A sulfonated asphalt for drilling fluid and a method for preparing the same
By modifying SEBS to prepare quaternary ammonium modified SEBS and then combining it with sulfonated asphalt to form an interpenetrating network structure, the problems of insufficient thermal stability and shale inhibition ability of traditional sulfonated asphalt under high temperature and high pressure are solved, and efficient plugging and wellbore stabilization of drilling fluid with sulfonated asphalt are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANDONG DESHUNYUAN PETROLEUM SCI&TECH CO LTD
- Filing Date
- 2026-03-02
- Publication Date
- 2026-05-12
AI Technical Summary
Traditional sulfonated asphalt has poor thermal stability under high temperature and pressure and weak shale inhibition ability, which limits its application in complex strata.
Quaternized ammonium modified SEBS is prepared by quaternization modification and then compounded with sulfonated asphalt to form an interpenetrating network structure, which enhances the plugging performance and thermal stability. Furthermore, the pyridine quaternary ammonium salt cationic groups are firmly adsorbed onto the surface of the wellbore rock, neutralizing the negative charge of the clay and inhibiting the hydration and swelling of the clay.
It maintains good filtration loss reduction and wellbore stability under high temperature and high pressure, improves the toughness and impact resistance of the plugging layer, promotes the uniform dispersion of sulfonated asphalt in drilling fluid, and prevents agglomeration.
Smart Images
Figure CN121759179B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of drilling fluid treatment agents, specifically to a sulfonated asphalt for drilling fluid and its preparation method. Background Technology
[0002] As oil and gas exploration and development advances into deeper, ultra-deep, and complex formations, geological conditions become increasingly demanding, placing higher requirements on the comprehensive performance of drilling fluid treatment agents. Sulfonated asphalt is a widely used anti-collapse and plugging agent in drilling engineering. Its molecular structure contains both hydrophilic sulfonate groups and lipophilic asphaltenes, which can adsorb onto the wellbore surface to form a protective film, sealing rock pores and micro-fractures, reducing drilling fluid filtrate intrusion, and thus stabilizing the wellbore. However, traditional sulfonated asphalt suffers from poor thermal stability and weak shale suppression capabilities, limiting its application in complex formations. Therefore, avoiding this problem is key to solving the issue. For example, Chinese invention patent CN105885809B discloses a sulfonated asphalt for drilling fluid, its preparation method, and its application. The sulfonated asphalt obtained by this invention has high water solubility, high dispersion in drilling fluid, low production cost, and low high-temperature and high-pressure filtrate loss. However, its shale suppression performance and wellbore stability still need improvement. Summary of the Invention
[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide a sulfonated asphalt for drilling fluid and its preparation method. The sulfonated asphalt for drilling fluid of the present invention has good filtration loss reduction performance under high temperature and high pressure, and also has good shale inhibition performance and wellbore stability performance.
[0004] To achieve the above objectives, the present invention provides the following technical solution: a sulfonated bitumen for drilling fluid, comprising the following weight components: 20-25 parts by weight of bitumen, 2-4 parts by weight of quaternized modified SEBS, 35-40 parts by weight of kerosene, and 6-8 parts by weight of fuming sulfuric acid.
[0005] Furthermore, the preparation method of the quaternized modified SEBS is as follows:
[0006] S1: Dissolve SEBS in chloroform. After dissolution, add 1,4-dichloromethoxybutane and anhydrous tin tetrachloride dropwise using a constant pressure dropping funnel. After the addition is complete, react at 45-55℃ for 3-4 hours. After the reaction is complete, place the reaction solution in methanol to precipitate flocculent precipitate, and wash with tetrahydrofuran. Repeat 3-4 times, and dry to obtain chloromethylated SEBS.
