Amino modified polyanionic cellulose filtrate reducer and preparation method thereof

Abstract

According to the amido-modified polyanionic cellulose filtrate reducer and the preparation method thereof, amido functional groups are introduced into a molecular structure, and a final product is modified into a zwitterionic type product, so that the temperature resistance of the amido-modified polyanionic cellulose filtrate reducer can be improved, and the temperature resistance of the product can reach 160 DEG C. Besides, due to introduction of amido and a long alkylene oxide chain in the molecular structure, the adsorption capacity and the film-forming lubricating capacity of a modified product can be improved, the filtrate loss reduction performance of the product is remarkably improved, the filtrate loss reduction performance at the normal temperature is improved by at least 30% compared with that of conventional polyanionic cellulose, and the filtrate loss after aging at 160 DEG C is smaller than 13 mL. The amido modified polyanionic cellulose filtrate reducer provided by the invention is good in temperature resistance and obvious in filtrate reduction effect.

Description

Technical Field

[0001] The invention relates to an amine-modified polyanionic cellulose fluid loss reducer, a preparation method and application thereof in drilling fluid, and belongs to the technical field of petroleum engineering. Background Art

[0002] Drilling fluid filtrate reducer can reduce filtration and improve mud cake quality in drilling fluid. It is an important chemical treatment agent for maintaining stable drilling fluid performance, improving drilling fluid rheology, reducing the loss of harmful liquids to the formation, stabilizing the well wall, ensuring the regularity of the well diameter and the oil and gas layer.

[0003] Compared with traditional fluid loss reducers such as sulfonated lignite, sulfonated asphalt and sulfonated phenolic resin with poor environmental performance, polyanionic cellulose is becoming more and more popular due to its advantages such as biodegradability, good environmental performance, abundant material sources and low price. However, the biggest problem of conventional polyanionic cellulose is its insufficient temperature resistance, and the maximum operating temperature is only 120℃. How to further improve the temperature resistance of polyanionic cellulose by structural modification has become a hot topic in current research. Summary of the invention

[0004] The invention provides an amine-modified polyanionic cellulose fluid loss reducer and a preparation method thereof. Firstly, an amine functional group is introduced into the molecular structure of the polyanionic cellulose, so that the final product is modified into a zwitterionic type, which is beneficial to improving the temperature resistance of the product. Secondly, by introducing an amine group and a long alkylene oxide chain into the molecular structure, the adsorption capacity and film-forming lubrication capacity of the modified product can be improved, and the product can be promoted to form a thin and tough filter cake on the surface of the well wall, which is beneficial to improving the fluid loss reduction performance of the product.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions.

[0006] The present invention provides an amino-modified polyanionic cellulose fluid loss reducer, which is characterized in that the amino-modified polyanionic cellulose fluid loss reducer has a general structural formula of: , where m is a natural number between 300 and 1000; R 1 CH 2 COONa; R 2 , R 3 H or , and R 2 , R 3 H; R 4 , R 5 is hydrogen or methyl; n is 2-14.

[0007] The present invention also provides a method for preparing an amino-modified polyanionic cellulose fluid loss reducer, which is characterized in that the preparation steps are: (1) Etherification modification: After the refined cotton is crushed, it is added into a reaction container together with a reaction solvent, and then an alkalizing agent is added. The alkalizing reaction is carried out at a certain temperature for a certain time, and then an etherifying agent is added. The etherification reaction is carried out at a certain temperature for a certain time. After the reaction is completed, the product is filtered to obtain polyanionic cellulose; (2) Epoxidation modification: the polyanionic cellulose prepared in step (1) is added into a reaction vessel, an aqueous solution of an alkalizing agent is added, and then a certain amount of epichlorohydrin is added, and the mixture is stirred for reaction at a certain temperature for a certain time. After the reaction is completed, the mixture is washed with deionized water until neutral, and then washed with anhydrous ethanol and filtered to obtain epoxidized polyanionic cellulose; (3) Amination modification: The epoxidized polyanionic cellulose prepared in step (2) and the reaction solvent are added into a reaction vessel, and then a certain amount of aminating agent is added. The mixture is stirred and reacted at a certain temperature for a certain time. After the reaction is completed, the mixture is washed and filtered with anhydrous ethanol to obtain amino-modified polyanionic cellulose.

