A wetting dispersant, a water-based drilling fluid comprising the same, and a preparation method thereof

Abstract

The application belongs to the field of oil field chemistry, and relates to a wetting dispersant, a water-based drilling fluid containing the same and a preparation method. The preparation method of the wetting dispersant comprises the following steps: (1) mixing an ester compound and a first emulsifier to prepare a first solution; (2) mixing deionized water and a second emulsifier to prepare a second solution; (3) under stirring, dropping the first solution into the second solution to perform emulsification, so as to obtain an emulsion; (4) dissolving an aromatic compound and / or an amide compound and an initiator in water, and performing heating reaction to obtain a prepolymer; (5) dropping the emulsion into the prepolymer, and continuing to perform heating reaction to obtain a polymer; and (6) adding a polymerization inhibitor to terminate the reaction, and performing precipitation, centrifugation and drying to obtain a solid powder. The wetting dispersant has significant wetting reversal and high-temperature dispersion stability, can effectively reduce the adhesion of oil sand bitumen to a drill pipe, disperse oil sand particles, reduce well bottom deposition, and improve the performance of a drilling fluid.

Description

Technical Field

[0001] This invention belongs to the field of oilfield chemistry and relates to a wetting and dispersing agent, a water-based drilling fluid containing the same, and a method for preparing the same. In particular, it relates to a wetting and dispersing agent used in oil sands extraction and drilling processes to control the adhesion and dispersion of oil sand particles and reduce bottom hole deposition, and a method for preparing the same. Background Technology

[0002] Canada has abundant oil sands reserves, and the proportions of the four components in its oil sands bitumen vary depending on the oil sands origin and the methods used in extraction and analysis. Generally, Canadian oil sands bitumen contains approximately 10%–20% saturated components, 30%–40% aromatic components, 30%–40% resins, and 10%–20% asphaltenes. The resins are composed of polycyclic aromatic hydrocarbons with relatively large molecular weights and containing heteroatoms, exhibiting strong polarity and significantly increasing the viscosity and ductility of the bitumen. Asphaltenes, the component with the largest relative molecular weight and strongest polarity in bitumen, are composed of polycyclic aromatic hydrocarbons and heteroatoms. Their content directly affects the hardness, viscosity, and temperature stability of the oil sands bitumen; higher content results in greater viscosity.

[0003] During extraction and drilling, the high proportion of gum and bituminous substances in oil sands leads to high adhesion, low wettability, and particle agglomeration problems, posing significant challenges to the normal operation of drilling equipment (such as drill pipes and drill strings). The gum and bituminous substances in oil sands easily adhere to the drill pipe surface, causing equipment instability, increased friction, decreased drilling speed, and significant bituminous deposition at the bottom of the well, further clogging the mud circulation system. Therefore, developing a highly efficient chemical treatment agent that can effectively reduce the adhesion of oil sands bituminous substances, improve wettability, and disperse oil sand particles is crucial to solving these problems.

[0004] Existing wetting and dispersing agents are mainly designed for general oil-based mud or sand blockage problems, and their effectiveness is generally unsatisfactory under oil sand high-asphalt conditions. Traditional treatment agents, such as nonionic surfactants and sulfonated asphalt, have drawbacks such as low contact angle reduction rate, poor high-temperature stability, and insufficient dispersibility, and cannot significantly reduce the risks of equipment adhesion and wellbore deposition.

[0005] Therefore, how to provide a wetting and dispersing agent that combines wettability and dispersibility and meets the drilling requirements of oil sand wells has become an urgent technical problem to be solved. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a wetting and dispersing agent, a water-based drilling fluid containing the same, and a method for preparing them.

[0007] Specifically, the present invention is implemented through the following scheme: A method for preparing a wetting and dispersing agent, comprising: (1) Mix the ester compound with the first emulsifier to prepare the first solution; (2) Mix deionized water with the second emulsifier to prepare the second solution; (3) Under stirring, the first solution is added dropwise to the second solution to emulsify, thereby obtaining an emulsion; (4) Dissolve aromatic compounds and / or amide compounds with an initiator in water and react them under heating to obtain a prepolymer; (5) The emulsion is dripped into the prepolymer and heated to continue the reaction to obtain the polymer; (6) Add an inhibitor to terminate the reaction, and after precipitation, centrifugation and drying, a solid powder is obtained.

[0008] In the above-mentioned method for preparing the wetting and dispersing agent, the mass ratio of the ester compound, the aromatic compound, and the amide compound is (5~35):(5~25):(10~20).

[0009] In the above-mentioned method for preparing the wetting and dispersing agent, the mass ratio of the ester compound to the first emulsifier is 20:1 to 60:1; the mass ratio of the deionized water to the second emulsifier is 15:1 to 50:1; and the mass ratio of the first emulsifier to the second emulsifier is (0.8 to 1.2):1.

[0010] In the above-mentioned method for preparing the wetting and dispersing agent, the amount of the initiator added is 0.1% to 5% of the total mass of the monomer; the amount of the polymerization inhibitor added is 0.001% to 1% of the total mass of the polymer.

[0011] In the above-mentioned method for preparing wetting and dispersing agents, the ester compound is one or more of octadecyl acrylate, octadecyl methacrylate, monooctadecyl maleate, and vinyl acetate.