[0007] S2: Add deionized water and sodium azide to the reactor and mix well to obtain an aqueous solution of sodium azide. Then disperse nicotinic chloride hydrochloride in acetone and stir thoroughly at 0-5℃ to obtain a mixture. Add the mixture dropwise to the aqueous solution of sodium azide, keeping the dropper below the liquid surface during the dropwise addition. After the dropwise addition is complete, stir the reaction at 0-5℃ for 3-4 hours. After the reaction is complete, the layering phenomenon occurs. Remove the lower water layer and take the upper yellow transparent solution. Place it in toluene at a temperature maintained at 60-65℃ and stir for 2-3 hours until no more nitrogen gas is released. After cooling at 0-5℃, a solid precipitates out. Filter and freeze dry to obtain 3-pyridine isocyanate.
[0008] S3: Add 3-pyridine isocyanate and 2-aminobenzene-1,3,5-tricarboxylic acid to N,N-dimethylformamide solvent, mix well, and stir at room temperature for 4-6 hours. After the reaction is completed, slowly add the reaction solution to anhydrous diethyl ether with stirring, collect the precipitate, filter, wash and dry to obtain intermediate 1.
[0009] S4: Under nitrogen protection, chloromethylated SEBS was added to N,N-dimethylformamide solvent and stirred at 60-80℃ until completely dissolved. Then, intermediate 1 was added and mixed evenly. The temperature was raised to 80-90℃ and the reaction was stirred for 24-48 hours. After the reaction was completed, the mixture was cooled to room temperature and the reaction solution was slowly added dropwise to methanol under stirring. The precipitate was collected, filtered, washed and dried to obtain quaternized modified SEBS.
[0010] In the above steps, the chlorine on the chloromethylated SEBS undergoes a quaternization reaction with the nitrogen atom on the pyridine ring in intermediate 1 to obtain quaternized modified SEBS with pyridine quaternary ammonium salt cationic groups in the side chain.
[0011] Furthermore, the ratio of SEBS, chloroform, 1,4-dichloromethoxybutane, and anhydrous tin tetrachloride in S1 is 2-2.2g:60-65mL:7.2-7.4mL:0.8-1mL.
[0012] Furthermore, the ratio of deionized water, sodium azide, nicotinic acid chloride hydrochloride, acetone, and toluene in S2 is 12-15 mL: 3.9-4.1 g: 3.56-3.66 g: 15-18 mL: 10-12 mL.
[0013] Furthermore, the ratio of N,N-dimethylformamide, 3-pyridine isocyanate, and 2-aminobenzene-1,3,5-tricarboxylic acid in S3 is 35-45 mL: 2.4-2.5 g: 4.5-4.6 g.
[0014] Furthermore, the ratio of N,N-dimethylformamide, chloromethylated SEBS, and intermediate 1 in S4 is 50-60 mL: 1.5-1.6 g: 1.1-1.2 g.
[0015] Further, the preparation method of the sulfonated bitumen for drilling fluid is as follows: the bitumen is crushed and added to kerosene along with quaternized ammonium modified SEBS. The mixture is refluxed at 100-110℃ for 1-2 hours. After the temperature is cooled to 50-60℃, fuming sulfuric acid is added and the reaction continues for 2-3 hours. Then, the pH of the system is adjusted to 8-9 using a 20% sodium hydroxide solution. The kerosene solvent is recovered by distillation. The resulting solid is dried in an oven and crushed to obtain the sulfonated bitumen for drilling fluid.
[0016] Furthermore, the drying temperature in the oven is 110-120°C.
[0017] Compared with the prior art, the present invention has the following beneficial technical effects:
[0018] This invention achieves a synergistic improvement in sealing performance, inhibition performance, and thermal stability by modifying SEBS and then compounding it with sulfonated asphalt.
