A sulfonated anti-collapse drilling fluid and its preparation method

Abstract

The present invention discloses a sulfonated anti-collapse drilling fluid and a preparation method thereof, relating to the technical field of drilling fluids. A sulfonated anti-collapse drilling fluid comprises the following raw materials in parts by weight: deionized water: 100 parts, bentonite: 2 - 6 parts, filtration reducer: 4 - 8 parts, pH regulator: 0.5 - 2 parts, plugging agent: 2 - 5 parts, sulfonated material: 2 - 6 parts, modified anti-collapse agent: 3 - 5 parts, weighting agent: 20 - 30 parts; in the present invention, lignin reacts with 1,2-epoxy-9-decene to generate modified lignin; the modified lignin reacts with polyetheramine to generate polyetheramine-modified lignin; nano-silica reacts with 3-isocyanatopropyltrimethoxysilane to generate silane-modified nano-silica; the polyetheramine-modified lignin reacts with the silane-modified nano-silica to generate a modified anti-collapse agent. The drilling fluid prepared by the present invention has good anti-collapse performance and filtration reduction performance.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling fluids, and specifically relates to a sulfonated anti-collapse drilling fluid and a preparation method thereof. Background Art

[0002] With the continuous growth of global energy demand, the oil extraction industry faces many challenges. During the oil extraction process, drilling fluid, as a key medium in the drilling engineering, its performance directly affects the drilling efficiency and safety. The main functions of drilling fluid include carrying cuttings, stabilizing the wellbore, cooling the drill bit, and balancing formation pressure, etc. Among them, the anti-collapse performance is one of the important indicators of the drilling fluid performance. Under complex geological conditions, such as high temperature, high pressure, high salinity and other environments, the anti-collapse performance of drilling fluid is particularly important. However, the existing drilling fluids on the market still have some deficiencies in terms of anti-collapse performance. For example, some traditional drilling fluids have poor stability in high-temperature environments, which easily lead to problems such as wellbore collapse, increasing the risk and cost of drilling operations. In addition, some drilling fluids have weak resistance to salt pollution and cannot meet the requirements of drilling in high-salinity formations.

[0003] The Chinese invention patent with the publication number CN114456780A discloses a high-temperature and high-density anti-collapse drilling fluid composition, its drilling fluid, preparation method and application. The drilling fluid, the high-temperature and high-density anti-collapse drilling fluid composition includes: bentonite, filtration reducer, inhibitor, sodium hydroxide and anti-collapse agent; the drilling fluid prepared by this patent has poor anti-collapse performance. In view of the above problems, researchers have been constantly exploring and innovating, and are committed to developing a drilling fluid with excellent anti-collapse performance. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a sulfonated anti-collapse drilling fluid and a preparation method thereof.

[0005] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0006] A sulfonated anti-collapse drilling fluid, comprising the following raw materials in parts by weight:

[0007] Deionized water: 100 parts, bentonite: 2 - 6 parts, filtration reducer: 4 - 8 parts, pH regulator: 0.5 - 2 parts, plugging agent: 2 - 5 parts, sulfonated material: 2 - 6 parts, modified anti-collapse agent: 3 - 5 parts, weighting agent: 20 - 30 parts;

[0008] The modified anti-collapse agent is prepared by the following method:

[0009] S1: Under nitrogen protection, DMSO (dimethyl sulfoxide), 1,2-epoxy-9-decene, lignin, catalyst C-94, and 1-butyl-3-methylimidazolium methanesulfonate ionic liquid are stirred and mixed evenly, heated to 80 - 90 °C, and reacted for 3 - 5 h to obtain modified lignin;

[0010] S2: DMF (N,N-dimethylformamide), modified lignin, and polyetheramine are stirred and mixed evenly, then triethylamine is added, heated to 70 - 85 °C, and reacted for 8 - 12 h to obtain polyetheramine-modified lignin;

[0011] S3: An ethanol and water mixture and nano-silica are mixed and ultrasonicated, then 3-isocyanatopropyltrimethoxysilane and triethylamine are added, and reacted at 70 - 85 °C for 4 - 6 h to obtain silane-modified nano-silica;

[0012] S4: Under nitrogen protection, DMF and silane-modified nano-silica are stirred and mixed evenly, heated to 50 - 70 °C, and polyetheramine-modified lignin and dibutyltin dilaurate are added in batches, and reacted for 4 - 6 h to obtain a modified anti-collapse agent.

