A high-temperature resistant multifunctional liquid desulfurizer for drilling fluid and its preparation method

Abstract

The present patent application discloses a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid and a preparation method thereof. The desulfurizer comprises the following raw materials in parts by weight: main agent 1: 1,3,5-tributyl-hexahydro-s-triazine, 30-40%; main agent 2: triethanolamine, 10-15%; main agent 3: nano zinc oxide, 10-15%; solvent: sulfolane, 5-10%; adsorbent: graphene oxide, 10-15%; suspending agent: carboxymethyl cellulose, 0.1-0.2%; defoaming agent: one or more of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, and methylphenyl silicone oil, 0.1-0.5%; dispersant: one or two of sodium polyacrylate and sodium polycarboxylate, 1-5%; and the remainder is water. The desulfurizer of the present invention is based on the high-efficiency desulfurization of triazine and alcoholamine liquid desulfurizers, and introduces graphene oxide and nano zinc oxide to improve the adsorption capacity and temperature resistance of the desulfurizer, reduce the drilling fluid loss, and improve the rheological properties. It can be used in both water-based and oil-based drilling fluids, has high desulfurization efficiency and fast speed, and meets the needs of on-site drilling desulfurization construction.

Description

Technical Field

[0001] The invention relates to the field of desulfurization in oil and gas fields, and in particular to a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid and a preparation method thereof. Background Art

[0002] Hydrogen sulfide (H2S) is a highly toxic, flammable, colorless gas with a rotten egg odor. Exposure to concentrations of 10 ppm can cause eye irritation. At 100 ppm, exposure can cause coughing, eye irritation, and loss of smell within 3-15 minutes. At 1000 ppm, unconsciousness can occur immediately, resulting in permanent brain damage or even brain death.

[0003] Currently, my country's Sichuan Basin, Tarim Basin, and Ordos Basin all contain high-sulfur gas reservoirs. During drilling in high-sulfur gas reservoirs, hydrogen sulfide intrusion into the drilling fluid can cause the following hazards: ① It can reduce the pH or alkalinity of the drilling fluid, affecting its performance, deteriorating its rheological and filtration properties, affecting cuttings transport, wellbore stability, and causing pressure surges during tripping and drilling. ② It can corrode drill tools, causing hydrogen embrittlement of metals, leading to sudden breakage of downhole tubing, failure of wellhead equipment, and rupture of surface manifolds and instruments, potentially causing uncontrolled blowouts or fires. ③ Hydrogen sulfide can circulate with the drilling fluid and diffuse into the air, causing poisoning and other personal injuries.

[0004] Therefore, when encountering H2S gas intrusion during oil and gas drilling, timely removal of H2S from the drilling fluid is crucial. Currently, desulfurizers are primarily added to the drilling fluid, relying on physical adsorption or chemical reactions to improve the removal efficiency of H2S in water-based or oil-based drilling fluids. Desulfurizers typically include solid and liquid desulfurizers. Solid desulfurizers include copper-, iron-, and zinc-based desulfurizers, but they suffer from low desulfurization efficiency, flocculation and precipitation, and impacts on drilling fluid rheology and filtration. Liquid desulfurizers, primarily triazines and alcoholamines, remove sulfur primarily through chemical reactions, resulting in high desulfurization efficiency. However, they suffer from disadvantages such as foaming, product instability, and poor temperature resistance. Currently, no patents have been published for desulfurizers suitable for both water-based and oil-based drilling fluids. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, the present invention aims to provide a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid and a preparation method thereof. The desulfurizer prepared by the present invention has the advantages of both liquid and solid desulfurizers. On the basis of the efficient desulfurization of triazine and alcohol amine liquid desulfurizers, the advantages of nanomaterials are utilized to introduce graphene oxide and nano zinc oxide, thereby improving the adsorption capacity and temperature resistance of the desulfurizer, reducing the filtration loss of drilling fluid, and improving the rheological properties. The desulfurizer can be used in both water-based and oil-based drilling fluids, has high desulfurization efficiency and fast speed, and meets the needs of on-site drilling desulfurization construction.

