Multifunctional chelated asphalt and preparation method thereof

Abstract

The invention relates to multifunctional chelated asphalt and a preparation method thereof, and the multifunctional chelated asphalt comprises water-based multifunctional chelated asphalt and oil-based multifunctional chelated asphalt, the heavy catalytic oil slurry asphalt comprises the following components: 70-75 parts of purified heavy catalytic oil slurry asphalt, 8-12 parts of a chelating agent, 3-5 parts of an anionic emulsifier, 6-10 parts of fuming sulfuric acid, 5-8 parts of deionized water and 0.5-1 part of a stabilizer. The oil-based multifunctional chelated asphalt is prepared from the following components in parts by weight: 72-78 parts of purified heavy catalytic slurry asphalt, 10-15 parts of a chelating agent, 4-6 parts of a nonionic emulsifier, 5-8 parts of fuming sulfuric acid, 3-6 parts of white oil and 0.8-1.2 parts of a stabilizer, the chelated asphalt for the environment-friendly water-based / oil-based drilling fluid, which is suitable for offshore drilling operation, disclosed by the invention can be used for effectively improving the properties of plugging cracks, stabilizing the rheological property, improving the quality of a mud cake and the like of the drilling fluid; the anti-sloughing agent has the advantages of good anti-sloughing effect, stable rheological property, good adaptability, environmental protection and good high-temperature stability.

Description

Technical Field

[0001] This invention belongs to the field of drilling fluid treatment agent technology, specifically relating to multifunctional chelated asphalt and its preparation method. Background Technology

[0002] Asphalt-based treatment agents for drilling fluids are indispensable key materials in oil drilling. Their core functions are preventing collapse, reducing filtration loss, lubrication, and stabilizing mud rheology. Currently, the mainstream products are sulfonated asphalt, emulsified asphalt, and modified compound asphalt. Among them, modified sulfonated asphalt is made by sulfonating medium-temperature coal tar pitch and then compounding it with high-temperature hard coal tar pitch. Although this improves the high-temperature filtration loss reduction performance, it relies solely on physical compounding modification. The molecules lack chelating active sites and cannot form stable coordination bonds with formation metal ions or mineral surfaces. This results in poor mud cake density, limited crack sealing and collapse prevention effects, and poor product dispersibility due to the lack of emulsification treatment, leading to inadequate mud rheology control. Other methods involve adding sulfonated asphalt powder to increase the softening point, but these are used in road engineering. Their emulsification systems and component designs do not consider the high temperature, high pressure, and formation compatibility requirements of drilling fluids, and lack chelation modification, failing to meet the requirements for reducing filtration loss and preventing collapse in drilling fluids. Traditional heavy catalytic cracking and sulfonation of oil slurry to produce sulfonated asphalt... The existing drilling fluid asphalt treatment agents generally suffer from several drawbacks. Firstly, they lack chelation modification, resulting in a narrow control range for sodium sulfonate content. This leads to an imbalance in the product's water / oil solubility, poor compatibility with drilling fluids, and some products contain trace amounts of toxic additives, which can easily contaminate the formation, making them unsuitable for offshore drilling. Secondly, existing drilling fluid emulsified asphalt suffers from weak bonding between the emulsifier and asphalt, poor high-temperature stability, and a significant decrease in high-temperature and high-pressure filtration loss rate after aging at 150℃. Furthermore, the reduction rate of mud cake tortuosity and torque is low, easily causing instability in mud rheology during drilling, affecting drilling efficiency. In summary, existing asphalt-based treatment agents for drilling fluids generally suffer from defects such as lack of chelation structure, limited performance, poor high-temperature stability, poor compatibility, and some products being environmentally unfriendly, failing to meet the comprehensive requirements of offshore drilling for environmental protection, high-temperature stability, and high anti-collapse and filtration loss reduction. Therefore, it is essential to provide a multifunctional chelated asphalt with good anti-collapse effect, stable rheology, good compatibility, environmental friendliness, and good high-temperature stability, as well as its preparation method. Summary of the Invention

[0003] (a) Technical issues

[0004] In view of the above-mentioned existing technology, this application mainly addresses the following technical problems:

[0005] 1. How to solve the problems of existing drilling fluid sulfonated / emulsified asphalt lacking chelate structure, having weak coordination with formation minerals and metal ions, poor effect in sealing cracks, preventing collapse and reducing filtration loss, and severe performance degradation after aging at 150℃;

