Sulfonated asphalt for drilling fluid and preparation method thereof

Abstract

The invention discloses sulfonated asphalt for drilling fluid and a preparation method of the sulfonated asphalt. The preparation method comprises the following steps: (1) dissolving crushed asphalt in an organic solvent, adding halogenated imide, stirring and heating; (2) sulfite and / or hydrosulfite are / is added into the mixed material obtained in the step (1) for a reaction, the reaction temperature ranges from 150 DEG C to 210 DEG C, and the reaction time ranges from 10 min to 24 h; and (3) after the reaction in the step (2) is completed, cooling, recovering an oil phase, concentrating a water phase, drying and crushing to obtain the sulfonated asphalt for the drilling fluid. The sulfonated asphalt for the drilling fluid is good in anti-sloughing performance and stability, and the preparation method of the sulfonated asphalt has the characteristics that the reaction temperature is easy to control, the reaction is sufficient, the sulfonation is uniform, the production cost is low, the product quality is stable, and large-scale production can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of asphalt, and particularly relates to a method for preparing sulfonated asphalt for drilling fluid. Background Art

[0002] With the development of high-difficulty drilling technologies such as deep wells, directional wells and horizontal wells, the performance requirements of drilling fluid additives have gradually increased. Sulfonated asphalt, as a multifunctional drilling fluid additive with good performance and low cost, has multiple properties such as reducing the high-temperature and high-pressure filtration loss of drilling fluid, increasing the lubricity of mud cake, and improving the high-temperature stability of drilling fluid. It plays an important role in protecting geological reservoirs and is particularly suitable for the drilling of deep wells and ultra-deep wells.

[0003] Sulfonated asphalt currently used is a product obtained by sulfonation, neutralization and post-treatment of asphalt and a sulfonating agent (concentrated sulfuric acid or sulfur trioxide) under certain conditions. For example, US3489842 uses petroleum asphalt as raw material and sulfur trioxide as sulfonating agent, performs sulfonation, and neutralizes with sodium hydroxide to prepare sulfonated asphalt, which is used as a fluid loss reducer for oil drilling. US3970690 uses petroleum asphalt as raw material and sulfur trioxide as sulfonating agent, treats at 80°C for 3 hours, neutralizes with calcium hydroxide, filters, neutralizes and concentrates the filtrate with sodium hydroxide, and dries to prepare sulfonated asphalt powder. CN1037916A discloses a preparation process for a sulfonated asphalt drilling mud treating agent, which uses gaseous sulfur trioxide as a sulfonating agent and light oil as a solvent, performs a sulfonation reaction at a reaction temperature of 20 to 40°C to prepare sulfonated asphalt. The method obtains gaseous SO3 by evaporating fuming sulfuric acid, which solves the problem of storage and transportation of liquid sulfur trioxide, but the production process is complicated and an additional acid distillation kettle needs to be configured. CN1239133A discloses a sulfonated asphalt for high-temperature and high-pressure drilling fluid and a preparation method thereof, wherein a mixture of coal tar and petroleum asphalt is used as raw materials, dissolved in liquid alkanes such as octane, nonane, decane or 1,2-dichloroethane non-polar halogenated alkane solvent, and sulfur trioxide is used as a sulfonating agent, and a brown-black sulfonated asphalt product is obtained through sulfonation, neutralization, and drying. When sulfur trioxide is used as a sulfonating agent in the production of sulfonated asphalt, it has the characteristics of strong sulfonation ability, fast reaction, high conversion rate, low raw material unit consumption, and low cost; however, since sulfur trioxide has strong oxidizing properties and strong reaction activity, the reaction is difficult to control, and it is easy to produce side reactions such as multiple sulfonation, coking, and oxidation, and there are problems such as high equipment requirements, difficulty in storing and transporting sulfur trioxide, and high danger in the production process. CN106318344A discloses a sulfonated asphalt for drilling fluid and a preparation method thereof, wherein the method uses concentrated sulfuric acid and phosphorus pentoxide as sulfonating agents, utilizes SO3 generated by the in-situ reaction of concentrated sulfuric acid and phosphorus pentoxide to perform temperature-controlled sulfonation on asphalt, and obtains sulfonated asphalt through a potassium hydroxide solution neutralization step. The reaction conditions of concentrated sulfuric acid and phosphorus pentoxide are harsh, the obtained SO3 is less, and the sulfonation efficiency is low. CN103805219A discloses a preparation process for sulfonated asphalt, wherein the process uses an asphalt dissolving tank to dissolve solid asphalt and then adds it to kerosene, waits for the asphalt to be completely dissolved, adds sulfuric acid to carry out sulfonation reaction, waits for the sulfonation reaction to be completed, recycles kerosene, neutralizes and dries to obtain sulfonated asphalt. When sulfonated asphalt is sulfonated with concentrated sulfuric acid and oleum, the reaction activity of the sulfonating agent is low, the sulfonation effect is poor, the acid consumption is large, the equipment is severely corroded, the waste acid is seriously polluted, the sulfonation efficiency is not high, and the product quality is unstable. In the subsequent neutralization reaction, due to the presence of a large amount of unreacted sulfuric acid, a large amount of Na2SO4 inorganic salt is introduced into the product, resulting in severe foaming and poor stability of the product, which affects the product performance of sulfonated asphalt. In summary, the above sulfonated asphalt production technologies all have defects to varying degrees, and it is urgent to develop a new sulfonated asphalt preparation method suitable for drilling fluid. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings and defects of the prior art and provide a sulfonated asphalt for drilling fluid and a preparation method thereof. The sulfonated asphalt for drilling fluid of the present invention has good anti-collapse performance and stability performance, and its preparation method has the characteristics of easy control of reaction temperature, sufficient reaction, uniform sulfonation, low production cost, stable product quality, and large-scale production.