[0012] In the above-mentioned method for preparing the wetting and dispersing agent, the aromatic compound is one or more of styrene, vinylpyridine, acrylamide benzenesulfonic acid, and sodium p-styrenesulfonate.

[0013] In the above-mentioned method for preparing wetting and dispersing agents, the amide compound is one or more of acrylamide, N,N-dimethylacrylamide, potassium acrylamide benzoate, N-vinylformamide, and N-hydroxymethylacrylamide.

[0014] The initiator in the above-mentioned method for preparing the wetting and dispersing agent includes one or more of the following: ammonium persulfate, potassium persulfate, azobisisobutyronitrile, benzoyl peroxide, and ammonium persulfate-sodium bisulfite composite system.

[0015] In the above-mentioned method for preparing the wetting and dispersing agent, the first emulsifier and the second emulsifier are each independently selected from one or more of the following: sodium laurylate, sodium stearate, sodium palmitate, sodium lauryl sulfonate, sodium alkylbenzene sulfonate, sodium dodecyl sulfate, sodium stearyl ether sulfate, sodium phosphate salt, potassium alkyl phosphate salt, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, sorbitan laurate, sorbitan monooleate, Tween 20, Tween 80, cocamidopropyl betaine, lauramidopropyl betaine, cocoyl hydroxysulfonate betaine, sodium lauroyl glutamate, and sodium cocoyl sarcosinate.

[0016] The above-mentioned method for preparing wetting and dispersing agents includes one or more of hydroquinone, tert-butylcatechol, TEMPO, and ethylenediaminetetraacetic acid.

[0017] In the above-mentioned method for preparing the wetting and dispersing agent, the heating temperature in step (4) is 40~70℃ and the reaction time is 0.5~4 hours; the heating temperature in step (5) is 50~80℃ and the reaction time is 1~6 hours.

[0018] A wetting and dispersing agent is prepared using the method described above.

[0019] The aforementioned wetting and dispersing agent is compounded with the encapsulating agent in a mass ratio of 2:1 to 10:1; wherein the encapsulating agent includes one or more of lignin sulfonate, mixed metal layered hydroxide, modified starch, nano silica, and polyacrylamide.

[0020] A water-based drilling fluid comprising the aforementioned wetting and dispersing agent.

[0021] A method for preparing a water-based drilling fluid, comprising: (1) Add the above wetting and dispersing agent to the base slurry and stir for 30-60 minutes; (2) Adjust the pH to 8-10, add functional additives, and continue to stir evenly to obtain water-based drilling fluid.

[0022] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: (1) The contact angle reduction rate of the wetting and dispersing agent of the present invention is significantly enhanced. Traditional wetting agents, such as nonionic surfactants or sulfonated bitumen, mainly achieve wettability regulation through adsorption of a single functional group. However, in oil sands with high bitumen content, the contact angle reduction rate is low due to insufficient adsorption sites, with the contact angle only decreasing from 82° to 60°~70°.

[0023] The wetting and dispersing agent of this invention, through molecular structure innovation and compound synergy, reduces the contact angle from 82° to 35° in the application of Canadian oil sands blocks, increasing the contact angle reduction rate by 0.57 times, and reducing the adhesion of the drill string surface by 75% to 80%, while traditional technology only reduces it by 30% to 40%.

[0024] (2) The present invention provides a breakthrough improvement in the high-temperature dispersion stability of water-based drilling fluid. This invention constructs a dual electrostatic-spatial stabilization mechanism by combining a wetting and dispersing agent with a coating agent in a specific ratio: on the one hand, the sulfonic acid groups of lignin sulfonate are used to maintain the surface charge density of particles, and on the other hand, nano-SiO2 provides rigid steric hindrance, thereby effectively inhibiting high-temperature flocculation.

[0025] The test results show that the system has excellent high temperature resistance: after aging at 120℃ for 16 h, the oil sand anti-sticking rate is still as high as 92%±2% (compared to only 48%~55% for traditional technology); at the same time, the filtration loss is controlled at ≤10 mL (compliant with API standards), which is 40% lower than that of conventional systems. Attached Figure Description

[0026] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention.

[0027] Figure 1 The image shows the adhesion of steel bars after adding different amounts of wetting and dispersing agent. It compares the asphalt adhesion on the surface of the steel bars after adding different amounts of the wetting and dispersing agent of the present invention, and intuitively reflects the relationship between its anti-adhesion effect and the amount added. Figure 2 The adhesion of the aging tank after adding different amounts of wetting and dispersing agents showed that the adhesion rate decreased in all cases. Figure 3 A visual comparison of the effect of the wetting and dispersing agent prepared in Example 5 on the steel rod: (a) Before addition, the steel rod was severely coated with asphalt; (b) After adding 3% wetting and dispersing agent, the surface of the steel rod was clean, proving its excellent anti-adhesion performance. Figure 4 The following is a visual comparison of the effects of the wetting and dispersing agent prepared in Example 5 on the aging tank; (a) before the addition of the wetting and dispersing agent, the aging tank was severely adhered; (b) after the addition of 3% wetting and dispersing agent, there was basically no adhesion in the aging tank. Figure 5 The thermogravimetric analysis (TGA) diagram of the wetting and dispersing agent prepared in Example 5 shows that the product has excellent thermal stability at high temperatures, providing a basis for its application in high-temperature downhole environments. Detailed Implementation

[0028] To fully understand the purpose, features, and effects of this invention, the following detailed embodiments are provided. Except as described below, the process methods of this invention employ conventional methods or apparatus in the art. Unless otherwise specified, the terms and expressions used below have the meanings commonly understood by those skilled in the art.

