Sulfonated crown ether-lignin copolymer and its application in drilling fluid viscosity reducer
The use of sulfonated crown ether-lignin copolymers has solved the problems of low viscosity reduction efficiency and high-temperature degradation of drilling fluids under high salinity and high temperature conditions, thus achieving high-temperature stability and long-term use of drilling fluids.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SINOPEC OILFIELD SERVICE CORPORATION
- Filing Date
- 2024-12-04
- Publication Date
- 2026-06-05
Smart Images
Figure BDA0005170248380000091 
Figure BDA0005170248380000101
Abstract
Description
Technical Field
[0001] This invention belongs to the field of drilling fluid viscosity reducer technology, specifically relating to sulfonated crown ether-lignin copolymer and its application in drilling fluid viscosity reducers. Background Technology
[0002] As my country's shallow and medium-depth oil and gas resources become increasingly depleted, oil and gas development is gradually moving towards deeper formations. With increasing well depth, drilling fluid density also increases, resulting in more drill cuttings and placing higher demands on solids control equipment. If the solids control equipment fails to meet these requirements, the content of inferior solid phases in the drilling fluid will rise, and with increasing circulation cycles, the abrasiveness of drill cuttings in the drilling fluid will increase, leading to stronger dispersion and an irreversible increase in drilling fluid viscosity. This makes controlling drilling fluid performance increasingly difficult.
[0003] Generally, there are two methods to reduce drilling fluid viscosity. The first is dilution with water. This method has the advantage of rapid viscosity reduction, but its disadvantage is that it increases the total amount of waste drilling fluid, putting pressure on subsequent treatment. The second method is to add drilling fluid viscosity reducers. Currently, commonly used viscosity reducers include tannins, tannins, and lignins, as well as their modifications. Existing modification methods mainly focus on sulfonation modification, including lignin sulfonates, iron-chromium lignin sulfonates (FCLS), sulfonated tannins, etc. However, because FCLS contain heavy metal ions and have a certain impact on the environment, their use is currently prohibited. Sulfonated tannins and sulfonated lignin have poor salt resistance and are less effective in formations with high formation water salinity. Du Juntao et al. (Fine Petrochemicals, 2015, 32(2):16-19) synthesized two copolymer viscosity reducers, AMPS / St / AA and AMPS / St / IA. Both of these agents can reduce drilling fluid viscosity by less than 70% at a dosage of 0.5%, and have a temperature resistance of up to 260℃, but their salt resistance is poor. Wang Feilong et al. (Drilling Fluids and Completion Fluids, 2017, 34(6):8-12) synthesized sulfonated styrene-maleic anhydride (SSMA). This viscosity reducer showed good salt resistance. In 4.0% brine-based slurry, the viscosity reduction rate reached 53.33% at a dosage of 1.0%, and the temperature resistance reached 220℃. However, when the salt content in the drilling fluid increased to more than 5.0%, the viscosity reduction efficiency of the above viscosity reducer decreased sharply.
[0004] In summary, when the salt content increases to above 5.0%, the viscosity-reducing efficiency of all viscosity reducers decreases sharply, indicating that current synthetic viscosity reducers all suffer from insufficient salt resistance. Furthermore, synthetic copolymer viscosity reducers with good salt resistance are prone to high-temperature degradation and chain scission, which adversely affects drilling fluids. Therefore, there is an urgent need to research a biodegradable, environmentally friendly, high-temperature resistant, and high-salt resistant drilling fluid viscosity reducer. Summary of the Invention
[0005] To address the weakness of commonly used drilling fluid viscosity reducers in resisting divalent salts, this application proposes a sulfonated crown ether-lignin copolymer, which, when used in drilling fluids, can improve the drilling fluid's resistance to divalent salts and its auxiliary temperature resistance.
[0006] The technical solution of the present invention is as follows:
[0007] In a first aspect, the present invention provides a method for preparing a sulfonated crown ether-lignin copolymer, comprising: reacting sulfonated crown ether-lignin, propylene sulfonate and allyl polyethylene glycol in the presence of an initiator to obtain the sulfonated crown ether-lignin copolymer.