[0006] 2. How to solve the problems of existing products being disconnected from emulsification and sulfonation processes, resulting in poor dispersibility, low compatibility with water-based / oil-based drilling fluids, and imbalance of water-soluble / oil-soluble properties, leading to unstable mud rheology and poor torque reduction effect;

[0007] 3. How to solve the problem that some existing asphalt treatment agents contain toxic additives, polluting the formation and marine environment, and failing to meet the environmental protection requirements for marine drilling;

[0008] 4. How to optimize the synergistic process of sulfonation and chelation, accurately control the sodium sulfonate content, achieve a balance between the water-soluble and oil-soluble properties of the product, improve the curvature of the sludge cake and its stability under high temperature and high pressure, simplify the production process, and achieve industrial scale-up.

[0009] (II) Technical Solution

[0010] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multifunctional chelated asphalt with good anti-collapse effect, stable rheology, good adaptability, environmental friendliness, and good high-temperature stability, as well as its preparation method.

[0011] The objective of this invention is achieved as follows: In a first aspect, a multifunctional chelated asphalt comprises the following raw materials in parts by weight: 70-78 parts purified heavy catalytic asphalt, 8-15 parts chelating agent, 3-6 parts emulsifier, 5-10 parts fuming sulfuric acid, 5-8 parts deionized water, and 0.5-1.2 parts stabilizer.

[0012] The chelating agent is a compound system of organic polyamine-alkali lignin graft copolymer and zinc nitrate, with zinc nitrate accounting for 5-8% of the total weight of the chelating agent; the SO3 content of the fuming sulfuric acid is 25-30 wt%.

[0013] In this invention, the multifunctional chelated asphalt includes water-based multifunctional chelated asphalt and oil-based multifunctional chelated asphalt. The water-based multifunctional chelated asphalt, by weight, is composed of the following components: 70-75 parts purified heavy catalytic oil slurry asphalt, 8-12 parts chelating agent, 3-5 parts anionic emulsifier, 6-10 parts fuming sulfuric acid, 5-8 parts deionized water, and 0.5-1 parts stabilizer.

[0014] The oil-based multifunctional chelated asphalt, by weight, is composed of the following components: 72-78 parts purified heavy catalytic asphalt, 10-15 parts chelating agent, 4-6 parts nonionic emulsifier, 5-8 parts fuming sulfuric acid, 3-6 parts white oil, and 0.8-1.2 parts stabilizer.

[0015] Furthermore, the organic polyamine-alkali lignin graft copolymer is synthesized from the following raw materials in parts by weight: 20-30 parts ethylenediamine, 15-25 parts methyl acrylate, 40-50 parts alkali lignin, and 5-10 parts formaldehyde.

[0016] Specifically, the chelating agent includes a primary chelating agent and an auxiliary chelating agent. The primary chelating agent is an organic polyamine-alkali lignin graft copolymer, synthesized from organic polyamine (ethylenediamine), methyl acrylate, alkali lignin, and formaldehyde in a weight ratio of 20-30:15-25:40-50:5-10. The auxiliary chelating agent is zinc nitrate, accounting for 5-8% of the total weight of the chelating agent. The total amount of chelating agent added is 8-15% of the weight of the base asphalt.

[0017] Furthermore, the emulsifier is one of sodium dodecylbenzenesulfonate or polyoxyethylene octylphenol ether OP-10.

[0018] In this invention, the anionic emulsifier is sodium dodecylbenzenesulfonate, used in the preparation of water-based multifunctional chelated asphalt; the nonionic emulsifier is polyoxyethylene octylphenol ether OP-10, used in the preparation of oil-based multifunctional chelated asphalt.

[0019] Specifically, anionic emulsifiers belong to the category of ionic emulsifiers. Ionic emulsifiers also include cationic and amphoteric emulsifiers; among them, ① anionic emulsifiers include carboxylates (R-COONa), sulfonates (RSO3Na, such as sodium dodecylbenzenesulfonate), sulfates (ROSO3Na), and phosphates (ROPO3Na); ② cationic emulsifiers include alkylamines (R-NHCH2CH2CH2NH2, such as C... 18 H 37 -NH-CH2CH2CH2NH2, i.e., N-octadecylpropylene diamine), primary amine salts (R-NH2HCl), secondary amine salts (R-NH2(CH3)Cl), tertiary amine salts (R-NH(CH3)2Cl), quaternary amine salts (RN(CH3)4Cl), amides (such as R-CO-NH-(CH2)2-NH(CH2)2-NH2), imidazoline salts (such as C... 17 H 33 -C(=N)-N-CH2CH2NH2), ethylene oxide diamines, and amination lignins (such as lignin amine quaternary ammonium salt condensates); ③ zwitterionic emulsifiers include amino acid type (R-NHCH2CH2COOH) and betaine type (RN(CH3)2CH2COOH); ④ nonionic emulsifiers include polyoxyethylene type (RO-(CH2CH20)nH, such as polyoxyethylene octylphenol ether OP-10) and polyol type (R-COOC(CH2OH)3).