[0029] The wetting and dispersing agent provided by this invention is synthesized by polymerization of ester compounds, aromatic compounds, and / or amide compounds under initiation conditions. Different monomer types, monomer concentrations, and reaction times are used during polymer synthesis to carry out binary and ternary polymerization reactions to prepare the wetting and dispersing agent.

[0030] Specifically, the preparation method of the wetting and dispersing agent of the present invention includes the following steps: (1) Mix the ester compound with the first emulsifier to prepare the first solution; (2) Mix deionized water with the second emulsifier to prepare the second solution; (3) Under stirring, the first solution is added dropwise to the second solution to emulsify, thereby obtaining an emulsion; (4) Dissolve aromatic compounds and / or amide compounds with an initiator in water and react them under heating to obtain a prepolymer; (5) The emulsion is dripped into the prepolymer and heated to continue the reaction to obtain the polymer; (6) Add an inhibitor to terminate the reaction, and after precipitation, centrifugation and drying, a solid powder is obtained.

[0031] The wetting and dispersing agent of this invention exhibits significant contact angle reduction and high-temperature dispersion stability, effectively reducing the adhesion of oil sand bitumen to the drill pipe, dispersing oil sand particles, reducing bottom hole deposition, and improving drilling fluid performance. This wetting and dispersing agent demonstrates excellent performance in drilling operations with high bitumen content oil sand, increasing the contact angle reduction rate to 72% and the drill string adhesion reduction rate to 91.6%, significantly outperforming commercially available products.

[0032] In some preferred embodiments, the method for preparing the wetting and dispersing agent of the present invention includes the following steps: (1) Mix the ester compound with the emulsifier to prepare the first solution.

[0033] Mixing ester compounds with emulsifiers allows the hydrophobic ester compounds to be effectively dispersed and encapsulated by the emulsifiers, significantly reducing the interfacial tension between them and the subsequent aqueous phase. This lays the foundation for the formation of a uniform and stable oil-in-water emulsion, thereby ensuring the uniformity and efficiency of the subsequent polymerization reaction.

[0034] In some preferred embodiments, the mass ratio of the ester compound to the emulsifier is 20:1 to 60:1, for example, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1 or 60:1, or any value between any two of the above values.

[0035] In practice, when the proportion of esters is too high, the emulsifier is insufficient to form a complete and dense interfacial film, the emulsion is prone to stratification and demulsification, and the droplets are prone to aggregation and unevenness, which affects the polymerization reaction and product performance. When the proportion of emulsifier is too high, the viscosity of the system increases and the fluidity deteriorates. Excessive emulsifier is prone to forming micelles that encapsulate monomers, reducing the effective reaction concentration and affecting the purity of the product.

[0036] In some preferred embodiments, the ester compound is industrial grade or higher octadecyl acrylate C. 21 H 40 O2), octadecyl methacrylate (C 22 H 42 O2), maleate monooctadecyl ester (C 22 H 40 One or more of O4 and vinyl acetate.

[0037] The emulsifier is one or more of cationic emulsifiers, nonionic emulsifiers, and amphoteric emulsifiers. In some preferred embodiments, the emulsifier includes one or more of sodium laurylate, sodium stearate, sodium palmitate, sodium lauryl sulfonate, sodium alkylbenzene sulfonate, sodium dodecyl sulfate, sodium stearyl ether sulfate, sodium phosphate salt, potassium alkyl phosphate salt, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, sorbitan laurate, sorbitan monooleate, Tween 20, Tween 80, cocamidopropyl betaine, lauramidopropyl betaine, cocoyl hydroxysulfonate betaine, sodium lauroyl glutamate, and sodium cocoyl sarcosinate.

[0038] (2) Mix deionized water with emulsifier to prepare a second solution.

[0039] The purpose of mixing deionized water with the emulsifier is to form a homogeneous aqueous emulsifier solution.

[0040] The emulsifier may be the same as or different from the emulsifier used in step (1).

[0041] In some preferred embodiments, the mass ratio of deionized water to emulsifier is 15:1 to 50:1, for example, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1 or 50:1, or any value between any two of the above values.

[0042] In practice, it has been found that when too much deionized water is used, the emulsifier concentration is too low, which may lead to emulsion instability and easy separation; when too little deionized water is used, the system becomes too viscous, which is not conducive to the uniform formation of the emulsion and subsequent dropwise addition operations.

[0043] (3) While stirring, the first solution is added dropwise to the second solution to emulsify and obtain an emulsion.

[0044] High-speed shear emulsification uniformly disperses ester compounds in the aqueous phase as tiny droplets, forming an oil-in-water emulsion. This increases the reaction contact area, making the subsequent polymerization reaction more uniform and efficient.

[0045] Preferably, in order to obtain a uniform emulsion, the stirring speed should be ≥8000 rpm.

[0046] In some preferred embodiments, the mass ratio of the first emulsifier to the second emulsifier is (0.8~1.2):1. (4) Dissolve aromatic compounds and / or amide compounds with an initiator in water and react them under heating to obtain a prepolymer.