[0008] The reaction solvent in the etherification modification and amination modification steps is one of ethanol, isopropanol, acetone, tetrahydrofuran and a mixture thereof.

[0009] The alkalizing agent in the etherification modification and epoxidation modification steps is sodium hydroxide or potassium hydroxide, and the molar ratio of the alkalizing agent to the molar ratio of the hydroxyl groups in the refined cotton is 0.5-1:1.

[0010] The etherifying agent in the etherification modification step is sodium chloroacetate or chloroacetic acid, and the molar ratio of the etherifying agent to the molar ratio of hydroxyl groups in the refined cotton is 0.3-0.4:1.

[0011] In the etherification modification step, the alkalization reaction temperature is 20-40° C., and the alkalization reaction time is 1-4 hours.

[0012] In the etherification modification step, the etherification reaction temperature is 50-90° C., and the etherification reaction time is 2-5 hours.

[0013] In the epoxidation modification step, the molar ratio of the alkalizing agent to the molar ratio of the hydroxyl groups in the refined cotton is 1-2:1, and the molar ratio of the epichlorohydrin to the molar ratio of the hydroxyl groups in the refined cotton is 1-2:3.

[0014] In the epoxidation modification step, the epoxidation reaction temperature is 20-50° C., and the epoxidation reaction time is 3-8 hours.

[0015] The aminating agent structure in the amination modification step is , where R 4 , R 5 is hydrogen or methyl; n is 2-14.

[0016] In the amination modification step, the molar ratio of the aminating agent to the molar ratio of the hydroxyl groups in the refined cotton is 1-3:3.

[0017] In the amination modification step, the amination reaction temperature is 30-60° C., and the amination reaction time is 4-6 hours.

[0018] The amino-modified polyanionic cellulose fluid loss reducer can be used as a fluid loss reducer for water-based drilling fluid.

[0019] The present invention introduces an amine functional group into the molecular structure of polyanionic cellulose to modify the final product into a zwitterionic type, and the temperature resistance of the product reaches 160°C. In addition, the introduction of amine groups and long alkylene oxide chains in the molecular structure can improve the adsorption capacity and film-forming lubrication ability of the modified product, and the fluid loss reduction performance of the product is significantly improved. The fluid loss reduction performance at room temperature is improved by at least 30% compared with conventional polyanionic cellulose, and the fluid loss after aging at 160°C is less than 13mL. The present invention provides an amine-modified polyanionic cellulose fluid loss reducer with good temperature resistance and obvious fluid loss reduction effect. Implementation

[0020] The present invention is described in detail below with reference to embodiments and comparative examples.

[0021] Example 1

[0022] (1) Etherification modification: Weigh 20 g of crushed refined cotton and add it to a reaction container, then add 250 mL of isopropanol, then add 0.185 mol of NaOH, heat the reaction container to 40 ° C, react for 2 h, then add 0.13 mol of sodium chloroacetate, then raise the reaction temperature to 60 ° C, react for 3 h, then cool down, filter the product, and obtain polyanionic cellulose; (2) Epoxidation modification: The polyanionic cellulose prepared in step (1) was added into a reaction vessel, and then 0.37 mol NaOH, 250 mL deionized water and 0.185 mol epichlorohydrin were added, and the mixture was heated to 40°C and reacted for 6 h. After the reaction, the mixture was washed with deionized water until neutral, and then washed with anhydrous ethanol and filtered to obtain epoxidized polyanionic cellulose. (3) Amination modification: The structure of the aminating agent is: , where n is 8, R 4 and R 5 All are methyl groups. Add the epoxidized polyanionic cellulose prepared in step (2) into a reaction vessel, add 250 mL of isopropanol, and then add 0.185 mol of an aminating agent, and stir the reaction at 45°C for 5 h. After the reaction is completed, wash and filter with anhydrous ethanol to obtain amino-modified polyanionic cellulose.

