cr It is 0.22 to 0.29, preferably 0.27 to 0.29.

[0046] The third aspect of the present invention provides an 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%, based on water as 100%.

[0047] Beneficial effects:

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

[0049] The lignin sulfonate in the present invention 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 dismantling the bentonite grid structure and reducing the viscosity of the drilling fluid; the proanthocyanidins are rich in phenolic hydroxyl groups, which give the product strong adsorption on the bentonite surface and are not easy to desorb at high temperatures; the present invention organically combines the two raw materials to enable the product to have excellent viscosity reduction and adsorption properties at the same time.

[0050] The present invention can form a stronger molecular skeleton through cross-linking between lignin sulfonate and proanthocyanidin molecules, thereby further improving the temperature resistance of the product.

[0051] The invention can further improve the temperature resistance and salt resistance and enhance the adsorption performance on the bentonite surface by graft copolymerizing the two cross-linked natural macromolecules with the two vinyl monomers.

[0052] The high temperature resistant and environmentally friendly viscosity reducer of the present invention has excellent viscosity reducing performance in high temperature environment and high density drilling fluid, and the temperature resistance reaches 180°C, and at 2.2g / cm3 The viscosity reduction rate of the dense bentonite-based slurry is more than 70%, the biological toxicity is 100000mg / L~140000mg / L, and the biodegradation rate is BOD5 / COD Cr It is 0.22~0.29. DETAILED DESCRIPTION

[0053] The present invention will be further described below in conjunction with the embodiments, but the present invention is not limited by these embodiments.

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

[0055] The hawthorn extract in the present invention is purchased from Shandong Gushuo Biotechnology Co., Ltd., and has a weight average molecular weight of 3,000.

[0056] The sodium lignin sulfonate in the present invention is purchased from Shanghai Waidian 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] The formaldehyde in the present invention was purchased from Tianjin Huakun Chemical Co., Ltd. with a concentration of 36%.

[0058] The acrylic acid in the present invention is purchased from Shandong Mingyue Chemical Co., Ltd. with a purity of 99%.

[0059] The maleic acid in the present invention is purchased from Shandong Hui'an Chemical Co., Ltd. with a purity of 99%.

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

[0061] The biological toxicity EC of the high temperature resistant and environmentally friendly viscosity reducer in the present invention 50 The test is in accordance with SY / T6787-2010 "Technical Requirements for Environmental Protection of Water-soluble Oilfield Chemicals".

[0062] The biodegradation rate of the high temperature resistant and environmentally friendly viscosity reducer in the present invention is BOD5 / COD Cr The test is in accordance with SY / T6787-2010 "Technical Requirements for Environmental Protection of Water-soluble Oilfield Chemicals".

[0063] The six-speed rotation viscometer in the present invention was purchased from Qingdao Haitongda Special Instrument Co., Ltd., and the specification / model is ZNN-D6.

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

[0065] Example 1

[0066] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0067] The preparation method is as follows:

[0068] 1) Add 12.5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0069] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 h, dry it at a temperature of 80° C. for 24 h, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A1.

[0071] Biotoxicity EC of sample A1 50 135100mg / L, biodegradation rate BOD5 / COD Cr It is 0.28.

[0072] Example 2

[0073] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0074] The preparation method is as follows:

[0075] 1) Add 20 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0076] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 h, dry it at a temperature of 80° C. for 24 h, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A2.

[0078] Biotoxicity EC of sample A2 50 124700mg / L, biodegradation rate BOD5 / COD Cr is 0.27.

[0079] Example 3

[0080] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0081] The preparation method is as follows:

[0082] 1) Add 5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0083] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 h, dry it at a temperature of 80° C. for 24 h, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A3.

[0085] Biotoxicity EC of sample A3 50 130400mg / L, biodegradation rate BOD5 / COD Cr is 0.27.

[0086] Example 4

[0087] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0088] The preparation method is as follows:

[0089] 1) Add 12.5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0090] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 6.94 g of formaldehyde (concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 h, dry it at a temperature of 80° C. for 24 h, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A4.