[0047] This step is the prepolymerization stage, where aromatic compounds and / or amide compounds undergo copolymerization under the action of an initiator to generate prepolymer chains containing active end groups, preparing for subsequent grafting or copolymerization with ester compounds in the emulsion.

[0048] In some preferred embodiments, the aromatic compound is one or more of styrene, vinyl chloride, maleic anhydride, and sodium p-styrene sulfonate.

[0049] In some preferred embodiments, the amide compound is one or more of acrylamide, N,N-dimethylacrylamide, potassium acrylamide benzoate, N-vinylformamide, and N-hydroxymethylacrylamide.

[0050] In some preferred embodiments, the initiator includes one or more of ammonium persulfate, potassium persulfate, azobisisobutyronitrile (AIBN), benzoyl peroxide, and an ammonium persulfate-sodium bisulfite complex system; the amount of the initiator added is 0.1% to 5% of the total mass of the monomers.

[0051] In some preferred embodiments, the heating temperature in step (4) is 40~70°C, and the reaction time is 0.5~4 hours. For example, the heating temperature is 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, or 70°C, or any value between any two of the above; the reaction time is 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, or 4 hours, or any value between any two of the above.

[0052] In some preferred embodiments, the ratio of aromatic compounds and / or amide compounds to water is 1:(2~10). For example, the ratio of aromatic compounds and / or amide compounds to water is 1:10, 1:5, 3:10, 2:5 or 1:2, or any value between any two of the above.

[0053] In some preferred embodiments, the mass ratio of the ester compound, the aromatic compound, and the amide compound is (20~35):(5~25):(10~20). For example, the mass ratio of the ester compound, the aromatic compound, and the amide compound is 20:5:10, 25:5:10, 30:5:10, 35:5:10, 20:10:10, 20:15:10, 20:20:10, 20:25:10, 20:5:15, 20:5:20, or any value between any two of the above.

[0054] (5) The emulsion is dropped into the prepolymer and heated to continue the reaction to obtain the polymer.

[0055] In this step, an emulsion of ester monomers containing unsaturated double bonds is dropwise added to a prepolymer containing active chain ends. Under heating and the action of an initiator, the ester monomers in the emulsion undergo a graft copolymerization reaction with the prepolymer. The long-chain alkyl groups of the ester monomers are chemically grafted onto the main chain or side chain of the prepolymer, thereby forming an amphiphilic polymer that simultaneously contains hydrophilic (from sulfonic acid groups, amide groups, etc. in the prepolymer) and lipophilic (from the long-chain alkyl groups of the ester monomers) segments, which is the final product, the wetting and dispersing agent.

[0056] In some preferred embodiments, the heating temperature is 50~80℃, and the reaction time is 1~6 hours. For example, the heating temperature is 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, or 80℃, or any value between any two of the above; the reaction time is 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours, or any value between any two of the above.

[0057] (6) Adding a polymerization inhibitor to terminate the reaction yields a polymer, which is then precipitated, centrifuged, and dried to obtain a solid powder.

[0058] Adding polymerization inhibitors is to capture polymer chain free radicals, rapidly terminate chain growth reactions, control polymer molecular weight, prevent excessive cross-linking or degradation, and ensure stable product performance.

[0059] In some preferred embodiments, the polymerization inhibitor includes one or more of hydroquinone, tert-butylcatechol, TEMPO, and ethylenediaminetetraacetic acid.

[0060] In some preferred embodiments, the amount of the polymerization inhibitor added is 0.001% to 1% of the total mass of the polymer.

[0061] More preferably, when the polymerization inhibitor is a phenolic compound, the amount added is 0.01%~0.5%; when the polymerization inhibitor is TEMPO, the amount added is 0.001%~0.1%.

[0062] In some preferred embodiments, the polymer is added to the precipitation solution, stirred for 10 minutes, centrifuged and the supernatant is discarded. The operation is repeated, and the mixture is vacuum dried and ground to obtain a white polymer solid powder.

[0063] The precipitate solution is anhydrous ethanol, acetone, sodium chloride aqueous solution (10% w / w) or n-hexane-acetone mixture (volume ratio 1:1), and its volume ratio to the polymerization reaction solution is 1:2 to 1:4. The precipitation process is controlled by vacuum drying temperature of 30 to 65°C and standing time of 4 to 12 hours.

[0064] The wetting and dispersing agent prepared according to the method of the present invention can significantly reduce the adhesion of oil sand asphalt to drill pipes and drill tools, while dispersing oil sand particles, reducing the problems of bottom hole asphalt deposition and surface adhesion to vibrating screens, thereby improving drilling efficiency and reducing equipment energy consumption and maintenance costs.

[0065] In some preferred embodiments, the wetting and dispersing agent and the encapsulating agent are compounded in a mass ratio of 2:1 to 10:1.

[0066] In some preferred embodiments, the encapsulating agent includes one or more of lignin sulfonate, sulfonated pitch, mixed metal layered hydroxide (MMH), salt-modified starch, nano silica, and polyacrylamide (PAM).

[0067] When the wetting and dispersing agent is combined with the encapsulating agent, particle agglomeration can be prevented through a dual stabilizing effect of electrostatics and steric hindrance. Specifically, the sulfonic acid groups of lignin sulfonate help maintain the charge density on the particle surface, while nano-silica forms a rigid steric barrier, effectively inhibiting flocculation at high temperatures. Therefore, the combined use of the wetting and dispersing agent and the encapsulating agent of this invention further improves wellbore stability and drilling efficiency.