[0008] By reacting sulfonated crown ether-lignin with propylene sulfonate and allyl polyethylene glycol, a sulfonated crown ether-lignin copolymer is formed. This copolymer has a chelating effect on calcium ions and excellent high-temperature stability. When used in drilling fluid viscosity reducers, it can significantly improve the viscosity reducer's resistance to divalent salts and temperature resistance. It can resist 10.0 wt% CaCl2 and has a temperature resistance of up to 220℃.
[0009] As a specific embodiment of the present invention, the mass ratio of sulfonated crown ether-lignin, propylene sulfonate, allyl polyethylene glycol and initiator, calculated as lignin, is (2000-3000):(400-1200):(300-600):(200-500).
[0010] As a specific embodiment of the present invention, the propylene sulfonate includes at least one of sodium propylene sulfonate and sodium methpropylene sulfonate.
[0011] In a specific embodiment of the present invention, the allyl polyethylene glycol has the molecular formula CH2=CHCH2O(CH2CH2O). n H, where n is 5-8.
[0012] As a specific embodiment of the present invention, the initiator includes at least one of potassium persulfate, ammonium persulfate, and sodium persulfate.
[0013] As a specific embodiment of the present invention, a polymerization inhibitor is added after the reaction is completed.
[0014] As a specific embodiment of the present invention, the polymerization inhibitor includes at least one of sodium dimethyl dithiocarbamate, sodium sulfide and sodium nitrite.
[0015] As a specific embodiment of the present invention, the mass ratio of the polymerization inhibitor to the sulfonated crown ether-lignin calculated as lignin is (30-50):(2000-3000).
[0016] As a specific embodiment of the present invention, the method for preparing the sulfonated crown ether-lignin includes: under alkaline conditions and in the presence of aldehydes, the crown ether reacts with lignin to generate crown ether-lignin; the crown ether-lignin reacts with a sulfonating agent under alkaline conditions to obtain the sulfonated crown ether-lignin.
[0017] As a specific embodiment of the present invention, the aldehyde includes formaldehyde.
[0018] As a specific embodiment of the present invention, the crown ether is an azacrown ether; preferably, the azacrown ether includes at least one of aza14-crown ether-4, diaza14-crown ether-4, aza15-crown ether-5, diaza15-crown ether-5, aza18-crown ether-6, and diaza18-crown ether-6.
[0019] In this application, azeotropic crown ethers and lignin are combined via an aldehyde reaction, followed by sulfonation of the crown ether-lignin mixture with salt. Crown ethers are highly rigid, and their combination with lignin improves the temperature resistance of the copolymer. Furthermore, the nitrogen-containing crown ether, i.e., azeotropic crown ether, promotes the binding of vacancy within the crown ether to lignin, ensuring a higher degree of binding and further enhancing high-temperature resistance. Moreover, its greater number of active sites ensures its binding with drilling fluid, guaranteeing its stability as a viscosity reducer in the drilling fluid and ensuring its high-temperature stability, thus solving the problem of high-temperature degradation and chain scission in existing viscosity reducers.
[0020] As a specific embodiment of the present invention, the sulfonation reaction system further includes a trivalent metal salt, preferably a trivalent iron salt; preferably, the mass ratio of the trivalent metal salt to lignin is (10-30):(2000-3000);
[0021] As a specific embodiment of the present invention, the sulfonating agent includes at least one of sulfites; preferably, the mass ratio of the sulfites to lignin is (800-1600):(2000-3000);
[0022] In a specific embodiment of the present invention, the pH of the sulfonation reaction system is 9 to 11.
[0023] Secondly, a sulfonated crown ether-lignin copolymer is provided, which is prepared by the above-described preparation method.
[0024] Thirdly, a drilling fluid viscosity reducer is provided, comprising the above-mentioned sulfonated crown ether-lignin copolymer or the sulfonated crown ether-lignin copolymer prepared by the above method.
[0025] Fourthly, the application of the aforementioned drilling fluid viscosity reducers in drilling fluids is provided.