[0005] The first aspect of the present invention provides a method for preparing sulfonated asphalt for drilling fluid, the preparation method comprising the following steps:

[0006] (1) dissolving the crushed asphalt in an organic solvent, adding a halogenated imide, stirring and heating;

[0007] (2) adding sulfite and / or bisulfite to the mixed material obtained in step (1) to carry out a reaction at a temperature of 150-210° C. for a reaction time of 10 min-24 h;

[0008] (3) After the reaction in step (2) is completed, the reaction is cooled, the oil phase is recovered, and the water phase is concentrated, dried, and crushed to obtain sulfonated asphalt for drilling fluid.

[0009] In step (1), the asphalt is selected from at least one of natural asphalt, petroleum asphalt and oxidized asphalt. The asphalt has a saturated content of less than 15wt%, preferably 5wt%-12wt%, and an asphaltene content of more than 7wt%, preferably 11wt%-40wt%.

[0010] In step (1), the particle size of the crushed asphalt is above 60 mesh, preferably 80-90 mesh.

[0011] In step (1), the organic solvent is selected from at least one of dichloromethane, 1,2-dichloroethane, n-hexane, cyclohexane, heptane, octane, decane, gasoline, diesel, carbon tetrachloride, and kerosene, preferably at least one of n-hexane, carbon tetrachloride, and diesel.

[0012] In step (1), the amount of the organic solvent used can be sufficient to fully dissolve the asphalt. Generally, the concentration of the asphalt in the organic solvent is 0.05-5.0 g / mL.

[0013] In step (1), the weight ratio of the asphalt to the halogenated imide is 1-15:1, preferably 4-9:1.

[0014] The halogenated imide reagent is selected from at least one of N-chlorosuccinimide (NCS), N-bromosuccinimide (NBS), and N-iodosuccinimide (NIS); preferably at least one of N-chlorosuccinimide (NCS) and N-bromosuccinimide (NBS).

[0015] In step (1), the heating is heating to a temperature of 150-210°C, preferably 190-200°C.

[0016] In step (2), the sulfite is selected from at least one of sodium sulfite, potassium sulfite, calcium sulfite, and magnesium sulfite, preferably potassium sulfite; the bisulfite is selected from at least one of sodium bisulfite, potassium bisulfite, calcium bisulfite, and magnesium bisulfite, preferably potassium bisulfite.

[0017] In step (2), the weight ratio of the asphalt to potassium sulfite and / or potassium bisulfite is 1-10:1, preferably 6-9:1.