[0068] In another aspect, the present invention also provides a water-based drilling fluid comprising a wetting and dispersing agent prepared according to the method of the present invention.

[0069] In some preferred embodiments, the water-based drilling fluid contains 0.1-2% by mass of wetting and dispersing agent, for example, 0.1%, 0.3%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, 1.5%, 1.7% or 2%, or any value between any two of the above.

[0070] Furthermore, the present invention also provides a method for preparing the above-mentioned water-based drilling fluid, comprising: (1) Add the above wetting and dispersing agent to the base slurry and stir for 30-60 minutes; (2) Adjust the pH to 8-10, add functional additives, and continue to stir evenly to obtain water-based drilling fluid.

[0071] In some preferred embodiments, the base slurry is bentonite slurry, and the wetting and dispersing agent is stirred in the bentonite slurry at a rate of 800~1200 rpm for 30~60 min.

[0072] Optionally, the functional additives include, but are not limited to, filtration loss reducers (such as sulfonated lignite) and thickeners (such as xanthan gum).

[0073] When wetting and dispersing agents are compounded with encapsulating agents, simply add the wetting and dispersing agents and encapsulating agents to the base slurry in sequence and stir.

[0074] In some preferred embodiments, the method for preparing the water-based drilling fluid of the present invention further includes: testing the rheological properties, filtration loss, and inhibition performance of the water-based drilling fluid after high-temperature aging.

[0075] In practice, the wetting and dispersing agent of the present invention has good miscibility with drilling fluid and does not significantly affect the performance of drilling fluid.

[0076] Example The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments, unless otherwise specified, were performed according to conventional methods and conditions. The raw materials used in the following embodiments were all commercially available.

[0077] Example 1 (1) Mix 20 parts of octadecyl acrylate with 1 part of Tween 80 to prepare the first solution; (2) Mix 40 parts of deionized water with 1 part of Tween 80 to prepare the second solution; (3) At a speed of 10,000 rpm, the first solution was added dropwise to the second solution for emulsification, and the mixture was stirred for 10 minutes to obtain an emulsion; (4) Add 15 parts of sodium p-styrene sulfonate and 10 parts of acrylamide and 200 parts of deionized water to a three-necked flask and stir until homogeneous; add 0.5 parts of the initiator ammonium persulfate-sodium bisulfite composite system, heat to 60°C and react for 2 hours to obtain the prepolymer; (5) The emulsion is dripped into the prepolymer and heated to 60°C for 4 hours to obtain the polymer; (6) Add 0.1 parts hydroquinone to terminate the reaction, precipitate the product with acetone, centrifuge and dry to obtain a white powdery wetting and dispersing agent.

[0078] Example 2 (1) Mix 25 parts of octadecyl methacrylate with 1 part of emulsifier Tween 20 to prepare the first solution; (2) Mix 50 parts of deionized water with 1.5 parts of emulsifier Tween 20 to prepare a second solution; (3) While stirring at 10,000 rpm, the first solution was added dropwise to the second solution for emulsification. The mixture was stirred for 10 minutes to obtain an emulsion. (4) Add 12 parts of acrylamide and 10 parts of sulfonated styrene and 250 parts of deionized water to a three-necked flask and stir until homogeneous; add 0.6 parts of potassium persulfate initiator, heat to 65°C and react for 4 hours to obtain the prepolymer; (5) The emulsion obtained in step (3) is added dropwise into the above prepolymer and the reaction is continued at 65°C for 3 hours; (6) After the reaction is completed, cool to room temperature and add 0.1 parts of tert-butylcatechol as a polymerization inhibitor to terminate the reaction; precipitate the product with anhydrous ethanol, centrifuge and dry to obtain a white powdery wetting and dispersing agent.

[0079] Example 3 (1) Mix 30 parts of octadecyl acrylate with 1.5 parts of emulsifier Span 80 to prepare the first solution; (2) Mix 100 parts of deionized water with 3 parts of emulsifier Span 80 to prepare a second solution; (3) While stirring at 10,000 rpm, the first solution was added dropwise to the second solution for emulsification. The mixture was stirred for 10 minutes to obtain an emulsion. (4) Add 20 parts of sodium p-styrene sulfonate and 15 parts of acrylamide and 150 parts of deionized water to a three-necked flask and stir until homogeneous; add 0.8 parts of initiator azobisisobutyronitrile (AIBN), heat to 70°C and react for 3 hours to obtain the prepolymer; (5) The emulsion obtained in step (3) is added dropwise into the above prepolymer and the reaction is continued at 70°C for 5 hours; (6) After the reaction is completed, cool to room temperature and add 0.1 parts of hydroquinone as a polymerization inhibitor to terminate the reaction; precipitate the product with sodium chloride aqueous solution (10% w / w), centrifuge and dry to obtain a white powdery wetting and dispersing agent.

