Bio-based filtrate reducer as well as preparation method and application thereof

Abstract

The invention provides a bio-based filtrate reducer as well as a preparation method and application thereof. The environment-friendly zwitterionic bio-based filtrate reducer is obtained by taking waste small dragon shrimp and crab shells as raw materials, treating the raw materials by adopting an acid-alkali method to obtain glycosaminoglycan, performing carboxylation modification on the glycosaminoglycan through monochloroacetic acid, and copolymerizing the glycosaminoglycan with a propenyl monomer, a quaternary ammonium salt monomer and 2-acrylamide-2-methylpropanesulfonic acid. The bio-toxicity EC50 value of the bio-based filtrate reducer provided by the invention is greater than 100000 mg / L, the biodegradability BOD / CODcr value is greater than 0.05, and the bio-based filtrate reducer belongs to a non-toxic and easily degradable level; the prepared filtrate reducer has good filtrate reduction property and temperature resistance at normal temperature and 100-200 DEG C, and still has excellent temperature resistance and salt resistance after being added into brine base slurry or saturated brine; the prepared filtrate reducer is wide in raw material source and low in price, can be applied to geological drilling operation to maintain the stability of a well wall, and provides guarantee for smooth proceeding of the geological drilling operation.

Description

Technical Field

[0001] This invention belongs to the field of filtration loss reducing agents, and particularly relates to a bio-based filtration loss reducing agent, its preparation method, and its application. Background Technology

[0002] Filtration of drilling fluid is inevitable in geological drilling operations, and excessive filtration can easily lead to wellbore collapse and instability. Therefore, controlling filtration loss is one of the key technologies in drilling fluids, and adding filtration reducers to the drilling fluid is a direct means of reducing filtration loss. Currently, widely used filtration reducers in drilling fluids, such as sulfonated lignite and sulfonated phenolic resin, while having good performance, are increasingly showing problems of high toxicity and poor biodegradability. With the continuous improvement of domestic and international environmental laws and regulations and the increasing demands for environmental protection, it is necessary to develop low-toxicity, easily degradable, and environmentally friendly filtration reducers.

[0003] Currently, the research and development of environmentally friendly filtration loss reducers mainly includes synthetic polymers such as modified cellulose, modified starch, modified lignin, and miscellaneous sugars. These polymers are diverse and have excellent filtration loss reduction performance, but their high cost and easy degradation under high temperature conditions limit their application in geological drilling.

[0004] Existing technology discloses a modified oligochitosan and its preparation method, copolymers and their preparation methods, and applications in drilling fluids. The oligochitosan contains benzene rings and alkenyl groups, which are further combined with carboxylic acid groups and siloxane groups to obtain copolymers. These copolymers possess advantages such as non-toxicity, good biocompatibility, and excellent biodegradability, and can be used as environmentally friendly drilling fluid filtration reducers to reduce filtration loss through a protective coating mechanism. The problem with this invention is its relatively complex process and high synthesis cost.

[0005] Existing technology also discloses a high-temperature resistant chitosan filtration loss reducer, its preparation method, and its application. It is mainly obtained by graft copolymerization of chitosan, monomer 1, monomer 2, 2-acrylamido-2-methylbenzenesulfonic acid, and maleic anhydride. It exhibits good high-temperature resistance, capable of reducing filtration loss at temperatures up to 180℃. The raw materials are inexpensive, the synthesis process is simple, and it is relatively environmentally friendly. However, the problem with this invention is that the salt and calcium resistance of the synthesized filtration loss reducer is unknown.

[0006] Given the shortcomings of existing filtration loss reducing agents, it is necessary to improve them. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a bio-based filtration loss reducer, its preparation method, and its application. This invention proposes an environmentally friendly zwitterionic bio-based filtration loss reducer prepared from waste crayfish shells and / or crab shells. It possesses excellent filtration loss reduction performance, environmental friendliness, and temperature and salt resistance. The raw materials are widely available, the synthesis conditions are mild, the synthesis route is simple, and the synthesis cost is low. It can be used in geological drilling operations to maintain wellbore stability, ensuring the smooth progress of geological drilling operations.

[0008] The present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a bio-based filtration loss reducing agent, comprising the following raw materials in parts by weight: 15-30 parts of aminopolysaccharide, 10-20 parts of 2-acrylamide-2-methylpropanesulfonic acid, 10-20 parts of propylene monomer, 15-30 parts of quaternary ammonium salt monomer, 0.05-0.25 parts of crosslinking agent, and 1-2 parts of initiator;

[0010] The aminopolysaccharide is a product obtained by extracting crayfish shells and / or crab shells using an acid-base method.