[0013] In step S1, the feeding mass ratio of the lignin to 1,2-epoxy-9-decene is 10:(1 - 2).

[0014] In step S2, the feeding mass ratio of the modified lignin to polyetheramine is 5:(1 - 2).

[0015] In step S3, the feeding mass ratio of the nano-silica to 3-isocyanatopropyltrimethoxysilane is 10:(3 - 6).

[0016] In step S4, the feeding mass ratio of the polyetheramine-modified lignin to silane-modified nano-silica is 20:(2 - 5).

[0017] The filtrate reducer is carboxymethyl cellulose.

[0018] The pH regulator is one of potassium carbonate, sodium hydroxide, and potassium hydroxide; the plugging agent is sulfonated asphalt.

[0019] The sulfonated material is sulfonated phenolic resin.

[0020] The weighting agent is barite powder.

[0021] A preparation method of a sulfonated anti-collapse drilling fluid, comprising the following steps:

[0022] (1) Weigh by parts by weight: deionized water: 100 parts, bentonite: 2 - 6 parts, filtration reducer: 4 - 8 parts, pH regulator: 0.5 - 2 parts, plugging agent: 2 - 5 parts, sulfonated material: 2 - 6 parts, modified anti-collapse agent: 3 - 5 parts, weighting agent: 20 - 30 parts;

[0023] (2) Add deionized water and bentonite to a container, stir for 15 - 25 min, then stop stirring and seal for curing for 24 h to obtain pre-hydrated bentonite slurry; successively add the filtration reducer, pH regulator, plugging agent, sulfonated material, and modified anti-collapse agent to the pre-hydrated bentonite slurry in the above proportions, stir and mix evenly, and finally add the weighting agent and stir evenly to obtain sulfonated anti-collapse drilling fluid.

[0024] Due to the above technical solutions, the beneficial effects of the present invention include:

[0025] (1) In the present invention, the phenolic hydroxyl group in lignin reacts with the double bond in 1,2-epoxy-9-decene to generate modified lignin, and the epoxy group in the modified lignin reacts with the amino group in polyetheramine to generate polyetheramine-modified lignin; nano-silica reacts with 3-isocyanatopropyltrimethoxysilane to generate silane-modified nano-silica; finally, the hydroxyl group in the polyetheramine-modified lignin reacts with the isocyanate group in the silane-modified nano-silica to generate a modified anti-collapse agent.

[0026] (2) The synergistic effect of polyetheramine-modified lignin and silane-modified nano-silica in the modified anti-collapse agent prepared in the present invention can form a composite structure with multiple functions, which can simultaneously improve the stability, lubricity, filtration control ability, and support performance of the drilling fluid, thus significantly improving the rolling recovery rate of the drilling fluid. Specific Embodiments

[0027] The following is further described in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0028] Example 1 Preparation of modified anti-collapse agent:

[0029] S1: Under nitrogen protection, successively add 300 ml of DMSO, 10 g of 1,2-epoxy-9-decene, 100 g of lignin, 4 g of catalyst C-94, and 2 g of 1-butyl-3-methylimidazolium methanesulfonate ionic liquid to the reactor, stir and mix evenly, heat up to 80 °C, react for 5 h, then cool to room temperature, add 500 ml of deionized water and stir evenly, centrifuge, wash with 100 ml of ether and then wash with 100 ml of deionized water, and dry in vacuum at 80 °C for 4 h to obtain modified lignin;

[0030] S2: Add 250 ml of DMF, 50 g of modified lignin, and 10 g of polyetheramine (JEFFAMINE® M-1000) into the reactor, stir and mix evenly, then add 10 ml of triethylamine, heat up to 70 °C, after reacting for 12 h, cool down to room temperature, add 15 ml of 3 wt% dilute hydrochloric acid, carry out vacuum distillation at 70 °C for 2 h, and vacuum dry at 60 °C for 5 h to obtain polyetheramine-modified lignin;