[0092] Biotoxicity EC of sample A4 50 125500mg / L, biodegradation rate BOD5 / COD Cr It is 0.28.

[0093] Example 5

[0094] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0095] The preparation method is as follows:

[0096] 1) Add 12.5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0097] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (concentration 36%), and stirring the mixture at 80° C. and 200 r / min for 2 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 h, dry it at a temperature of 80° C. for 24 h, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A5.

[0099] Biotoxicity EC of sample A550 The biodegradation rate is 132880 mg / L, BOD5 / COD Cr It is 0.29.

[0100] Example 6

[0101] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0102] The preparation method is as follows:

[0103] 1) Add 12.5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0104] 2) heating the mixed solution in step 1) to 98° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (concentration 36%), stirring at 98° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 h, dry it at a temperature of 80° C. for 24 h, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A6.

[0106] Biotoxicity EC of sample A6 50 125900mg / L, biodegradation rate BOD5 / COD Cr It is 0.28.

[0107] Example 7

[0108] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0109] The preparation method is as follows:

[0110] 1) Add 12.5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0111] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 4 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 h, dry it at a temperature of 80° C. for 24 h, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A7.

[0113] Biotoxicity EC of sample A7 50 133100mg / L, biodegradation rate BOD5 / COD Cr is 0.27.

[0114] Example 8

[0115] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0116] The preparation method is as follows:

[0117] 1) Add 12.5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 7 with NaOH;

[0118] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 4 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 h, dry it at a temperature of 80° C. for 24 h, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A8.

[0120] Biotoxicity EC of sample A8 50 129300mg / L, biodegradation rate BOD5 / COD Cr It is 0.29.

[0121] Example 9

[0122] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0123] The preparation method is as follows:

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

[0125] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of glyoxal (concentration 36%), and stirring the mixture at 80° C. at a rate of 200 r / min for 2 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 h, dry it at a temperature of 80° C. for 24 h, and crush it to obtain an anti-high viscosity reduction agent A9.

[0127] Biotoxicity EC of sample A9 50 The biodegradation rate is 134640 mg / L, BOD5 / COD Cr It is 0.29.

[0128] Example 10

[0129] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0130] The preparation method is as follows:

[0131] 1) Add 12.5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0132] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir and react at a rate of 200 r / min at a temperature of 80° C. for 4 hours, dry at a temperature of 80° C. for 24 hours, and crush to obtain a high temperature resistant and environmentally friendly viscosity reducer A10.

[0134] Biotoxicity EC of sample A10 50 114450mg / L, biodegradation rate BOD5 / COD Cr It is 0.28.

[0135] Embodiment 11

[0136] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0137] The preparation method is as follows:

[0138] 1) Add 12.5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0139] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir and react at a rate of 200 r / min at a temperature of 80° C. for 4 hours, dry at a temperature of 80° C. for 24 hours, and crush to obtain a high temperature resistant and environmentally friendly viscosity reducer A11.

[0141] Biotoxicity EC of sample A11 50 135100mg / L, biodegradation rate BOD5 / COD Cr It is 0.29.

[0142] Example 12

[0143] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0144] The preparation method is as follows:

[0145] 1) Add 12.5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0146] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 hours, dry it at a temperature of 80° C. for 24 hours, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A12.

[0148] Biotoxicity EC of sample A12 50 The biodegradation rate is 119910 mg / L, BOD5 / COD Cr is 0.26.

[0149] Embodiment 13

[0150] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0151] The preparation method is as follows:

[0152] 1) Add 12.5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0153] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 hours, dry it at a temperature of 80° C. for 24 hours, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A13.

[0155] Biotoxicity EC of sample A13 50 92510mg / L, biodegradation rate BOD5 / COD Cr is 0.24.

[0156] Embodiment 14

[0157] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0158] The preparation method is as follows:

[0159] 1) Add 17.5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0160] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 hours, dry it at a temperature of 80° C. for 24 hours, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A14.