[0026] Beneficial effects of this application
[0027] 1. By reacting sulfonated crown ether-lignin with propylene sulfonate and allyl polyethylene glycol, a sulfonated crown ether-lignin copolymer is formed. This copolymer has a chelating effect on calcium ions and excellent high-temperature stability. When used as a viscosity reducer, it can significantly improve the viscosity reducer's resistance to divalent salts and temperature resistance. It can resist 8.0 wt% CaCl2 and the temperature resistance can reach 240℃.
[0028] 2. Azacrown ethers are bonded to lignin via the Mannich reaction using aldehydes, followed by sulfonation of the crown ether-lignin combination with sulfite. Crown ethers are highly rigid, and their combination with lignin enhances the copolymer's temperature resistance. Furthermore, the nitrogen-containing crown ether, specifically azacrown ether, promotes the binding of vacancy within the crown ether to lignin, ensuring a higher degree of bonding and further improving high-temperature resistance. Moreover, its numerous active sites ensure its binding with drilling fluid, guaranteeing its stability as a viscosity reducer within the drilling fluid and ensuring its high-temperature stability, thus addressing the problem of high-temperature degradation and chain scission in existing viscosity reducers.
[0029] 3. The synthetic copolymer viscosity reducer is stable and will not degrade in drilling fluid, thus extending the service life of drilling fluid. Detailed Implementation
[0030] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.
[0031] Example 1:
[0032] A method for preparing a sulfonated crown ether-lignin copolymer includes the following steps:
[0033] 1) Add 300g of aza-14-crown-4 and 50g of NaOH to a 10L reactor in sequence, slowly add 3000g of deionized water, stir at 300rpm, and continue the reaction for 30min after the reactants are completely dissolved.
[0034] 2) Add 300g of formaldehyde and 2000g of lignin to the reactor in sequence, raise the reaction temperature to 80℃, increase the stirring speed to 1500rpm, and continue the reaction for 5h.
[0035] 3) Stop stirring and let the system temperature drop to room temperature. Then transfer the reaction product to a low-temperature rotary evaporator to remove the remaining formaldehyde. Then return the product to the reactor mentioned above.
[0036] 4) Nitrogen gas is introduced into the reactor above to remove oxygen for 30 minutes;
[0037] 5) Add 100g NaOH, 800g Na2SO3 and 10g FeCl3 to the above reactor respectively, raise the reaction temperature to 80℃, set the stirring speed to 600rpm, and continue the reaction for 3h.
[0038] 6) Add 400g sodium propylene sulfonate, 300g allyl polyethylene glycol (molecular weight 278Da) and 1000g deionized water to the above reactor in sequence. Cool the reactor with a condenser and keep the temperature constant at 50°C. Set the stirring speed to 300rpm and add an aqueous solution containing 200g potassium persulfate dropwise. After the addition is complete, lower the temperature and raise it to 60°C and continue the reaction for 5 hours.
[0039] 7) Add 30g of sodium dimethyl dithiocarbamate to the above reactor and continue stirring for 20min;
[0040] 8) After the reaction is complete, place the gel-like product in a vacuum filtration device and rinse it with deionized water several times until the filtrate no longer contains the reactants. Dry the product in an oven at 100°C and pulverize it through a 200-mesh sieve to obtain the powder, which is the sulfonated crown ether-lignin copolymer.
[0041] Example 2:
[0042] The difference from Example 1 is that the polymerization inhibitor was replaced with 30g of sodium sulfide.
[0043] Example 3:
[0044] The difference from Example 1 is that the molecular weight of allyl polyethylene glycol is 366 Da.
[0045] Example 4:
[0046] A method for preparing a sulfonated crown ether-lignin copolymer includes the following steps:
[0047] 1) Add 400g of diaza-15-crown-5 and 60g of NaOH to a 10L reactor in sequence, slowly add 4000g of deionized water, stir at 400rpm, and continue the reaction for 40min after the reactants are completely dissolved.
[0048] 2) Add 400g of formaldehyde and 2500g of lignin to the reactor in sequence, raise the reaction temperature to 90℃, increase the stirring speed to 1800rpm, and continue the reaction for 6h.
[0049] 3) Stop stirring and let the system temperature drop to room temperature. Then transfer the reaction product to a low-temperature rotary evaporator to remove the remaining formaldehyde. Then return the product to the reactor mentioned above.