[0006] The technical solution adopted by the present invention is as follows: A high-temperature resistant multifunctional liquid desulfurizer for drilling fluid, comprising the following raw material proportions in parts by weight:

[0007] Main agent 1: 1,3,5-tributyl-hexahydro-s-triazine, 30-40%;

[0008] Main agent 2: triethanolamine, 10-15%;

[0009] Main agent 3: nano zinc oxide, 10-15%;

[0010] Solvent: sulfolane, 5-10%;

[0011] Adsorbent: graphene oxide, 10-15%;

[0012] Suspending agent: carboxymethyl cellulose, 0.1-0.2%;

[0013] Defoaming agent: one or more of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, methylphenyl silicone oil, 0.1-0.5%;

[0014] Dispersant: one or both of sodium polyacrylate and sodium polycarboxylate, 1-5%;

[0015] The rest is water.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The desulfurizer prepared by the above-mentioned ratio has the advantages of both liquid and solid desulfurizers. On the basis of the high-efficiency desulfurization of triazine and alcoholamine liquid desulfurizers, it takes advantage of the advantages of nanomaterials and introduces graphene oxide and nano zinc oxide to fully enhance the adsorption capacity and temperature resistance of the desulfurizer, reduce drilling fluid loss, improve rheological properties, and can be used in both water-based and oil-based drilling fluids. It has high desulfurization efficiency and fast speed, meeting the needs of on-site drilling desulfurization construction. Specifically, it is embodied in:

[0018] The nitrogen and carbon atoms on the 1.1,3,5-tributyl-hexahydro-s-triazine molecule alternate, and the nitrogen atoms have an electron-withdrawing inductive effect. Protonation of the nitrogen atoms increases the electrophilicity of the carbon atoms on the six-membered ring. In the presence of H2S nucleophiles, the electrophilicity of triazine encourages the nucleophile to attack, resulting in a rapid and highly selective reaction and excellent sulfur removal.

[0019] 2. Graphene oxide, as an adsorbent, can form a multifunctional nanocomposite structure with nano-zinc oxide. Graphene oxide has a significantly higher specific surface area and a layered structure, resulting in excellent chemical and physical properties. Its loose, porous, sponge-like powder exhibits excellent adsorption, a large adsorption capacity, and superior sulfur removal. Furthermore, this multifunctional nanocomposite structure can improve the rheological and fluid loss properties of drilling fluids, imparting them with favorable rheological properties. Increasing shear stress improves the fluid's rock-carrying capacity and reduces fluid loss, mitigating the negative effects of other desulfurizers on drilling fluid performance. Furthermore, graphene oxide and nano-zinc oxide exhibit excellent temperature resistance, ensuring high-temperature sulfur removal.

[0020] 3. Triethanolamine reacts with hydrogen sulfide to convert hydrogen sulfide into sulfide ions, and then adsorbs them to achieve the purpose of sulfur removal.

[0021] 4. The nano zinc oxide added in this scheme also has nano effect, high specific surface area and significant chemical reaction characteristics, which can quickly adsorb hydrogen sulfide in large quantities and produce chemical reactions to generate sulfides, thereby achieving the purpose of removing hydrogen sulfide.

[0022] 5. The sulfolane added in this solution absorbs hydrogen sulfide by physical adsorption, has good solubility for H2S, and has good selectivity for H2S.

[0023] 6. Adding the suspending agent and dispersant of this solution can make the graphene oxide and nano zinc oxide uniformly and stably dispersed and suspended in the solution, so that the overall desulfurization performance of the desulfurizer is uniform and stable.

[0024] 7. Since the contact between hydrogen sulfide and drilling fluid will produce a large number of bubbles, which will hinder the full mixing of gas and liquid, adding an appropriate amount of defoaming agent can eliminate the large number of bubbles generated and ensure a fast and efficient desulfurization effect.

[0025] As a preferred embodiment of the present invention, the raw material ratio is:

[0026] Main agent 1: 1,3,5-tributyl-hexahydro-s-triazine, 30-40%;

[0027] Main agent 2: triethanolamine, 10-15%;

[0028] Main agent 3: nano zinc oxide, 10-15%;

[0029] Solvent: sulfolane, 5-10%;

[0030] Adsorbent: graphene oxide, 10-15%;

[0031] Suspending agent: carboxymethyl cellulose, 0.1-0.2%;

[0032] Defoaming agent: one or more of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, methylphenyl silicone oil, 0.1-0.5%;

[0033] Dispersant: one or both of sodium polyacrylate and sodium polycarboxylate, 1-5%;

[0034] The rest is water.

[0035] The desulfurizer prepared by adopting the above raw material ratio has more stable properties and better comprehensive performance.