[0011] Preferably, the method for preparing the aminopolysaccharide includes:

[0012] The shells of crayfish and / or crabs were dissolved in sodium hydroxide solution A, hydrochloric acid solution, hydrogen peroxide solution and sodium hydroxide solution B in sequence. After the reaction was complete, the mixture was washed and dried to obtain amino polysaccharides.

[0013] The propylene monomer includes at least one of acrylamide, N,N-dimethylacrylamide, and methacrylamide;

[0014] The quaternary ammonium salt monomer includes at least one of 3-chloro-2-hydroxypropyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, and dimethyldiallylammonium chloride;

[0015] The crosslinking agent is N,N-methylenebisacrylamide;

[0016] The initiator includes at least one of sodium persulfate, potassium persulfate, and ammonium persulfate.

[0017] Secondly, the present invention also provides a method for preparing the aforementioned bio-based filtration loss reducing agent, comprising the following steps:

[0018] Aminopolysaccharide and monochloroacetic acid were dissolved in sodium hydroxide solution C. After the reaction was complete, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer and quaternary ammonium salt monomer were added. The pH was adjusted to 9-10. After stirring, crosslinking agent and initiator were added and the reaction was continued. After the reaction was completed, the mixture was washed and dried to obtain the bio-based filtration loss reducer.

[0019] Preferably, crayfish shells and / or crab shells are placed in a 1-2 mol / L sodium hydroxide solution A and reacted for 24-30 hours, then in a 1-2 mol / L hydrochloric acid solution and reacted for 24-30 hours, then in a 5-8% hydrogen peroxide solution and reacted for 24-30 hours, and finally in a 10-12% sodium hydroxide solution B and reacted for 4-6 hours. After washing and drying, aminopolysaccharides are obtained.

[0020] Preferably, aminopolysaccharide and monochloroacetic acid are dissolved in sodium hydroxide solution C and reacted at a temperature of 40-45℃ and a stirring speed of 400-600 r / min for 3-5 h. Then, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer and quaternary ammonium salt monomer are added, the pH is adjusted to 9-10, and after stirring, crosslinking agent and initiator are added and the reaction continues. After the reaction is completed, the product is washed and dried to obtain the bio-based filtration loss reducer.

[0021] Preferably, aminopolysaccharide and monochloroacetic acid are dissolved in sodium hydroxide solution C. After the reaction is complete, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer and quaternary ammonium salt monomer are added. The pH is adjusted to 9-10, and the mixture is stirred at 60-70℃ and 400-600 r / min for 3-5 h. A crosslinking agent and an initiator are added, and the reaction is continued to be stirred for 1-2 h. After the reaction is completed, the mixture is washed and dried to obtain a bio-based filtration loss reducer.

[0022] Preferably, in the step of dissolving aminopolysaccharide and monochloroacetic acid in sodium hydroxide solution C, the mass fraction of sodium hydroxide solution C is 20-25%.

[0023] The mass-to-volume ratio of the aminopolysaccharide, monochloroacetic acid, and sodium hydroxide solution C is (15~30)g:(40~60)g:(100~120)mL.

[0024] Preferably, the mass ratio of the aminopolysaccharide, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer, quaternary ammonium salt monomer, crosslinking agent, and initiator is (15~30):(10~20):(10~20):(15~30):(0.05~0.25):(1~2).

[0025] Preferably, the mass-to-volume ratio of the crayfish shell and / or crab shell, sodium hydroxide solution A, hydrochloric acid solution, hydrogen peroxide, and sodium hydroxide solution B is 1g:(10~50)mL:(10~50)mL:(10~50)mL:(5~30)mL.

[0026] Thirdly, the present invention also provides the application of the bio-based filtration reducer described above or the bio-based filtration reducer prepared by the preparation method described above in the preparation of drilling fluid.

[0027] The bio-based filtration loss reducer, its preparation method, and its application of the present invention have the following advantages compared to the prior art:

[0028] 1. The preparation method of the bio-based filtration loss reducing agent of the present invention involves using waste crayfish and crab shells as raw materials, treating them with an acid-base method to obtain amino polysaccharides, modifying them with monochloroacetic acid carboxylation, and then copolymerizing them with propylene monomers, quaternary ammonium salt monomers, and 2-acrylamide-2-methylpropanesulfonic acid to obtain an environmentally friendly zwitterionic bio-based filtration loss reducing agent. The environmentally friendly zwitterionic temperature- and salt-resistant bio-based filtration loss reducing agent provided by the present invention has a molecular weight of 200,000 to 400,000 and a biotoxicity EC50. 50 With a concentration greater than 100,000 mg / L and a biodegradable BOD / CODcr value greater than 0.05, it belongs to the non-toxic and easily degradable category. The filtration loss reducer exhibits good filtration loss reduction and temperature resistance at room temperature and 100~200℃. When added to brine-based slurry or saturated brine, it still has excellent temperature and salt resistance, overcoming the problems of easy degradation, poor environmental performance, and difficult degradation under high temperature conditions in existing technologies. The filtration loss reducer has a wide range of raw material sources, mild and easy-to-control synthesis conditions, simple synthesis route, and low cost, making it economically applicable and marketable. It can be used in geological drilling operations to maintain wellbore stability and provide a guarantee for the smooth progress of geological drilling operations. The above preparation method and application realize the high-value utilization of natural polymer materials.