[0018] In step (2), the reaction temperature is 190-200° C., and the reaction time is 1-3 h.

[0019] In step (3), the cooling is cooling to 10-30°C, preferably cooling to room temperature.

[0020] In step (3), the drying conditions are: temperature of 110-140° C. and time of 1-5 h.

[0021] The second aspect of the present invention provides a sulfonated asphalt for drilling fluid prepared by the above method.

[0022] The technical indicators of the sulfonated asphalt for drilling fluid are as follows:

[0023] The volatile matter content is ≤10.0wt%, the water-soluble matter is ≥70.0wt%, the oil-soluble matter is ≥25.0wt%, the metal sulfonate group (such as potassium sulfonate group) content is ≥10.0wt%, preferably the metal sulfonate group content is ≥15.0wt%, the high temperature and high pressure filtration loss at 150℃ (mL / 30min) is ≤25.0mL, preferably the high temperature and high pressure filtration loss at 150℃ (mL / 30min) is ≤20.0mL.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] The present invention uses halogenated imide reagents as halogenating agents, firstly performs halogenation reaction on asphalt, and then replaces halogen atoms to generate sulfonates by reacting with potassium sulfite and potassium bisulfite. The sulfonation reaction is easy to effectively control, thus solving the problem that the existing SO3 sulfonation method is difficult to control.

[0026] Compared with the existing process, the present invention does not require special SO3 storage and transportation equipment, nor does it require additional acid distillation tanks and other equipment. It can greatly reduce the production equipment requirements and dangers of sulfonated asphalt and is suitable for large-scale production.

[0027] The present invention utilizes the halogenated imide first halogenation and then sulfonation substitution reaction, which has higher reaction activity and can greatly improve the reaction efficiency of sulfonation. Compared with the concentrated sulfuric acid and oleum sulfonation method, the present invention can improve the sulfonation effect and product quality of the product. The potassium sulfonate content of asphalt is better than the industry standards and similar products. At the same time, the introduction of metal ions such as potassium ions in sulfite and hydrogen sulfite can improve the anti-collapse ability of sulfonated asphalt. The potassium sulfonate content of the sulfonated asphalt product of the present invention is ≥15wt%, and the high-temperature and high-pressure filtration loss reduction is 150°C (mL / 30min)≤20mL, which are better than the values ​​specified in Q / SHCG 3-2011 "Technical Requirements for Asphalt Treatment Agents for Drilling Fluids".

[0028] The method of the present invention has the characteristics of simple production process, low equipment requirements, easy control of sulfonation reaction temperature, sufficient reaction, uniform sulfonation, low production cost, stable product quality, and large-scale production. It can be widely used in the sulfonation production of asphalts such as natural asphalt, petroleum asphalt, coal asphalt, etc. The sulfonated asphalt prepared by the method has stable quality and can be applied to water-based, oil-based and synthetic-based drilling fluids, can effectively inhibit hydration of shale, plug microcracks, improve mud cake quality, reduce high-temperature and high-pressure filtration loss, improve the stability of the well wall, and meet the requirements of complex formation exploration and development. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the embodiments.

[0030] According to SY / T 5794-2010 "Evaluation Methods for Asphalt in Drilling Fluids" and Q / SHCG 3-2011 "Technical Requirements for Asphalt Treatment Agents for Drilling Fluids", the specific evaluation method for this product is as follows:

[0031] 1. Determination of volatile matter content

[0032] (1) Weigh 3g-5g of the sample (mass is m1, accurate to 0.0001g) and place it in a weighing bottle with a constant mass.

[0033] (2) Dry the sample in an oven at 105±3℃ for 2 h, take it out and place it in a desiccator. After cooling to room temperature, weigh its mass (mass is m2, accurate to 0.0001 g).

[0034] (3) Calculate the moisture content of the sample according to the formula:

[0035] W1=(m1-m2) / m1×100%

[0036] Where: W1-volatile matter content, expressed as percentage (%);

[0037] m1-mass of the sample before drying, in grams (g);

[0038] m2-mass of the sample after drying, in grams (g).