[0019] The ethylene-butadiene segment thermoplastic elastomer backbone of quaternized SEBS exhibits good compatibility with sulfonated asphalt, forming an interpenetrating network structure within the system. This enhances the toughness and impact resistance of the sealing layer, ensuring that the sulfonated asphalt used in the drilling fluid of this invention maintains good filtration loss reduction performance even under high temperature and pressure. Furthermore, the multiple carboxyl groups introduced in intermediate 1 can crosslink with multivalent metal ions such as calcium and magnesium ions in an alkaline drilling fluid environment, further enhancing the cohesive strength and thermal stability of the network. The pyridine quaternary ammonium salt cationic groups introduced at the ends of the quaternized SEBS molecular chains can... The strong electrostatic effect firmly adsorbs onto the negatively charged surface of wellbore rock and clay particles, significantly neutralizing the negative charge of the clay, inhibiting clay hydration, expansion, and dispersion, maintaining wellbore stability, and improving the shale suppression performance and wellbore stability of the sulfonated asphalt used in the drilling fluid of this invention. The quaternized ammonium modified SEBS has both hydrophilic quaternary ammonium salts and carboxyl groups and lipophilic SEBS main chains and benzene rings, making it a highly efficient amphiphilic polymer that can act as a dispersant and stabilizer, promoting the uniform dispersion of sulfonated asphalt particles in the drilling fluid system, preventing their agglomeration, and ensuring that the plugging agent particles can act uniformly and effectively on the wellbore. Attached Figure Description
[0020] Figure 1 This is the synthesis reaction formula for intermediate 1. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0022] The reagents used in the following specific embodiments are of analytical grade. Additionally:
[0023] Asphalt: 70# road petroleum asphalt was selected, with a penetration of 69.6 / 0.1mm at 25℃;
[0024] SEBS: Hydrogenated styrene-butadiene copolymer, grade A1535, manufactured by KETEN Polymer Trading (Shanghai) Co., Ltd.
[0025] Fuming sulfuric acid: 20% fuming sulfuric acid.
[0026] Example 1
[0027] (1) Dissolve 2g of SEBS in 60mL of chloroform. After dissolution, add 7.2mL of 1,4-dichloromethoxybutane and 0.8mL of anhydrous tin tetrachloride dropwise using a constant pressure dropping funnel. After the addition is complete, react at 45℃ for 3h. After the reaction is complete, place the reaction solution in methanol to precipitate flocculent precipitate, and wash with tetrahydrofuran. Repeat 3 times, dry, and obtain chloromethylated SEBS.
[0028] (2) Add 12 mL of deionized water and 3.9 g of sodium azide to the reactor, mix well to obtain sodium azide aqueous solution, then disperse 3.56 g of nicotinic chloride hydrochloride in 15 mL of acetone, stir thoroughly at 0 °C to obtain a mixture, add the mixture dropwise to the sodium azide aqueous solution, keeping the dropper below the liquid surface during the dropwise addition, stir the reaction at 0 °C for 3 h after the dropwise addition is completed, the reaction is separated into layers, remove the lower water layer, take the upper yellow transparent solution, and place it in 10 mL of toluene at 60 °C, stir for 2 h until no more nitrogen gas is released, cool at 0 °C and a solid precipitates out, filter and freeze dry to obtain 3-pyridine isocyanate;
[0029] (3) Add 2.4 g of 3-pyridine isocyanate and 4.5 g of 2-aminobenzene-1,3,5-tricarboxylic acid to 35 mL of N,N-dimethylformamide solvent, mix well, and stir at room temperature for 4 h. After the reaction is complete, slowly add the reaction solution dropwise to anhydrous diethyl ether with stirring, collect the precipitate, filter, wash and dry to obtain intermediate 1, as shown. Figure 1 As shown;
[0030] (4) Under nitrogen protection, 1.5 g of chloromethylated SEBS was added to 50 mL of N,N-dimethylformamide solvent and stirred at 60 °C until completely dissolved. Then, 1.1 g of intermediate 1 was added and mixed evenly. The temperature was raised to 80 °C and stirred for 24 h. After the reaction was completed, the mixture was cooled to room temperature. The reaction solution was slowly added dropwise to methanol under stirring. The precipitate was collected, filtered, washed and dried to obtain quaternized modified SEBS.