[0023] Example 2 (1) Etherification modification: Weigh 20 g of crushed refined cotton and add it to a reaction container, then add 250 mL of isopropanol, then add 0.37 mol of NaOH, heat the reaction container to 20 ° C, react for 3 hours, then add 0.14 mol of chloroacetic acid, then raise the reaction temperature to 70 ° C, react for 4 hours, then cool down, filter the product and obtain polyanionic cellulose; (2) Epoxidation modification: The polyanionic cellulose prepared in step (1) was added into a reaction vessel, and then 0.74 mol NaOH, 250 mL deionized water and 0.15 mol epichlorohydrin were added, and the mixture was heated to 30°C and reacted for 7 h. After the reaction, the mixture was washed with deionized water until neutral, and then washed with anhydrous ethanol and filtered to obtain epoxidized polyanionic cellulose. (3) Amination modification: The structure of the aminating agent is: , wherein n is 6, R4 is methyl, and R5 is hydrogen. The epoxidized polyanionic cellulose prepared in step (2) is added to a reaction vessel, and then 250 mL of isopropanol and 0.37 mol of an aminating agent are added, and then stirred at 50°C for 5.5 h. After the reaction is completed, the mixture is washed and filtered with anhydrous ethanol to obtain amino-modified polyanionic cellulose.

[0024] Example 3 (1) Etherification modification: Weigh 20 g of crushed refined cotton and add it to a reaction container, then add 250 mL of isopropanol, then add 0.25 mol of KOH, heat the reaction container to 30 ° C, react for 4 hours, then add 0.13 mol of sodium chloroacetate, then raise the reaction temperature to 80 ° C, react for 4 hours, then cool down, filter the product to obtain polyanionic cellulose; (2) Epoxidation modification: Add the polyanionic cellulose prepared in step (1) into a reaction vessel, then add 0.5 mol KOH, 250 mL deionized water and 0.222 mol epichlorohydrin, heat to 50°C, react for 8 h, wash with deionized water until neutral after the reaction, then wash with anhydrous ethanol and filter to obtain epoxidized polyanionic cellulose; (3) Amination modification: The structure of the aminating agent is: , wherein n is 10, R4 is hydrogen, and R5 is methyl. The epoxidized polyanionic cellulose prepared in step (2) is added to a reaction vessel, and then 250 mL of isopropanol and 0.2 mol of aminating agent are added, and then stirred at 60°C for 4 h. After the reaction is completed, the mixture is washed and filtered with anhydrous ethanol to obtain amino-modified polyanionic cellulose.

[0025] Example 4 (1) Etherification modification: Weigh 20 g of crushed refined cotton and add it to a reaction container, then add 250 mL of ethanol, then add 0.3 mol of KOH, heat the reaction container to 25 ° C, react for 1 hour, then add 0.12 mol of sodium chloroacetate, then raise the reaction temperature to 55 ° C, react for 2 hours, then cool down, filter the product and obtain polyanionic cellulose; (2) Epoxidation modification: Add the polyanionic cellulose prepared in step (1) into a reaction vessel, then add 0.4 mol KOH, 250 mL deionized water and 0.125 mol epichlorohydrin, heat to 25°C, react for 3 h, wash with deionized water until neutral after the reaction, then wash with anhydrous ethanol and filter to obtain epoxidized polyanionic cellulose; (3) Amination modification: The structure of the aminating agent is: , wherein n is 4, and R4 and R5 are both hydrogen. The epoxidized polyanionic cellulose prepared in step (2) is added to a reaction vessel, and then 250 mL of ethanol and 0.125 mol of an aminating agent are added, and then stirred at 35°C for 4 h. After the reaction is completed, the mixture is washed and filtered with anhydrous ethanol to obtain amino-modified polyanionic cellulose.