[0020] Of course, in actual use, compound emulsifiers can also be used, such as cation-cation compound, cation-non compound, anion-anion compound, and anion-non compound.

[0021] In the production of chelated asphalt, adding a small amount of chemical additives can reduce the amount of emulsifier used, lower production costs, and improve the activity of the emulsifier, thereby improving the storage stability of the chelated asphalt. For example, adding inorganic salts, such as strong acid-weak base salts like CaCl2, CMgCl2, NH4Cl, and FeCl3, can enhance the double electron layer effect between chelated asphalt particles, increase the potential, and prevent the aggregation of chelated asphalt particles. For anionic emulsifiers, NaSO4, Na2CO3, and Na2SiO3 can be added. Adding water-soluble polymers can exist in the chelated asphalt in a network or linear form, which can isolate the chelated asphalt particles and enhance the adhesion of the chelated asphalt.

[0022] Furthermore, the stabilizer is one of sodium carboxymethyl cellulose or aluminum distearate.

[0023] In this invention, sodium carboxymethyl cellulose is used as a stabilizer in the preparation process of water-based multifunctional chelated asphalt; aluminum distearate is used as a stabilizer in the preparation process of oil-based multifunctional chelated asphalt.

[0024] Furthermore, the softening point of the purified heavy catalytic oil slurry asphalt is 80~90℃, and it is obtained by heavy catalytic oil slurry through vacuum distillation and 200-mesh plate and frame filtration.

[0025] In this invention, the water-based multifunctional chelated asphalt is a dark brown free-flowing powder with a pH value of 8-10, a residue of ≤10% on a 100-mesh wet sieve, a moisture content of ≤10%, a water-soluble content of ≥50%, and a sodium sulfonate content of 6-13%; the oil-based multifunctional chelated asphalt is a dark brown free-flowing powder with a residue of ≤10% on a 200-mesh wet sieve, a moisture content of ≤10%, an oil-soluble content of ≥30%, and a demulsification voltage of ≥350V.

[0026] The applications of the multifunctional chelated asphalt produced in this invention include chelated asphalt surface treatment pavements (such as slurry seal, micro-surfacing, fog seal, and layered chelated asphalt surface treatment), chelated asphalt penetration pavements, chelated asphalt macadam pavements, chelated asphalt concrete pavements, cold recycling of old asphalt pavement materials, bagged ambient temperature asphalt mixtures, as well as prime coats, tack coats, seal coats, base coats, pothole fillers, and crack fillers.

[0027] Secondly, a method for preparing the multifunctional chelated asphalt as described above, the method comprising chelating agent preparation, matrix asphalt purification, and water-based / oil-based chelated asphalt preparation, the specific steps of which are as follows:

[0028] Step 1: Preparation of chelating agent (organic polyamine-alkali lignin graft copolymer (main chelating agent))

[0029] S11: Mix ethylenediamine and methyl acrylate at a ratio of 20-30:15-25 by weight, stir and react at 60-70℃ for 3-4 hours to obtain a terminal amino hyperbranched polymer.

[0030] S12: Alkali lignin and deionized water are mixed in a solid-liquid ratio of 1:3-5 to form an aqueous solution. Then, terminal amino hyperbranched polymer, formaldehyde and initiator are added. The polycondensation reaction is carried out at 75-85℃ for 4-5 hours. After vacuum drying and pulverization, organic polyamine-alkali lignin graft copolymer is obtained.

[0031] In this invention, the terminal amino hyperbranched polymer (NH2-HBP) is synthesized by mixing ethylenediamine and methyl acrylate in a ratio of 20-30:15-25 by weight and stirring at 60-70°C for 3-4 hours to obtain the terminal amino hyperbranched polymer.