[0031] (5) 20 parts by weight of asphalt were crushed and added together with 2 parts by weight of quaternized modified SEBS to 35 parts by weight of kerosene. The mixture was refluxed at 100°C for 1 hour. After the temperature was cooled to 50°C, 6 parts by weight of fuming sulfuric acid were added and the reaction was continued for 2 hours. Then, the pH of the system was adjusted to 8 using a 20% sodium hydroxide solution. The kerosene solvent was recovered by distillation. The resulting solid was dried in an oven at 110°C and crushed to obtain sulfonated asphalt for drilling fluid.
[0032] Example 2
[0033] (1) Dissolve 2.2g of SEBS in 65mL of chloroform. After dissolution, add 7.4mL of 1,4-dichloromethoxybutane and 1mL of anhydrous tin tetrachloride dropwise using a constant pressure dropping funnel. After the addition is complete, react at 55℃ for 4h. After the reaction is complete, place the reaction solution in methanol to precipitate flocculent precipitate, and wash with tetrahydrofuran. Repeat 4 times, dry, and obtain chloromethylated SEBS.
[0034] (2) Add 15 mL of deionized water and 4.1 g of sodium azide to the reactor and mix them evenly to obtain an aqueous solution of sodium azide. Then disperse 3.66 g of nicotinic chloride hydrochloride in 18 mL of acetone and stir thoroughly at 5 °C to obtain a mixture. Add the mixture dropwise to the aqueous solution of sodium azide while keeping the dropper below the liquid surface. After the addition is complete, stir the reaction at 5 °C for 4 h. After the reaction is complete, the layering phenomenon occurs. Remove the lower water layer and take the upper yellow transparent solution. Place it in 12 mL of toluene at 65 °C and stir for 3 h until no more nitrogen gas is released. After cooling at 5 °C, a solid precipitates out. Filter and freeze dry to obtain 3-pyridine isocyanate.
[0035] (3) Add 2.5 g of 3-pyridine isocyanate and 4.6 g of 2-aminobenzene-1,3,5-tricarboxylic acid to 45 mL of N,N-dimethylformamide solvent, mix well, stir and react at room temperature for 6 h. After the reaction is completed, slowly add the reaction solution to anhydrous diethyl ether under stirring, collect the precipitate, filter, wash and dry to obtain intermediate 1;
[0036] (4) Under nitrogen protection, 1.6 g of chloromethylated SEBS was added to 60 mL of N,N-dimethylformamide solvent and stirred at 80 °C until completely dissolved. Then, 1.2 g of intermediate 1 was added and mixed evenly. The temperature was raised to 90 °C and stirred for 48 h. After the reaction was completed, the mixture was cooled to room temperature. The reaction solution was slowly added dropwise to methanol under stirring. The precipitate was collected, filtered, washed and dried to obtain quaternized modified SEBS.
[0037] (5) 25 parts by weight of asphalt were crushed and added together with 4 parts by weight of quaternized modified SEBS to 40 parts by weight of kerosene. The mixture was refluxed at 110°C for 2 hours. After the temperature was cooled to 60°C, 8 parts by weight of fuming sulfuric acid were added and the reaction was continued for 3 hours. Then, the pH of the system was adjusted to 9 using a 20% sodium hydroxide solution. The kerosene solvent was recovered by distillation. The resulting solid was dried in an oven at 120°C and crushed to obtain sulfonated asphalt for drilling fluid.
[0038] Example 3
[0039] (1) Dissolve 2.1 g of SEBS in 62 mL of chloroform. After dissolution, add 7.3 mL of 1,4-dichloromethoxybutane and 0.9 mL of anhydrous tin tetrachloride dropwise using a constant pressure dropping funnel. After the addition is complete, react at 50 °C for 3 h. After the reaction is complete, place the reaction solution in methanol to precipitate flocculent precipitate, and wash with tetrahydrofuran. Repeat 3 times, dry, and obtain chloromethylated SEBS.
