Preparation method of high temperature and salt resistant fluid loss reducer for drilling fluid

Abstract

This invention belongs to the field of petroleum development and discloses a method for preparing a high-temperature and salt-resistant fluid loss reducer for drilling fluid. The method involves dissolving N-(3-acetylphenyl)-N-vinylmethacrylamide and p-acetamidobenzenesulfonyl chloride in tetrahydrofuran, followed by the addition of catalysts copper bromide and sodium carbonate. Nitrogen is introduced, and the mixture is heated to react. The mixture is then extracted with chloroform and concentrated to obtain Product A. Purified water, acrylamide, acrylic acid, AMPS, hexadecyldimethylallyl ammonium chloride, and Product A are added to a liquid preparation tank. The pH is adjusted with NaOH, the temperature is lowered, nitrogen is flushed, and a chain transfer agent, an oxidizing agent, and a reducing agent are added to obtain a white elastic solid. After shearing, the solid is dried, ground, and sieved to obtain a white powder, which is a high-temperature and salt-resistant fluid loss reducer for drilling fluid. This product can be used as a fluid loss reducer for saturated brine drilling fluid under high-temperature conditions of 220°C.

Description

Technical Field

[0001] The invention belongs to the field of petroleum development, and more particularly relates to a method for preparing a high-temperature and salt-resistant fluid loss reducer for drilling fluid. Background Art

[0002] Polyacrylamide is commonly used in drilling fluids and is a synthetic product with excellent performance and low cost. It exhibits excellent thickening, drag reduction, fluid loss reduction, and flocculation properties. However, its disadvantages are also significant: poor shear stability, salt tolerance, and thermal stability. However, these can be improved through chemical modification. 2-Acrylamido-2-methylpropanesulfonic acid (AMPS) is the most commonly used modifying monomer. AMPS can form multi-component copolymers with acrylamide and other functional monomers, effectively improving heat and salt resistance and finding application in oilfield applications. The introduction of different monomers into these copolymers can impart varying properties. Among the commonly used groups, sulfonyl and pyrrolidone groups offer excellent salt and temperature resistance, amide groups offer excellent adsorption properties, and carboxyl groups offer excellent hydration capabilities.

[0003] However, as oil and gas drilling continues to go deeper, formation temperatures are rising, and more and more salt rock and salt-gypsum layers are being encountered. This places higher demands on the temperature and salt resistance of drilling fluids, and current products struggle to meet these high demands. This necessitates the search for more suitable functional monomers to improve performance. Summary of the Invention

[0004] The main purpose of the present invention is to synthesize a new functional monomer and provide a method for preparing a high-temperature and salt-resistant fluid loss reducer for drilling fluid.

[0005] The technical solution adopted by the present invention is: a method for preparing a high temperature and salt resistant fluid loss reducer for drilling fluid, characterized in that the steps are:

[0006] (1) Weigh 150 parts by mass of N-(3-acetylphenyl)-N-vinylmethacrylamide and 306 parts by mass of p-acetamidobenzenesulfonyl chloride;

[0007] (2) Add 300 parts of tetrahydrofuran solvent into a three-necked flask, add the raw materials from step 1), add 2 parts of copper bromide and 2 parts of sodium carbonate;

[0008] (3) Continuously introduce nitrogen, raise the temperature to 90°C, and react for 12 hours;

[0009] (4) Extract with chloroform several times, combine the extracts, and concentrate to obtain the final product, functional monomer A. The reaction formula is as follows: ;

[0010] (5) Add 750-850 parts of purified water, 450-550 parts of acrylamide (AM), 60-80 parts of acrylic acid (AA), 80-100 parts of AMPS, 5-20 parts of hexadecyldimethylallyl ammonium chloride (C16DMAAC), and 10-40 parts of functional monomer A to the liquid preparation tank by mass and stir thoroughly.