[0031] S3: Add 600 ml of ethanol and water mixture (ethanol / water (V / V) = 9:1) and 100 g of nano-silica into the reactor, ultrasonically vibrate for 20 min, then add 30 g of 3-isocyanatopropyltrimethoxysilane and 15 ml of triethylamine, react at 70 °C for 6 h, then cool down to room temperature, centrifuge and filter, wash successively with 150 ml of toluene, 150 ml of absolute ethanol, and 150 ml of 50 wt% ethanol aqueous solution, and then vacuum dry at 70 °C for 6 h to obtain silane-modified nano-silica;

[0032] S4: Under nitrogen protection, add 1000 ml of DMF and 20 g of silane-modified nano-silica into the reactor, stir and dissolve, heat up to 50 °C, then add 200 g of polyetheramine-modified lignin in batches (40 g per batch, batch interval 20 min), then add 8 g of catalyst dibutyltin dilaurate, after reacting for 6 h, add 800 ml of ice water to precipitate and filter, vacuum dry at 50 °C for 6 h to obtain the modified anti-collapse agent.

[0033] Example 2 Preparation of the modified anti-collapse agent:

[0034] S1: Under nitrogen protection, add 300 ml of DMSO, 15 g of 1,2-epoxy-9-decene, 100 g of lignin, 5 g of catalyst C-94, and 2 g of 1-butyl-3-methylimidazolium methanesulfonate ionic liquid into the reactor, stir and mix evenly, heat up to 85 °C, after reacting for 4 h, cool down to room temperature, add 500 ml of deionized water and stir evenly, centrifuge, wash with 100 ml of diethyl ether and then wash with 100 ml of deionized water, vacuum dry at 80 °C for 4 h to obtain modified lignin;

[0035] S2: Add 250 ml of DMF, 50 g of modified lignin, and 15 g of polyetheramine (JEFFAMINE® M-1000) into the reactor, stir and mix evenly, then add 12 ml of triethylamine, heat up to 80 °C, after reacting for 10 h, cool down to room temperature, add 15 ml of 3 wt% dilute hydrochloric acid, carry out vacuum distillation at 70 °C for 2 h, and vacuum dry at 60 °C for 5 h to obtain polyetheramine-modified lignin;

[0036] S3: Add 600 ml of ethanol and water mixture (ethanol / water (V / V) = 9:1) and 100 g of nano-silica into the reactor, ultrasonically vibrate for 20 min, then add 50 g of 3-isocyanatopropyltrimethoxysilane and 15 ml of triethylamine. After reacting at 80 °C for 5 h, cool to room temperature, centrifuge and filter, wash successively with 150 ml of toluene, 150 ml of absolute ethanol, and 150 ml of 50 wt% ethanol aqueous solution, and then vacuum dry at 70 °C for 6 h to obtain silane-modified nano-silica;

[0037] S4: Under nitrogen protection, add 1000 ml of DMF and 35 g of silane-modified nano-silica into the reactor, stir to dissolve, heat up to 60 °C, then add 200 g of polyetheramine-modified lignin in batches (40 g per batch, batch interval 20 min), then add 10 g of catalyst dibutyltin dilaurate, after reacting for 5 h, add 800 ml of ice water to precipitate and filter, vacuum dry at 50 °C for 6 h to obtain the modified anti-collapse agent.

[0038] Example 3 Preparation of modified anti-collapse agent:

[0039] S1: Under nitrogen protection, add 300 ml of DMSO, 20 g of 1,2-epoxy-9-decene, 100 g of lignin, 5 g of catalyst C-94, and 2 g of 1-butyl-3-methylimidazolium methanesulfonate ionic liquid into the reactor, stir and mix evenly, heat up to 90 °C, after reacting for 3 h, cool to room temperature, add 600 ml of deionized water and stir evenly, centrifuge, wash with 100 ml of ether and then wash with 100 ml of deionized water, vacuum dry at 80 °C for 4 h to obtain modified lignin;

[0040] S2: Add 250 ml of DMF, 50 g of modified lignin, and 20 g of polyetheramine (JEFFAMINE® M-1000) into the reactor, stir and mix evenly, then add 15 ml of triethylamine, heat up to 85 °C, after reacting for 8 h, cool to room temperature, add 15 ml of 3 wt% dilute hydrochloric acid, carry out reduced pressure distillation at 70 °C for 2 h, vacuum dry at 60 °C for 5 h to obtain polyetheramine-modified lignin;