[0029] 2. The bio-based filtration loss reducer of the present invention is obtained by extracting amino polysaccharides from crayfish shells and / or crab shells. These amino groups have a unique natural zwitterionic polymer structure. The positively charged amino groups are the core for achieving charge neutralization and efficient adsorption, while the abundant hydroxyl groups help to enhance adsorption and film-forming capabilities. This natural structure gives it excellent filtration loss reduction potential, and the active groups provide strong modifiability. By modifying and grafting the amino polysaccharide, abundant carboxyl functional groups, amide groups, quaternary ammonium groups, and sulfonic acid groups are introduced, which enhances the steric hindrance of the molecular chain and the clay adsorption capacity, thereby improving the filtration loss reduction capacity, thermal stability, and salt resistance of the synthesized material. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 The Fourier transform infrared spectrum is of the bio-based filtration reduction agent prepared in Example 1. Detailed Implementation

[0032] To facilitate understanding of the present invention, a more comprehensive description of the invention will be provided below in conjunction with specific embodiments. Preferred embodiments of the invention are given in the specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0033] The order in which the embodiments are described below is not intended to limit the preferred order of the embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". Various embodiments of the invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0034] This invention provides a bio-based filtration loss reducer, comprising the following raw materials in parts by weight: 15-30 parts of aminopolysaccharide, 2-acrylamide-2-methylpropanesulfonic acid (chemical formula C7H12H2O) 13 NO4S (CAS No.: 15214-89-8) 10~20 parts, propylene monomer 10~20 parts, quaternary ammonium salt monomer 15~30 parts, crosslinking agent 0.05~0.25 parts, initiator 1~2 parts;

[0035] Among them, aminopolysaccharide is a product obtained by extracting crayfish shells and / or crab shells using an acid-base method.

[0036] In some embodiments, the method for preparing aminopolysaccharides includes:

[0037] The shells of crayfish and / or crabs were dissolved in sodium hydroxide solution A, hydrochloric acid solution, hydrogen peroxide solution and sodium hydroxide solution B in sequence. After the reaction was complete, the mixture was washed and dried to obtain amino polysaccharides.

[0038] The propylene monomer includes at least one of acrylamide (chemical formula C3H5NO, CAS No.: 79-06-1), N,N-dimethylacrylamide (CAS No.: 2680-03-7, chemical formula C5H9NO), and methacrylamide (CAS No.: 79-39-0, chemical formula C4H7NO);

[0039] Quaternary ammonium salt monomers include 3-chloro-2-hydroxypropyl-trimethylammonium chloride (CAS No.: 3327-22-8, Chemical Formula: C6H). 15 Cl2NO), methacryloyloxyethyltrimethylammonium chloride (CAS No. 5039-78-1, chemical formula C9H) 18 ClNO2), dimethyl diallyl ammonium chloride (CAS No.: 7398-69-8, chemical formula: C8H) 16 At least one of ClN);

[0040] The crosslinking agent is N,N-methylenebisacrylamide (CAS No.: 110-26-9, chemical formula C7H). 10 N2O2);

[0041] The initiator includes at least one of sodium persulfate (Na2S2O8), potassium persulfate (K2S2O8), and ammonium persulfate ((NH4)2S2O8).

[0042] Based on the same inventive concept, the present invention also provides a method for preparing the above-mentioned bio-based filtration reduction agent, comprising the following steps:

[0043] Aminopolysaccharide and monochloroacetic acid (chemical formula C2H3ClO2) were dissolved in sodium hydroxide solution C. After the reaction was complete, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer and quaternary ammonium salt monomer were added. The pH was adjusted to 9-10. After stirring, crosslinking agent and initiator were added and the reaction continued. After the reaction was completed, the product was washed and dried to obtain the bio-based filtration loss reducer.

[0044] In some embodiments, crayfish shells and / or crab shells are placed in a sodium hydroxide solution A with a concentration of 1-2 mol / L and reacted for 24-30 hours, then in a hydrochloric acid solution with a concentration of 1-2 mol / L and reacted for 24-30 hours, then in hydrogen peroxide solution with a mass fraction of 5-8% and reacted for 24-30 hours, and finally in sodium hydroxide solution B with a mass fraction of 10-12% and reacted for 4-6 hours. After washing and drying, aminopolysaccharides are obtained.

