A lubricant, its preparation and use

Abstract

The present application relates to a kind of lubricant and its preparation method and application.The lubricant includes the following components: palm oil base compound, modified organic molybdenum complex, sulfurized olefin and nano tungsten disulfide.The present application designs the component of lubricant, and prepares a kind of high-temperature stability good, environmental protection oil-based drilling fluid lubricant.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field drilling fluid additives, specifically to a lubricant, its preparation method and application, and particularly to a high-temperature lubricant for oil-based drilling fluids suitable for complex working conditions such as ultra-deep wells and horizontal wells with large displacement. It also relates to a composite lubricant and its preparation process that can maintain excellent lubrication performance, thermal stability and environmental friendliness even at a high temperature of 220℃. Background Technology

[0002] As oil and gas exploration extends to deeper formations (>8000m) and shale oil and gas development, extended reach wells face challenges such as bottomhole temperatures exceeding 200℃ and high friction in horizontal sections. Existing technologies suffer from the following problems: 1. High-temperature failure: Traditional graphite / sulfurized alkane lubricants experience carbon chain breakage above 180℃, increasing the lubrication coefficient to over 0.15; 2. Poor compatibility: Additives precipitate at high temperatures (see "Drilling Fluids and Completion Fluids," 2021, Issue 3), leading to a decrease in the dynamic-plastic ratio of the drilling fluid exceeding 30%; 3. Environmental deficiencies: Sulfide content exceeds standards (e.g., the European REACH regulation limits sulfur content to <1.5wt%), and biodegradability is less than 50% (OECD 301B standard); 4. Existing high-temperature lubricants are mostly used in water-based drilling fluids, with limited compatibility and effectiveness in oil-based drilling fluids.

[0003] Therefore, how to prepare a high-temperature stable and environmentally friendly oil-based drilling fluid lubricant has become an urgent problem to be solved. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a lubricant, its preparation method, and its application. By designing the components of the lubricant, a high-temperature stable and environmentally friendly oil-based drilling fluid lubricant has been prepared.

[0005] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a lubricant comprising the following components: a palm oil-based compound, a modified organic molybdenum complex, a sulfurized olefin, and nano-tungsten disulfide.

[0006] In this invention, a composite lubricating film integrating "chemical adsorption-physical deposition-tribochemical reaction" is constructed by synergistic compounding of modified organic molybdenum complex, nano-tungsten disulfide and sulfurized olefins: organic molybdenum generates a MoS2 chemical adsorption film in situ under frictional heat, sulfurized olefins release active sulfur to form an extreme pressure reaction film, and nano-WS2 provides a physical lubrication layer through interlayer slip effect and surface filling effect. The three work together to achieve a low coefficient of friction (<0.08) and high extreme pressure carrying capacity (>900N) across the entire temperature range from room temperature to 220℃. At the same time, the "consumption-regeneration" mechanism of nano-WS2 in sulfur-containing environments endows the lubricating film with excellent high-temperature self-healing performance.

[0007] Preferably, the modified organomolybdenum complex is prepared by a complexation reaction of ammonium thiomolybdate and a C16-C18 (e.g., C17) fatty acid amide.

[0008] In this invention, ammonium thiomolybdate provides highly active molybdenum and sulfur sources, ensuring rapid in-situ generation of a MoS2 lubricating film during friction. The C16-C18 long-chain fatty acid amide not only forms a stable complex structure with molybdenum through its amide groups, improving the product's solubility and dispersibility in oil-based systems, but its long-chain alkyl groups also endow the molecule with excellent oil solubility and interfacial adsorption capacity, enabling the complex to preferentially adsorb onto the metal surface to form an oriented adsorption layer. Furthermore, the moderate length of the C16-C18 carbon chains provides sufficient steric hindrance to prevent complex aggregation and allows for orderly decomposition under frictional heat, controlling the MoS2 generation rate and preventing excessively thick or brittle films. This achieves continuous and stable generation of the MoS2 film at 220°C, significantly improving the extreme pressure anti-wear performance and high-temperature durability of the lubricant.

[0009] Preferably, the modified organic molybdenum complex has a molybdenum content of 8 wt%-10 wt%, for example, it can be 8.3 wt%, 8.6 wt%, 9 wt%, 9.4 wt% or 9.7 wt%, etc.

[0010] Preferably, the sulfur content of the sulfurized olefin is ≤1.2 wt%, for example, it can be 0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt%, or 1.0 wt%, etc.