[0039] 2. Determination of water-soluble content

[0040] (1) Take 0.2-0.3 g of absorbent cotton and put it into a roll made of lens paper. Dry it at 105±3℃ to constant weight and set aside.

[0041] (2) Fold the lens cleaning paper that has been weighed to a constant weight in half and lay it flat on a clean weighing paper. Then lay the absorbent cotton evenly in the middle of the lens cleaning paper. Weigh 0.5g of the sample (mass is m9, accurate to 0.0001g) that has been ground and passed through a standard sieve with a side length of 0.28mm, and pour it on the center of the absorbent cotton.

[0042] (3) First wrap the sample tightly with absorbent cotton, then wrap the cotton tightly with lens cleaning paper, and finally wrap the sample with thread (mass m 10 , accurate to 0.1 mg).

[0043] Note: No sample should leak out during the packing process, and the sample should not be clearly visible in the packed sample package. Put the sample package into the sample cup in the extractor, and hang the sample cup under the micro condenser in the extractor.

[0044] (4) Pour 250mL-300mL of water into the extractor. Place the extractor in an electric heating jacket and heat it until the effluent is colorless. Take out the sample cup, place the paper roll in a drying oven, dry it at 105±3℃ for 2h, take it out and place it in a desiccator, cool it for 30min, and weigh it (mass is m 11 , accurate to 0.1 mg).

[0045] (5) Calculate the water solubility according to the formula:

[0046] W4=(m 10 -m 11 ) / m9×100%

[0047] Where: W4-water solubility, %;

[0048] m9-sample mass, g;

[0049] m 10 -Mass of absorbent cotton, lens cleaning paper and sample, g;

[0050] m 11 -Mass of absorbent cotton, lens cleaning paper and residue, g.

[0051] 3. Determination of oil-soluble matter content

[0052] (1) Place 0.2-0.3 g of cotton wool, a piece of lens cleaning paper, and a piece of suitable thread in a weighing bottle, dry at 105±3℃ to constant weight, and set aside.

[0053] (2) Fold the lens cleaning paper that has been weighed to a constant weight in half and lay it flat on a clean weighing paper. Then lay the absorbent cotton evenly in the middle of the lens cleaning paper. Weigh 0.5 g (mass m) of the sample that has been ground and passed through a standard sieve with a side length of 0.28 mm. 12 , accurate to 0.1 mg), pour it onto the center of the cotton wool.

[0054] (3) First wrap the sample tightly with absorbent cotton, then wrap the cotton tightly with lens cleaning paper, and finally wrap the sample with thread (mass m 13 , accurate to 0.1 mg).

[0055] Note: No sample should leak out during the packing process, and the sample should not be clearly visible in the packed sample package. Put the sample package into the sample cup in the extractor, and hang the sample cup under the micro condenser in the extractor.

[0056] (4) Inject 250mL-300mL of carbon tetrachloride into the extractor. Place the extractor in an electric heating mantle and heat it and keep it boiling until the effluent is colorless. Take out the sample cup, place the paper roll in a drying oven, dry it at 105±3℃ for 2h, take it out and place it in a dryer, cool it for 30min, and then weigh it (mass is m 14 , accurate to 0.1 mg).

[0057] (5) Calculate the oil solubility rate according to the formula:

[0058] W 5＝ (m 13 -m 14 ) / m 12 ×100%

[0059] In the formula: W5-oil solubility rate, %;

[0060] m 12 - Sample mass, g;

[0061] m 13 -Mass of absorbent cotton, lens cleaning paper and sample, g;

[0062] m 14 -Mass of absorbent cotton, lens cleaning paper and residue, g.

[0063] 4. Content of metal sulfonic acid group (taking potassium sulfonate group as an example)

[0064] 4.1 Determination of free sulfate

[0065] (1) Weigh 0.5 g of sample (mass is m3, accurate to 0.0001 g), place it in a 200 mL beaker, add 50 mL of distilled water, and heat to boil for 10 min.