[0040] (2) Add 14 mL of deionized water and 4 g of sodium azide to the reactor and mix them evenly to obtain an aqueous solution of sodium azide. Then disperse 3.62 g of nicotinic chloride hydrochloride in 16 mL of acetone and stir thoroughly at 2 °C to obtain a mixture. Add the mixture dropwise to the aqueous solution of sodium azide while keeping the dropper below the liquid surface. After the addition is complete, stir the reaction at 2 °C for 3 h. After the reaction is complete, the layering phenomenon occurs. Remove the lower water layer and take the upper yellow transparent solution. Place it in 11 mL of toluene at 62 °C and stir for 2 h until no more nitrogen gas is released. After cooling at 2 °C, a solid precipitates out. Filter and freeze dry to obtain 3-pyridine isocyanate.
[0041] (3) Add 2.45 g of 3-pyridine isocyanate and 4.55 g of 2-aminobenzene-1,3,5-tricarboxylic acid to 40 mL of N,N-dimethylformamide solvent, mix well, stir and react at room temperature for 5 h. After the reaction is completed, slowly add the reaction solution to anhydrous diethyl ether under stirring, collect the precipitate, filter, wash and dry to obtain intermediate 1;
[0042] (4) Under nitrogen protection, 1.55 g of chloromethylated SEBS was added to 55 mL of N,N-dimethylformamide solvent and stirred at 70 °C until completely dissolved. Then, 1.15 g of intermediate 1 was added and mixed evenly. The temperature was raised to 85 °C and stirred for 36 h. After the reaction was completed, the mixture was cooled to room temperature. The reaction solution was slowly added dropwise to methanol under stirring. The precipitate was collected, filtered, washed and dried to obtain quaternized modified SEBS.
[0043] (5) 22 parts by weight of asphalt were crushed and added together with 3 parts by weight of quaternized modified SEBS to 38 parts by weight of kerosene. The mixture was refluxed at 105°C for 1.5 h. After the temperature was cooled to 55°C, 7 parts by weight of fuming sulfuric acid were added and the reaction was continued for 2 h. Then, the pH of the system was adjusted to 8 using a 20% sodium hydroxide solution. The kerosene solvent was recovered by distillation. The resulting solid was dried in an oven at 115°C and crushed to obtain sulfonated asphalt for drilling fluid.
[0044] Example 4
[0045] (1) Dissolve 2.05 g of SEBS in 61 mL of chloroform. After dissolution, add 7.25 mL of 1,4-dichloromethoxybutane and 0.85 mL of anhydrous tin tetrachloride dropwise using a constant pressure dropping funnel. After the addition is complete, react at 48 °C for 3 h. After the reaction is complete, place the reaction solution in methanol to precipitate flocculent precipitate, and wash with tetrahydrofuran. Repeat 3 times and dry to obtain chloromethylated SEBS.
[0046] (2) Add 13 mL of deionized water and 3.95 g of sodium azide to the reactor, mix well to obtain sodium azide aqueous solution, then disperse 3.6 g of nicotinic chloride hydrochloride in 16 mL of acetone, stir thoroughly at 1 °C to obtain a mixture, add the mixture dropwise to the sodium azide aqueous solution, keeping the dropper below the liquid surface during the dropwise addition, stir the reaction at 1 °C for 3 h after the dropwise addition is completed, the reaction is separated into layers, remove the lower water layer, take the upper yellow transparent solution, and place it in 10 mL of toluene at 61 °C, stir for 2 h until no more nitrogen gas is released, cool at 1 °C and a solid precipitates out, filter and freeze dry to obtain 3-pyridine isocyanate;
[0047] (3) Add 2.42 g of 3-pyridine isocyanate and 4.52 g of 2-aminobenzene-1,3,5-tricarboxylic acid to 38 mL of N,N-dimethylformamide solvent, mix well, stir and react at room temperature for 4 h. After the reaction is completed, slowly add the reaction solution to anhydrous diethyl ether under stirring, collect the precipitate, filter, wash and dry to obtain intermediate 1;
[0048] (4) Under nitrogen protection, 1.52 g of chloromethylated SEBS was added to 52 mL of N,N-dimethylformamide solvent and stirred at 65 °C until completely dissolved. Then, 1.12 g of intermediate 1 was added and mixed evenly. The temperature was raised to 82 °C and stirred for 30 h. After the reaction was completed, the mixture was cooled to room temperature. The reaction solution was slowly added dropwise to methanol under stirring. The precipitate was collected, filtered, washed and dried to obtain quaternized modified SEBS.