[0011] (6) Adjust the pH to 6-7 with NaOH and cool to 0-2°C;

[0012] (7) After blowing N2 for 15 minutes, add 0.01-0.3 parts of chain transfer agent, 0.02-0.1 parts of oxidant, 0.02-0.1 parts of reducing agent, and 0.02-0.1 parts of initiator. After the temperature of the reaction liquid rises and the wire is drawn, remove the nitrogen and seal the reactor. After the reaction is completed, a white elastic solid product is obtained;

[0013] (8) The white elastic solid product is crushed into a machine and then placed in an oven for drying to obtain white solid particles;

[0014] (9) Grind the white solid particles and pass them through an 80-mesh sieve to obtain a white powder which is a high-temperature and salt-resistant fluid loss reducer for drilling fluid.

[0015] The chain transfer agent is a mixture of one or more of aliphatic mercaptans, xanthogenic acid disulfides, polyphenols, sulfur, halides and nitroso compounds.

[0016] The oxidant is one or more of tert-butyl hydroperoxide, potassium persulfate, sodium persulfate, and ammonium persulfate.

[0017] The initiator is one or more of azobisisobutylimidazoline hydrochloride, azobisisobutyronitrile, azobisisovaleronitrile and azobisisobutylamidine hydrochloride.

[0018] The reducing agent is one or more of potassium metabisulfite, sodium metabisulfite, ferrous sulfate, ammonium ferrous sulfate, and sodium methanesulfinate.

[0019] The present invention has the following beneficial effects: N-(3-acetylphenyl)-N-vinylmethacrylamide contains functional groups -CO and a benzene ring. The -CO carbonyl group undergoes an addition reaction with water to generate two -OH groups. The -OH groups readily form hydrogen bonds with water, adsorbing water while also improving salt resistance. As a rigid group, the benzene ring is resistant to damage at high temperatures and is shear-resistant, resulting in excellent high-temperature resistance. This significantly contributes to the stability of drilling fluids, high-temperature and high-pressure fluid loss and wall formation, and resistance to salt and calcium corrosion. p-Acetamidobenzenesulfonyl chloride contains functional groups -CONH and -SO2. -CONH slowly hydrolyzes at high temperatures to form -COOH, which readily forms hydrogen bonds with water, adsorbing water while also providing high salt resistance. The -SO2 sulfonyl group has unique physicochemical properties. The sulfonyl group can slightly increase the solubility of the product and provide two hydrogen bond acceptors. Furthermore, the sulfonyl group is relatively stable and resistant to damage. The introduction of the sulfonyl group improves the product's high-temperature and salt resistance. Product A combines the advantageous functional groups of the two raw materials, and the reaction also generates a pyrrolidone group. This functional group has a stable structure and is not easily destroyed at high temperatures, further improving the high-temperature resistance. DETAILED DESCRIPTION

[0020] Example 1: 1) Weigh 150 parts by mass of N-(3-acetylphenyl)-N-vinylmethacrylamide and 306 parts by mass of p-acetamidobenzenesulfonyl chloride;

[0021] 2) Add 300 parts of tetrahydrofuran solvent into a three-necked flask, add the raw materials from step 1), add 2 parts of copper bromide and 2 parts of sodium carbonate;

[0022] 3) Continue to introduce nitrogen, raise the temperature to 90°C, and react for 12 hours;

[0023] 4) Extracting with chloroform several times, combining the extracts, and concentrating to obtain the final product, functional monomer A;

[0024] 5) Add 796 parts of purified water, 520 parts of acrylamide (AM), 70 parts of acrylic acid (AA), 88 parts of AMPS, 10 parts of hexadecyldimethylallyl ammonium chloride (C16DMAAC), and 15 parts of the final product functional monomer A to the liquid preparation tank and stir thoroughly.

[0025] 6) Adjust the pH to 6.5 with NaOH and cool to 1.6°C;

[0026] 7) After N2 was introduced for 15 minutes, 0.1 parts of sodium hypophosphite, 0.03 parts of tert-butyl hydroperoxide, 0.04 parts of ammonium ferrous sulfate, and 0.03 parts of azobisisobutyronitrile were added. After the reaction solution temperature increased and a wire was drawn, the nitrogen was removed and the reactor was sealed. After the reaction was completed, a white elastic solid product was obtained;

[0027] 8) The white elastic solid product is crushed into pieces by a machine and then placed in an oven for drying to obtain white solid particles;

[0028] 9) Grind the white solid particles and pass them through an 80-mesh sieve. The resulting white powder is the high-temperature and salt-resistant fluid loss reducer for drilling fluid.