[0066] (2) After adjusting the pH to less than or equal to 1 with 15 wt% hydrochloric acid solution, add 3.5-4.0 g of activated carbon, stir for 5 min, boil for 3 min, filter with qualitative medium-speed filter paper into a 250 mL beaker while hot, and finally wash with 1% hydrochloric acid until there is no sulfate (check with 1 wt% barium chloride solution).

[0067] (3) When the filtrate is heated and concentrated to about 100 mL, the pH is adjusted to 4-5 with a 5 wt % sodium hydroxide solution, and then 5 mL of a 10 wt % barium chloride solution is added dropwise to precipitate sulfate at 60-80° C. for 1 hour.

[0068] (4) The precipitate is filtered with a quantitative slow filter paper and washed with distilled water at about 80°C until there is no chloride ion (check with 1wt% silver nitrate solution). The precipitate and filter paper are placed in a crucible with a constant mass, incinerated on an electric furnace, moved into a high-temperature furnace, and burned at 800-900°C for 1 hour. The precipitate is taken out and placed in a desiccator, cooled to room temperature, and then weighed (mass is m4, accurate to 0.0001g).

[0069] 4.2 Determination of total sulfur content

[0070] (1) Weigh 0.5g of sample (mass is m5, accurate to 0.0001g), put it into a 30mL crucible, add about 5-10mL of distilled water to dissolve the sample, then add 5mL of 10% barium chloride aqueous solution, slowly heat to boiling while stirring. When it is almost dry, add 10mL of barium hydroxide colloidal solution, evaporate until it is almost dry, transfer to a high-temperature furnace, and burn at 800-900℃ for 1h.

[0071] (2) Dissolve the above-mentioned burning residue with 10 mL of 15 wt% hydrochloric acid solution until the precipitate is free of black and gray (otherwise it should be redone), transfer it into a 100 mL beaker, boil and filter, and wash with distilled water until there is no chloride ion (check with 1 wt% silver nitrate solution).

[0072] (3) Place the precipitate and filter paper in a constant weight crucible, incinerate in an electric furnace, move into a high temperature furnace, burn at 800-900°C for 1 hour, take out and place in a desiccator, cool to room temperature and weigh (mass is m6, accurate to 0.0001g)

[0073] 4.3 Calculation of potassium sulfonate content

[0074] W2=(m6 / m5-m4 / m3)×0.5103×100%

[0075] Where:

[0076] W2-potassium sulfonate content, expressed as a percentage (%);

[0077] m3-the mass of the sample when determining free sulfate, in grams (g);

[0078] m4-the mass of barium sulfate when determining free sulfate, in grams (g);

[0079] m5-the mass of the sample when measuring total sulfur, in grams (g);

[0080] m6-the mass of barium sulfate when total sulfur is measured, in grams (g);

[0081] 0.5103-The ratio of potassium sulfonate to barium sulfate, dimension is 1.

[0082] 5. Determination of high temperature and high pressure filtration loss reduction rate

[0083] (1) Preparation of drilling fluid base slurry: Take 350 mL of distilled water, slowly add 14.0 g of sodium bentonite for drilling fluid test under stirring, stir at high speed for 20 min, pour into a curing tank and let stand for 24 h, then add 7.0 g of iron chromium lignin sulfonate and 7.0 g of evaluation soil, stir at low speed for 30 min, adjust the pH value to 10 with 20 wt% sodium hydroxide, and stir at high speed for 20 min to obtain the base slurry.

[0084] (2) Add 7.0 g of the sample to be tested to the base slurry and stir at low speed for 30 min. Adjust the pH value to 10 with 20 wt % sodium hydroxide and stir at high speed for 20 min. Stop stirring at least twice during stirring to scrape off the mud, soil powder or sample adhering to the wall of the cup. Stir at low speed (not exceeding 4000 r / min, appropriately controlled according to the viscosity of the slurry) for 1 h and measure the HTHP (150 °C, 3.5 MPa) filtration loss according to GB / T 16783.1.