[0049] (5) 22 parts by weight of asphalt were crushed and added together with 2 parts by weight of quaternized modified SEBS to 36 parts by weight of kerosene. The mixture was refluxed at 102°C for 1 hour. After the temperature was cooled to 52°C, 6 parts by weight of fuming sulfuric acid were added and the reaction was continued for 2 hours. Then, the pH of the system was adjusted to 8 using a 20% sodium hydroxide solution. The kerosene solvent was recovered by distillation. The resulting solid was dried in an oven at 112°C and crushed to obtain sulfonated asphalt for drilling fluid.
[0050] Example 5
[0051] (1) Dissolve 2.15 g of SEBS in 64 mL of chloroform. After dissolution, add 7.35 mL of 1,4-dichloromethoxybutane and 0.95 mL of anhydrous tin tetrachloride dropwise using a constant pressure dropping funnel. After the addition is complete, react at 52 °C for 4 h. After the reaction is complete, place the reaction solution in methanol to precipitate flocculent precipitate, and wash with tetrahydrofuran. Repeat 4 times, dry, and obtain chloromethylated SEBS.
[0052] (2) Add 14 mL of deionized water and 4.05 g of sodium azide to the reactor and mix them evenly to obtain an aqueous solution of sodium azide. Then disperse 3.64 g of nicotinic chloride hydrochloride in 17 mL of acetone and stir thoroughly at 4 °C to obtain a mixture. Add the mixture dropwise to the aqueous solution of sodium azide while keeping the dropper below the liquid surface. After the addition is complete, stir the reaction at 4 °C for 4 h. After the reaction is complete, the layering phenomenon occurs. Remove the lower water layer and take the upper yellow transparent solution. Place it in 12 mL of toluene at 64 °C and stir for 3 h until no more nitrogen gas is released. After cooling at 3 °C, a solid precipitates out. Filter and freeze dry to obtain 3-pyridine isocyanate.
[0053] (3) Add 2.48 g of 3-pyridine isocyanate and 4.58 g of 2-aminobenzene-1,3,5-tricarboxylic acid to 42 mL of N,N-dimethylformamide solvent, mix well, stir and react at room temperature for 6 h. After the reaction is completed, slowly add the reaction solution to anhydrous diethyl ether under stirring, collect the precipitate, filter, wash and dry to obtain intermediate 1;
[0054] (4) Under nitrogen protection, 1.58 g of chloromethylated SEBS was added to 58 mL of N,N-dimethylformamide solvent and stirred at 75 °C until completely dissolved. Then, 1.18 g of intermediate 1 was added and mixed evenly. The temperature was raised to 88 °C and stirred for 40 h. After the reaction was completed, the mixture was cooled to room temperature. The reaction solution was slowly added dropwise to methanol under stirring. The precipitate was collected, filtered, washed and dried to obtain quaternized modified SEBS.
[0055] (5) 24 parts by weight of asphalt were crushed and added together with 4 parts by weight of quaternized modified SEBS to 39 parts by weight of kerosene. The mixture was refluxed at 108°C for 2 hours. After the temperature was cooled to 58°C, 8 parts by weight of fuming sulfuric acid were added and the reaction was continued for 3 hours. Then, the pH of the system was adjusted to 9 using a 20% sodium hydroxide solution. The kerosene solvent was recovered by distillation. The resulting solid was dried in an oven at 118°C and crushed to obtain sulfonated asphalt for drilling fluid.
[0056] Comparative Example 1
[0057] The main difference between this comparative example and Example 5 is that chloromethylated SEBS is used instead of quaternized modified SEBS.
[0058] Comparative Example 2
[0059] The main difference between this comparative example and Example 5 is that quaternized modified SEBS is not added.