[0036] As a preferred embodiment of the present invention, the 1,3,5-tributyl-hexahydro-s-triazine is prepared by the following method:

[0037] (1) Add butylamine and ethanol solution into a reaction vessel with a volume ratio of butylamine to ethanol of 1:1, stir with a stirring device and adjust the speed to 450-550 rpm / min, and control the temperature to 18-25°C;

[0038] (2) adding formaldehyde dropwise at a rate of 0.8-1.2 mL / min. The amount of formaldehyde added is the same as that of butylamine. After the addition of formaldehyde is complete, the reaction is continued for 2.5-3.5 hours to obtain a crude product.

[0039] (3) Ethyl acetate solution and distilled water are added to the crude product for extraction, and the crude product is allowed to stand for separation. The organic layer is retained and distilled under reduced pressure. The obtained product is purified again by column chromatography to obtain 1,3,5-tributyl-hexahydro-s-triazine.

[0040] The 1,3,5-tributyl-hexahydro-s-triazine prepared by the above method has few impurities and high purity. When it is used as a main agent and mixed with other components, the by-products produced can be minimized, and the desulfurization performance of the prepared desulfurizer is better.

[0041] As a preferred embodiment of the present invention, the graphene oxide is prepared by the following method:

[0042] (1) 150-180 mg of graphite powder was mixed with 18-25 mL of sulfuric acid, stirred at 20-30° C., and 6-10 mL of nitric acid was added. After stirring for 20-25 h, 40 mL of distilled water was added, and then centrifuged. The precipitate was washed with distilled water for at least three times and dried.

[0043] (2) Take 35-45 mg of the dried product from step (1), add 8-12 mL of sulfuric acid, stir and mix at 12-18°C, add 100-140 mg of potassium permanganate during the process, stir for 20-25 h, and add 25-35 mL of distilled water during the process;

[0044] (3) Add 5-8 mL of hydrogen peroxide and centrifuge for 30-45 minutes to obtain a precipitate;

[0045] (4) The precipitate was washed at least three times with 3-5 mL of chloric acid and then washed at least three times with deionized water;

[0046] (5) Add 35-45 mg of NaHCO 3 to the resulting mixture, adjust the pH to 7-7.5, centrifuge to obtain a precipitate, and dry the precipitate to obtain graphene oxide.

[0047] The graphene oxide prepared by the above method has a significant layered structure and a large specific surface area. When used as an adsorbent, it can disperse nano-zinc oxide to the greatest extent to form a nano-composite structure, and the prepared desulfurizer has better desulfurization performance.

[0048] The present invention also provides a method for preparing a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid, comprising the following steps:

[0049] (1) Place 1,3,5-tributyl-hexahydro-s-triazine, triethanolamine, and sulfolane in a reaction kettle, heat to 35-45°C, and stir until uniformly mixed;

[0050] (2) Add defoamer and dispersant and continue stirring until the mixture is uniform;

[0051] (3) Add suspending agent and stir until the mixture is uniform.

[0052] (4) Adding an adsorbent, nano zinc oxide and water, ultrasonically treating for 0.8-1.2 hours while stirring, and then cooling to room temperature to prepare a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid.

[0053] By adopting the above-mentioned preparation method of the present invention, a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid can be prepared by using desulfurizer raw materials with a special raw material ratio. The desulfurizer has the advantages of both liquid desulfurizers and solid desulfurizers, can be used in both water-based and oil-based drilling fluids, has high desulfurization efficiency and speed, and has strong temperature resistance. It can also reduce the drilling fluid loss and improve the rheological properties.

[0054] The above preparation method adds adsorbent and nano zinc oxide and then conducts ultrasonic treatment for 0.8-1.2 hours while stirring. On the one hand, the nano zinc oxide can be evenly distributed on the surface of graphene oxide and fully compounded with it, and the properties of the two after compounding are stable; on the other hand, the overall performance of the desulfurizer can be more stable. DETAILED DESCRIPTION

[0055] Typical embodiments that embody the features and advantages of the present invention are described in detail in the following description. It should be understood that the present invention is capable of various variations in different embodiments without departing from the scope of the present invention, and that the descriptions and illustrations are intended to be illustrative rather than limiting.

[0056] Example 1

[0057] This embodiment discloses a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid, which comprises the following raw material ratios in parts by weight:

[0058] Main agent 1: 1,3,5-tributyl-hexahydro-s-triazine, 35%;

[0059] Main agent 2: triethanolamine, 12%;

[0060] Main agent 3: nano zinc oxide, 13%;

[0061] Solvent: sulfolane, 8%;

[0062] Adsorbent: graphene oxide, 12%;

[0063] Suspending agent: carboxymethyl cellulose, 0.15%;

[0064] Defoaming agent: one or more of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, and methylphenyl silicone oil, 0.3%;

[0065] Dispersant: one or both of sodium polyacrylate and sodium polycarboxylate, 2%;

[0066] The rest is water.