[0080] Example 4 (1) Mix 18 parts of octadecyl methacrylate with 0.5 parts of emulsifier Tween 80 to prepare the first solution; (2) Mix 100 parts of deionized water with 3 parts of emulsifier Tween 80 to prepare the second solution; (3) At a speed of 10,000 rpm, the first solution is added dropwise to the second solution for emulsification, and the mixture is stirred for 10 minutes to obtain an emulsion; (4) Add 15 parts of styrene and 12 parts of N,N-dimethylacrylamide and 300 parts of deionized water to a three-necked flask and stir until homogeneous; add 0.5 parts of potassium persulfate initiator, heat to 70°C and react for 3 hours to obtain the prepolymer; (5) The emulsion obtained in step (3) is added dropwise into the above prepolymer and the reaction is continued at 70°C for 5 hours; (6) After the reaction is completed, cool to room temperature and add 0.1 part hydroquinone as a polymerization inhibitor to terminate the reaction; precipitate the product with acetone, centrifuge and dry to obtain a white powdery wetting and dispersing agent.

[0081] Example 5 (1) Mix 20 parts of monooctadecyl maleate with 0.5 parts of sodium dodecyl sulfate emulsifier to prepare the first solution; (2) Mix 100 parts of deionized water with 3 parts of emulsifier sodium dodecyl sulfate to prepare a second solution; (3) At a speed of 10,000 rpm, the first solution is added dropwise to the second solution for emulsification, and the mixture is stirred for 10 minutes to obtain an emulsion; (4) Add 20 parts of vinylpyridine and 15 parts of potassium acrylamide benzoate and 150 parts of deionized water to a three-necked flask and stir until homogeneous; add 0.2 parts of ammonium persulfate and 0.2 parts of sodium bisulfite initiator, heat to 50°C and react for 3 hours to obtain the prepolymer; (5) The emulsion obtained in step (3) is added dropwise into the above prepolymer and the reaction is continued at 55°C for 5 hours; (6) After the reaction is completed, cool to room temperature and add 0.1 part hydroquinone as a polymerization inhibitor to terminate the reaction; precipitate the product with acetone, centrifuge and dry to obtain a white powdery wetting and dispersing agent.

[0082] Example 6 (1) Mix 15 parts of vinyl acetate with 1.0 part of emulsifier Tween 80 to prepare the first solution; (2) Mix 70 parts of deionized water with 1.5 parts of emulsifier Tween 80 to prepare a second solution; (3) At a speed of 10,000 rpm, the first solution is added dropwise to the second solution for emulsification, and the mixture is stirred for 10 minutes to obtain an emulsion; (4) Add 25 parts of acrylamide benzenesulfonic acid and 10 parts of N-vinylformamide and 100 parts of deionized water to a three-necked flask and stir until homogeneous; add 0.5 parts of potassium persulfate initiator, heat to 50°C and react for 3 hours to obtain the prepolymer; (5) The emulsion obtained in step (3) is added to the above prepolymer and the reaction is continued at 50°C for 5 hours; (6) After the reaction is completed, cool to room temperature and add 0.1 part hydroquinone as a polymerization inhibitor to terminate the reaction; precipitate the product with acetone, centrifuge and dry to obtain a white powdery wetting and dispersing agent.

[0083] Example 7 (1) Mix 10 parts of octadecyl methacrylate, 15 parts of vinyl acetate and 0.5 parts of sodium dodecyl sulfate emulsifier to prepare the first solution; (2) Mix 100 parts of deionized water with 2 parts of emulsifier sodium dodecyl sulfate to prepare a second solution; (3) At a speed of 10,000 rpm, the first solution is added dropwise to the second solution for emulsification, and the mixture is stirred for 10 minutes to obtain an emulsion; (4) Add 15 parts of sodium p-styrene sulfonate and 15 parts of acrylamide to an aqueous solution of 300 parts of deionized water in a three-necked flask and stir until homogeneous; add 0.5 parts of ammonium persulfate as an initiator, heat to 70°C and react for 2 hours to obtain the prepolymer; (5) The emulsion obtained in step (3) is added dropwise into the above prepolymer and the reaction is continued at 70°C for 4 hours; (6) After the reaction is completed, cool to room temperature and add 0.05 parts of tert-butylcatechol as a polymerization inhibitor to terminate the reaction; precipitate the product with anhydrous ethanol, centrifuge and dry to obtain a white powdery wetting and dispersing agent.

[0084] Comparative Example 1 Commercially available wetting and anti-sticking agent 1: purchased from Zhengzhou Jingyuan Slurry Materials Co., Ltd., product number FT-342.

[0085] Comparative Example 2 Commercially available wetting and anti-sticking agent 2: purchased from Qingzhou Tianyi Chemical Co., Ltd., product number FT-342.

[0086] Comparative Example 3 Commercially available wetting and anti-sticking agent 3: purchased from Puyang Meijing Chemical Materials Co., Ltd., product number DWF-I.

[0087] Performance testing 1. Contact Angle Reduction Rate Test 1.1 Standards The contact angle test clause in SY / T 5613-2019 "Evaluation Method for Shale Inhibitors in Drilling Fluids" was referenced and optimized in combination with the characteristics of the oil sand asphalt system.

[0088] 1.2 Test Methods The N80 steel sheet was successively polished with 400#, 800#, and 1200# sandpaper, ultrasonically degreased with anhydrous ethanol for 10 min, dried, and then evenly coated with Canadian oil sand asphalt. It was then placed in a 60℃ oven for 2 h to cure, thus obtaining a hydrophobic asphalt steel sheet sample.