[0032] Synthesis of graft copolymer: Alkali lignin and deionized water are mixed in a solid-liquid ratio of 1:3-5 to form an aqueous solution. The above-mentioned terminal amino hyperbranched polymer and formaldehyde (accounting for 5-10 parts by weight of total raw materials) are added. Ammonium persulfate / sodium bisulfite initiator (mass ratio 1:1, total addition amount is 0.5-1% of the system) are added. The reaction is stirred and polycondensed at 75-85℃ for 4-5 hours. After the reaction is completed, the product is dried under reduced pressure and pulverized to obtain the organic polyamine-alkali lignin graft copolymer (main chelating agent).

[0033] S13: A chelating agent is prepared by mixing organic polyamine-alkali lignin graft copolymer with zinc nitrate at a ratio of 92-95:5-8 parts by weight.

[0034] Step 2: Base Asphalt Purification

[0035] The purified heavy catalytic oil slurry asphalt was obtained by vacuum distillation at 200-220℃ and filtration through a 200-mesh plate and frame filter.

[0036] Specifically, in this invention, the heavy catalytic oil slurry is subjected to vacuum distillation (temperature 200-220℃, vacuum degree -0.08~-0.09MPa) to remove light components, and then subjected to plate and frame filtration (200 mesh filter) to remove solid catalyst particles, thereby obtaining purified heavy catalytic oil slurry asphalt with a softening point of 80-90℃, which is ready for use.

[0037] Step 3: Preparation of Multifunctional Chelated Asphalt

[0038] S31: Heat the purified heavy catalytic oil slurry asphalt to 120-140℃ to melt it, add emulsifier and stabilizer or add emulsifier, stabilizer and white oil, and shear emulsify at 3000-5000r / min for 15-25min to obtain asphalt liquid;

[0039] S32: Cool the asphalt liquid to 55-65℃, slowly add fuming sulfuric acid, and stir the reaction for 1.5-2.5 hours to obtain sulfonated asphalt liquid;

[0040] S33: Heat the sulfonated asphalt liquid to 65-75℃, add the chelating agent, and stir at 1000-2000r / min for 2.5-3.5h for chelation reaction;

[0041] S34: After spray drying, it is crushed through a 100-mesh or 200-mesh sieve to produce multifunctional chelated asphalt.

[0042] In this invention, ① the preparation steps of water-based multifunctional chelated bitumen are as follows:

[0043] S31: Emulsion preparation: Heat the purified heavy catalytic oil slurry asphalt to 120-130℃ to melt it, add anionic emulsifier and stabilizer, and shear and emulsify it in a high-speed shear machine at 3000-4000r / min for 15-20min to obtain asphalt emulsion for later use.

[0044] S32: Sulfonation reaction: Cool the asphalt emulsion to 60-65℃, slowly add fuming sulfuric acid, stir and react for 2-2.5 hours, and control the sodium sulfonate content at 6-13% to obtain sulfonated asphalt emulsion.

[0045] S33: Chelation modification: Heat the sulfonated asphalt emulsion to 70-75℃, add chelating agent (organic polyamine-alkali lignin graft copolymer + zinc nitrate), stir at 1000-1500r / min for 3-3.5h for chelation reaction, and adjust the pH to 8-10 with 10wt% NaOH solution during the reaction.

[0046] S34: Post-processing: The chelation reaction solution is spray-dried and then pulverized through a 100-mesh sieve to obtain water-based multifunctional chelated asphalt (blackish-brown free-flowing powder).

[0047] ②The preparation steps of oil-based multifunctional chelated bitumen are as follows:

[0048] S41: Oil phase dispersion: Heat the purified heavy catalytic oil slurry asphalt to 130-140℃ to melt it, add nonionic emulsifier, stabilizer and white oil, and shear and disperse it in a high-speed shear machine at a speed of 4000-5000 r / min for 20-25 min to obtain asphalt oil phase dispersion for later use.

[0049] S42: Sulfonation reaction: Cool the oil phase dispersion to 55-60℃, slowly add fuming sulfuric acid, and stir the reaction for 1.5-2 hours to obtain sulfonated asphalt oil phase liquid;

[0050] S43: Chelation modification: The sulfonated asphalt oil phase liquid is heated to 65-70℃, and a chelating agent (organic polyamine-alkali lignin graft copolymer + zinc nitrate) is added. The chelation reaction is carried out by stirring at 1500-2000r / min for 2.5-3h to obtain chelated asphalt oil phase liquid.

[0051] S44: Post-processing: The chelated asphalt oil phase liquid is vacuum dried, and then pulverized through a 200-mesh sieve to obtain oil-based multifunctional chelated asphalt (blackish-brown free-flowing powder).