[0067] Among them, 1,3,5-tributyl-hexahydro-s-triazine is prepared by the following method:

[0068] (1) Add 10 ml of butylamine and 10 ml of ethanol solution into a reaction vessel, stir with a stirring device and adjust the speed to 500 rpm / min, and control the temperature to 20°C;

[0069] (2) Add 10 mL of formaldehyde dropwise at a rate of 1 mL / min. After the addition of formaldehyde is complete, continue the reaction for 3 h to obtain a crude product;

[0070] (3) Ethyl acetate solution and distilled water are added to the crude product for extraction, and the crude product is allowed to stand for separation. The organic layer is retained and distilled under reduced pressure. The obtained product is purified again by column chromatography to obtain 1,3,5-tributyl-hexahydro-s-triazine.

[0071] Wherein, graphene oxide is prepared by the following method:

[0072] (1) 160 mg of graphite powder was mixed with 20 mL of sulfuric acid, stirred at 25°C using a magnetic stirrer, and 8 mL of nitric acid was added. After stirring for 24 h, the precipitate was washed three times with distilled water and finally dried in an oven at 50°C.

[0073] (2) 40 mg of the dried product from step (1) was added to 10 mL of sulfuric acid and stirred at 14°C using a magnetic stirrer. 120 mg of potassium permanganate was added during the mixture, and the mixture was stirred for 24 h. 30 mL of distilled water was added during the mixture.

[0074] (3) Add 6 mL of hydrogen peroxide, and after 45 minutes, centrifuge at 4000 rpm / min for 10 minutes to obtain a precipitate;

[0075] (4) The precipitate was washed three times with 3 mL of chloric acid and then three times with deionized water;

[0076] (5) Add 40 mg of NaHCO 3 to the resulting mixture, adjust the pH to 7-7.5, centrifuge to obtain a precipitate, and dry the precipitate to obtain graphene oxide.

[0077] This embodiment also discloses a method for preparing the high-temperature resistant multifunctional liquid desulfurizer for drilling fluid, comprising the following steps:

[0078] (1) Place 1,3,5-tributyl-hexahydro-s-triazine, triethanolamine, and sulfolane in a stainless steel reactor, heat to 40°C, and stir for 30 minutes until the mixture is uniform;

[0079] (2) Add defoamer and dispersant and continue stirring for 15 minutes until the mixture is uniform;

[0080] (3) Add suspending agent and stir for 30 minutes until the mixture is uniform.

[0081] (4) Adding adsorbent, nano zinc oxide and water, ultrasonically treating for 1 hour while stirring, and then cooling to room temperature to prepare a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid.

[0082] Example 2

[0083] This embodiment discloses a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid, which comprises the following raw material ratios in parts by weight:

[0084] Main agent 1: 1,3,5-tributyl-hexahydro-s-triazine, 30%;

[0085] Main agent 2: triethanolamine, 15%;

[0086] Main agent 3: nano zinc oxide, 10%;

[0087] Solvent: sulfolane, 5%;

[0088] Adsorbent: graphene oxide, 10%;

[0089] Suspending agent: carboxymethyl cellulose, 0.1%;

[0090] Defoaming agent: one or more of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, and methylphenyl silicone oil, 0.1%;

[0091] Dispersant: one or both of sodium polyacrylate and sodium polycarboxylate, 1%;

[0092] The rest is water.

[0093] The 1,3,5-tributyl-hexahydro-s-triazine and graphene oxide used in this embodiment are the same as those in Example 1.

[0094] The desulfurizing agent preparation method of this embodiment comprises the following steps:

[0095] (1) Place 1,3,5-tributyl-hexahydro-s-triazine, triethanolamine, and sulfolane in a stainless steel reactor, heat to 35°C, and stir for 30 minutes until the mixture is uniform;

[0096] (2) Add defoamer and dispersant and continue stirring for 15 minutes until the mixture is uniform;

[0097] (3) Add suspending agent and stir for 30 minutes until the mixture is uniform.

[0098] (4) Adding adsorbent, nano zinc oxide and water, ultrasonic treatment for 0.8 h, stirring at the same time, and then cooling to room temperature to prepare a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid.