[0041] S3: Add 800 ml of ethanol and water mixture (ethanol / water (V / V) = 9:1) and 100 g of nano-silica into the reactor, ultrasonically vibrate for 20 min, then add 60 g of 3-isocyanatopropyltrimethoxysilane and 15 ml of triethylamine. After reacting at 85 °C for 4 h, cool to room temperature, centrifuge and filter, wash successively with 150 ml of toluene, 150 ml of absolute ethanol, and 150 ml of 50 wt% ethanol aqueous solution, and then vacuum dry at 70 °C for 6 h to obtain silane-modified nano-silica;

[0042] S4: Under nitrogen protection, add 1000 ml of DMF and 50 g of silica-modified nano-silica into the reactor, stir to dissolve, heat up to 70 °C, then add 200 g of polyetheramine-modified lignin in batches (40 g per batch, with a 20-minute interval between batches), then add 15 g of the catalyst dibutyltin dilaurate, after reacting for 4 h, add 800 ml of ice water for precipitation and filtration, and dry in vacuum at 50 °C for 6 h to obtain the modified anti-collapse agent.

[0043] Example 4 Preparation of sulfonated anti-collapse drilling fluid:

[0044] (1) Weigh: 1000 g of deionized water, 20 g of bentonite, 40 g of filtrate reducer (carboxymethyl cellulose), 5 g of pH regulator (potassium carbonate), 20 g of plugging agent (sulfonated asphalt), 20 g of sulfonated material (sulfonated phenolic resin), 30 g of modified anti-collapse agent (prepared in Example 1), 200 g of weighting agent (barite powder);

[0045] (2) Add deionized water and bentonite into the container, stir for 15 min, then stop stirring and cure in a closed state for 24 h to obtain pre-hydrated bentonite slurry; sequentially add the filtrate reducer, pH regulator, plugging agent, sulfonated material, and modified anti-collapse agent into the pre-hydrated bentonite slurry according to the weights weighed above, stir at a high speed for 50 min, with a rotation speed of 5000 r / min, and finally add the weighting agent and stir evenly to obtain the sulfonated anti-collapse drilling fluid.

[0046] Example 5 Preparation of sulfonated anti-collapse drilling fluid:

[0047] (1) Weigh: 1000 g of deionized water, 40 g of bentonite, 60 g of filtrate reducer (carboxymethyl cellulose), 10 g of pH regulator (potassium hydroxide), 30 g of plugging agent (sulfonated asphalt), 40 g of sulfonated material (sulfonated phenolic resin), 40 g of modified anti-collapse agent (prepared in Example 2), 250 g of weighting agent (barite powder);

[0048] (2) Add deionized water and bentonite into the container, stir for 20 min, then stop stirring and cure in a closed state for 24 h to obtain pre-hydrated bentonite slurry; sequentially add the filtrate reducer, pH regulator, plugging agent, sulfonated material, and modified anti-collapse agent into the pre-hydrated bentonite slurry according to the weights weighed above, stir at a high speed for 60 min, with a rotation speed of 5000 r / min, and finally add the weighting agent and stir evenly to obtain the sulfonated anti-collapse drilling fluid.

[0049] Example 6 Preparation of sulfonated anti-collapse drilling fluid:

[0050] (1) Weigh: 1000 g of deionized water, 60 g of bentonite, 80 g of filtrate reducer (carboxymethyl cellulose), 20 g of pH regulator (sodium hydroxide), 50 g of plugging agent (sulfonated asphalt), 60 g of sulfonated material (sulfonated phenolic resin), 50 g of modified anti-collapse agent (prepared in Example 3), and 300 g of weighting agent (barite powder);

[0051] (2) Add deionized water and bentonite to a container. After stirring for 25 min, stop stirring and carry out sealed curing for 24 h to obtain pre-hydrated bentonite slurry. Add the filtrate reducer, pH regulator, plugging agent, sulfonated material, and modified anti-collapse agent to the pre-hydrated bentonite slurry in sequence according to the weighed weights above, and stir at high speed for 70 min with a rotation speed of 5000 r / min. Finally, add the weighting agent and stir evenly to obtain sulfonated anti-collapse drilling fluid.