[0085] Example 1

[0086] Add 2000mL of n-hexane into a 3000mL three-necked flask, add 100g of 80-mesh natural asphalt and petroleum asphalt mixture (asphaltenes content is 40wt%, saturated content is 10wt%, of which natural asphalt accounts for 30wt% of the mixture) under constant stirring, and after fully dissolved, add 33g of N-chlorosuccinimide (NCS) and stir evenly; heat the obtained mixture to 150°C, add 25g of potassium sulfite after the temperature stabilizes, and keep the temperature at 150°C for 10min. After the reaction is completed, cool to room temperature, separate the oil layer, recover the oil layer, concentrate the water phase, dry and crush to obtain brown-black sulfonated asphalt powder.

[0087] The technical indicators of the sulfonated asphalt prepared in this example are shown in Table 1, and the contents are all by weight:

[0088] Table 1 Technical indicators of sulfonated asphalt product prepared in Example 1

[0089]

[0090]

[0091] Example 2

[0092] Add 600mL of carbon tetrachloride into a 1000mL three-necked flask, add 150g of 80-mesh petroleum asphalt (asphaltene content is 11wt%, saturated content is 12wt%) under constant stirring, and after it is fully dissolved, add 25g of N-bromosuccinimide (NBS) and stir evenly; heat the obtained mixture to 170°C, add 18.75g of potassium bisulfite after the temperature stabilizes, and keep the temperature at 170°C for reaction for 2h. After the reaction is completed, cool to room temperature, separate the oil layer, recover the oil layer, concentrate the aqueous phase, dry and crush to obtain a brown-black sulfonated asphalt powder.

[0093] The technical indicators of the sulfonated asphalt prepared in this example are shown in Table 2, and the contents are all by weight:

[0094] Table 2 Technical indicators of sulfonated asphalt product prepared in Example 2

[0095] project Technical indicators Volatile content, wt% 7 Water soluble matter, wt% 71.5 Oil soluble matter, wt% 26.4 Potassium sulfonate content, wt% 18 High temperature and high pressure filtration loss, mL, 150℃ (mL / 30min) 14

[0096] Example 3

[0097] Add 300 mL of diesel to a 500 mL three-necked flask, add 300 g of 90-mesh oxidized asphalt (asphaltene content is 23 wt%, saturated content is 9 wt%) under constant stirring, and after it is fully dissolved, add 20 g of N-iodosuccinimide (NIS) and stir evenly; heat the obtained mixture to 195° C., and after the temperature stabilizes, add 30 g of a mixture of potassium sulfite and potassium bisulfite (mass ratio of potassium sulfite to potassium bisulfite = 3:1), and maintain the temperature at 195° C. for 24 hours. After the reaction is completed, cool to room temperature, separate the oil layer, recover the oil layer, concentrate the aqueous phase, dry and crush, and obtain a brown-black sulfonated asphalt powder.

[0098] The technical indicators of the sulfonated asphalt prepared in this example are shown in Table 3, and the contents are all by weight:

[0099] Table 3 Technical indicators of sulfonated asphalt product prepared in Example 3

[0100]

[0101]

[0102] Example 4

[0103] Add 480mL of carbon tetrachloride into a 1000mL three-necked flask, add 120g of 90-mesh petroleum asphalt and oxidized asphalt mixture (asphaltenes content is 20wt%, saturated content is 10wt%, of which petroleum asphalt accounts for 70wt% of the mixture) under constant stirring, and after sufficient dissolution, add 24g of N-chlorosuccinimide (NCS) and N-bromosuccinimide (NBS) mixture (NCS to NBS mass ratio = 2:1), and stir evenly; heat the obtained mixture to 190°C, and after the temperature stabilizes, add 17g of potassium sulfite and potassium bisulfite mixture (potassium sulfite to potassium bisulfite mass ratio = 5:3), and keep the temperature at 190°C for reaction for 2.5h. After the reaction is completed, cool to room temperature, separate the oil layer, recover the oil layer, concentrate the water phase, dry and crush, and obtain brown-black sulfonated asphalt powder.

