A method for preparing and using a modified lignite-based resin

Abstract

The application relates to the technical field of drilling fluids, and discloses a preparation method and application of modified resin based on lignite, which comprises the following steps: S1. Polybutylene adipate glycol and hexamethylene diisocyanate are reacted under the action of a dibutyltin dilaurate catalyst; after the reaction, a chain extender is continuously added to perform a chain extension reaction; finally, glutamic acid is added to perform a reaction, so that a polyurethane solution is obtained; S2. The polyurethane solution is added to lignite resin; the mixture is stirred at 60-65 DEG C for 20-30 min; and drying is performed, so that modified resin based on lignite is obtained. The modified resin based on lignite prepared by the application solves the problems that the existing lignite resin product has high moisture content and high water-insoluble content, and has good filtration reduction effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drilling fluid, in particular to a preparation method and application of modified resin based on lignite. BACKGROUND

[0002] In traditional drilling fluid treatment agents, lignite resin is often used to improve the filtration performance due to its wide source and low cost, but the content of active groups (such as carboxyl and hydroxyl) in the molecular structure of lignite resin is limited, and the molecular chain regularity is poor, which cannot meet the use requirements in complex drilling environments. The water content of traditional lignite resin is usually more than 15%, and the water-insoluble content is as high as 20-30%, which cannot meet the requirements of the new standard Q / SHCG 0166-2023 (water content ≤10%, water-insoluble content ≤15%), seriously affecting the dispersibility and stability of lignite resin in drilling fluid. The molecular chain of lignite resin is prone to thermal oxidative degradation at a high temperature of 120℃ or above, losing the control ability of the filtration amount of drilling fluid, resulting in thickening of the drilling fluid filter cake and sudden increase of the filtration amount, and further causing well wall collapse, sticking and other risks. For example, application No. 202010614775.3 discloses a drilling fluid filtration reducer lignite resin and a preparation method thereof, which has good filtration reduction effect, but the water-insoluble content of lignite resin is high. In the prior art, lignite resin is modified by methods such as sulfonation and hydroxymethylation, but the modified product still has the problem of single function, which cannot meet the demand for high-performance drilling fluid treatment agents in deep well, ultra-deep well and complex formation drilling operations. Therefore, it is a key problem to be solved in the field of drilling fluid technology to develop a lignite-based modified resin with excellent temperature resistance, salt resistance and high filtration reduction performance. SUMMARY

[0003] PROBLEMS SOLVED BY THE INVENTION

[0004] In view of the deficiencies of the prior art, the present application provides a preparation method and application of modified resin based on lignite, aiming to solve the problems of high water content and water-insoluble content of existing lignite resin products and poor salt resistance.

[0005] TECHNICAL SCHEME

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a preparation method of modified resin based on lignite, comprising the following steps:

[0007] S1. Polyhexanedioic acid-1,4-butanediol glycol and hexamethylene diisocyanate are reacted under the action of dibutyltin dilaurate catalyst, then a chain extender is added for chain extension reaction, and finally glutamic acid is added for reaction to obtain a polyurethane solution;

[0008] S2. The polyurethane solution is added to the lignite resin, stirred and mixed at 60-65°C for 20-30 min, dried, and a modified lignite-based resin is obtained.

[0009] Further, the preparation method of the polyurethane solution is as follows:

[0010] The reaction bottle is added with 0.006-0.009 mol polyhexanedioic acid-1,4-butanediol glycol, vacuum dried at 110-120°C for 2-3 h, cooled to 75-80°C, and then 0.02-0.03 mol hexamethylene diisocyanate and 0.1-0.12 mmol dibutyltin dilaurate are continuously added under nitrogen gas, reacted for 1-2 h, then the temperature is kept at 65-70°C, 0.01-0.016 mol chain extender is continuously added, reacted for 1-1.5 h, the temperature is adjusted to 40-45°C, 0.005-0.006 mol glutamic acid is added, reacted for 1-3 h, and then 65-70 mL deionized water is added at room temperature after the reaction is completed, stirred and mixed to obtain a polyurethane solution.