[0052] Comparative Example 1

[0053] A preparation method of sulfonated anti-collapse drilling fluid is basically the same as that of Example 5, except that the modified anti-collapse agent is replaced with a modified anti-collapse agent prepared by the following method with the same weight:

[0054] The preparation method of the modified anti-collapse agent in this comparative example is basically the same as that of Example 2, except that the lignin added in step S1 is replaced with aminated lignin prepared by the following method with the same weight:

[0055] Add 400 g of deionized water and 20 g of lignin to a reactor. After stirring and dissolving, add 10 wt% acetic acid solution dropwise until the pH value is 5. Stir, then add 3 g of paraformaldehyde, stir and mix evenly, add 1.5 g of diethanolamine, and heat and reflux for 6 h under stirring conditions to obtain an aqueous solution of aminated lignin. Vacuum dry the aqueous solution of aminated lignin at 60 °C for 24 h and pulverize to obtain aminated lignin.

[0056] Comparative Example 2

[0057] A preparation method of sulfonated anti-collapse drilling fluid is basically the same as that of Example 5, except that the modified anti-collapse agent is replaced with a modified anti-collapse agent prepared by the following method with the same weight:

[0058] The preparation method of the modified anti-collapse agent in this comparative example is basically the same as that of Example 2, except that the polyetheramine added in step S2 is replaced with polyetheramine with a molecular weight of 400 (Jeffamine D400) with the same weight.

[0059] Comparative Example 3

[0060] A preparation method of sulfonated anti-collapse drilling fluid is basically the same as that of Example 5, except that the modified anti-collapse agent is replaced with a modified anti-collapse agent prepared by the following method with the same weight:

[0061] The preparation method of the modified anti-collapse agent in this comparative example is basically the same as that in Example 2, except that the polyetheramine added in step S2 is replaced with polyetheramine (Jeffamine D2000) with a molecular weight of 2000 and the same weight.

[0062] Comparative Example 4

[0063] The preparation method of a sulfonated anti-collapse drilling fluid is basically the same as that in Example 5, except that the modified anti-collapse agent is replaced with a modified anti-collapse agent prepared by the following method with the same weight:

[0064] The preparation method of the modified anti-collapse agent in this comparative example is basically the same as that in Example 2, except that the polyetheramine added in step S2 is replaced with 1,6-hexanediamine with the same weight.

[0065] Comparative Example 5

[0066] The preparation method of a sulfonated anti-collapse drilling fluid is basically the same as that in Example 5, except that the modified anti-collapse agent is replaced with a modified anti-collapse agent prepared by the following method with the same weight:

[0067] The preparation method of the modified anti-collapse agent in this comparative example is basically the same as that in Example 2, except that the 1,2-epoxy-9-decene added in step S1 is replaced with glycidyl methacrylate with the same weight.

[0068] Comparative Example 6

[0069] The preparation method of a sulfonated anti-collapse drilling fluid is basically the same as that in Example 5, except that the modified anti-collapse agent is replaced with 35 g of polyetheramine-modified lignin and 6 g of silane-modified nano-silica prepared in Example 2.

[0070] Comparative Example 7

[0071] The preparation method of a sulfonated anti-collapse drilling fluid is basically the same as that in Example 5, except that the modified anti-collapse agent is replaced with a modified anti-collapse agent prepared by the following method with the same weight:

[0072] The preparation method of the modified anti-collapse agent in this comparative example is basically the same as that in Example 2, except that the lignin used in step S1 is replaced with guaiacyl-syringyl lignin (source: calcium lignosulfonate from cotton plant produced by Henan Qiangxing Chemical Co., Ltd., number average molecular weight 8250).

[0073] Comparative Example 8

[0074] A high-temperature and high-density anti-collapse drilling fluid prepared by using the raw materials and method in Example 1 of the patent with the publication number CN114456780A.