[0104] The technical indicators of the sulfonated asphalt prepared in this example are shown in Table 4, and the contents are all by weight:

[0105] Table 4 Technical indicators of sulfonated asphalt product prepared in Example 4

[0106] project Technical indicators Volatile content, wt% 7.4 Water soluble matter, wt% 71 Oil soluble matter, wt% 26 Potassium sulfonate content, wt% 17.8 High temperature and high pressure filtration loss, mL, 150℃ (mL / 30min) 15

[0107] Example 5

[0108] Add 700 mL of n-hexane into a 2000 mL three-necked flask, add 210 g of a 90-mesh natural asphalt and oxidized asphalt mixture (asphaltenes content is 20 wt%, saturated content is 8 wt%, of which natural asphalt accounts for 15 wt% of the mixture) under constant stirring, and after sufficient dissolution, add 30 g of a mixture of N-chlorosuccinimide (NCS) and N-iodosuccinimide (NIS) (NCS to NIS mass ratio = 5:2), and stir evenly; heat the obtained mixture to 195°C, and after the temperature stabilizes, add 26 g of a mixture of potassium sulfite and potassium bisulfite (potassium sulfite to potassium bisulfite mass ratio = 1:4), and keep the temperature at 195°C for 1.5 hours. After the reaction is completed, cool to room temperature, separate the oil layer, recover the oil layer, concentrate the water phase, dry and crush, and obtain a brown-black sulfonated asphalt powder.

[0109] The technical indicators of the sulfonated asphalt prepared in this example are shown in Table 5, and the contents are all by weight:

[0110] Table 5 Technical indicators of sulfonated asphalt product prepared in Example 5

[0111] project Technical indicators Volatile content, wt% 6 Water soluble matter, wt% 72 Oil soluble matter, wt% 27 Potassium sulfonate content, wt% 18.4 High temperature and high pressure filtration loss, mL, 150℃ (mL / 30min) 13

[0112] Example 6

[0113] Add 825 mL of n-hexane to a 2000 mL three-necked flask, add 165 g of 90-mesh natural asphalt (asphaltene content is 25 wt%, saturated content is 5 wt%) under constant stirring, and after it is fully dissolved, add 21 g of a mixture of N-bromosuccinimide (NBS) and N-iodosuccinimide (NIS) (NBS to NIS mass ratio = 8:3), and stir evenly; heat the obtained mixture to 200°C, and after the temperature stabilizes, add 18 g of a mixture of potassium sulfite and potassium bisulfite (potassium sulfite to potassium bisulfite mass ratio = 3:7), and keep the temperature at 200°C for 2 hours. After the reaction is completed, cool to room temperature, separate the oil layer, recover the oil layer, concentrate the water phase, dry and crush, and obtain a brown-black sulfonated asphalt powder.

[0114] The technical indicators of the sulfonated asphalt prepared in this example are shown in Table 6, and the contents are all by weight:

[0115] Table 6 Technical indicators of sulfonated asphalt product prepared in Example 6

[0116] project Technical indicators Volatile content, wt% 8 Water soluble matter, wt% 71 Oil soluble matter, wt% 26 Potassium sulfonate content, wt% 17.1 High temperature and high pressure filtration loss, mL, 150℃ (mL / 30min) 17

[0117] Comparative Example 1

[0118] Add 500 mL of n-hexane into a 1000 mL three-necked flask, add 100 g of 90-mesh petroleum asphalt (asphalt content is 11 wt%, saturated content is 12 wt%) under constant stirring, and stir to fully dissolve the asphalt to obtain a reaction raw material; add 7 g of concentrated sulfuric acid (98 wt%) dropwise to the reaction raw material, control the sulfonation reaction temperature to 25°C, and the reaction time to 40 min; after the reaction is completed, add KOH solution (10 wt%) until the pH value is 8; distill the product (temperature is 90°C) and dry (105°C, 2h) to obtain a brown-black solid sulfonated asphalt powder.

[0119] The technical indicators of the sulfonated asphalt prepared in this comparative example are shown in Table 7, and the contents are all by weight:

[0120] Table 7 Technical indicators of sulfonated asphalt products prepared in Comparative Example 1

[0121] project Technical indicators Volatile content, wt% 9 Water soluble matter, wt% 71 Oil soluble matter, wt% 25 Potassium sulfonate content, wt% 12 High temperature and high pressure filtration loss, mL, 150℃ (mL / 30min) 24

[0122] By comparing the above embodiments with the comparative examples and similar products in the industry, it is found that the sulfonated asphalt of the present invention can meet the relevant technical requirements of the industry, the potassium sulfonate content is ≥15.0wt%, the high temperature and high pressure filtration loss reduction is 150℃ (mL / 30min) ≤20.0mL, and its plugging and anti-collapse effect is greatly improved. At the same time, the method of the present invention has the characteristics of simple production process, easy control of reaction temperature, sufficient reaction, uniform sulfonation, low production cost, stable product quality, and large-scale production.