[0162] Biotoxicity EC of sample A14 50 127800mg / L, biodegradation rate BOD5 / COD Cr It is 0.28.

[0163] Embodiment 15

[0164] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0165] The preparation method is as follows:

[0166] 1) Add 20 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0167] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 hours, dry it at a temperature of 80° C. for 24 hours, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A15.

[0169] Biotoxicity EC of sample A15 50 112400mg / L, biodegradation rate BOD5 / COD Cr is 0.30.

[0170] Example 16

[0171] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0172] The preparation method is as follows:

[0173] 1) Add 10 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0174] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir and react at a rate of 200 r / min at a temperature of 80° C. for 4 hours, dry at a temperature of 80° C. for 24 hours, and crush to obtain a high temperature resistant and environmentally friendly viscosity reducer A16.

[0176] Biotoxicity EC of sample A16 50 91900mg / L, biodegradation rate BOD5 / COD Cr is 0.22.

[0177] Embodiment 17

[0178] This embodiment provides a high temperature resistant and environmentally friendly viscosity reducing agent.

[0179] The preparation method is as follows:

[0180] 1) Add 30 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0181] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 h, dry it at a temperature of 80° C. for 24 h, and crush it to obtain a high temperature resistant and environmentally friendly viscosity reducer A17.

[0183] Biotoxicity EC of sample A17 50 166400mg / L, biodegradation rate BOD5 / COD Cr is 0.35.

[0184] Comparative Example 1

[0185] This comparative example provides a viscosity reducing agent.

[0186] The method described in Example 1 was followed, except that in step 1), no proanthocyanidins were added, as follows:

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

[0188] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 80° C. at a rate of 200 r / min for 4 h, dry at 80° C. for 24 h, and crush to obtain viscosity reducer D1.

[0190] Biotoxicity EC of sample D1 50124000mg / L, biodegradation rate BOD5 / COD Cr is 0.26.

[0191] Comparative Example 2

[0192] This comparative example provides a viscosity reducing agent.

[0193] The method described in Example 1 is carried out, except that sodium lignin sulfonate is not added in step 1), specifically as follows:

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

[0195] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[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 the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 h, dry the mixture at a temperature of 80° C. for 24 h, and crush the mixture to obtain a viscosity reducer D2.

[0197] Biotoxicity EC of sample D2 50 147300mg / L, biodegradation rate BOD5 / COD Cr It is 0.29.

[0198] Comparative Example 3

[0199] This comparative example provides a viscosity reducing agent.

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

[0201] 1) Add 12.5 kg of sodium lignin sulfonate (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 into a three-necked flask equipped with a thermometer and a stirrer, stir until completely dissolved to obtain a mixed solution, and then adjust the pH of the mixed solution to 9 with NaOH;

[0202] 2) heating the mixed solution in step 1) to 80° C. in a constant temperature water bath, then adding 2.78 g of formaldehyde (mass concentration 36%), stirring at 80° C. and reacting at a rate of 200 r / min for 2 h;

[0203] 3) adding 0.016 g of ammonium persulfate to the mixed solution after the reaction in step 2), continuing to stir the mixture at a rate of 200 r / min at a temperature of 80° C. for 4 h, drying the mixture at a temperature of 80° C. for 24 h, and crushing the mixture to obtain a viscosity reducer D3.

[0204] Biotoxicity EC of sample D3 50 153200mg / L, biodegradation rate BOD5 / COD Cr It is 0.32.

[0205] Comparative Example 4

[0206] This comparative example provides a viscosity reducing agent.

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

[0208] Biotoxicity EC of sample D4 50 12400mg / L, biodegradation rate BOD5 / COD Cr is 0.12.