[0026] Example 5 (1) Etherification modification: Weigh 20 g of crushed refined cotton and add it to a reaction container, then add 250 mL of acetone, then add 0.35 mol of NaOH, heat the reaction container to 25 ° C, react for 4 hours, then add 0.148 mol of sodium chloroacetate, then raise the reaction temperature to 50 ° C, react for 5 hours, then cool down, filter the product and obtain polyanionic cellulose; (2) Epoxidation modification: Add the polyanionic cellulose prepared in step (1) into a reaction vessel, then add 0.6 mol NaOH, 250 mL deionized water and 0.2 mol epichlorohydrin, heat to 45°C, react for 5 h, wash with deionized water until neutral after the reaction, then wash with anhydrous ethanol and filter to obtain epoxidized polyanionic cellulose; (3) Amination modification: The structure of the aminating agent is: , wherein n is 12, and R4 and R5 are both methyl groups. The epoxidized polyanionic cellulose prepared in step (2) is added to a reaction vessel, and then 250 mL of ethanol and 0.125 mol of an aminating agent are added, and then stirred at 35°C for 4 h. After the reaction is completed, the mixture is washed and filtered with anhydrous ethanol to obtain amino-modified polyanionic cellulose.

[0027] Example 6 (1) Etherification modification: Weigh 20 g of crushed refined cotton and add it to a reaction container, then add 250 mL of tetrahydrofuran, then add 0.185 mol of NaOH, heat the reaction container to 20 ° C, react for 4 hours, then add 0.148 mol of sodium chloroacetate, then raise the reaction temperature to 50 ° C, react for 5 hours, then cool down, filter the product and obtain polyanionic cellulose; (2) Epoxidation modification: The polyanionic cellulose prepared in step (1) was added into a reaction vessel, and then 0.37 mol NaOH, 250 mL deionized water and 0.125 mol epichlorohydrin were added, and the mixture was heated to 20°C and reacted for 8 h. After the reaction, the mixture was washed with deionized water until neutral, and then washed with anhydrous ethanol and filtered to obtain epoxidized polyanionic cellulose. (3) Amination modification: The structure of the aminating agent is: , wherein n is 14, and R4 and R5 are both methyl groups. The epoxidized polyanionic cellulose prepared in step (2) is added to a reaction vessel, and then 250 mL of tetrahydrofuran and 0.125 mol of an aminating agent are added, and then stirred at 30°C for 6 h. After the reaction is completed, the mixture is washed and filtered with anhydrous ethanol to obtain amino-modified polyanionic cellulose.

[0028] Example 7 (1) Etherification modification: Weigh 20 g of crushed refined cotton and add it to a reaction container, then add 250 mL of isopropanol, then add 0.37 mol of NaOH, heat the reaction container to 35 ° C, react for 1 hour, then add 0.111 mol of sodium chloroacetate, then raise the reaction temperature to 90 ° C, react for 2 hours, then cool down, filter the product and obtain polyanionic cellulose; (2) Epoxidation modification: The polyanionic cellulose prepared in step (1) was added into a reaction vessel, and then 0.74 mol NaOH, 250 mL deionized water and 0.25 mol epichlorohydrin were added, and the mixture was heated to 50°C and reacted for 3 h. After the reaction, the mixture was washed with deionized water until neutral, and then washed with anhydrous ethanol and filtered to obtain epoxidized polyanionic cellulose. (3) Amination modification: The structure of the aminating agent is: , wherein n is 2, and R4 and R5 are both methyl groups. The epoxidized polyanionic cellulose prepared in step (2) is added to a reaction vessel, and then 250 mL of isopropanol and 0.37 mol of an aminating agent are added, and then stirred at 60°C for 4 h. After the reaction is completed, the mixture is washed and filtered with anhydrous ethanol to obtain amino-modified polyanionic cellulose.

[0029] Comparative Example 1 (1) Etherification modification: Weigh 20 g of crushed refined cotton and add it to a reaction container, then add 250 mL of isopropanol, then add 0.25 mol of KOH, heat the reaction container to 60 ° C, react for 4 hours, then add 0.13 mol of sodium chloroacetate, then raise the reaction temperature to 80 ° C, react for 4 hours, then cool down, filter the product to obtain polyanionic cellulose; Comparative Example 2 (1) Etherification modification: Weigh 20 g of crushed refined cotton and add it to a reaction container, then add 250 mL of isopropanol, then add 0.25 mol of KOH, heat the reaction container to 60 ° C, react for 4 hours, then add 0.13 mol of sodium chloroacetate, then raise the reaction temperature to 80 ° C, react for 4 hours, then cool down, filter the product to obtain polyanionic cellulose; (2) Epoxidation modification: Add the polyanionic cellulose prepared in step (1) into a reaction vessel, then add 0.5 mol KOH, 250 mL deionized water and 0.222 mol epichlorohydrin, heat to 50°C, react for 8 h, wash with deionized water until neutral after the reaction, then wash with anhydrous ethanol and filter to obtain epoxidized polyanionic cellulose; Test Example 1 Measure 1L of distilled water, 3g of sodium bicarbonate and 60g of evaluation soil, stir at high speed for 50min, and cure at room temperature for 24h to obtain fresh water-based slurry for evaluation.