[0052] In this invention, ① sulfonation reaction: the polycyclic aromatic hydrocarbons in the purified heavy catalytic cracking asphalt undergo an electrophilic substitution reaction with fuming sulfuric acid to introduce sulfonic acid groups (-SO3H), which are then neutralized to generate sodium sulfonate groups (-SO3Na). The reaction formula is as follows: , Ar is the parent nucleus of polycyclic aromatic hydrocarbons; ② Chelation reaction: The active sites such as amino (-NH2), phenolic hydroxyl (-OH), and carboxyl (-COOH) groups in the chelating agent react with formation metal ions (M n+ Stable coordination chelate bonds are formed, while Zn generated from the decomposition of zinc nitrate... 2+ It forms a secondary chelate network with the sodium sulfonate group and phenolic hydroxyl group in the asphalt molecule, as shown in the following reaction formula: , , where R is the molecular chain of organic polyamine-alkali lignin graft copolymer; for Metal ions, etc.

[0053] Furthermore, the initiator in S12 is ammonium persulfate / sodium bisulfite, and its addition amount is 0.5-1% of the total mass of the system, with the mass ratio of ammonium persulfate to sodium bisulfite being 1:1.

[0054] Furthermore, the dropping rate of the fuming sulfuric acid in S32 is 0.8-2 mL / min.

[0055] In this invention, the dropping rates of fuming sulfuric acid in S32 and S42 are 1-2 mL / min and 0.8-1.5 mL / min, respectively.

[0056] Furthermore, the inlet air temperature of the spray drying in S34 is 180-200℃, and the outlet air temperature is 80-90℃; the vacuum drying temperature in S44 is 90-100℃, and the vacuum degree is -0.07~-0.08MPa.

[0057] (III) Beneficial Effects

[0058] 1. Significant chelating and anti-collapse effect: The introduced organic polyamine-alkali lignin graft copolymer chelating agent provides multiple active chelating sites such as amino and phenolic hydroxyl groups, which can bind with formation metal ions (Ca... 2+ Mg 2+ Zn 2+ Stable coordination bonds are formed on the surface of the aggregate, which significantly improves the ability of asphalt to seal cracks. After aging at 150℃, the high temperature and high pressure filtration loss rate is ≥60%, the mud cake curvature is ≥90%, and the anti-collapse performance is far superior to that of existing sulfonated asphalt.

[0059] 2. Stable mud rheology: The emulsification process disperses the asphalt evenly in micro-droplets, and the sodium sulfonate groups introduced by sulfonation enhance hydrophilicity / lipophilicity. The chelated structure further improves the binding force with drilling fluid. The torque reduction rate of water-based products is ≥60%, and the demulsification voltage of oil-based products is ≥350V, which effectively stabilizes mud rheology and improves drilling efficiency.

[0060] 3. Excellent compatibility with water-based and oil-based products: The formulation of chelating agents and emulsifiers is designed separately for water-based and oil-based drilling fluids. The water-based products have a water-soluble content of ≥50%, and the oil-based products have an oil-soluble content of ≥30%. The wet screening residue is ≤10%, which solves the problems of poor compatibility and imbalance of water-soluble and oil-soluble properties of existing products.

[0061] 4. Environmentally friendly and suitable for marine drilling: The product contains no toxic additives, the production process produces no harmful waste, it is non-toxic and does not pollute the formation and marine environment, and it is resistant to salt and calcium and magnesium ions, fully meeting the environmental protection and working conditions requirements of marine drilling.

[0062] 5. Excellent high-temperature stability: The chelated structure and sodium sulfonate groups form a dual high-temperature stable network. After aging at 150℃, the product performance does not show significant degradation, which is far superior to traditional emulsified asphalt.

[0063] 6. The production process is easy to industrialize: The preparation process of this invention is simple, the reaction conditions are mild, and the process parameters are easy to control. It can be directly modified from existing sulfonated / emulsified asphalt production equipment, making it suitable for large-scale industrial production. Attached Figure Description

[0064] Figure 1 This is a flowchart of the preparation method of the water-based multifunctional chelated bitumen of the present invention.

[0065] Figure 2 This is a flowchart of the preparation method of the oil-based multifunctional chelated bitumen of the present invention. Detailed Implementation

[0066] This invention produces water-based / oil-based multifunctional chelated asphalt through a five-step process: chelating agent preparation, matrix asphalt pretreatment, emulsification-sulfonation synergy, chelation modification, and post-treatment. The chelating agent is a compound system of organic polyamine-alkali lignin graft copolymer (main chelating agent) and zinc nitrate (auxiliary chelating agent). The emulsifier is selected specifically for water-based / oil-based applications. Fuming sulfuric acid is used as the sulfonating agent. The matrix asphalt is purified heavy catalytic oil slurry asphalt (which has the best sulfonation reaction activity).