[0099] Example 3

[0100] This embodiment discloses a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid, which comprises the following raw material ratios in parts by weight:

[0101] Main agent 1: 1,3,5-tributyl-hexahydro-s-triazine, 40%;

[0102] Main agent 2: triethanolamine, 10%;

[0103] Main agent 3: nano zinc oxide, 15%;

[0104] Solvent: sulfolane, 10%;

[0105] Adsorbent: graphene oxide, 15%;

[0106] Suspending agent: carboxymethyl cellulose, 0.2%;

[0107] Defoaming agent: one or more of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, and methylphenyl silicone oil, 0.5%;

[0108] Dispersant: one or both of sodium polyacrylate and sodium polycarboxylate, 4%;

[0109] The rest is water.

[0110] The 1,3,5-tributyl-hexahydro-s-triazine and graphene oxide used in this embodiment are the same as those in Example 1.

[0111] The desulfurizing agent preparation method of this embodiment comprises the following steps:

[0112] (1) Place 1,3,5-tributyl-hexahydro-s-triazine, triethanolamine, and sulfolane in a stainless steel reactor, heat to 45°C, and stir for 30 minutes until the mixture is uniform;

[0113] (2) Add defoamer and dispersant and continue stirring for 15 minutes until the mixture is uniform;

[0114] (3) Add suspending agent and stir for 30 minutes until the mixture is uniform.

[0115] (4) Adding adsorbent, nano zinc oxide and water, ultrasonic treatment for 1.2 hours while stirring, and then cooling to room temperature to prepare a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid.

[0116] Desulfurization efficiency test of desulfurizer

[0117] The high-temperature resistant multifunctional liquid desulfurizer for drilling fluid prepared by the present invention, the commonly used solid desulfurizer basic zinc carbonate, and the liquid desulfurizer alcohol ether amide complex were added to water-based and oil-based drilling fluids to evaluate their effects on rheology and fluid loss, and to test the desulfurization rate.

[0118] Water-based drilling fluid formula: 4% bentonite slurry

[0119] +0.4%CMC-LV+0.5%KPAM+1%NH4HPAN+3%FT-1+2%SPNH+2%SMP.

[0120] Oil-based drilling fluid formula: white oil + 5% emulsifier HFMO + 20% CaCl2 solution + 3% organic soil HFEL + 5% lime + 5% fluid loss reducer HFLO + 4% ultrafine calcium carbonate.

[0121] The test methods for evaluation are as follows:

[0122] Prepare 400mL of drilling fluid, add a 2% mass concentration of desulfurizer (the drilling fluid in Examples 1-3 uses a high-temperature resistant multifunctional liquid desulfurizer, basic zinc carbonate, and an alcohol ether amide complex), pour it into a special aging tank to prevent hydrogen sulfide pollution, open the aging tank valve stem after sealing, use a 500ppm hydrogen sulfide gas cylinder (the rest is nitrogen) to fill the aging tank with 1MPa hydrogen sulfide gas, and then roll age for 16 hours at a temperature of 150°C. Test the rheology and filtration loss performance of the drilling fluid before and after adding the desulfurizer, and use a pump-suction hydrogen sulfide detector to test the hydrogen sulfide concentration in the aging tank after aging to evaluate the desulfurization efficiency. The high-temperature and high-pressure filtration loss test temperature condition is 150 degrees Celsius. The test results of the evaluation are shown in the following table:

[0123] Table 1 Basic properties and sulfur removal efficiency of water-based drilling fluid

[0124]

[0125]

[0126] Table 2 Basic properties and desulfurization efficiency of oil-based drilling fluid

[0127]

[0128] As can be seen from Tables 1 and 2, the high-temperature resistant multifunctional liquid desulfurizer for drilling fluid of the present invention can be used in both water-based and oil-based drilling fluids, has a temperature resistance of up to 150°C, and has a desulfurization efficiency of >99%. The desulfurization performance is significantly improved, and the rheological properties of the drilling fluid can be improved, the dynamic-plastic ratio is increased, the rock-carrying effect is enhanced, and the filtration loss of the drilling fluid is significantly reduced, thus meeting the technical requirements for desulfurization of drilling fluid in high-sulfur formations on site.