[0050] 4) Nitrogen gas is introduced into the reactor above to remove oxygen for 30 minutes;
[0051] 5) Add 200g NaOH, 1000g Na2SO3 and 20g FeCl3 to the above reactor respectively, raise the reaction temperature to 90℃, set the stirring speed to 800rpm, and continue the reaction for 4h.
[0052] 6) Add 800g sodium methpropylene sulfonate, 400g allyl polyethylene glycol (molecular weight 410 Da) and 1300g deionized water to the above reactor in sequence. Cool the reactor with a condenser and increase the temperature to 55°C. Set the stirring speed to 400 rpm and add an aqueous solution containing 300g potassium persulfate dropwise. After the addition is complete, lower the temperature and raise it to 70°C. Continue the reaction for 6 hours.
[0053] 7) Add 35g of sodium dimethyl dithiocarbamate to the above reactor and continue stirring for 25min;
[0054] 8) After the reaction is complete, place the gel-like product in a vacuum filtration device and rinse it with deionized water several times until the filtrate no longer contains the reactants. Dry the product in an oven at 100°C and pulverize it through a 200-mesh sieve to obtain the powder, which is the sulfonated crown ether-lignin copolymer.
[0055] Example 5:
[0056] In step 6), the 300g potassium persulfate was replaced with 300g ammonium persulfate, and the rest was the same as in Example 4.
[0057] Example 6:
[0058] A method for preparing a sulfonated crown ether-lignin copolymer includes the following steps:
[0059] 1) Add 500g of aza-14-crown-4 and 70g of NaOH to a 10L reactor in sequence, slowly add 4000g of deionized water, stir at 400rpm, and continue the reaction for 45min after the reactants are completely dissolved.
[0060] 2) Add 500g of formaldehyde and 2500g of lignin to the reactor in sequence, raise the reaction temperature to 90℃, increase the stirring speed to 2500rpm, and continue the reaction for 7h.
[0061] 3) Stop stirring and let the system temperature drop to room temperature. Then transfer the reaction product to a low-temperature rotary evaporator to remove the remaining formaldehyde. Then return the product to the reactor mentioned above.
[0062] 4) Nitrogen gas is introduced into the reactor above to remove oxygen for 30 minutes;
[0063] 5) Add 250g NaOH, 1200g Na2SO3 and 20g FeCl3 to the above reactor respectively, raise the reaction temperature to 90℃, set the stirring speed to 1000rpm, and continue the reaction for 4h.
[0064] 6) Add 1000g sodium propylene sulfonate, 500g allyl polyethylene glycol (molecular weight 366Da) and 1800g deionized water to the reactor in sequence. Cool the reactor with a condenser and increase the temperature to 55°C. Set the stirring speed to 400rpm and add an aqueous solution containing 400g potassium persulfate dropwise. After the addition is complete, lower the temperature and raise it to 70°C. Continue the reaction for 7 hours.
[0065] 7) Add 40g of sodium dimethyl dithiocarbamate to the above reactor and continue stirring for 25min;
[0066] 8) After the reaction is complete, place the gel-like product in a vacuum filtration device and rinse it with deionized water several times until the filtrate no longer contains the reactants. Dry the product in an oven at 100°C and pulverize it through a 200-mesh sieve to obtain the powder, which is the sulfonated crown ether-lignin copolymer.
[0067] Example 7:
[0068] A method for preparing a sulfonated crown ether-lignin copolymer includes the following steps:
[0069] 1) Add 600g of diaza-15-crown-5 and 80g of NaOH to a 10L reactor in sequence, slowly add 5000g of deionized water, stir at 500rpm, and continue the reaction for 50min after the reactants are completely dissolved.
[0070] 2) Add 600g of formaldehyde and 3000g of lignin to the reactor in sequence, raise the reaction temperature to 100℃, increase the stirring speed to 3000rpm, and continue the reaction for 8h.
[0071] 3) Stop stirring and let the system temperature drop to room temperature. Then transfer the reaction product to a low-temperature rotary evaporator to remove the remaining formaldehyde. Then return the product to the reactor mentioned above.