[0209] Test Case

[0210] 1) Measure 300 mL of distilled water and place it in a cup, add 0.42 g of anhydrous sodium carbonate (weighed to 0.01 g), 12.0 g of bentonite for drilling fluid test slurry (weighed to 0.01 g), stir at a rate of 120 r / min for 20 min, stop at least twice to scrape off the bentonite adhering to the container wall, and seal and cure for 24 h at a temperature of (25±3) ° C. Then, add 756 g of barite powder (weighed to 0.1 g) at a rate of 1000 r / min, stop at least twice to scrape off the barite adhering to the container wall, and stir at a rate of 1000 r / min for 10 min to obtain a fresh water weighted base slurry; then use a six-speed rotary viscometer to measure the base slurry Read the readings and determine the density of the base slurry according to GB / T16783.1-2014. The density of the fresh water-weighted base slurry should be (2.20±0.05) g / cm 3 Within the range, The reading should be within the range of 155 to 185. If it is not within the range, the amount of bentonite and / or barite can be adjusted appropriately.

[0211] 2) Take two portions of the fresh water weighted slurry prepared in step 1), stir one portion of the slurry at a rate of 1000 r / min for 10 min, put it into a roller heating furnace, roll it at a temperature of 120°C for 16 h, cool it to (25±3)°C, stir it at a rate of 1000 r / min for 5 min, and measure the reading at 100 rpm. Add 10g (accurately weighed to 0.01g) of sample to the second base slurry under stirring with a glass rod, stir at a rate of 1000r / min for 10min, put it into a roller heating furnace, roll it at a temperature of 180℃ for 16h, wait for it to cool to (25±3)℃, stir at a rate of 1000r / min for 5min, and measure the reading at 100rpm.

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

[0213]

[0214] In formula (1):

[0215] Y——viscosity reduction rate, %;

[0216] ——Base slurry reading at 100r / min;

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

[0218] 3) According to steps 1) and 2), the viscosity reduction rates 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 were determined.

[0219] Table 1 Viscosity reduction test results

[0220] Samples to be tested Viscosity reduction rate / % Fresh water weighted 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] From the test results in Table 1, it can be seen that at a density of 2.2 g / cm 3The high temperature resistant and environmentally friendly viscosity reducers A1-A17 prepared in Examples 1-17 of the present invention are added to the freshwater weighted bentonite-based slurry, and after aging for 16 hours at a temperature of 180°C, 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 can be as high as 70%-76%, which is much better than the commonly used iron chromium lignin sulfonate (Comparative Example 4) and the viscosity reducers D1-D3 prepared in Comparative Examples 1-3 in China, indicating that the high temperature resistant and environmentally friendly viscosity reducers A1-A17 prepared in Examples 1-17 of the present 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 used to explain the present invention and do not constitute any limitation to 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 words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A high temperature resistant and environmentally friendly viscosity reducing agent, characterized in that: The raw materials for preparing the high temperature resistant and environmentally friendly viscosity reducing agent include raw materials I containing sulfonic acid groups, raw materials II containing phenolic hydroxyl groups, and monomers A containing carboxyl groups; the monomers A containing carboxyl groups include monomers A1 shown in formula I and monomers A2 shown in formula II; In Formula I, R1 and R2 are the same or different and are independently selected from hydrogen, C1-C 20 alkyl; In formula II, R3 and R4 are the same or different and are independently selected from hydrogen, C1-C 20 alkyl.

2. The high temperature resistant and environmentally friendly viscosity reducing agent according to claim 1, characterized in that: The mass ratio of the sulfonic acid group-containing raw material I to the phenolic hydroxyl group-containing raw material II is 1:(0.25-4), preferably 1:(0.5-2); the mass ratio of the carboxyl group-containing monomer A to the total mass of the sulfonic acid group-containing raw material I and the phenolic hydroxyl group-containing raw material II is 1:(5-10), preferably 1:(6-9), more preferably 1:(7-8); And / or, the mass ratio of the monomer A1 to the monomer A2 is 1:(0.5-1), preferably 1:(0.6-0.9), and more preferably 1:(0.7-0.8).