[0089] Prepare drilling fluid containing 0.3% of the target wetting and dispersing agent according to the specified ratio (base fluid is water + 5% sodium bentonite + 0.8% lignin cellulose, hydrated for 24 h), and divide it into a blank group and an additive group. After stirring evenly, let it stand for hydration for 24 h and adjust the pH to 8.

[0090] On a contact angle measuring instrument, 2 μL of deionized water was dropped onto the surface of the asphalt steel sheet, and the initial contact angle θ0 was recorded. This was repeated three times, and the average value was taken. The asphalt steel sheet sample was completely immersed in the additive-based slurry (or blank slurry) for 30 minutes. After removal, the surface liquid was dried with nitrogen gas, and the contact angle θ1 of the water droplet on the sample surface after treatment was immediately measured. This was repeated three times, and the average value was taken. The contact angle reduction rate was calculated using the following formula: Contact angle reduction rate (%) = (θ0 - θ1) / θ0 × 100%. 1.3 Test Results Table 1 shows the contact angle reduction rate of the wetting and dispersing agents of Examples 1-7 and Comparative Examples 1-3.

[0091] The initial contact angle θ0 was tested to be 82°.

[0092] Table 1 Summary of contact angle reduction rate.

[0093]

[0094] As can be seen from the above, the comparative experiments of the wetting and dispersing agents in Examples 1 to 7 with commercially available wetting and anti-sticking agents show the following advantages: (1) Contact angle reduction rate and contact angle: The contact angle reduction rate of the wetting and dispersing agent of the present invention is significantly higher than that of commercially available products, which meets the wetting requirements of oil sand with high bitumen content; (2) Drill string adhesion reduction rate: Test results show that the drill string adhesion reduction rate of Example 5 is 90.75%, and the drill string adhesion reduction rate of Comparative Example 2 of commercial products is 21.2%, which significantly reduces drilling energy consumption and equipment wear.

[0095] 2. Adhesion rate test 2.1 Test Method The wetting and dispersing agent of Example 5 was prepared in proportions of 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, and 0.30% to the target drilling fluid (base slurry is water + 5% sodium bentonite + 0.8% lignin cellulose, hydrated for 24 h). It was divided into a blank group and an additive group. After stirring evenly, the mixture was allowed to stand for hydration for 24 h and the pH was adjusted to 8.

[0096] Wipe the 306# steel bar or stainless steel aging tank with anhydrous ethanol, dry it in a 60℃ oven for 2 hours, cool it to room temperature, and weigh it. Record the initial mass: the steel bar is recorded as m1, and the aging tank as m0. Accurately weigh the set amount of wetting and dispersing agent, prepare a 300 mL aqueous solution, stir at 500 rpm for 30 minutes until completely dissolved, and transfer it to the aging tank. Add 30.0 g of oil sand sample. If testing with a steel bar, add the pretreated steel bar simultaneously. Seal the tank and place it in a roller heating furnace for hot rolling aging at 50℃ for 0.5 hours (aging furnace speed 50 rpm). After aging, remove the steel bar or pour out the slurry from the aging tank, rinse with tap water to remove loose oil sand, dry it, and weigh it again: the steel bar is recorded as m2, and the aging tank as m3.

[0097] The adhesion rate of the steel rod and the adhesion rate of the aging tank are calculated using the following formulas: Steel rod adhesion rate (%) = (m2 - m1) / 30.0g × 100% Adhesion rate of aging tank (%) = (m3- m0) / 30.0g× 100%.

[0098] 2.2 Test Results Figure 1 and Figure 2 The adhesion rates of steel bars and aging tanks under different dosages are shown. Six dosage gradients of 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, and 0.30% were set, and curves were plotted with the dosage of wetting and dispersing agent as the x-axis and the adhesion rate as the y-axis. The data shows that as the dosage of wetting and dispersing agent increases, the adhesion rate of the aging tank shows a significant decreasing trend, which intuitively reflects the positive correlation between the anti-adhesion effect of the wetting and dispersing agent of this invention and the dosage.

[0099] Figure 3 and Figure 4 The images show a direct comparison of the effects of the wetting and dispersing agent in Example 5 on steel bars and aging tanks. Figure 3(a) Before the addition of the wetting and dispersing agent, the steel rod was severely coated with asphalt after hot rolling aging in the blank system; (b) After the addition of 0.3% of the wetting and dispersing agent of Example 5, the surface of the steel rod was clean and there was no obvious adhesion. Figure 4 (a) Before the addition of the wetting and dispersing agent, the inner wall of the aging tank was severely adhered; (b) After the addition of 0.3% of the wetting and dispersing agent of Example 5, there was basically no adhesion inside the aging tank, further confirming the anti-adhesion effect of the wetting and dispersing agent of the present invention.

[0100] 3. Thermogravimetric analysis test 3.1 Test Method The wetting and dispersing agent samples (5–10 mg) prepared in Example 5 were analyzed using a thermogravimetric analyzer under the conditions of nitrogen flow rate of 50 mL / min, heating rate of 10 °C / min and temperature range of room temperature to 450 °C, and the mass change curve with temperature was recorded.

[0101] 3.2 Test Results Thermogravimetric analysis of wetting and dispersing agents is shown in [link to analysis]. Figure 5 The test results show that the wetting and dispersing agent prepared in Example 5 has excellent thermal stability at high temperatures, providing a theoretical basis for its application in high-temperature downhole environments.