[0011] Further, the chain extender is any one of 2,2-dimethylol butyric acid, 1,2-propanediol, 1,4-butanediol, and a sodium sulfonate intermediate.

[0012] Further, the preparation method of the sodium sulfonate intermediate is as follows:

[0013] Step 1: 3-dimethylamino-1-propanol and malonyl chloride are added to N,N-dimethylformamide solvent, stirred and mixed, and then triethylamine catalyst is continuously added, reacted at 45-50°C for 1-2 h, distilled under reduced pressure after the reaction is completed, washed, and an intermediate 1 is obtained;

[0014] Step 2: The intermediate 1 and 3-chloro-2-hydroxypropanesulfonic acid sodium are added to 25-30 mL of a 5-6% mass fraction sodium hydroxide aqueous solution, reacted at 50-55°C for 5-7 h, cooled, and then 0.1 mol / L hydrochloric acid is added dropwise to adjust the pH to neutral, and rotary evaporation is performed to obtain a sodium sulfonate intermediate.

[0015] Further, in Step 1, the amount ratio of N,N-dimethylformamide solvent, 3-dimethylamino-1-propanol, malonyl chloride, and triethylamine catalyst is 50-60 mL: 1-2 mmol: 0.5-1 mmol: 0.01-0.02 mmol.

[0016] Further, in Step 2, the mass ratio of the intermediate 1 and 3-chloro-2-hydroxypropanesulfonic acid sodium is 1.2-1.4 mmol: 2.4-2.8 mmol.

[0017] Further, in S2, the mass ratio of the polyurethane solution and the lignite resin is 10-15 g: 35-40 g.

[0018] Further, the application in the drilling fluid.

[0019] (Three beneficial technical effects

[0020] By wrapping lignite resin with the hydrophobic segment of the polyurethane solution (such as butylene adipate), the water content is reduced, which meets the Q / SHCG 0166-2023 standard (≤10%); the stable composite structure is formed by physical wrapping and chemical adsorption between the polyurethane molecular chain and the lignite resin molecules, which can coat the originally difficult-to-dissolve macromolecular impurities in the lignite resin inside the composite system; at the same time, the hydrophilic groups (carboxyl and sodium sulfonate groups) introduced by the chain extender and the carboxyl groups capped by glutamic acid can improve the dispersion and solubility of the modified resin in water, reduce the water-insoluble content, and meet the requirements of the new standard for product purity.

[0021] The flexible structure of the polyurethane segment and the rigid skeleton of the lignite resin form a complementary structure, which can build an "elastic plugging network" in the drilling fluid, uniformly adsorb on the surface of the bentonite particles, reduce the interparticle pores, and form a thin and dense filter cake; at the same time, the carboxyl groups introduced by capping the polyurethane with glutamic acid can form coordination bonds with metal ions in the drilling fluid, further improving the filter cake bonding strength and reducing the fluid loss, which is much better than traditional lignite resin, effectively reducing the leakage of drilling fluid into the formation, and having good salt resistance. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the infrared spectrum of the polyurethane in the polyurethane solution of Example 4. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application is described clearly and completely, obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0024] In order to better understand the above technical scheme, the above technical scheme will be described in detail in combination with the drawings and specific embodiments in the description.

[0025] Lignite resin, purchased from Xinxiang Xilei Oilfield Chemicals Co., Ltd., production batch number: 20240236-01.

[0026] Polybutylene adipate glycol (Mn=2000).