[0029] Example 2: 1) Weigh 150 parts by mass of N-(3-acetylphenyl)-N-vinylmethacrylamide and 306 parts by mass of p-acetamidobenzenesulfonyl chloride;

[0030] 2) Add 300 parts of tetrahydrofuran solvent to a three-necked flask, add the raw material from 1), 2 parts of copper bromide, and 2 parts of sodium carbonate;

[0031] 3) Continue to introduce nitrogen, raise the temperature to 90°C, and react for 12 hours;

[0032] 4) Extracting with chloroform several times, combining the extracts, and concentrating to obtain the final product, functional monomer A;

[0033] 5) Add 786 parts of purified water, 520 parts of acrylamide (AM), 70 parts of acrylic acid (AA), 88 parts of AMPS, 10 parts of hexadecyldimethylallyl ammonium chloride (C16DMAAC), and 25 parts of the final product functional monomer A to the liquid preparation tank and stir thoroughly;

[0034] 6) Adjust the pH to 6.5 with NaOH and cool to 1.5°C;

[0035] 7) After N2 was introduced for 15 minutes, 0.1 parts of sodium hypophosphite, 0.03 parts of tert-butyl hydroperoxide, 0.04 parts of ammonium ferrous sulfate, and 0.03 parts of azobisisobutyronitrile were added. After the reaction solution temperature increased and a wire was drawn, the nitrogen was removed and the reactor was sealed. After the reaction was completed, a white elastic solid product was obtained;

[0036] 8) The white elastic solid product is crushed into pieces by a machine and then placed in an oven for drying to obtain white solid particles;

[0037] 9) Grind the white solid particles and pass them through an 80-mesh sieve. The resulting white powder is the high-temperature and salt-resistant fluid loss reducer for drilling fluid.

[0038] Example 3: 1) Weigh 150 parts by mass of N-(3-acetylphenyl)-N-vinylmethacrylamide and 306 parts by mass of p-acetamidobenzenesulfonyl chloride;

[0039] 2) Add 300 parts of tetrahydrofuran solvent to a three-necked flask, add the raw material from 1), 2 parts of copper bromide, and 2 parts of sodium carbonate;

[0040] 3) Continue to introduce nitrogen, raise the temperature to 90°C, and react for 12 hours;

[0041] 4) Extracting with chloroform several times, combining the extracts, and concentrating to obtain the final product, functional monomer A;

[0042] 5) Add 776 parts of purified water, 520 parts of acrylamide (AM), 70 parts of acrylic acid (AA), 88 parts of AMPS, 10 parts of hexadecyldimethylallyl ammonium chloride (C16DMAAC), and 35 parts of the final product functional monomer A to the liquid preparation tank and stir thoroughly.

[0043] 6) Adjust the pH to 6.5 with NaOH and cool to 1.4°C;

[0044] 7) After N2 was introduced for 15 minutes, 0.1 parts of sodium hypophosphite, 0.03 parts of tert-butyl hydroperoxide, 0.04 parts of ammonium ferrous sulfate, and 0.03 parts of azobisisobutyronitrile were added. After the reaction solution temperature increased and a wire was drawn, the nitrogen was removed and the reactor was sealed. After the reaction was completed, a white elastic solid product was obtained;

[0045] 8) The white elastic solid product is crushed into pieces by a machine and then placed in an oven for drying to obtain white solid particles;

[0046] 9) Grind the white solid particles and pass them through an 80-mesh sieve to obtain a white powder which is a high-temperature and salt-resistant fluid loss reducer for drilling fluid.

[0047] Comparative Example 1: 1) Add 776 parts of purified water, 520 parts of acrylamide (AM), 70 parts of acrylic acid (AA), 88 parts of AMPS, and 10 parts of hexadecyldimethylallyl ammonium chloride (C16DMAAC) to a liquid preparation tank and stir thoroughly.

[0048] 2) Adjust the pH to 6.5 with NaOH and cool to 1.4°C;

[0049] 3) After N2 was introduced for 15 minutes, 0.1 parts of sodium hypophosphite, 0.03 parts of tert-butyl hydroperoxide, 0.04 parts of ammonium ferrous sulfate, and 0.03 parts of azobisisobutyronitrile were added. After the reaction solution temperature increased and a wire was drawn, the nitrogen was removed and the reactor was sealed. After the reaction was completed, a white elastic solid product was obtained.