[0045] Specifically, crayfish shells and / or crab shells are placed in a 1-2 mol / L sodium hydroxide solution A and reacted for 24-30 hours (to remove proteins and fats from the shells). After filtration and washing, a first solid product is obtained. The first solid product is then placed in a 1-2 mol / L hydrochloric acid solution and reacted for 24-30 hours (to dissolve calcium carbonate and the main inorganic components of the shells). After filtration and washing, a second solid product is obtained. The second solid product is then placed in a 5-8% hydrogen peroxide solution and reacted for 24-30 hours (to remove pigments and residual organic impurities). After filtration and washing, a third solid product is obtained. The third solid product is then placed in a 10-12% sodium hydroxide solution B (to further purify the polysaccharide) and reacted for 4-6 hours. After filtration, washing, and drying, a fourth solid product, namely aminopolysaccharide, is obtained.

[0046] In this invention, the crayfish shells and / or crab shells used are discarded crayfish shells and / or crab shells. The aminopolysaccharides extracted from these shells possess a unique natural zwitterionic polymer structure. The positively charged amino groups are the core components for achieving charge neutralization and efficient adsorption, while the abundant hydroxyl groups further enhance adsorption and film-forming capabilities. This natural structure endows it with excellent filtration loss reduction potential, and the active groups provide strong modifiability.

[0047] In some embodiments, aminopolysaccharide and monochloroacetic acid are dissolved in sodium hydroxide solution C and reacted at a temperature of 40-45°C and a stirring speed of 400-600 r / min for 3-5 h. Then, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer and quaternary ammonium salt monomer are added, the pH is adjusted to 9-10, and after stirring, a crosslinking agent and an initiator are added and the reaction continues. After the reaction is completed, the mixture is washed and dried to obtain a bio-based filtration loss reducer.

[0048] Specifically, by modifying and grafting aminopolysaccharides, abundant carboxyl functional groups, amide groups, quaternary ammonium groups, and sulfonic acid groups are introduced, enhancing the steric hindrance and clay adsorption capacity of the molecular chain, and improving the filtration loss reduction, thermal stability, and salt resistance of the synthesized materials. Specifically, monochloroacetic acid reacts with the hydroxyl / amino groups of aminopolysaccharides under alkaline conditions to introduce carboxyl groups (-COOH), propylene monomers (such as acrylamide) are grafted with intermediates to introduce amide groups (-CONH2), and quaternary ammonium salt monomers (such as dimethyl diallyl ammonium chloride) are copolymerized to introduce positively charged quaternary ammonium ions (-N). +(CH3)3, 2-acrylamide-2-methylpropanesulfonic acid, and sulfonic acid groups (-SO3H) are introduced after copolymerization; these groups are not simply "added", but are specifically designed to solve performance problems - carboxyl groups and sulfonic acid groups can improve hydrophilicity and salt resistance, quaternary ammonium groups can enhance the adsorption of clay (electrode neutralization), and amide groups can enhance thermal stability, together making the molecular chain "more active, with stronger adsorption force and better resistance to harsh environments (high temperature / high salt)".

[0049] The preparation method of the bio-based filtration loss reducing agent of the present invention involves using waste crayfish and crab shells as raw materials, treating them with an acid-base method to obtain amino polysaccharides, modifying them with monochloroacetic acid carboxylation, and then copolymerizing them with propylene monomers, quaternary ammonium salt monomers, and 2-acrylamide-2-methylpropanesulfonic acid to obtain an environmentally friendly zwitterionic bio-based filtration loss reducing agent. The environmentally friendly zwitterionic temperature- and salt-resistant bio-based filtration loss reducing agent provided by the present invention exhibits EC biotoxicity. 50 The concentration of the filtration loss reducer is greater than 100,000 mg / L, and the biodegradable BOD / CODcr value is greater than 0.05, classifying it as non-toxic and easily degradable. The prepared filtration loss reducer exhibits good filtration loss reduction and temperature resistance at room temperature and 100~200℃. When added to brine-based slurry or saturated brine, it still maintains excellent temperature and salt resistance. The raw materials for the filtration loss reducer are widely available and inexpensive, and can be used in geological drilling operations to maintain wellbore stability, ensuring the smooth progress of geological drilling operations. The preparation method and application achieve the high-value utilization of natural polymer materials.

[0050] In some embodiments, aminopolysaccharides and monochloroacetic acid are dissolved in sodium hydroxide solution C. After the reaction is complete, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer and quaternary ammonium salt monomer are added, the pH is adjusted to 9-10, and the mixture is stirred at 60-70°C and 400-600 r / min for 3-5 h. A crosslinking agent and an initiator are added, and the reaction is continued to be stirred for 1-2 h. After the reaction is completed, the mixture is washed and dried to obtain a bio-based filtration loss reducer.

[0051] In some embodiments, in the step of dissolving aminopolysaccharides and monochloroacetic acid in sodium hydroxide solution C, the mass fraction of sodium hydroxide solution C is 20-25%.