[0027] Example 1

[0028] A preparation method of a lignite-based modified resin, comprising the following steps:

[0029] S1. 0.006 mol polyhexanedioic acid-1,4-butanediol glycol was added to a reaction bottle, vacuum dried at 110°C for 2 h, cooled to 75°C, and 0.02 mol hexamethylene diisocyanate and 0.1 mmol dibutyltin dilaurate were continuously added thereto under nitrogen gas, reacted for 1 h, then the temperature was kept at 65°C, 0.01 mol chain extender was continuously added, reacted for 1 h, the temperature was adjusted to 40°C, 0.005 mol glutamic acid was added, reacted for 1 h, and after the reaction was completed, 65 mL of deionized water was added at room temperature, and the mixture was stirred to obtain a polyurethane solution;

[0030] S2. 10 g of the polyurethane solution was added to 35 g of lignite resin, and the mixture was stirred at 60°C for 20 min, and dried to obtain a lignite-based modified resin.

[0031] Further, the chain extender is 2,2-dimethylol butyric acid.

[0032] The preparation method of the sodium sulfonate intermediate is:

[0033] Step one: 1 mmol of 3-dimethylamino-1-propanol and 0.5 mmol of malonyl chloride were added to 50 mL of N,N-dimethylformamide solvent, stirred and mixed, 0.01 mmol of triethylamine catalyst was continuously added, reacted at 45°C for 1 h, and after the reaction was completed, it was distilled under reduced pressure, washed, and an intermediate 1 was obtained;

[0034] Step two: 1.2 mmol of intermediate 1, 2.4 mmol of 3-chloro-2-hydroxypropane sulfonic acid sodium were added to 25 mL of 5% sodium hydroxide aqueous solution, reacted at 50°C for 5 h, cooled, 0.1 mol / L hydrochloric acid was added dropwise to adjust the pH to neutral, and rotary evaporation was performed to obtain a sodium sulfonate intermediate.

[0035] Example 2

[0036] A preparation method of a lignite-based modified resin, comprising the following steps:

[0037] S1. 0.009 mol polyhexanedioic acid-1,4-butanediol glycol was added to a reaction bottle, vacuum dried at 120°C for 3 h, cooled to 80°C, and 0.03 mol hexamethylene diisocyanate and 0.12 mmol dibutyltin dilaurate were continuously added thereto under nitrogen gas, reacted for 2 h, then the temperature was kept at 70°C, 0.016 mol chain extender was continuously added, reacted for 1.5 h, the temperature was adjusted to 45°C, 0.006 mol glutamic acid was added, reacted for 3 h, and after the reaction was completed, 70 mL of deionized water was added at room temperature, and the mixture was stirred to obtain a polyurethane solution;

[0038] S2. 15 g of the polyurethane solution was added to 40 g of the lignite resin, and the mixture was stirred at 65°C for 30 min, and dried to obtain a modified lignite-based resin.

[0039] The chain extender was 1,2-propanediol.

[0040] The preparation method of the sodium sulfonate intermediate was as follows:

[0041] Step one: 2 mmol of 3-dimethylamino-1-propanol and 1 mmol of malonyl chloride were added to 60 mL of N,N-dimethylformamide solvent, and the mixture was stirred, 0.02 mmol of triethylamine catalyst was continuously added, and the reaction was carried out at 50°C for 2 h. After the reaction was completed, the product was distilled under reduced pressure, washed, and an intermediate 1 was obtained;

[0042] Step two: 1.4 mmol of the intermediate 1, 2.8 mmol of 3-chloro-2-hydroxypropanesulfonic acid sodium were added to 30 mL of a 6% sodium hydroxide aqueous solution, and the reaction was carried out at 55°C for 7 h. After cooling, 0.1 mol / L hydrochloric acid was added dropwise to adjust the pH to neutral, and rotary evaporation was performed to obtain a sodium sulfonate intermediate.