[0072] 4) Nitrogen gas is introduced into the reactor above to remove oxygen for 30 minutes;
[0073] 5) Add 300g NaOH, 1600g Na2SO3 and 30g FeCl3 to the above reactor respectively, raise the reaction temperature to 100℃, set the stirring speed to 1200rpm, and continue the reaction for 5h.
[0074] 6) Add 1200g sodium methpropylene sulfonate, 600g allyl polyethylene glycol (molecular weight 322 Da) and 2000g deionized water to the reactor in sequence. Cool the reactor with a condenser and increase the temperature to 60°C. Set the stirring speed to 500 rpm and add 500g potassium persulfate dropwise. After the addition is complete, lower the temperature and raise it to 80°C. Continue the reaction for 8 hours.
[0075] 7) Add 50g of sodium dimethyl dithiocarbamate to the above reactor and continue stirring for 30min;
[0076] 8) After the reaction is complete, place the gel-like product in a vacuum filtration device and rinse it with deionized water several times until the filtrate no longer contains the reactant monomers. Place the product in an oven at 100°C to dry it, pulverize it through a 200-mesh sieve, and obtain the powder, which is the aminosulfonated crown ether-lignin copolymer drilling fluid viscosity reducer.
[0077] Example 8:
[0078] A method for preparing a sulfonated crown ether-lignin copolymer includes the following steps:
[0079] 1) In a 10L reactor, add 300g of aza-14-crown ether-4, 300g of diaza-18-crown ether-6 and 80g of NaOH in sequence, slowly add 5000g of deionized water, stir at 500rpm, and continue the reaction for 50min after the reactants are completely dissolved.
[0080] 2) Add 600g of formaldehyde and 3000g of lignin to the reactor in sequence, raise the reaction temperature to 100℃, increase the stirring speed to 3000rpm, and continue the reaction for 8h.
[0081] 3) Stop stirring and let the system temperature drop to room temperature. Then transfer the reaction product to a low-temperature rotary evaporator to remove the remaining formaldehyde. Then return the product to the reactor mentioned above.
[0082] 4) Nitrogen gas is introduced into the reactor above to remove oxygen for 30 minutes;
[0083] 5) Add 300g NaOH, 1600g Na2SO3 and 30g FeCl3 to the above reactor respectively, raise the reaction temperature to 100℃, set the stirring speed to 1200rpm, and continue the reaction for 5h.
[0084] 6) Add 1200g sodium methpropylene sulfonate, 600g allyl polyethylene glycol (molecular weight 410 Da) and 2000g deionized water to the above reactor in sequence. Cool the reactor with a condenser and increase the temperature to 60°C. Set the stirring speed to 500 rpm and add 500g sodium persulfate dropwise. After the addition is complete, lower the temperature and raise it to 80°C. Continue the reaction for 8 hours.
[0085] 7) Add 50g of sodium nitrite to the above reactor and continue stirring for 30 minutes;
[0086] 8) After the reaction is complete, place the gel-like product in a vacuum filtration device and rinse it with deionized water several times until the filtrate no longer contains the reactants. Dry the product in an oven at 100°C and pulverize it through a 200-mesh sieve to obtain the powder, which is the sulfonated crown ether-lignin copolymer.
[0087] Comparative Example 1:
[0088] A method for preparing a sulfonated crown ether-lignin copolymer includes the following steps:
[0089] 1) Add 600g of diaza-18-crown-6 and 80g of NaOH to a 10L reactor in sequence, slowly add 5000g of deionized water, stir at 500rpm, and continue the reaction for 50min after the reactants are completely dissolved.
[0090] 2) Add 3000g of lignin to the above reactor, raise the reaction temperature to 100℃, increase the stirring speed to 3000rpm, and continue the reaction for 8h;
[0091] 3) Add 30g of FeCl3 to the above reactor, raise the reaction temperature to 100℃, set the stirring speed to 1200rpm, and continue the reaction for 5h.
[0092] 4) Add 1200g sodium methpropylene sulfonate, 600g allyl polyethylene glycol (molecular weight 410 Da) and 2000g deionized water to the reactor in sequence. Cool the reactor with a condenser and increase the temperature to 60°C. Set the stirring speed to 500 rpm and add 500g sodium persulfate dropwise. After the addition is complete, lower the temperature and raise it to 80°C. Continue the reaction for 8 hours.