[0052] The mass-to-volume ratio of aminopolysaccharide, monochloroacetic acid, and sodium hydroxide solution C is (15~30)g:(40~60)g:(100~120)mL.

[0053] In some embodiments, the mass ratio of aminopolysaccharide, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer, quaternary ammonium salt monomer, crosslinking agent, and initiator is (15~30):(10~20):(10~20):(15~30):(0.05~0.25):(1~2).

[0054] Preferably, the mass ratio of aminopolysaccharide, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer, quaternary ammonium salt monomer, crosslinking agent, and initiator is 30:20:20:30:(0.05~0.25):(1~2).

[0055] In some embodiments, the mass-to-volume ratio of crayfish shells and / or crab shells, sodium hydroxide solution A, hydrochloric acid solution, hydrogen peroxide, and sodium hydroxide solution B is 1g:(10~50)mL:(10~50)mL:(10~50)mL:(5~30)mL.

[0056] In some embodiments, the pH is adjusted to 9-10, and the pH adjusting reagents used include a 1 mol / L NaOH solution and a 1 mol / L hydrochloric acid solution.

[0057] In some embodiments, aminopolysaccharides and monochloroacetic acid are dissolved in sodium hydroxide solution C and reacted at a temperature of 40-45°C and a stirring speed of 400-600 r / min for 3-5 h. Then, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer and quaternary ammonium salt monomer are added, the pH is adjusted to 9-10, and after stirring, a crosslinking agent and an initiator are added and the reaction continues. After the reaction is completed, the mixture is washed and dried to obtain a bio-based filtration loss reducer. The washing agent used is anhydrous ethanol, the drying temperature is 65-80°C, and after drying, the mixture is ground and sieved to obtain a bio-based filtration loss reducer with a sieve mesh size of 100-200 mesh.

[0058] The environmentally friendly zwitterionic temperature- and salt-resistant bio-based filtration loss reducer provided by this invention has a molecular weight of 200,000 to 400,000 and a biotoxicity EC50. 50 The concentration of the filtration loss reducer is greater than 100,000 mg / L, and the biodegradable BOD / CODcr value is greater than 0.05, classifying it as non-toxic and easily degradable. The filtration loss reducer exhibits good filtration loss reduction and temperature resistance at room temperature and 100-200℃. When added to brine-based slurry or saturated brine, it still maintains excellent temperature and salt resistance, overcoming the problems of easy degradation, poor environmental performance, and difficulty in degradation under high-temperature conditions found in existing technologies. The filtration loss reducer has widely available raw materials, mild and easily controllable synthesis conditions, a simple synthesis route, and low cost, making it economically viable and marketable. It can be applied in geological drilling operations to maintain wellbore stability, ensuring the smooth progress of geological drilling operations. The above preparation method and application achieve the high-value utilization of natural polymer materials.

[0059] Based on the same inventive concept, the present invention also provides the application of the above-mentioned bio-based filtration reducer or the bio-based filtration reducer prepared by the above-mentioned preparation method in the preparation of drilling fluid.

[0060] The following specific embodiments further illustrate the bio-based filtration loss reducing agent of the present invention, its preparation method, and its application. This section further illustrates the content of the present invention in conjunction with specific embodiments, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0061] Example 1

[0062] This embodiment provides a method for preparing a bio-based filtration loss reducing agent, including the following steps:

[0063] S1. Wash and dry the discarded crayfish and crab shells (including crayfish shells and crab shells, with a mass ratio of crayfish shells to crab shells of 1:1) for later use.

[0064] S2. Dissolve waste crayfish and crab shells in a 1 mol / L sodium hydroxide solution A and react for 24 hours, then react in a 1 mol / L hydrochloric acid solution for 24 hours, then react in a 5% hydrogen peroxide solution for 24-30 hours, and finally react in a 10% sodium hydroxide solution B for 4 hours. After washing and drying, aminopolysaccharide is obtained. The mass-volume ratio of waste crayfish and crab shells, sodium hydroxide solution A, hydrochloric acid solution, hydrogen peroxide, and sodium hydroxide solution B is 1 g:30 mL:20 mL:40 mL:25 mL.

[0065] S3. Dissolve 30 g of amino polysaccharide in 100 mL of 20% sodium hydroxide solution C, add 45 g of monochloroacetic acid, and stir at a reaction temperature of 40 °C and a speed of 500 r / min for 3 h to obtain the intermediate product of the filtration loss reducer.

[0066] S4. Continue to add 20g acrylamide, 20g 2-acrylamide-2-methylpropanesulfonic acid, and 30g dimethyldiallylammonium chloride to the reaction system of step S3. Adjust the pH to 10, and stir at 65℃ and 500 r / min for 3h. Then add 0.2g N,N-methylenebisacrylamide and 2g ammonium persulfate, and continue stirring for 1h. After the reaction is completed, wash and dry to obtain the bio-based filtration reducer.