[0075] The bentonite model used in the examples and comparative examples of the present application is Bentone 38; the lignin used in the examples and comparative examples of the present application is guaiacyl-syringyl-p-hydroxyphenyl lignin unless otherwise specified, with a number average molecular weight of about 9000 and a p-hydroxyphenyl lignin monomer content of 38.5wt%; the particle size of the barite powder is 400 mesh, produced by Shijiazhuang Mayue Building Materials Co., Ltd.; the nano-silica used is hydroxyl-modified nano-silica, model As-200, produced by Shenyang Chemical Co., Ltd.; the model of carboxymethyl cellulose is CMC-HVT, produced by Hebei Yezhiyuan New Materials Co., Ltd.; the model of sulfonated asphalt is BFT-1, produced by Tianjin Binpu Technology Development Co., Ltd.; the model of sulfonated phenolic resin is SMP-II, produced by Henan Ocean Chemical Technology Co., Ltd.

[0076] The sulfonated anti-collapse drilling fluid prepared in the embodiment and the comparative example was subjected to a high temperature and high pressure filtration loss test. The test was conducted in accordance with GB / T 16783.1-2014 "Field Test of Drilling Fluids in the Petroleum and Natural Gas Industry Part 1: Water-Based Drilling Fluids". The experimental conditions were 220°C × 16h. The test results are shown in Table 1.

[0077] The drilling fluid system was tested for cuttings rolling recovery rate at a test temperature of 120°C and an aging time of 16 hours.

[0078] The experimental steps of rolling recovery rate are as follows: take 20g mudstone cuttings (1.7-3.35mm) and place them in an aging tank, add 40g drilling fluid (pH adjusted to 8), place the aging tank in a roller heating furnace and heat roll at 150℃ for 16h, take it out and cool it, pour out the liquid, dry the remaining cuttings at 105℃ to constant weight, and sieve it with a 40-mesh screen to obtain the first-time recovered shale. The ratio of the mass of the residual cuttings that do not pass through the 40-mesh screen to the mass of the initial cuttings is the hot rolling recovery rate. Put the first-time recovered shale into the aging tank again, heat roll it at 150℃ for 2h, take it out and use the same method to obtain the secondary shale, and calculate the secondary hot rolling recovery rate.

[0079] Table 1 Drilling fluid performance indicators

[0080]

[0081] It can be seen from Table 1 that the sulfonated anti-collapse drilling fluid prepared in the present application has excellent rolling recovery rate and high temperature and high pressure fluid loss reduction performance.

[0082] The modified anti-collapse agent prepared by the present invention uses guaiacyl-syringyl-p-hydroxyphenyl lignin as the matrix material. The double bond of 1,2-epoxy-9-decene reacts with the phenolic hydroxyl group of lignin to obtain modified lignin containing epoxy functional groups. Then, the epoxy group of the modified lignin reacts with the amino group of polyetheramine. Since there are multiple epoxy groups on the modified lignin, polyetheramine-modified lignin with a cross-linked network can be formed. Due to the presence of polyetheramine chain segments, the dispersion performance of the modified lignin material can be improved. Finally, the isocyanate group on the surface of silane-modified nano-SiO₂ reacts with the hydroxyl group of polyetheramine-modified lignin to form an organic-inorganic hybrid network structure. The hybrid structure contains flexible ether bonds provided by polyetheramine, unreacted polar amino groups, and siloxane bonds, which can cooperate to form a "rigid-flexible composite plugging layer". Moreover, the surface of the modified anti-collapse agent contains a large number of functional groups such as hydroxyl groups, methoxy groups, and amino groups, which enhances the hydrogen bond and electrostatic adsorption ability to clay, thereby effectively blocking the penetration of water molecules and inhibiting the hydration swelling of shale. The flexible chain segments of polyetheramine can maintain flexibility at high temperatures, avoiding the cracking of the filter cake due to thermal stress, thus significantly reducing the HTHP filtration loss. Through the structural synergistic effect and functional group optimization of polyetheramine-modified lignin, the problems of poor high-temperature resistance and rolling recovery rate of traditional anti-collapse agents are solved, and it is especially suitable for drilling operations in deep wells, ultra-deep wells, and environmentally sensitive areas.