3. The high temperature resistant and environmentally friendly viscosity reducing agent according to claim 1 or 2, characterized in that: The sulfonic acid group-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; And / or, the raw material II containing phenolic hydroxyl group is selected from proanthocyanidins; preferably, the proanthocyanidins are extracted from at least one of grapes, hawthorn, peanuts, ginkgo, thuja sutchuenensis, thuja sutchuenensis, blueberries and black beans; And / or, in Formula I, R1 and R2 are the same or different and are independently selected from hydrogen, C1-C 10 Straight chain alkyl, C3-C 10 Branched chain alkyl; And / or, in Formula II, R3 and R4 are the same or different and are independently selected from hydrogen, C1-C 10 Straight chain alkyl, C3-C 10 Branched chain alkyl.

4. The high temperature resistant and environmentally friendly viscosity reducing agent according to claim 3, characterized in that: The sulfonation degree of the lignin sulfonate is 0.3 to 1.0, preferably 0.6 to 1.0, and more preferably 0.8 to 1.0; and / or, the weight average molecular weight of the lignin sulfonate is 2000 to 12000, preferably 4000 to 10000, more preferably 6000 to 8000; And / or, the weight average molecular weight of the proanthocyanidin is 500-3000, preferably 1000-2000, more preferably 1500-2000.

5. A method for preparing a high temperature resistant and environmentally friendly viscosity reducing agent as claimed in any one of claims 1 to 4, characterized in that: The steps include: 1) mixing a sulfonic acid group-containing raw material I, a phenolic hydroxyl group-containing raw material II and water to obtain a mixed solution, and performing a first reaction in the presence of a cross-linking agent to obtain a first product; 2) In the presence of an initiator, the first product obtained in step 1) is mixed with the carboxyl-containing monomer A to carry out a second reaction to obtain the high temperature resistant and environmentally friendly viscosity reducer.

6. The preparation method according to claim 5, characterized in that: In step 1), the cross-linking agent is selected from aldehyde cross-linking agents; preferably, the aldehyde cross-linking agent is selected from at least one of formaldehyde, acetaldehyde and glyoxal; and / or, the ratio of the mass of the cross-linking agent to the total weight of the raw material I containing sulfonic acid groups and the raw material II containing phenolic hydroxyl groups is 1:(10-30), preferably 1:(15-25), more preferably 1:(18-22); And or, the water is selected from any one of tap water, deionized water, and distilled water; And / or, in the mixed solution, the total mass concentration of the raw material I containing a sulfonic acid group and the raw material II containing a phenolic hydroxyl group is 10% to 40%, preferably 20% to 30%; and / or, 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; further preferably, the alkali metal hydroxide is selected from at least one of sodium hydroxide and potassium hydroxide; And / or, the conditions of the first reaction include: temperature of 60°C to 100°C, preferably 70°C to 90°C, more preferably 75°C to 85°C, time of 2h to 4h, stirring rate of 100r / min to 300r / min, preferably 150r / min to 250r / min.

7. The preparation method according to claim 5 or 6, characterized in that: In step 2), the initiator is selected from at least one of ammonium cerium nitrate, potassium persulfate, and ammonium persulfate; And / or, 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); And / or, the conditions of the second reaction include: reaction temperature of 60°C to 100°C, preferably 70°C to 90°C, more preferably 75°C to 85°C, time of 4h to 6h, stirring rate of 100r / min to 300r / min, preferably 150r / min to 250r / min.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The second reaction further includes drying and crushing; preferably, the drying conditions include: reaction temperature of 80° C. and reaction time of 24 hours.

9. The preparation method according to any one of claims 5 to 8, characterized in that: The biological toxicity of the high temperature resistant and environmentally friendly viscosity reducer is 100000mg / L to 140000mg / L; the biodegradation rate BOD5 / COD Cr It is 0.22~0.

29.

10. An application of the high temperature resistant and environmentally friendly viscosity reducer according to any one of claims 1 to 4 or the high temperature resistant and environmentally friendly viscosity reducer prepared by the preparation method according to any one of claims 5 to 9 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%, calculated as 100% by water.

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