[0043] Example 3

[0044] A preparation method of a modified lignite-based resin included the following steps:

[0045] S1. 0.0075 mol of polyhexanedioic acid-1,4-butanediol glycol was added to a reaction bottle, and vacuum drying was carried out at 115°C for 2 h. The temperature was lowered to 78°C, and 0.025 mol of hexamethylene diisocyanate and 0.11 mmol of dibutyltin dilaurate were continuously added under nitrogen gas. The reaction was carried out for 2 h, and then the temperature was maintained at 68°C. 0.013 mol of a chain extender was continuously added, and the reaction was carried out for 1.2 h. The temperature was adjusted to 43°C, 0.0055 mol of glutamic acid was added, and the reaction was carried out for 2 h. After the reaction was completed, 68 mL of deionized water was added at room temperature, and the mixture was stirred to obtain a polyurethane solution;

[0046] S2. 12 g of the polyurethane solution was added to 38 g of the lignite resin, and the mixture was stirred at 63°C for 25 min, and dried to obtain a modified lignite-based resin.

[0047] The chain extender was 1,4-butanediol.

[0048] The preparation method of the sodium sulfonate intermediate was as follows:

[0049] Step one: 1.5 mmol of 3-dimethylamino-1-propanol and 0.75 mmol of malonyl chloride were added to 55 mL of N,N-dimethylformamide solvent, the mixture was stirred, 0.015 mmol of triethylamine catalyst was continuously added, and the reaction was carried out at 47°C for 1.5 h. After the reaction was completed, it was distilled under reduced pressure, washed, and an intermediate 1 was obtained.

[0050] Step two: 1.3 mmol of intermediate 1, 2.6 mmol of 3-chloro-2-hydroxypropanesulfonic acid sodium were added to 27 mL of 5.5% mass fraction of sodium hydroxide aqueous solution, and the reaction was carried out at 53°C for 6 h. After cooling, 0.1 mol / L hydrochloric acid was added dropwise to adjust the pH to neutral, and rotary evaporation was performed to obtain a sodium sulfonate intermediate.

[0051] Example 4

[0052] A preparation method of a lignite-based modified resin, comprising the following steps:

[0053] S1. 0.006 mol of polyhexanedioic acid-1,4-butanediol glycol was added to a reaction bottle, vacuum dried at 110°C for 2 h, cooled to 75°C, and 0.02 mol of hexamethylene diisocyanate and 0.1 mmol of dibutyltin dilaurate were continuously added under nitrogen gas, reacted for 1 h, then the temperature was maintained at 65°C, 0.01 mol of a chain extender was continuously added, reacted for 1 h, the temperature was adjusted to 40°C, 0.005 mol of glutamic acid was added, and reacted for 1 h. After the reaction was completed, 65 mL of deionized water was added at room temperature, the mixture was stirred, and a polyurethane solution was obtained; according to Figure 1 From the infrared spectrum of the polyurethane, an absorption peak of S=O of the sulfonic acid group appeared at 1247 cm -1 An absorption peak of urethane (CO-NH) appeared at 1730 cm -1 An absorption peak of methyl (-CH3) or methylene (-CH2-) appeared at 2964 cm -1 An absorption peak of -NH appeared at 3354 cm -1 An absorption peak of -NH appeared at 3354 cm

[0054] S2. 15 g of the polyurethane solution was added to 40 g of lignite resin, and the mixture was stirred at 65°C for 30 min and dried to obtain a lignite-based modified resin.

[0055] The chain extender is a sodium sulfonate intermediate.

[0056] The preparation method of the sodium sulfonate intermediate is as follows:

[0057] Step one: 2 mmol of 3-dimethylamino-1-propanol and 1 mmol of malonyl chloride were added to 60 mL of N,N-dimethylformamide solvent, the mixture was stirred, 0.02 mmol of triethylamine catalyst was continuously added, and the reaction was carried out at 50°C for 2 h. After the reaction was completed, it was distilled under reduced pressure, washed, and the intermediate 1 was obtained;

[0058] Step two: 1.3 mmol of intermediate 1, 2.6 mmol of 3-chloro-2-hydroxypropanesulfonic acid sodium were added to 27 mL of 5.5% mass fraction of sodium hydroxide aqueous solution, and the reaction was carried out at 53°C for 6 h. After cooling, 0.1 mol / L hydrochloric acid was added dropwise to adjust the pH to neutral, and rotary evaporation was performed to obtain the sodium sulfonate intermediate.