[0050] 4) The white elastic solid product is crushed into pieces by a machine and then placed in an oven for drying to obtain white solid particles;

[0051] 5) Grind the white solid particles and pass them through an 80-mesh sieve to obtain a white powder.

[0052] Comparative Example 2: 1) Add 741 parts of purified water, 520 parts of acrylamide (AM), 70 parts of acrylic acid (AA), 88 parts of AMPS, 10 parts of hexadecyldimethylallyl ammonium chloride (C16DMAAC), 35 parts of N-(3-acetylphenyl)-N-vinylmethacrylamide, and 35 parts of p-acetamidobenzenesulfonyl chloride to a liquid preparation tank and stir thoroughly.

[0053] 2) Adjust the pH to 6.5 with NaOH and cool to 1.8°C;

[0054] 3) After N2 was introduced for 15 minutes, 0.1 parts of sodium hypophosphite, 0.03 parts of tert-butyl hydroperoxide, 0.04 parts of ammonium ferrous sulfate, and 0.03 parts of azobisisobutyronitrile were added. After the reaction solution temperature increased and a wire was drawn, the nitrogen was removed and the reactor was sealed. After the reaction was completed, a white elastic solid product was obtained.

[0055] 4) The white elastic solid product is crushed into pieces by a machine and then placed in an oven for drying to obtain white solid particles;

[0056] 5) Grind the white solid particles and pass them through an 80-mesh sieve to obtain a white powder.

[0057] Comparative Example 3: 1) Add 741 parts of purified water, 520 parts of acrylamide (AM), 70 parts of acrylic acid (AA), 88 parts of AMPS, 10 parts of hexadecyldimethylallyl ammonium chloride (C16DMAAC), 35 parts of N-(3-acetylphenyl)-N-vinylmethacrylamide, and 35 parts of N-((4-sulfonyl chloride)phenyl)acrylamide) to a liquid preparation tank and stir thoroughly.

[0058] 2) Adjust the pH to 6.5 with NaOH and cool to 1.7°C;

[0059] 3) After N2 was introduced for 15 minutes, 0.1 parts of sodium hypophosphite, 0.03 parts of tert-butyl hydroperoxide, 0.04 parts of ammonium ferrous sulfate, and 0.03 parts of azobisisobutyronitrile were added. After the reaction solution temperature increased and a wire was drawn, the nitrogen was removed and the reactor was sealed. After the reaction was completed, a white elastic solid product was obtained.

[0060] 4) The white elastic solid product is crushed into pieces by a machine and then placed in an oven for drying to obtain white solid particles;

[0061] 5) Grind the white solid particles and pass them through an 80-mesh sieve to obtain a white powder.

[0062] Performance test: The base slurry is prepared according to the method provided in the Petroleum and Natural Gas Industry Standard SY / T 7626-2021 of the People's Republic of China:

[0063] 1. Preparation of fresh water base slurry: Add 400ml of distilled water and 0.64g of anhydrous sodium carbonate into a high-stirring cup. Slowly add 16g of bentonite for drilling fluid test slurry under high-speed stirring and stir at high speed for 20 minutes.

[0064] 2. Prepare 6 parts of fresh water base slurry according to step 1, add the white powder products of Examples 1-3 and Comparative Examples 1-3 respectively under high-speed stirring, stir for 20 minutes, then add 120g of sodium chloride respectively, stir at high speed for 20 minutes, cure at room temperature for 16 hours, and measure the API filtration loss according to GB / T16783.1;

[0065] 3. Prepare 6 parts of fresh water base slurry according to step 1, add the white powder products of Examples 1-3 and Comparative Examples 1-3 respectively under high-speed stirring, stir for 20 minutes, then add 120g of sodium chloride respectively, stir at high speed for 20 minutes, put into a high-temperature tank and heat at 220℃ for 16 hours, and measure the API filtration loss according to GB / T16783.1.