[0030] 1.75 g of the amino-modified polyanionic cellulose of Examples 1-7, the polyanionic cellulose or epoxidized polyanionic cellulose prepared in Comparative Examples 1-2, and the commercially available polyanionic cellulose were added to 350 mL of the above-cured freshwater slurry, aged at different temperatures for 16 h, and then tested for filtration loss. The results are shown in Table 1.

[0031] Table 1 Filtration loss of samples in fresh water slurry

[0032] From the above results, it can be seen that in freshwater-based pulp, at room temperature of 25°C, the filtration loss reduction performance of the amine-modified polyanionic cellulose provided by the present invention is slightly better than that of the polyanionic cellulose, epoxidized polyanionic cellulose and commercially available polyanionic cellulose in the comparative example. After aging at 160°C for 16 hours, the filtration loss reduction effect of the amine-modified polyanionic cellulose provided by the present invention is significantly better than that of the polyanionic cellulose, epoxidized polyanionic cellulose and commercially available polyanionic cellulose in the comparative example. The comparative test data show that in freshwater-based pulp, the temperature resistance and filtration loss performance of the amine-modified polyanionic cellulose are significantly improved compared with the samples before modification, partially modified or commercially available.

[0033] Test Example 2 Add 45.0g sodium chloride, 5.0g anhydrous calcium chloride and 13.0g magnesium chloride to 1L distilled water, stir and dissolve to obtain composite brine. Take 350mL of composite brine in a high stirring cup, add 1.0g sodium bicarbonate and 35.0g evaluation soil, stir at high speed for 50min, and cure at room temperature for 24h to obtain composite brine base slurry.

[0034] 7 g of the amino-modified polyanionic cellulose of Examples 1-7, the polyanionic cellulose prepared in Comparative Examples 1-2, the epoxidized polyanionic cellulose and the commercially available sample were added to 350 mL of the above-mentioned cured composite brine-based slurry, aged at different temperatures for 16 h, and then tested for filtration loss. The results are shown in Table 2.

[0035] Table 2 Filtration loss of samples in composite salt water slurry

[0036] From the above results, it can be seen that in the composite salt water-based pulp, after aging at room temperature of 25°C. The filtration loss performance of the amine-modified polyanionic cellulose provided by the present invention is significantly better than that of the polyanionic cellulose, epoxidized polyanionic cellulose and commercially available polyanionic cellulose samples in the comparative example. After aging at 160°C for 16 hours, the filtration loss reduction effect of the amine-modified polyanionic cellulose provided by the present invention is far better than that of the polyanionic cellulose, epoxidized polyanionic cellulose and commercially available polyanionic cellulose samples in the comparative example. The comparative test data show that: in fresh water-based pulp, the temperature resistance and filtration loss performance of the amine-modified polyanionic cellulose are significantly improved compared with the samples before modification, partially modified or commercially available.

Claims

1. An amino-modified polyanionic cellulose fluid loss reducer, characterized in that The general structural formula of the amino-modified polyanionic cellulose fluid loss reducer is: , wherein m is a natural number between 300 and 1000; R1 is CH2COONa; R2 and R3 are H or , and R2 and R3 are not H at the same time; R4 and R5 are hydrogen or methyl; n is 2-14.