Claims

1. A method for preparing sulfonated asphalt for drilling fluid, characterized in that: The preparation method comprises the following steps: (1) dissolving the crushed asphalt in an organic solvent, adding a halogenated imide, stirring and heating; (2) adding potassium sulfite and / or potassium bisulfite to the mixed material obtained in step (1) to carry out a reaction at a temperature of 150-210° C. for a reaction time of 10 min-24 h; (3) After the reaction in step (2) is completed, the reaction is cooled, the oil phase is recovered, and the water phase is concentrated, dried, and crushed to obtain sulfonated asphalt for drilling fluid.

2. The preparation method according to claim 1, characterized in that: In step (1), the particle size of the crushed asphalt is above 60 mesh, preferably 80-90 mesh.

3. The preparation method according to claim 1, characterized in that: In step (1), the asphalt is selected from at least one of natural asphalt, petroleum asphalt, and oxidized asphalt; the saturated content of the asphalt is less than 15wt%, preferably the saturated content is 5wt%-12wt%, and the asphaltene content is more than 7wt%, preferably the asphaltene content is 11wt%-40wt%.

4. The preparation method according to claim 1, characterized in that: In step (1), the organic solvent is selected from at least one of dichloromethane, 1,2-dichloroethane, n-hexane, cyclohexane, heptane, octane, decane, gasoline, diesel, carbon tetrachloride, and kerosene, preferably at least one of n-hexane, carbon tetrachloride, and diesel.

5. The preparation method according to claim 1, characterized in that: In step (1), the halogenated imide reagent is selected from at least one of N-chlorosuccinimide (NCS), N-bromosuccinimide (NBS), and N-iodosuccinimide (NIS); preferably at least one of N-chlorosuccinimide (NCS) and N-bromosuccinimide (NBS).

6. The preparation method according to claim 1 or 5, characterized in that: In step (1), the weight ratio of the asphalt to the halogenated imide is 1-15:1, preferably 4-9:

1.

7. The preparation method according to claim 1, characterized in that: In step (1), the heating is heating to a temperature of 150-210°C, preferably 190-200°C.

8. The preparation method according to claim 1, characterized in that: In step (2), the sulfite is selected from at least one of sodium sulfite, potassium sulfite, calcium sulfite, and magnesium sulfite, preferably potassium sulfite; the bisulfite is selected from at least one of sodium bisulfite, potassium bisulfite, calcium bisulfite, and magnesium bisulfite, preferably potassium bisulfite.

9. The preparation method according to claim 1 or 8, characterized in that: In step (2), the weight ratio of the asphalt to the sulfite and / or bisulfite is 1-10:1, preferably 6-9:

1.

10. The preparation method according to claim 1, characterized in that: In step (2), the reaction temperature is 190-200° C., and the reaction time is 1-3 h.

11. The preparation method according to claim 1, characterized in that: In step (3), the cooling is cooling to 10-30°C; and / or, in step (3), the drying conditions are: temperature of 110-140°C and time of 1-5h.

12. A sulfonated asphalt for drilling fluid prepared according to the method according to any one of claims 1 to 11.

13. The sulfonated asphalt for drilling fluid according to claim 12, characterized in that: The sulfonated asphalt used in the drilling fluid has a volatile matter content of ≤10.0wt%, a water-soluble matter of ≥70.0wt%, an oil-soluble matter of ≥25.0wt%, a metal sulfonate content of ≥10.0wt%, preferably a metal sulfonate content of ≥15.0wt%, and a high-temperature and high-pressure filtration loss of 150°C (mL / 30min) ≤25.0mL, preferably a high-temperature and high-pressure filtration loss of 150°C (mL / 30min) ≤20.0mL.

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