[0093] 5) Add 50g of sodium nitrite to the above reactor and continue stirring for 30 minutes;
[0094] 6) After the reaction is complete, place the gel-like product in a vacuum filtration device and rinse it with deionized water several times until the filtrate no longer contains the reactants. Dry the product in an oven at 100°C and pulverize it through a 200-mesh sieve to obtain the powder, which is the sulfonated crown ether-lignin copolymer.
[0095] Comparative Example 2
[0096] Based on Example 8, lignin was replaced with methylcellulose (Tianjin Damao Chemical Reagent Factory, analytical grade), and the reaction yielded sulfonated crown ether-methylcellulose copolymer.
[0097] Comparative Example 3
[0098] Based on Example 8, sodium methylpropene sulfonate was removed in step 4).
[0099] Comparative Example 4
[0100] Based on Example 8, allyl polyethylene glycol is removed in step 4).
[0101] Implementation Results Example
[0102] Performance testing
[0103] Test program:
[0104] 1) Preparation of base slurry: 4.0wt% bentonite slurry (+0.5wt% Na2CO3), dispersed at 5000rpm for 20min, then sealed and aged for 16h, ready for use;
[0105] 2) Add 2.0% filtration loss reducer to the base slurry and stir at high speed at 5000 rpm. Measure the performance before and after rolling aging at 240℃ / 16h. In addition, measure the high temperature and high pressure water loss (240℃ / 3.5MPa) of the system after aging.
[0106] 3) Under the condition of a fixed 2.0 wt% filtration loss reducer, 0.5 wt%, 1.0 wt%, 5.0 wt%, 8.0 wt%, 10.0 wt%, and 15.0 wt% CaCl2 were added to the drilling fluid and stirred at high speed at 5000 rpm. The performance before and after rolling aging at 240℃ / 16h was measured. The performance test was carried out according to the drilling fluid test procedure of SY / T5621-1993. The apparent viscosity AV and API filtration loss FL of the sulfonated crown ether-lignin copolymers prepared in Examples 1-8 and Comparative Examples 1-4 added to the base slurry of (1) as viscosity reducers were measured. AP1 and HTHP filtration loss FL HTHP The results are shown in Table 1.
[0107] According to liquid transmission chromatography, the average molecular weight of the sulfonated crown ether-lignin copolymers prepared in Examples 1-8 and Comparative Examples 1-4 was determined to be between 8000 and 15000, as shown in Table 1.
[0108] Table 1. Effects of sulfonated crown ether-lignin copolymers prepared in Examples 1-8 and Comparative Examples 1-4 on drilling fluid properties.
[0109]
[0110] As can be seen from the results in Table 1, for different polymerization inhibitors provided in Examples 1 and 2, the viscosity reducer prepared using sodium sulfide as the polymerization inhibitor has a higher molecular weight and apparent viscosity AV at room temperature or high temperature than the viscosity reducer prepared using sodium dimethyl dithiocarbamate as the polymerization inhibitor.
[0111] The difference between Examples 1 and 3 lies in the molecular weight of allyl polyethylene glycol. It can be seen that the higher molecular weight of allyl polyethylene glycol is beneficial to increasing the molecular weight of the polymer, and the filtration performance of the prepared viscosity reducer after aging at room temperature and 240°C for 16 hours is also significantly improved.
[0112] Examples 4 and 5 show the results of different initiators. It can be seen that the viscosity reducer prepared using sodium persulfate as an initiator has similar results to the viscosity reducer prepared using ammonium persulfate as an initiator.
[0113] The results of Examples 1-8 show that the sulfonated crown ether-lignin copolymer prepared in this study, when added to drilling fluid as a viscosity reducer, exhibits stable system performance, maintaining good viscosity and low water loss even at 240°C. However, the lack of a sulfonation process (Comparative Example 1), the substitution of lignin with methylcellulose (Comparative Example 2), or the absence of certain segments in the copolymer (Comparative Examples 3 and 4) significantly reduces its filtration loss reduction performance, especially after aging at 240°C, where the filtration loss exceeds 45 mL.