[0067] The present invention will be further described below with reference to the embodiments and / or accompanying drawings.

[0068] Example 1

[0069] like Figure 1As shown, the preparation of water-based multifunctional chelated bitumen includes the following steps:

[0070] Step 1: Chelating agent preparation: 25 parts of ethylenediamine and 20 parts of methyl acrylate were mixed and stirred at 65°C for 3.5 h to obtain the terminal amino hyperbranched polymer;

[0071] Step 2: Prepare an aqueous solution by mixing 45 parts of alkali lignin with 135 parts of deionized water, add the above-mentioned terminal amino hyperbranched polymer, 8 parts of formaldehyde, and 0.8 parts of initiator (ammonium persulfate / sodium bisulfite = 1:1), and perform polycondensation reaction at 80°C for 4.5 h. After drying under reduced pressure, pulverize to obtain organic polyamine-alkali lignin graft copolymer.

[0072] Step 3: Mix 95 parts of the copolymer with 5 parts of zinc nitrate to obtain a chelating agent;

[0073] Step 4: Purification of base asphalt: The heavy catalytic oil slurry is distilled under reduced pressure at 210℃ (vacuum degree -0.085MPa) and filtered through a 200-mesh plate and frame filter to obtain purified heavy catalytic oil slurry asphalt (softening point 85℃).

[0074] Step 5: Preparation of water-based chelated bitumen: Heat 72 parts of purified bitumen to 125℃ to melt, add 4 parts of sodium dodecylbenzenesulfonate and 0.8 parts of sodium carboxymethyl cellulose, and shear emulsify at 3500r / min for 18min;

[0075] Step 6: Cool to 62℃, add 8 parts of fuming sulfuric acid (SO3 content 28wt%) dropwise at 1.5mL / min, and stir the reaction for 2.2h;

[0076] Step 7: Heat to 72℃, add 10 parts of chelating agent, stir at 1200r / min for 3.2h, and adjust the pH to 9 with 10wt% NaOH;

[0077] Step 8: After spray drying (inlet air 190℃, outlet air 85℃), the mixture is pulverized through a 100-mesh sieve to obtain water-based multifunctional chelated asphalt.

[0078] Table 1. Relevant Technical Indicators and Standards for Water-Based Multifunctional Chelated Asphalt

[0079]

[0080] Performance testing of this invention: Dark brown free-flowing powder, pH=9, 7.2% residue on a 100-mesh wet sieve, 6.8% moisture, 56.3% water-soluble content, 9.5% sodium sulfonate content, 68.5% filtration loss after aging at 150℃ under high temperature and high pressure, 94.2% mud cake tortuosity, 65.8% torque reduction rate, non-toxic, and has excellent compatibility with water-based drilling fluids.

[0081] This invention relates to a multifunctional chelated asphalt and its preparation method. Through a synergistic process of introducing a chelating agent, emulsification, sulfonation, and chelation, a multifunctional chelated asphalt is prepared. This is an environmentally friendly water-based / oil-based drilling fluid chelated asphalt suitable for marine drilling operations, effectively improving the drilling fluid's properties such as crack sealing, rheological stability, and mud cake quality. The preparation method of this invention includes three core processes: chelating agent preparation, matrix asphalt purification, and water-based / oil-based chelated asphalt preparation. The chelating agent is a compound system of organic polyamine-alkali lignin graft copolymer and zinc nitrate. Through the synergistic process of emulsification, sulfonation, and chelation, the asphalt possesses multiple active chelating sites, simultaneously achieving multiple properties such as high-temperature stability, environmental friendliness, and high compatibility. This invention has the advantages of good anti-collapse effect, stable rheology, good compatibility, environmental friendliness, and good high-temperature stability.

[0082] Example 2

[0083] like Figure 2 As shown, the preparation of oil-based multifunctional chelated bitumen includes the following steps:

[0084] S1: Preparation of chelating agent: Same as in Example 1 (steps 1-3);

[0085] S2: Base asphalt purification: Same as in Example 1 (step 4);

[0086] S3: Preparation of oil-based chelated bitumen: 75 parts of purified bitumen were heated to 135℃ to melt, and 5 parts of OP-10, 1.0 part of aluminum distearate and 4 parts of white oil were added. The mixture was sheared and dispersed at 4500r / min for 22min.