[0011] Preferably, the sulfur content of the sulfurized olefin is 0.2 wt%-1.0 wt%, for example, it can be 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt% or 0.9 wt%, etc.

[0012] In this invention, the sulfur content of the sulfurized olefin is limited to ≤1.2wt% (preferably 0.2-1.0wt%), mainly based on a balance between environmental regulations, high-temperature stability, and lubrication performance. First, the low sulfur content complies with the requirement of ≤1.5wt% sulfur in international environmental regulations such as EU REACH, significantly reducing biotoxicity (LC50>10000mg / L) and meeting the needs of operations in ecologically sensitive areas. Second, under ultra-high temperature conditions of 220℃, excessive active sulfur can lead to high-temperature sulfur corrosion on the drill surface (generating a brittle FeS layer), while a sulfur content of ≤1.2wt% can both form an extreme pressure reaction film (FeS / FeS2) through controlled release and avoid excessive corrosion. In addition, this sulfur content range forms an optimal synergy with the modified organic molybdenum—too low a sulfur content cannot fully promote the in-situ generation of MoS2, while too high a content will destroy the layered structure of nano-WS2. The preferred range of this invention ensures the stable construction of the synergistic lubrication film of the ternary system, maintaining a high extreme pressure strength of 950N while achieving a high-temperature sedimentation stability of <5%.

[0013] Preferably, the average particle size of the nano-tungsten dioxide is ≤100 nm, for example, it can be 20 nm, 40 nm, 50 nm, 60 nm or 80 nm.

[0014] Preferably, the specific surface area of ​​the nano-tungsten dioxide is ≥150 m². 2 / g, for example, could be 160 m 2 / g、170 m 2 / g、180 m 2 / g、190 m 2 / g or 200 m 2 / g etc.

[0015] Preferably, the interlayer spacing of the nano-tungsten dioxide is 0.80-0.85 nm, for example, it can be 0.81 nm, 0.82 nm, 0.825 nm, 0.83 nm or 0.84 nm, etc.

[0016] Preferably, the lubricant comprises the following components in parts by weight: 45-60 parts of palm oil-based compound (e.g., 48, 50, 53, 55, or 58 parts, etc.), 15-25 parts of modified organic molybdenum complex (e.g., 16, 18, 20, 22, or 24 parts, etc.), 10-18 parts of sulfurized olefin (e.g., 12, 14, 15, 16, or 17 parts, etc.), and 5-8 parts of nano-tungsten disulfide (e.g., 5.5, 6, 6.5, 7, or 7.5 parts, etc.).

[0017] Preferably, the lubricant further comprises a high-temperature stabilizer.

[0018] Preferably, the high-temperature stabilizer includes benzotriazole high-temperature stabilizers.

[0019] Preferably, based on 45-60 parts by weight of the palm oil-based compound, the high-temperature stabilizer is 3-5 parts by weight, for example, 3.5 parts, 3.7 parts, 4 parts, 4.2 parts, or 4.5 parts, etc.

[0020] Preferably, the lubricant further comprises a bio-based emulsifier.

[0021] Preferably, the HLB value of the bio-based emulsifier is 8-10, for example, it can be 8.3, 8.5, 9, 9.3 or 9.6, etc.

[0022] Preferably, based on 45-60 parts by weight of the palm oil-based compound, the bio-based emulsifier is 2-4 parts by weight, for example, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, or 3.5 parts, etc.

[0023] Preferably, the bio-based emulsifier comprises sorbitan monooleate.

[0024] Preferably, the palm oil-based compound includes methyl palmitate.

[0025] Preferably, the water content of the palm oil-based compound is <0.1%, for example, it can be 0.02%, 0.04%, 0.05%, 0.06% or 0.08%.

[0026] In a second aspect, the present invention provides a method for preparing a lubricant as described in the first aspect, the method comprising the following steps: (1) Mix and disperse the palm oil-based compound with the modified organomolybdenum complex; (2) Add sulfurized olefins and nano-tungsten disulfide, and disperse; (3) Add a high-temperature stabilizer and heat to 115-125℃ for 1.5-2.5 h; (4) After cooling to 55-65℃, add bio-based emulsifier and shear emulsify to obtain the lubricant.