[0066] The results are as follows:

[0067] In the above table, Comparative Example 1 did not add the new functional monomer, and the fluid loss reduction effect was poor. From the experimental results of Examples 1-3, it can be seen that as the amount of the new monomer A increases, the high temperature and salt resistance of the fluid loss reducer also improves.

[0068] It can be seen from Comparative Example 2 and Example 3 that the raw materials are directly involved in the polymerization reaction without reaction, and the resulting product has a poor filtration reduction effect, which is far inferior to the product with the addition of the new functional monomer A. The reason is that 4-acetamidobenzenesulfonyl chloride has no double bond and cannot participate in the polymerization, and the temperature and salt resistance effect cannot be exerted.

[0069] Comparative Example 3: Raw materials used: N-((4-sulfonyl chloride)phenyl)acrylamide Its structure is similar to that of p-acetamidobenzenesulfonyl chloride, but it contains a double bond and can participate in polymerization. The reaction of the raw materials N-((4-sulfonyl chloride)phenyl)acrylamide and N-(3-acetylphenyl)-N-vinylmethacrylamide produces a large number of byproducts, resulting in a small amount of Product A. Furthermore, the mixing of the raw materials at once can easily produce a high level of impurities. The purity of Comparative Example 3 is over 30% lower than that of Examples 1-3, requiring a significantly increased dosage when used as a fluid loss additive.

Claims

1. A method for preparing a high temperature and salt resistant fluid loss reducer for drilling fluid, characterized in that: The steps are: (1) Weigh 150 parts by mass of N-(3-acetylphenyl)-N-vinylmethacrylamide and 306 parts by mass of p-acetamidobenzenesulfonyl chloride; (2) Add 300 parts of tetrahydrofuran solvent into a three-necked flask, add the raw materials from step 1), and then add 2 parts of copper bromide and 2 parts of sodium carbonate as catalyst; (3) Continuously introduce nitrogen, raise the temperature to 90°C, and react for 12 hours; (4) Extract with chloroform several times, combine the extracts, and concentrate to obtain the final product, functional monomer A. The reaction formula is as follows: ； (5) Add 750-850 parts of purified water, 450-550 parts of acrylamide (AM), 60-80 parts of acrylic acid (AA), 80-100 parts of AMPS, 5-20 parts of hexadecyldimethylallyl ammonium chloride (C16DMAAC), and 10-40 parts of functional monomer A to the liquid preparation tank by mass and stir thoroughly. (6) Adjust the pH to 6-7 with NaOH and cool to 0-2°C; (7) After blowing N2 for 15 minutes, add 0.01-0.3 parts of chain transfer agent, 0.02-0.1 parts of oxidant, 0.02-0.1 parts of reducing agent, and 0.02-0.1 parts of initiator. After the temperature of the reaction liquid rises and the wire is drawn, remove the nitrogen and seal the reactor. After the reaction is completed, a white elastic solid product is obtained; (8) The white elastic solid product is crushed into a machine and then placed in an oven for drying to obtain white solid particles; (9) Grind the white solid particles and pass them through an 80-mesh sieve to obtain a white powder which is a high-temperature and salt-resistant fluid loss reducer for drilling fluid.

2. The method for preparing a high-temperature and salt-resistant fluid loss reducer for drilling fluid according to claim 1, wherein: The chain transfer agent is a mixture of one or more of aliphatic mercaptans, xanthogenic acid disulfides, polyphenols, sulfur, halides and nitroso compounds.

3. The method for preparing a high-temperature and salt-resistant fluid loss reducer for drilling fluid according to claim 1, wherein: The oxidant is one or more of tert-butyl hydroperoxide, potassium persulfate, sodium persulfate, and ammonium persulfate.

4. The method for preparing a high-temperature and salt-resistant fluid loss reducer for drilling fluid according to claim 1, wherein: The initiator is one or more of azobisisobutylimidazoline hydrochloride, azobisisobutyronitrile, azobisisovaleronitrile and azobisisobutylamidine hydrochloride.

5. The method for preparing a high-temperature and salt-resistant fluid loss reducer for drilling fluid according to claim 1, characterized in that: The reducing agent is one or more of potassium metabisulfite, sodium metabisulfite, ferrous sulfate, ammonium ferrous sulfate, and sodium methanesulfinate.

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