[0067] Example 2

[0068] The preparation method of the bio-based filtration loss reducer provided in this embodiment is the same as that in Example 1, except that in step S4, acrylamide is replaced with N,N-dimethylacrylamide and ammonium persulfate is replaced with potassium persulfate. All other process parameters are the same as in Example 1.

[0069] Example 3

[0070] The preparation method of the bio-based filtration loss reducer provided in this embodiment is the same as that in Example 1, except that in step S4, dimethyl diallyl ammonium chloride is replaced with methacryloyloxyethyl trimethyl ammonium chloride, and ammonium persulfate is replaced with sodium persulfate. All other process parameters are the same as in Example 1.

[0071] Example 4

[0072] The preparation method of the bio-based filtration loss reducer provided in this embodiment is the same as that in Example 1, except that in step S4, acrylamide is replaced with methacrylamide and dimethyl diallyl ammonium chloride is replaced with 3-chloro-2-hydroxypropyl-trimethylammonium chloride. All other process parameters are the same as in Example 1.

[0073] Comparative Example 1

[0074] The preparation method of the bio-based filtration loss reducer provided in this comparative example is the same as that in Example 1, except that in steps S3 to S4, the mass of aminopolysaccharide is 30g, the mass of acrylamide is 60g, the mass of 2-acrylamide-2-methylpropanesulfonic acid is 60g, and the mass of dimethyl diallyl ammonium chloride is 15g, that is, the mass ratio of aminopolysaccharide, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, and dimethyl diallyl ammonium chloride is 1:2:2:0.5. All other process parameters are the same as those in Example 1.

[0075] Comparative Example 2

[0076] The preparation method of the bio-based filtration reduction agent provided in this comparative example is the same as that in Example 1, except that in steps S3 to S4, the mass of aminopolysaccharide is 30g, the mass of acrylamide is 15g, the mass of 2-acrylamide-2-methylpropanesulfonic acid is 30g, and the mass of dimethyl diallyl ammonium chloride is 15g, that is, the mass ratio of aminopolysaccharide, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, and dimethyl diallyl ammonium chloride is 2:1:2:1. All other process parameters are the same as those in Example 1.

[0077] Comparative Example 3

[0078] The preparation method of the bio-based filtration reduction agent provided in this comparative example is the same as that in Example 1, except that in steps S3 to S4, the mass of aminopolysaccharide is 30g, the mass of acrylamide is 15g, the mass of 2-acrylamide-2-methylpropanesulfonic acid is 22.5g, and the mass of dimethyl diallyl ammonium chloride is 7.5g, that is, the mass ratio of aminopolysaccharide, acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, and dimethyl diallyl ammonium chloride is 4:2:3:1. All other process parameters are the same as those in Example 1.

[0079] Comparative Example 4

[0080] The preparation method of the bio-based filtration loss reducer provided in this comparative example is the same as that in Example 1, except that in steps S3 to S4, the mass of aminopolysaccharide is 30g, the mass of acrylamide is 22.5g, the mass of 2-acrylamido-2-methylpropanesulfonic acid is 7.5g, and the mass of dimethyl diallyl ammonium chloride is 3.75g, that is, the mass ratio of aminopolysaccharide, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and dimethyl diallyl ammonium chloride is 4:3:1:0.5. All other process parameters are the same as those in Example 1.

[0081] Performance testing

[0082] 1. Filtration loss reduction performance test

[0083] The filtration reduction performance of the bio-based filtration reducers prepared in Examples 1-4 and Comparative Examples 1-4 was tested in accordance with GB / T16783.1-2014: Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry - Part 1: Water.

[0084] Freshwater-based slurry: Add 400 mL of tap water to a high-speed stirring cup, and add 16.0 g of bentonite and 0.8 g of sodium carbonate while stirring continuously. After stirring at high speed for 20 min, cure in a sealed container for 24 h.

[0085] Salt-based slurry: Add 400 mL of tap water to a high-speed stirring cup, add 16 g of bentonite and 0.8 g of sodium carbonate, as well as different concentrations of NaCl or CaCl2, while stirring continuously. After stirring at high speed for 20 min, cure in a sealed container for 24 h.

[0086] Relevant testing instruments and conditions: The API filtration loss (FL) of drilling fluid was tested using an APL medium-pressure filtration meter and a high-temperature, high-pressure filtration meter, respectively. API ) and high temperature and high pressure filtration loss (FL) HTHP The APL medium-pressure filtration tester requires 250 mL of sample, a test pressure of 0.69 MPa, a test temperature of room temperature, and a test time of 30 min; the high-temperature high-pressure filtration tester requires 150 mL of sample, a test pressure of 4.2 MPa, and test temperatures of 100, 120, 150, 180℃, and 200℃, with a test time of 30 min.