[0129] It can be clearly seen from Tables 1 and 2 that the high-temperature resistant multifunctional liquid desulfurizer for drilling fluid in Examples 1-3 can achieve a desulfurization rate of 100% in water-based and oil-based drilling fluids, while the existing commonly used solid desulfurizer, basic zinc carbonate, has a desulfurization rate of less than 40%, and the commonly used liquid desulfurizer, alcohol ether amide complex, has a desulfurization rate of less than 60%. It can be seen that the desulfurizer prepared by the present invention has a significantly higher desulfurization rate.

[0130] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A high-temperature resistant multifunctional liquid desulfurizer for drilling fluid, characterized in that: Calculated by weight, it includes the following raw material ratios: Main agent 1: 1,3,5-tributyl-hexahydro-s-triazine, 30-40%; Main agent 2: triethanolamine, 10-15%; Main agent 3: nano zinc oxide, 10-15%; Solvent: sulfolane, 5-10%; Adsorbent: graphene oxide, 10-15%; Suspending agent: carboxymethyl cellulose, 0.1-0.2%; Defoaming agent: one or more of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, and methylphenyl silicone oil, 0.1-0.5%; Dispersant: one or both of sodium polyacrylate and sodium polycarboxylate, 1-5%; The rest is water.

2. The high-temperature resistant multifunctional liquid desulfurizer for drilling fluid according to claim 1, characterized in that: The raw material ratio is: Main agent 1: 1,3,5-tributyl-hexahydro-s-triazine, 35-38%; Main agent 2: triethanolamine, 10-12%; Main agent 3: nano zinc oxide, 13-15%; Solvent: sulfolane, 5-8%; Adsorbent: graphene oxide, 10-12%; Suspending agent: carboxymethyl cellulose, 0.15%; Defoaming agent: one or more of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, methylphenyl silicone oil, 0.3-0.5%; Dispersant: one or both of sodium polyacrylate and sodium polycarboxylate, 2-4%; The rest is water.

3. A high temperature resistant multifunctional liquid desulfurizer for drilling fluid according to any one of claims 1-2, characterized in that: The 1,3,5-tributyl-hexahydro-s-triazine is prepared by the following method: (1) Add butylamine and ethanol solution into the reaction vessel, with the volume ratio of butylamine to ethanol being 1:1, stir with a stirring device and adjust the speed to 450-550 rpm / min, and control the temperature to 18-25°C; (2) Add formaldehyde dropwise at a rate of 0.8-1.2 mL / min. The amount of formaldehyde added is the same as that of butylamine. After the addition of formaldehyde is complete, continue the reaction for 2.5-3.5 hours to obtain a crude product. (3) Ethyl acetate solution and distilled water are added to the crude product for extraction, and the crude product is allowed to stand for separation. The organic layer is retained and distilled under reduced pressure. The obtained product is purified again by column chromatography to obtain 1,3,5-tributyl-hexahydro-s-triazine.

4. A high temperature resistant multifunctional liquid desulfurizer for drilling fluid according to any one of claims 1-2, characterized in that: The graphene oxide is prepared by the following method: (1) Mix 150-180 mg of graphite powder with 18-25 mL of sulfuric acid, stir at 20-30 °C, and add 6-10 mL of nitric acid. After stirring for 20-25 hours, wash the precipitate with distilled water for at least three times and dry it. (2) Take 35-45 mg of the dried product from step (1), add 8-12 mL of sulfuric acid, stir and mix at 12-18 °C, add 100-140 mg of potassium permanganate during the process, stir for 20-25 h, and add 25-35 mL of distilled water during the process; (3) Add 5-8 mL of hydrogen peroxide and centrifuge for 30-45 minutes to obtain a precipitate; (4) The precipitate was washed at least three times with 3-5 mL of chloric acid and then washed at least three times with deionized water; (5) Add 35-45 mg of NaHCO3 to the resulting mixture, adjust the pH to 7-7.5, and centrifuge to obtain a precipitate. The dried precipitate is graphene oxide.

5. The method for preparing a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid according to claim 1, characterized in that: The following steps are involved: (1) Place 1,3,5-tributyl-hexahydro-s-triazine, triethanolamine and sulfolane in a reaction kettle, heat to 35-45°C, and stir until mixed uniformly; (2) Add defoamer and dispersant and continue stirring until the mixture is evenly mixed; (3) Add suspending agent and stir until mixed evenly. (4) Add adsorbent, nano zinc oxide and water, ultrasonically treat for 0.8-1.2 hours, stir until the mixture is uniform, and cool to room temperature to prepare a high-temperature resistant multifunctional liquid desulfurizer for drilling fluid.

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