[0087] S4: Cool to 58℃, add 6 parts of fuming sulfuric acid (SO3 content 28wt%) dropwise at 1.2mL / min, and stir the reaction for 1.8h;

[0088] S5: Heat to 68℃, add 12 parts of chelating agent, stir at 1800r / min for chelation for 2.8h;

[0089] S6: After vacuum drying (95℃, -0.075MPa), it is pulverized through a 200-mesh sieve to obtain oil-based multifunctional chelated asphalt.

[0090] Table 2. Relevant Technical Indicators and Standards for Oil-Based Multifunctional Chelated Asphalt

[0091]

[0092] Performance testing of this invention: Dark brown free-flowing powder, 6.5% residue on a 200-mesh wet sieve, 7.1% moisture, 35.6% oil-soluble content, 8.2% sodium sulfonate content, 66.3% filtration loss after aging at 150℃ under high temperature and high pressure, 385V demulsification voltage, non-toxic, and has excellent compatibility with oil-based drilling fluids.

[0093] This invention relates to a multifunctional chelated asphalt and its preparation method. Through a synergistic process of introducing a chelating agent, emulsification, sulfonation, and chelation, a multifunctional chelated asphalt is prepared. This is an environmentally friendly water-based / oil-based drilling fluid chelated asphalt suitable for marine drilling operations, effectively improving the drilling fluid's properties such as crack sealing, rheological stability, and mud cake quality. The preparation method of this invention includes three core processes: chelating agent preparation, matrix asphalt purification, and water-based / oil-based chelated asphalt preparation. The chelating agent is a compound system of organic polyamine-alkali lignin graft copolymer and zinc nitrate. Through the synergistic process of emulsification, sulfonation, and chelation, the asphalt possesses multiple active chelating sites, simultaneously achieving multiple properties such as high-temperature stability, environmental friendliness, and high compatibility. This invention has the advantages of good anti-collapse effect, stable rheology, good compatibility, environmental friendliness, and good high-temperature stability.

[0094] Example 3

[0095] like Figure 1 As shown, this illustrates the preparation (optimized mix ratio) of water-based multifunctional chelated bitumen.

[0096] The difference from Example 1 is that the amount of chelating agent added is 8 parts, the amount of fuming sulfuric acid added is 6 parts, and the final water-based multifunctional chelated asphalt has the following properties: 8.5% residue on a 100-mesh wet sieve, 7.5% moisture, 52.1% water-soluble content, 6.8% sodium sulfonate content, 62.1% filtration loss rate after aging at 150℃ under high temperature and high pressure, 91.5% mud cake tortuosity, and 61.2% torque reduction rate.

[0097] Example 4

[0098] like Figure 2 As shown, this illustrates the preparation (optimized mix ratio) of oil-based multifunctional chelated bitumen.

[0099] The difference from Example 2 is that the amount of chelating agent added is 10 parts, the amount of fuming sulfuric acid added is 5 parts, and the final properties of the oil-based multifunctional chelated asphalt are: 7.8% residue on a 200-mesh wet sieve, 6.9% moisture, 32.5% oil-soluble content, 6.5% sodium sulfonate content, 63.5% filtration loss rate after aging at 150℃ under high temperature and high pressure, and 362V demulsification voltage.

[0100] In summary, the water-based / oil-based multifunctional chelated bitumen prepared by this invention meets all technical requirements. After aging at 150℃, the high-temperature and high-pressure filtration loss rate is ≥60%, the mud cake curvature is ≥90%, the torque reduction rate is ≥60%, the demulsification voltage of the oil-based product is ≥350V, and it is non-toxic and environmentally friendly. It also has excellent compatibility with drilling fluids and fully meets the working conditions and environmental protection requirements of marine drilling.

[0101] The multifunctional chelated asphalt of this invention can be directly added to water-based / oil-based drilling fluids at an addition rate of 2-3%. After stirring evenly, it is ready for use. It is suitable for marine drilling, deep well drilling, and drilling in complex formations. After addition, it can significantly improve the drilling fluid's ability to plug fractures, stabilize mud rheology, improve mud cake quality, and reduce filtration loss. At the same time, it will not cause pollution to the formation and marine environment. It can replace existing sulfonated asphalt and emulsified asphalt, and improve drilling efficiency and construction safety.