[0060] Performance testing
[0061] (1) High-temperature and high-pressure filtration loss reduction test: 350 mL of distilled water was taken, 14 g of API standard sodium bentonite (as slurry soil) was added, and the mixture was stirred at high speed for 20 min. After standing for 24 h, 3.5 g of iron-chromium lignin sulfonate was added, followed by 7 g of API standard sodium bentonite (as evaluation soil, used to simulate the highly hydrated and inferior solid phase of the intrusive drilling fluid system). The mixture was stirred at low speed for 20 min and then at high speed for 10 min to form the base slurry. 7 g of drilling fluid sulfonated asphalt samples prepared in Examples 1-5 and Comparative Examples 1-2 were added to the base slurry respectively. After stirring at low speed for 20 min, the pH was adjusted to 10 with a 20% sodium hydroxide solution. The mixture was stirred at high speed for 20 min and then at low speed for 30 min. The filtration loss at 150 °C and 3450 kPa was measured according to SY-T5621-93. The sealing performance was characterized by comparing the high-temperature and high-pressure filtration loss of each sample. The test results are shown in Table 1.
[0062] Table 1: High Temperature and High Pressure Filtration Loss Reduction Performance Test
[0063]
[0064] As can be seen from Table 1, the sulfonated bitumen for drilling fluid prepared in Examples 1-5 has good high-temperature and high-pressure filtration loss reduction performance.
[0065] (2) Zeta potential test: The Zeta potential of clay was measured after it reacted with sulfonated bitumen samples of drilling fluid prepared in Examples 1-5 and Comparative Examples 1-2. The clay was prepared into a base slurry at a ratio of 4g clay / 100mL water. A sample of 1.0% of the clay mass was added to the base slurry and stirred for 20min. After standing for 24h, the supernatant was taken to measure the Zeta potential. The test results are shown in Table 2.
[0066] Table 2: Zeta potential test
[0067]
[0068] As can be seen from Table 2, the sulfonated bitumen for drilling fluid prepared in Examples 1-5 has a small absolute value of Zeta potential, and has good shale suppression performance and wellbore stability performance.
[0069] The comparison shows that Comparative Example 1, which uses chloromethylated SEBS instead of quaternized SEBS, lacks quaternary ammonium salt cations and cannot be adsorbed onto the wellbore surface and clay particles through strong electrostatic interaction. This results in weak interfacial bonding between the sealing layer and the wellbore. Under high temperature and pressure, the clay particles hydrate and expand, squeezing and tearing the sealing membrane formed after asphalt sulfonation, leading to cracks in the membrane structure. Drilling fluid filtrate then infiltrates the formation along these cracks, increasing filtration loss. Therefore, the performance of Comparative Example 1 is reduced. Comparative Example 2, which does not contain quaternized SEBS, lacks the skeletal support of the SEBS elastomer network. The resulting sealing layer is prone to plastic deformation under high temperature and pressure, and will generate electrostatic repulsion with the negatively charged wellbore. This results in poor adhesion and easy detachment from the wellbore. Furthermore, the lack of SEBS dispersion and bonding properties causes asphalt particles to agglomerate, leading to uneven sealing layer and further amplifying filtration loss. Therefore, the performance of Comparative Example 2 is reduced.
[0070] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0071] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
[0072] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments.