[0114] Table 2 shows the changes in drilling fluid properties with CaCl2 after adding 2.0 wt% of the sulfonated crown ether-lignin copolymer from Example 5.
[0115] Table 2. Effects of different CaCl2 dosages on drilling fluid properties
[0116]
[0117] As shown in Table 2, the sulfonated crown ether-lignin copolymer provided by the present invention has strong calcium resistance. When the amount of CaCl2 added is not higher than 8.0 wt%, its viscosity changes slowly and its water loss also changes very slowly. This indicates that the treatment agent can resist 8.0 wt% CaCl2.
[0118] Any numerical value mentioned in this invention, if there is only a two-unit interval between any minimum and any maximum value, includes all values that increase by one unit each time from the minimum to the maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, or time, is stated as 201 to 300, in this specification it means specifically listing values such as 101-299, 102-298... and 198-202 and 199-201. For non-integer values, it may be appropriate to consider a unit of 0.1, 0.01, 0.001, or 0.0001. These are merely some specifically specified examples. In this application, in a similar manner, all possible combinations of numerical values between the listed minimum and maximum values are considered to have been disclosed.
[0119] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.
Claims
1. A method for preparing a sulfonated crown ether-lignin copolymer, characterized in that, include: Sulfonated crown ether-lignin, propylene sulfonate, and allyl polyethylene glycol react in the presence of an initiator to obtain the sulfonated crown ether-lignin copolymer.
2. The preparation method according to claim 1, characterized in that, The mass ratio of sulfonated crown ether-lignin, propylene sulfonate, allyl polyethylene glycol and initiator, calculated as lignin, is (2000-3000): (400-1200): (300-600): (200-500).
3. The preparation method according to claim 1 or 2, characterized in that, The propylene sulfonate includes at least one of sodium propylene sulfonate and sodium methpropylene sulfonate; And / or, the allyl polyethylene glycol has the molecular formula CH2=CHCH2O(CH2CH2O). n H, where n is 5-8; And / or, the initiator includes at least one of potassium persulfate, ammonium persulfate, and sodium persulfate; And / or, a polymerization inhibitor is added after the reaction is complete; Preferably, the polymerization inhibitor includes at least one of sodium dimethyl dithiocarbamate, sodium sulfide, and sodium nitrite; Preferably, the mass ratio of the polymerization inhibitor to the sulfonated crown ether-lignin (calculated as lignin) is (30-50):(2000-3000).
4. The preparation method according to any one of claims 1-3, characterized in that, The method for preparing the sulfonated crown ether-lignin includes: under alkaline conditions and in the presence of aldehydes, the crown ether reacts with lignin to generate crown ether-lignin; the crown ether-lignin reacts with a sulfonating agent under alkaline conditions to obtain the sulfonated crown ether-lignin.
5. The preparation method according to claim 4, characterized in that, The aldehydes include formaldehyde; And / or, the crown ether is an azacrown ether; preferably, the azacrown ether includes at least one of aza14-crown ether-4, diaza14-crown ether-4, aza15-crown ether-5, diaza15-crown ether-5, aza18-crown ether-6, and diaza18-crown ether-6.
6. The preparation method according to claim 4 or 5, characterized in that, The mass ratio of the crown ether, aldehyde and lignin is (300-600):(300-600):(2000-3000).
7. The preparation method according to any one of claims 4-6, characterized in that, The sulfonation reaction system also includes a trivalent metal salt, preferably a trivalent iron salt; preferably, the mass ratio of the trivalent metal salt to lignin is (10-30):(2000-3000); And / or, the sulfonating agent includes at least one of sulfites; preferably, the mass ratio of the sulfite to lignin is (800-1600):(2000-3000); And / or, the pH of the sulfonation reaction system is 9–11.
8. A sulfonated crown ether-lignin copolymer, prepared by any one of the preparation methods described in claims 1-7.
9. A drilling fluid viscosity reducer, characterized in that, Includes the sulfonated crown ether-lignin copolymer of claim 8.
10. The application of the drilling fluid viscosity reducer according to claim 9 in drilling fluid.