[0102] 4. Rheological testing 4.1 Test Method The wetting and dispersing agent of Example 5 was prepared at a ratio of 0.30% to the target drilling fluid (base slurry consisting of water + 5% sodium bentonite + 0.8% lignin cellulose + 0.4% nano silica, hydrated for 24 h). It was divided into a blank group and an additive group. After stirring evenly, the mixture was allowed to stand for hydration for 24 h, and the pH was adjusted to 8.

[0103] The rheological properties and filtration loss of the drilling fluid after hot rolling were determined in accordance with the test procedures specified in "Field Testing of Drilling Fluids for Petroleum and Natural Gas Industry - Part 1: Water-based Drilling Fluids" (GB / T16783.1—2014).

[0104] 4.2 Test Results When the test conditions were 120℃ / 16 h aging (aging furnace speed 50 rpm), the drilling fluid showed good stability.

[0105]

[0106] After adding 0.3% wetting and dispersing agent, the apparent viscosity of the drilling fluid increased from 12 mPa·s to 16 mPa·s, the API filtration loss decreased from 15 mL to 9 mL, and the adhesion rate decreased significantly from 63.5% to 5.2%. This indicates that the treatment agent can improve the filtration loss reduction performance of the drilling fluid while moderately increasing viscosity, and it has good stability after aging at 120℃ for 16 h.

[0107] The present invention has been disclosed above with reference to preferred embodiments. However, those skilled in the art should understand that these embodiments are merely illustrative of the invention and should not be construed as limiting its scope. It should be noted that any variations and substitutions equivalent to these embodiments should be considered to be covered within the scope of the claims. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for preparing a wetting and dispersing agent, characterized in that, include: (1) Mix the ester compound with the first emulsifier to prepare the first solution; (2) Mix deionized water with the second emulsifier to prepare the second solution; (3) Under stirring, the first solution is added dropwise to the second solution to emulsify, thereby obtaining an emulsion; (4) Dissolve aromatic compounds and / or amide compounds with an initiator in water and react them under heating to obtain a prepolymer; (5) The emulsion is dripped into the prepolymer and heated to continue the reaction to obtain the polymer; (6) Add an inhibitor to terminate the reaction, and after precipitation, centrifugation and drying, a solid powder is obtained.

2. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The mass ratio of the ester compound, the aromatic compound, and the amide compound is (5~35):(5~25):(10~20).

3. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The mass ratio of the ester compound to the first emulsifier is 20:1 to 60:1; the mass ratio of the deionized water to the second emulsifier is 15:1 to 50:1; and the mass ratio of the first emulsifier to the second emulsifier is (0.8 to 1.2):

1.

4. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The amount of the initiator added is 0.1% to 5% of the total mass of the monomer; the amount of the polymerization inhibitor added is 0.001% to 1% of the total mass of the polymer.

5. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The ester compound is one or more of octadecyl acrylate, octadecyl methacrylate, monooctadecyl maleate, and vinyl acetate.

6. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The aromatic compound is one or more of styrene, vinylpyridine, acrylamide benzenesulfonic acid, and sodium p-styrenesulfonate.

7. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The amide compound is one or more of acrylamide, N,N-dimethylacrylamide, potassium acrylamide benzoate, N-vinylformamide, and N-hydroxymethylacrylamide.

8. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The initiator includes one or more of the following: ammonium persulfate, potassium persulfate, azobisisobutyronitrile, benzoyl peroxide, and an ammonium persulfate-sodium bisulfite composite system.

9. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The first emulsifier and the second emulsifier are each independently selected from one or more of the following: sodium laurylate, sodium stearate, sodium palmitate, sodium lauryl sulfonate, sodium alkylbenzene sulfonate, sodium dodecyl sulfate, sodium stearyl ether sulfate, sodium phosphate salt, potassium alkyl phosphate salt, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, sorbitan laurate, sorbitan monooleate, Tween 20, Tween 80, cocamidopropyl betaine, lauramidopropyl betaine, cocoyl hydroxysulfonate betaine, sodium lauroyl glutamate, and sodium cocoyl sarcosinate.

10. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The polymerization inhibitor includes one or more of hydroquinone, tert-butylcatechol, TEMPO, and ethylenediaminetetraacetic acid.

11. The method for preparing the wetting and dispersing agent according to claim 1, characterized in that, The heating temperature in step (4) is 40~70℃ and the reaction time is 0.5~4 hours; the heating temperature in step (5) is 50~80℃ and the reaction time is 1~6 hours.

12. A wetting and dispersing agent, characterized in that, It is prepared by the method of any one of claims 1 to 11.

13. The wetting and dispersing agent according to claim 12, characterized in that, The wetting and dispersing agent and the encapsulating agent are compounded in a mass ratio of 2:1 to 10:1; The encapsulating agent includes one or more of lignin sulfonate, mixed metal layered hydroxide, modified starch, nano silica, and polyacrylamide.

14. A water-based drilling fluid, characterized in that, Includes the wetting and dispersing agent as described in any one of claims 12 or 13.

15. The method for preparing the water-based drilling fluid according to claim 14, characterized in that, include: (1) Add the wetting and dispersing agent according to any one of claims 12 or 13 to the base slurry and stir for 30 to 60 minutes; (2) Adjust the pH to 8-10, add functional additives, and continue to stir evenly to obtain water-based drilling fluid.

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