[0027] In this invention, a synergistic process of "gradient dispersion + high-temperature stabilization" is used to prepare the lubricant. Its advantage lies in solving the technical bottlenecks of nanomaterial agglomeration and high-temperature failure through the organic combination of staged physical dispersion and chemical stabilization. First, the gradient dispersion process adopts a stepwise strategy of "low-speed shear premixing - ultrasonic cavitation fine dispersion". Low-speed shearing initially dissolves and disperses the modified organic molybdenum and sulfurized olefins in the palm oil-based carrier. Subsequently, the cavitation effect generated by 40kHz ultrasound breaks down the nano-WS2 agglomerates to D90 < 500nm and induces long-chain molecules to form physical adsorption on the surface of nanoparticles. The first layer prevents secondary agglomeration. Then, high-temperature stabilization is carried out at 120°C under nitrogen protection. On the one hand, it promotes the formation of coordination bonds between benzotriazole stabilizers and metal ions, passivating the active sites on the surface of nano-WS2. On the other hand, it induces partial pre-reaction between the organic molybdenum complex and the sulfurized olefin through thermal induction, forming a stable intermediate transition structure. The two work together to achieve long-term stable dispersion of nanoparticles in the oil-based system (high-temperature sedimentation <5%). At the same time, the pre-constructed "nano-WS2-organic molybdenum-sulfurized olefin" interface bonding layer can respond quickly during friction to form a continuous and dense composite lubricating film.

[0028] Preferably, step (1) further includes a pretreatment step before mixing the palm oil-based compound with the modified organic molybdenum complex. The pretreatment method includes heating the palm oil-based compound to 75-85°C (e.g., 76°C, 78°C, 80°C, 82°C, or 84°C) and vacuum dehydrating it.

[0029] Preferably, the dispersion in step (1) includes shear dispersion.

[0030] Preferably, the shear dispersion speed is 1800-2200 rpm (e.g., 1900 rpm, 1950 rpm, 2000 rpm, 2050 rpm, or 2100 rpm, etc.).

[0031] Preferably, the shear dispersion time is 25-35 min, for example, it can be 26 min, 28 min, 30 min, 32 min or 34 min.

[0032] Preferably, the dispersion in step (2) includes ultrasonic dispersion.

[0033] Preferably, the frequency of the ultrasonic dispersion is 35-45 kHz, for example, it can be 36 kHz, 38 kHz, 40 kHz, 42 kHz or 44 kHz, etc.

[0034] Preferably, the ultrasonic dispersion time is 1-2 hours, for example, 1.2, 1.4, 1.5, 1.6 or 1.8 hours.

[0035] Preferably, the D90 particle size of the dispersed system in step (2) is <500 nm, for example, it can be 100 nm, 200 nm, 300 nm, 400 nm or 450 nm.

[0036] Preferably, the shear emulsification speed in step (4) is 4000-6000 rpm, for example, it can be 4500 rpm, 4700 rpm, 5000 rpm, 5200 rpm or 5500 rpm, etc.

[0037] Preferably, the shearing emulsification time in step (4) is 35-45 min, for example, it can be 36 min, 38 min, 40 min, 42 min or 44 min.

[0038] Preferably, step (4) after shear emulsification further includes a post-processing step, wherein the post-processing method includes vacuum filtration.

[0039] Thirdly, the present invention provides the application of the lubricant as described in the first aspect in oil-based drilling fluids.

[0040] Preferably, the oil-based drilling fluid includes oil-based drilling fluid for extended reach wells at depths of tens of thousands of meters.

[0041] Compared with the prior art, the present invention has at least the following beneficial effects: This invention achieves its goal under extreme operating conditions of 220℃ through component innovation (modified organic molybdenum + nano-WS2 + low-sulfur sulfurized olefins) and process optimization (gradient dispersion + high-temperature stabilization). (1) Lubricity: Lubrication coefficient ≤ 0.08 (steel-steel friction pair); (2) Durability: Extreme pressure film strength > 900 N, drill bit torque fluctuation < 10%; (3) Environmental friendliness: Biodegradability rate > 80%, no risk of biotoxicity; (4) Economic efficiency: Production costs are reduced by 25%-30%, which is suitable for the industrial needs of 10,000-meter deep wells.

[0042] (5) The product has a lubrication coefficient retention rate of >92% at 220℃, an extreme pressure film strength of 950 N, and a biodegradation rate of >80%, making it suitable for high-temperature working conditions in deep wells of 10,000 meters and horizontal wells with large displacement. Detailed Implementation

[0043] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0044] The sources of some of the raw materials used in the preparation of the embodiments and comparative examples of this invention are as follows.

[0045] The nano-tungsten disulfide was purchased from Ningbo Jinlei Nanomaterials Technology Co., Ltd., with the grade JL-WS2-N80.

[0046] Benzotriazole octyl ester has the CAS number 40880-90-0.