[0059] Comparative Example 1

[0060] This comparative example is different from Example 4 in that the sodium sulfonate intermediate is not added.

[0061] Comparative Example 2

[0062] This comparative example is different from Example 4 in that the polyurethane solution is not added.

[0063] The modified lignite-based resins prepared in the examples and comparative examples were evaluated for performance according to the standard Q / SHCG0166-2023 "Lignite Resin-Based Filtration Reducers for Drilling Fluids".

[0064] The evaluation of the filtration reduction performance of the product in the drilling fluid was carried out in fresh water mud and salt water mud. After aging at 180°C for 16 h, the high pressure filtration loss was determined using a 42-type high temperature and high pressure filtration instrument according to Q / SHCG0166-2023 "Lignite Resin-Based Filtration Reducers for Drilling Fluids". The compositions of the two evaluation systems are shown below:

[0065] Base mud formulation: In a sample cup containing 350 mL of distilled water, 0.79 (±0.05) g of anhydrous sodium carbonate and 22.5 (±0.5) g of bentonite for drilling fluid test mud were added, and stirred at high speed for 20 min, with at least two interruptions to scrape the sample adhering to the wall of the cup. It was sealed and cured at 25°C for 24 h.

[0066] Fresh water mud formulation: 350 mL of base mud was taken and 10.5 g of the sample of the present application was added, and stirred at high speed for 20 min, with two interruptions to scrape the sample adhering to the wall of the cup. The above mud was transferred to a high temperature tank and hot rolled at 180°C for 16 h.

[0067] Salt water slurry formulation: Take base slurry 350m, add 17.58 samples of the present application, high-speed stirring for 20 min, during which it should be interrupted twice to scrape the sample adhering to the cup wall, then add 52.5g of sodium chloride, high-speed stirring for 10 min, add 20% sodium hydroxide solution 2mL to adjust the pH. The above slurry is transferred to a high temperature tank, and hot rolling at 180℃ for 16h.

[0068] Table 1: Performance test

[0069] Example Water insolubles (%) Moisture (%) Fresh water mud, high temperature high pressure fluid loss (mL) Salt water mud, high temperature high pressure fluid loss (mL) Example 1 7.8 8.2 16.3 22.8 Example 2 8.5 8.3 17.1 24.3 Example 3 8.3 8.5 17.5 23.1 Example 4 7.4 8.0 15.4 21.7 Comparative Example 1 10.6 11.3 20.1 28.4 Comparative Example 2 15.7 14.5 25.7 31.1

[0070] As can be seen from Table 1, the modified resin based on lignite prepared by the present application has good salt resistance and temperature resistance, and at the same time has low water insolubility. The polyurethane molecular chain (containing adipic acid butanediol ester hydrophobic segment) locks the free water in the lignite resin by physical wrapping effect and efficiently removes the water during the drying process; the carboxyl groups introduced by the chain extender (such as 2,2-dimethylol butyric acid, sodium sulfonate intermediate) and the hydrophilic groups of sodium sulfonate cooperate with the terminal carboxyl groups capped with glutamic acid to greatly improve the dispersibility and solubility of lignite resin in water, and convert the originally insoluble macromolecular impurities (such as undegraded lignin) into dispersible components.