[0087] Eight g of the bio-based filtration reducer prepared in Examples 1-4 and Comparative Examples 1-4 were weighed and added to 400 mL of fresh water-based or brine-based drilling fluid. After thorough stirring, the filtration loss of the drilling fluid was measured. The results are shown in Table 1.

[0088] Table 1 - Effect of bio-based filtration reducers prepared in different embodiments on drilling fluid filtration loss

[0089]

[0090] Table 2 - Effects of different NaCl concentrations on drilling fluid filtrate loss (FL) API Impact

[0091]

[0092] Table 3 - Effects of CaCl2 concentration on drilling fluid filtrate loss (FL) API Impact

[0093]

[0094] Table 4 - Effect of different temperatures on drilling fluid filtrate loss

[0095]

[0096] As can be seen from Tables 1-4, the filtration loss reducing agents prepared in Examples 1-4 of the present invention have good filtration loss reducing performance and good temperature and salt resistance. However, in Comparative Examples 1-4, the problem is that changing the ratio of synthetic monomers during the preparation of the filtration loss reducing agent affects the grafting rate, molecular composition and effect of the synthetic reagent.

[0097] 2. Rheological property testing

[0098] 8g of the bio-based filtration reducer prepared in Examples 1-4 and Comparative Examples 1-4 were weighed and added to 400mL of fresh water-based or brine-based drilling fluid. After thorough stirring, the apparent viscosity, plastic viscosity, and dynamic shear force of the drilling fluid were measured using a six-speed rotational viscometer. The results are shown in Table 5.

[0099] Table 5 - Effects of bio-based fluid loss reducers prepared in different embodiments on drilling fluid plastic viscosity and dynamic shear force.

[0100]

[0101] As can be seen from Table 5, the filtration loss reducing agents prepared in Examples 1-4 of this invention have good rheological properties. The problem with Comparative Examples 1-4 is that changing the ratio of synthetic monomers during the preparation of the filtration loss reducing agents affects the grafting rate, molecular composition, and effectiveness of the synthetic reagents.

[0102] 3. Environmental performance evaluation

[0103] Referring to the luminescent bacteria method used in the "Technical Requirements for Environmental Protection of Water-Soluble Oilfield Chemicals" (SY / T 6787-2010) for evaluating the biotoxicity of water-soluble oilfield chemicals, EC 50 <1 mg / L, highly toxic; 1 < EC 50 ≤100 mg / L, highly toxic; 101 < EC 50 ≤1000 mg / L, poisoning; 1001 < EC50 ≤20000 mg / L, slightly toxic; EC 50 >20000 mg / L, non-toxic. Test results are shown in Table 6.

[0104] Referring to the "Technical Requirements for Environmental Protection of Water-Soluble Oilfield Chemicals" (SY / T 6787-2010), the BOD / CODcr ratio method is used to evaluate the biodegradability of aqueous oilfield chemicals. BOD / CODcr < 0.01 indicates difficult degradation; 0.01 ≤ BOD / CODcr < 0.05 indicates relatively difficult degradation; and BOD / CODcr ≥ 0.05 indicates easy degradation. The test results of the bio-based filtration loss reducers prepared in Examples 1-4 and Comparative Examples 1-4 are shown in Table 6.

[0105] Table 6 - Biotoxicity EC of bio-based filtration reduction agents prepared in different embodiments 50 and biodegradable BOD / CODcr value

[0106]

[0107] As shown in Table 6, the filtration loss reducing agents prepared in Examples 1-4 of this invention all have a biotoxicity greater than 100,000 mg / L and a BOD / CODcr value greater than 0.05, indicating that they are non-toxic and easily degradable. The test results demonstrate that the filtration loss reducing agents prepared in this invention have good environmental performance.

[0108] Figure 1 The Fourier transform infrared spectrum of the bio-based filtration reduction agent prepared in Example 1 is shown below. Figure 1 As can be seen from the spectrum of the bio-based filtration reducer prepared in Example 1, the spectrum is at 3450 cm⁻¹. -1 2926 cm -1 1654 cm -1 1576 cm -1 1412cm -1 1316 cm -1 1159 cm -1 1044 cm -1 and 622 cm -1 Characteristic peaks were observed at the positions corresponding to the NH stretching vibration, CH stretching vibration, C=O stretching vibration, CN stretching vibration, CO stretching vibration, C6-H2 stretching vibration, COC glycosidic bond stretching vibration, S=O stretching vibration, and CS stretching vibration, respectively. This indicates that the synthesized filtration reducer contains functional groups such as carboxyl, amide, sulfonic acid, and quaternary ammonium groups, and that all synthetic monomers were successfully grafted, achieving the expected goal.