2. A method for preparing an amino-modified polyanionic cellulose fluid loss reducer, characterized in that The preparation steps are: (1) Etherification modification: the refined cotton is crushed and added into a reaction container together with a reaction solvent, an alkalizing agent is added to carry out an alkalization reaction, and then an etherifying agent is added to carry out an etherification reaction. After the reaction is completed, the product is filtered to obtain polyanionic cellulose; (2) Epoxidation modification: the polyanionic cellulose prepared in step (1) is added into a reaction vessel, an aqueous solution of an alkalizing agent is added, and then epichlorohydrin is added to stir the reaction. After the reaction is completed, the mixture is washed with deionized water until neutral, and then washed with anhydrous ethanol and filtered to obtain epoxidized polyanionic cellulose; (3) Amination modification: the epoxidized polyanionic cellulose prepared in step (2) and the reaction solvent are added into a reaction vessel, an aminating agent is added and stirred for reaction, and after the reaction is completed, the mixture is washed and filtered with anhydrous ethanol to obtain amino-modified polyanionic cellulose.

3. The method for preparing an amino-modified polyanionic cellulose fluid loss reducer according to claim 2, characterized in that: The reaction solvent in the etherification modification and amination modification steps is one of ethanol, isopropanol, acetone, tetrahydrofuran and a mixture thereof.

4. The method for preparing an amino-modified polyanionic cellulose fluid loss reducer according to claim 2, characterized in that: The alkalizing agent in the etherification modification and epoxidation modification steps is sodium hydroxide or potassium hydroxide.

5. The method for preparing an amino-modified polyanionic cellulose fluid loss additive according to claim 2, characterized in that: The molar ratio of the alkalizing agent in the etherification modification step to the molar ratio of the hydroxyl groups in the refined cotton is 0.5-1:

1.

6. The method for preparing an amino-modified polyanionic cellulose fluid loss additive according to claim 2, characterized in that: The etherifying agent in the etherification modification step is sodium chloroacetate or chloroacetic acid.

7. The method for preparing an amino-modified polyanionic cellulose fluid loss additive according to claim 2, characterized in that: The molar ratio of the etherifying agent in the etherification modification step to the molar ratio of the hydroxyl groups in the refined cotton is 0.3-0.4:

1.

8. The method for preparing an amino-modified polyanionic cellulose fluid loss additive according to claim 2, characterized in that: In the etherification modification step, the alkalization reaction temperature is 20-40° C., and the alkalization reaction time is 1-4 hours.

9. The method for preparing an amino-modified polyanionic cellulose fluid loss additive according to claim 2, characterized in that: In the etherification modification step, the etherification reaction temperature is 50-90° C., and the etherification reaction time is 2-5 hours.

10. The method for preparing an amino-modified polyanionic cellulose fluid loss additive according to claim 2, characterized in that: The molar ratio of the alkalizing agent in the epoxidation modification step to the molar ratio of the hydroxyl groups in the refined cotton is 1-2:

1.

11. The method for preparing an amino-modified polyanionic cellulose fluid loss additive according to claim 2, characterized in that: The molar ratio of epichlorohydrin in the epoxidation modification step to the molar ratio of hydroxyl groups in the refined cotton is 1-2:

3.

12. The method for preparing an amino-modified polyanionic cellulose fluid loss additive according to claim 2, characterized in that: In the epoxidation modification step, the epoxidation reaction temperature is 20-50° C., and the epoxidation reaction time is 3-8 hours.

13. The method for preparing an amino-modified polyanionic cellulose fluid loss additive according to claim 2, characterized in that: The aminating agent structure in the amination modification step is , wherein R4 and R5 are hydrogen or methyl; n is 2-14.

14. The method for preparing an amino-modified polyanionic cellulose fluid loss additive according to claim 2, characterized in that: In the amination modification step, the molar ratio of the aminating agent to the molar ratio of the hydroxyl groups in the refined cotton is 1-3:

3.

15. The method for preparing an amino-modified polyanionic cellulose fluid loss additive according to claim 2, characterized in that: In the amination modification step, the amination reaction temperature is 30-60° C., and the amination reaction time is 4-6 hours.

16. The amino-modified polyanionic cellulose fluid loss additive according to claim 1, characterized in that: The amino-modified polyanionic cellulose fluid loss reducer is used as a fluid loss reducer for water-based drilling fluid.

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