[0071] Proportions 1-2 respectively lack the core process link of the present application (proportion 1 without sodium sulfonate intermediate, proportion 2 without polyurethane solution), and the performance is greatly deteriorated. After the sodium sulfonate intermediate is omitted in proportion 1, the hydrophilic group (sodium sulfonate) is insufficient, the dispersibility and solubility of lignite resin decrease, the insoluble impurities cannot be effectively dispersed, the water insoluble matter increases; at the same time, the salt resistance is lost, Na⁺ in the salt water system destroys the filter cake structure, leading to a sharp increase in filtration loss, and the water content exceeds the standard due to the decrease in polyurethane wrapping efficiency. Proportion 2 does not add polyurethane solution (only unmodified lignite resin), and the performance decreases. Without polyurethane solution, there is neither hydrophobic segment to reduce water content nor hydrophilic group to improve solubility, and the lignite resin retains the original defects (high water content and high insoluble matter); at the same time, the polyurethane-lignite interpenetrating network is missing, the molecular chain is easily degraded at 180℃, the filter cake structure is loose, and the filtration loss, temperature resistance and salt resistance are completely lost, which cannot meet the requirements of drilling fluid.

[0072] It should be noted that in this text, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement "including a…" does not exclude the presence of other identical elements in the process, method, article or equipment including the element.

[0073] The above examples are only used to illustrate the technical solutions of the present application, but not to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalent ones; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

[0074] Those skilled in the art should understand that the above only describes several specific embodiments of the present application, but not all embodiments.

Claims

1. A method for preparing a modified resin based on lignite, characterized in that, The method comprises the following steps: S1. reacting polybutylene adipate glycol and hexamethylene diisocyanate under the action of dibutyltin dilaurate catalyst, then adding a chain extender for chain extension reaction, and finally adding glutamic acid for reaction to obtain a polyurethane solution; S2. adding the polyurethane solution into lignite resin, stirring and mixing at 60-65 DEG C for 20-30 min, and drying to obtain a modified lignite-based resin; The preparation method of the polyurethane solution is as follows: 0.006-0.009 mol of polybutylene adipate glycol is added into a reaction bottle, vacuum drying is carried out at 110-120 DEG C for 2-3 h, the temperature is lowered to 75-80 DEG C, 0.02-0.03 mol of hexamethylene diisocyanate and 0.1-0.12 mmol of dibutyltin dilaurate are continuously added under nitrogen gas, reaction is carried out for 1-2 h, then the temperature is kept at 65-70 DEG C, 0.01-0.016 mol of chain extender is continuously added, reaction is carried out for 1-1.5 h, the temperature is adjusted to 40-45 DEG C, 0.005-0.006 mol of glutamic acid is added, reaction is carried out for 1-3 h, after the reaction is completed, 65-70 mL of deionized water is added at room temperature, and stirring and mixing are carried out to obtain a polyurethane solution; The chain extender is any one of 2,2-dimethylol butyric acid, 1,2-propanediol, 1,4-butanediol and a sodium sulfonate intermediate; The preparation method of the sodium sulfonate intermediate is as follows: Step one: 3-dimethylamino-1-propanol and malonyl chloride are added into N,N-dimethylformamide solvent, stirring and mixing are carried out, triethylamine catalyst is continuously added, reaction is carried out at 45-50 DEG C for 1-2 h, after the reaction is completed, vacuum distillation is carried out, and washing is carried out to obtain intermediate 1; Step two: intermediate 1 and 3-chloro-2-hydroxypropanesulfonic acid sodium are added into sodium hydroxide aqueous solution, reaction is carried out at 50-55 DEG C for 5-7 h, cooling is carried out, hydrochloric acid is added dropwise to adjust pH, and rotary evaporation is carried out to obtain a sodium sulfonate intermediate; In the step one, the mass ratio of N,N-dimethylformamide solvent, 3-dimethylamino-1-propanol, malonyl chloride and triethylamine catalyst is 50-60 mL: 1-2 mmol: 0.5-1 mmol: 0.01-0.02 mmol; In the step two, the mass ratio of intermediate 1 and 3-chloro-2-hydroxypropanesulfonic acid sodium is 1.2-1.4 mmol: 2.4-2.8 mmol; In the step S2, the mass ratio of the polyurethane solution and the lignite resin is 10-15 g: 35-40 g.

2. Use of the modified lignite-based resin according to claim 1, characterized in that, The application in drilling fluid.

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