[0109] It is understood that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0110] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.

Claims

1. A bio-based filtration loss reducer, characterized in that, The raw materials include the following parts by weight: 15-30 parts of aminopolysaccharide, 10-20 parts of 2-acrylamide-2-methylpropanesulfonic acid, 10-20 parts of propylene monomer, 15-30 parts of quaternary ammonium salt monomer, 0.05-0.25 parts of crosslinking agent, and 1-2 parts of initiator; The aminopolysaccharide is a product obtained by extracting crayfish shells and / or crab shells using an acid-base method.

2. The bio-based filtration loss reducer as described in claim 1, characterized in that, The method for preparing the aminopolysaccharide includes: The shells of crayfish and / or crabs were dissolved in sodium hydroxide solution A, hydrochloric acid solution, hydrogen peroxide solution and sodium hydroxide solution B in sequence. After the reaction was complete, the mixture was washed and dried to obtain amino polysaccharides. The propylene monomer includes at least one of acrylamide, N,N-dimethylacrylamide, and methacrylamide; The quaternary ammonium salt monomer includes at least one of 3-chloro-2-hydroxypropyltrimethylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, and dimethyldiallylammonium chloride; The crosslinking agent is N,N-methylenebisacrylamide; The initiator includes at least one of sodium persulfate, potassium persulfate, and ammonium persulfate.

3. A method for preparing a bio-based filtration loss reducing agent as described in any one of claims 1 to 2, characterized in that, Includes the following steps: Aminopolysaccharide and monochloroacetic acid were dissolved in sodium hydroxide solution C. After the reaction was complete, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer and quaternary ammonium salt monomer were added. The pH was adjusted to 9-10. After stirring, crosslinking agent and initiator were added and the reaction was continued. After the reaction was completed, the mixture was washed and dried to obtain the bio-based filtration loss reducer.

4. The method for preparing the bio-based filtration loss reducer as described in claim 3, characterized in that, Crayfish shells and / or crab shells are placed in a 1-2 mol / L sodium hydroxide solution A and reacted for 24-30 hours, then in a 1-2 mol / L hydrochloric acid solution and reacted for 24-30 hours, then in a 5-8% hydrogen peroxide solution and reacted for 24-30 hours, and finally in a 10-12% sodium hydroxide solution B and reacted for 4-6 hours. After washing and drying, aminopolysaccharides are obtained.

5. The method for preparing the bio-based filtration loss reducer as described in claim 3, characterized in that, Aminopolysaccharide and monochloroacetic acid were dissolved in sodium hydroxide solution C and reacted at a temperature of 40-45℃ and a stirring speed of 400-600 r / min for 3-5 h. Then, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer and quaternary ammonium salt monomer were added, the pH was adjusted to 9-10, and after stirring, crosslinking agent and initiator were added and the reaction continued. After the reaction was completed, the product was washed and dried to obtain the bio-based filtration loss reducer.

6. The method for preparing the bio-based filtration loss reducer as described in claim 3, characterized in that, Aminopolysaccharide and monochloroacetic acid were dissolved in sodium hydroxide solution C. After the reaction was complete, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer and quaternary ammonium salt monomer were added. The pH was adjusted to 9-10. The mixture was stirred at 60-70℃ and 400-600r / min for 3-5h. Crosslinking agent and initiator were added, and the reaction was continued for 1-2h. After the reaction was completed, the mixture was washed and dried to obtain the bio-based filtration loss reducer.

7. The method for preparing the bio-based filtration loss reducer as described in claim 3, characterized in that, In the step of dissolving aminopolysaccharide and monochloroacetic acid in sodium hydroxide solution C, the mass fraction of sodium hydroxide solution C is 20-25%. The mass-to-volume ratio of the aminopolysaccharide, monochloroacetic acid, and sodium hydroxide solution C is (15~30)g:(40~60)g:(100~120)mL.

8. The method for preparing the bio-based filtration loss reducer as described in claim 3, characterized in that, The mass ratio of the aminopolysaccharide, 2-acrylamide-2-methylpropanesulfonic acid, propylene monomer, quaternary ammonium salt monomer, crosslinking agent, and initiator is (15~30):(10~20):(10~20):(15~30):(0.05~0.25):(1~2).

9. The method for preparing the bio-based filtration loss reducer as described in claim 4, characterized in that, The mass-to-volume ratio of the crayfish shell and / or crab shell, sodium hydroxide solution A, hydrochloric acid solution, hydrogen peroxide, and sodium hydroxide solution B is 1g:(10~50)mL:(10~50)mL:(10~50)mL:(5~30)mL.

10. The application of a bio-based fluid loss reducer as described in any one of claims 1 to 2 or a bio-based fluid loss reducer prepared by any one of claims 3 to 9 in the preparation of drilling fluid.

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