[0083] In Comparative Example 2, the rolling recovery rate is poor because the molecular weight of polyetheramine is small and the molecular chain is short, resulting in limited flexibility provided and a decrease in inhibition performance, thus the rolling recovery rate is low. In Comparative Example 3, the rolling recovery rate is poor because the molecular weight of polyetheramine is large and the molecular chain is long. After forming a network structure, its molecular volume is too large to easily enter the interlayer structure of clay particles, reducing the ability to inhibit clay hydration swelling through intercalation. In Comparative Example 5, the rolling recovery rate is poor because the ester group in glycidyl methacrylate is easily decomposed at high temperatures. The reason for the poor performance of Comparative Example 7 is that the ortho-position of the phenolic hydroxyl group in the guaiacyl-syringyl lignin structure contains a methoxy group, and due to steric hindrance, the reaction with 1,2-epoxy-9-decene is difficult.

[0084] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. However, for those of ordinary skill in the art, without departing from the scope of the technical solution of the present invention, any equivalent changes such as slight modifications, evolutions, and modifications made using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications, and evolutions made to the above embodiments based on the essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A sulfonated anti-collapse drilling fluid, characterized in that, Comprising raw materials in the following parts by weight: Deionized water: 100 parts, bentonite: 2 - 6 parts, filtration loss reducer: 4 - 8 parts, pH regulator: 0.5 - 2 parts, plugging agent: 2 - 5 parts, sulfonated material: 2 - 6 parts, modified anti-collapse agent: 3 - 5 parts, weighting agent: 20 - 30 parts; The modified anti-collapse agent is prepared by the following method: S1: Under nitrogen protection, DMSO, 1,2-epoxy-9-decene, lignin, catalyst C-94, 1-butyl-3-methylimidazolium methanesulfonate ionic liquid are stirred and mixed evenly, heated to 80 - 90 °C, and reacted for 3 - 5 h to obtain modified lignin; S2: DMF, modified lignin, and polyetheramine are stirred and mixed evenly, then triethylamine is added, heated to 70 - 85 °C, and reacted for 8 - 12 h to obtain polyetheramine-modified lignin; S3: A mixture of ethanol and water, and nano-silica are mixed and ultrasonicated, then 3-isocyanatopropyltrimethoxysilane and triethylamine are added, and reacted at 70 - 85 °C for 4 - 6 h to obtain silane-modified nano-silica; S4: Under nitrogen protection, DMF and silane-modified nano-silica are stirred and mixed evenly, heated to 50 - 70 °C, and polyetheramine-modified lignin and dibutyltin dilaurate are added in batches, and reacted for 4 - 6 h to obtain the modified anti-collapse agent; In step S1, the feeding mass ratio of the lignin to 1,2-epoxy-9-decene is 10:(1 - 2); In step S2, the feeding mass ratio of the modified lignin to polyetheramine is 5:(1 - 2); In step S3, the feeding mass ratio of the nano-silica to 3-isocyanatopropyltrimethoxysilane is 10:(3 - 6); In step S4, the feeding mass ratio of the polyetheramine-modified lignin to silane-modified nano-silica is 20:(2 - 5); The lignin is guaiacyl-syringyl-p-hydroxyphenyl lignin; The filtration loss reducer is carboxymethyl cellulose; The plugging agent is sulfonated asphalt; The sulfonated material is sulfonated phenolic resin.

2. The sulfonated anti-collapse drilling fluid according to claim 1, wherein, The pH regulator is one of potassium carbonate, sodium hydroxide, and potassium hydroxide.

3. A sulfonated anti-collapse drilling fluid according to claim 1, characterized in that, The weighting agent is barite powder.

4. A method for preparing the sulfonated anti-collapse drilling fluid according to any one of claims 1-3, characterized in that, Comprising the following steps: (1) Weigh by parts by weight: deionized water: 100 parts, bentonite: 2 - 6 parts, filtration loss reducer: 4 - 8 parts, pH regulator: 0.5 - 2 parts, plugging agent: 2 - 5 parts, sulfonated material: 2 - 6 parts, modified anti-collapse agent: 3 - 5 parts, weighting agent: 20 - 30 parts; (2) Add deionized water and bentonite to a container, stir for 15 - 25 min, then stop stirring, and seal and cure for 24 h to obtain pre-hydrated bentonite slurry; add the filtration loss reducer, pH regulator, plugging agent, sulfonated material, and modified anti-collapse agent to the pre-hydrated bentonite slurry in the above proportions in sequence, stir and mix evenly, and finally add the weighting agent and stir evenly to obtain sulfonated anti-collapse drilling fluid.

Images