Claims
1. A sulfonated bitumen for drilling fluid, characterized in that it comprises the following weight components: 20-25 parts by weight of bitumen, 2-4 parts by weight of quaternized modified SEBS, 35-40 parts by weight of kerosene, and 6-8 parts by weight of fuming sulfuric acid; Among them, the quaternized modified SEBS is obtained by reacting chloromethylated SEBS with intermediate 1; Intermediate 1 is obtained by reacting 3-pyridine isocyanate with 2-aminophenyl-1,3,5-tricarboxylic acid; The preparation method of the quaternized modified SEBS is as follows: S1: Dissolve SEBS in chloroform. After dissolution, add 1,4-dichloromethoxybutane and anhydrous tin tetrachloride dropwise using a constant pressure dropping funnel. After the addition is complete, react at 45-55℃ for 3-4 hours. After the reaction is complete, place the reaction solution in methanol to precipitate flocculent precipitate, and wash with tetrahydrofuran. Repeat 3-4 times, and dry to obtain chloromethylated SEBS. S2: Add deionized water and sodium azide to the reactor and mix well to obtain an aqueous solution of sodium azide. Then disperse nicotinic chloride hydrochloride in acetone and stir thoroughly at 0-5℃ to obtain a mixture. Add the mixture dropwise to the aqueous solution of sodium azide, keeping the dropper below the liquid surface during the dropwise addition. After the dropwise addition is complete, stir the reaction at 0-5℃ for 3-4 hours. After the reaction is complete, the layering phenomenon occurs. Remove the lower water layer and take the upper yellow transparent solution. Place it in toluene at a temperature maintained at 60-65℃ and stir for 2-3 hours until no more nitrogen gas is released. After cooling at low temperature, a solid precipitates out. Filter and freeze dry to obtain 3-pyridine isocyanate. S3: Add 3-pyridine isocyanate and 2-aminobenzene-1,3,5-tricarboxylic acid to N,N-dimethylformamide solvent, mix well, and stir at room temperature for 4-6 hours. After the reaction is completed, slowly add the reaction solution to anhydrous diethyl ether with stirring, collect the precipitate, filter, wash and dry to obtain intermediate 1. S4: Under nitrogen protection, chloromethylated SEBS was added to N,N-dimethylformamide solvent and stirred at 60-80℃ until completely dissolved. Then, intermediate 1 was added and mixed evenly. The temperature was raised to 80-90℃ and the reaction was stirred for 24-48 hours. After the reaction was completed, the mixture was cooled to room temperature. The reaction solution was slowly added dropwise to methanol under stirring. The precipitate was collected, filtered, washed and dried to obtain quaternized modified SEBS. The ratio of SEBS, chloroform, 1,4-dichloromethoxybutane, and anhydrous tin tetrachloride in S1 is 2-2.2 g: 60-65 mL: 7.2-7.4 mL: 0.8-1 mL; The ratio of deionized water, sodium azide, nicotinic acid chloride hydrochloride, acetone, and toluene in S2 is 12-15 mL: 3.9-4.1 g: 3.56-3.66 g: 15-18 mL: 10-12 mL; The ratio of N,N-dimethylformamide, 3-pyridine isocyanate, and 2-aminobenzene-1,3,5-tricarboxylic acid in S3 is 35-45 mL: 2.4-2.5 g: 4.5-4.6 g. The ratio of N,N-dimethylformamide, chloromethylated SEBS, and intermediate 1 in S4 is 50-60 mL. 1.5-1.6g: 1.1-1.2g; The method for preparing sulfonated bitumen for drilling fluid is as follows: pulverize bitumen, add it together with quaternized ammonium modified SEBS into kerosene, reflux and dissolve at 100-110℃ for 1-2 hours, cool the temperature to 50-60℃, add fuming sulfuric acid, continue the reaction for 2-3 hours, then adjust the pH of the system to 8-9 using a 20% sodium hydroxide solution, distill to recover the kerosene solvent, dry the resulting solid in an oven, pulverize it, and obtain sulfonated bitumen for drilling fluid.
2. A method for preparing sulfonated bitumen for drilling fluid as described in claim 1, characterized in that, The method for preparing sulfonated bitumen for drilling fluid is as follows: pulverize bitumen, add it together with quaternized ammonium modified SEBS into kerosene, reflux and dissolve at 100-110℃ for 1-2 hours, cool the temperature to 50-60℃, add fuming sulfuric acid, continue the reaction for 2-3 hours, then adjust the pH of the system to 8-9 using a 20% sodium hydroxide solution, distill to recover the kerosene solvent, dry the resulting solid in an oven, pulverize it, and obtain sulfonated bitumen for drilling fluid.
3. The method for preparing sulfonated bitumen for drilling fluid according to claim 2, characterized in that, The drying temperature in the oven is 110-120℃.