[0102] The preparation process of this invention can be directly modified from existing sulfonated / emulsified asphalt production equipment, requiring only the addition of a chelating agent reactor and a high-speed shearing machine. The modification cost is low, the production process generates no harmful waste, meets the production requirements of green chemistry, and is suitable for large-scale industrial production.

Claims

1. A multifunctional chelated bitumen, characterized in that: The raw materials include the following parts by weight: 70-78 parts purified heavy catalytic oil slurry asphalt, 8-15 parts chelating agent, 3-6 parts emulsifier, 5-10 parts fuming sulfuric acid, 5-8 parts deionized water, and 0.5-1.2 parts stabilizer; The chelating agent is a compound system of organic polyamine-alkali lignin graft copolymer and zinc nitrate, with zinc nitrate accounting for 5-8% of the total weight of the chelating agent; the SO3 content of the fuming sulfuric acid is 25-30 wt%.

2. The multifunctional chelated bitumen as described in claim 1, characterized in that: The organic polyamine-alkali lignin graft copolymer is synthesized from the following raw materials in parts by weight: 20-30 parts ethylenediamine, 15-25 parts methyl acrylate, 40-50 parts alkali lignin, and 5-10 parts formaldehyde.

3. The multifunctional chelated asphalt as described in claim 2, characterized in that: The emulsifier is one of sodium dodecylbenzenesulfonate or polyoxyethylene octylphenol ether OP-10.

4. The multifunctional chelated asphalt as described in claim 3, characterized in that: The stabilizer is one of sodium carboxymethyl cellulose or aluminum distearate.

5. The multifunctional chelated asphalt as described in claim 4, characterized in that: The softening point of the purified heavy catalytic oil slurry asphalt is 80~90℃, and it is obtained by heavy catalytic oil slurry through vacuum distillation and 200-mesh plate and frame filtration.

6. The multifunctional chelated bitumen as described in claim 1, characterized in that: It also includes the following ingredients in parts by weight: 3-6 parts white oil.

7. A method for preparing multifunctional chelated bitumen as described in any one of claims 1-6, characterized in that: The preparation method includes chelating agent preparation, matrix asphalt purification, and chelated asphalt preparation, with the specific steps as follows: Step 1: Preparation of chelating agent S11: Mix ethylenediamine and methyl acrylate at a ratio of 20-30:15-25 by weight, stir and react at 60-70℃ for 3-4 hours to obtain a terminal amino hyperbranched polymer. S12: Alkali lignin and deionized water are mixed in a solid-liquid ratio of 1:3-5 to form an aqueous solution. Then, terminal amino hyperbranched polymer, formaldehyde and initiator are added. The polycondensation reaction is carried out at 75-85℃ for 4-5 hours. After vacuum drying and pulverization, organic polyamine-alkali lignin graft copolymer is obtained. S13: A chelating agent is prepared by mixing organic polyamine-alkali lignin graft copolymer with zinc nitrate at a ratio of 92-95:5-8 parts by weight. Step 2: Base Asphalt Purification The purified heavy catalytic oil slurry asphalt was obtained by vacuum distillation at 200-220℃ and filtration through a 200-mesh plate and frame filter. Step 3: Preparation of Multifunctional Chelated Asphalt S31: Heat the purified heavy catalytic oil slurry asphalt to 120-140℃ to melt it, add emulsifier and stabilizer or add emulsifier, stabilizer and white oil, and shear emulsify at 3000-5000r / min for 15-25min to obtain asphalt liquid; S32: Cool the asphalt liquid to 55-65℃, slowly add fuming sulfuric acid, and stir the reaction for 1.5-2.5 hours to obtain sulfonated asphalt liquid; S33: Heat the sulfonated asphalt liquid to 65-75℃, add the chelating agent, and stir at 1000-2000r / min for 2.5-3.5h for chelation reaction; S34: After spray drying, it is crushed through a 100-mesh or 200-mesh sieve to produce multifunctional chelated asphalt.

8. The method for preparing multifunctional chelated bitumen as described in claim 7, characterized in that: The initiator in S12 is ammonium persulfate / sodium bisulfite, and its addition amount is 0.5-1% of the total mass of the system, with the mass ratio of ammonium persulfate to sodium bisulfite being 1:

1.

9. The method for preparing multifunctional chelated bitumen as described in claim 7, characterized in that: The dropping rate of the fuming sulfuric acid in S32 is 0.8-2 mL / min.

10. The method for preparing multifunctional chelated bitumen as described in claim 7, characterized in that: The inlet air temperature of the spray dryer in S34 is 180-200℃, and the outlet air temperature is 80-90℃.

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