[0047] The No. 3 white oil was purchased from Sinopec Jingmen Petrochemical and its grade is No. 3 industrial white oil.

[0048] The organic clay used for preparing oil-based drilling fluid slurry was purchased from Zhejiang Fenghong New Material Co., Ltd., with the grade FHD-130DS.

[0049] The barite was purchased from Puyang Dongsheng Petroleum Drilling and Production Technology Co., Ltd., and its grade is Drilling Fluid Barite (Grade I).

[0050] Example 1 A lubricant and its preparation method are provided. The lubricant comprises the following components in parts by weight: 22 parts of modified organic molybdenum complex, 15 parts of low-sulfur isobutylene, 6.5 parts of nano-tungsten disulfide, 4 parts of benzotriazole octyl ester, 48 parts of palmitate methyl ester and 3.5 parts of sorbitan monooleate.

[0051] The preparation method of the modified organomolybdenum complex includes the following steps: ammonium thiomolybdate and hexadecylamide are added to a reaction vessel at a molar ratio of 1:2, toluene is used as solvent, and the mixture is heated to 120°C under nitrogen protection and stirred under reflux for 5 hours; after the reaction is completed, the solvent is removed by vacuum distillation, the obtained solid product is washed 2-3 times with anhydrous ethanol, and dried under vacuum at 80°C to constant weight to obtain the target product modified organomolybdenum complex.

[0052] The method for preparing the lubricant includes the following steps: (1) Take 48 kg of methyl palmitate and dehydrate it at 80℃ and -0.095 MPa; (2) Add 22 kg of modified organic molybdenum complex (molybdenum content 9 wt%), and shear at 2000 rpm for 30 min; (3) Add 15 kg of low-sulfur isobutylene (sulfur content 1.0 wt%) and 6.5 kg of nano WS2, and disperse ultrasonically (40 kHz / 1.5 h). (4) Add 4 kg of benzotriazole octyl ester and react at 120°C for 2 h under a nitrogen atmosphere; (5) Cool down to 60°C, add 3.5 kg of sorbitan monooleate, and emulsify at 5000 rpm for 40 min; (6) Vacuum filtration yields a light green viscous liquid, which is the lubricant.

[0053] Example 2 A lubricant and its preparation method are provided. The lubricant comprises the following components in parts by weight: 20 parts of modified organic molybdenum complex, 20 parts of low-sulfur isobutylene, 8 parts of nano-tungsten disulfide, 3 parts of benzotriazole octyl ester, 45 parts of palmitate methyl ester and 4 parts of sorbitan monooleate.

[0054] The method for preparing the lubricant includes the following steps: (1) Take 45 kg of methyl palmitate and dehydrate it at 80℃ and -0.095 MPa; (2) Add 20 kg of modified organic molybdenum complex (molybdenum content 9 wt%) and shear at 2000 rpm for 30 min; (3) Add 20 kg of low-sulfur isobutylene (sulfur content 1.0 wt%) and 8 kg of nano WS2, and disperse ultrasonically (40 kHz / 1.5 h). (4) Add 3 kg of benzotriazole octyl ester and react at 120°C for 2 h under a nitrogen atmosphere; (5) Cool down to 60°C, add 4 kg of sorbitan monooleate, and emulsify at 5000 rpm for 40 min; (6) Vacuum filtration yields a light green viscous liquid, which is the lubricant.

[0055] Example 3 A lubricant and its preparation method are provided. The lubricant comprises the following components in parts by weight: 25 parts of modified organic molybdenum complex, 18 parts of low-sulfur isobutylene, 8 parts of nano-tungsten disulfide, 5 parts of benzotriazole octyl ester, 60 parts of palmitate methyl ester and 4 parts of sorbitan monooleate.

[0056] The method for preparing the lubricant includes the following steps: (1) Take 60 kg of methyl palmitate and dehydrate it at 80℃ and -0.095 MPa; (2) Add 25 kg of modified organic molybdenum complex (molybdenum content 9 wt%) and shear at 2000 rpm for 30 min; (3) Add 18 kg of low-sulfur isobutylene (sulfur content 1.0 wt%) and 8 kg of nano WS2, and disperse ultrasonically (40 kHz / 1.5 h). (4) Add 5 kg of benzotriazole octyl ester and react at 120°C for 2 h under a nitrogen atmosphere; (5) Cool down to 60°C, add 4 kg of sorbitan monooleate, and emulsify at 5000 rpm for 40 min; (6) Vacuum filtration yields a light green viscous liquid, which is the lubricant.

[0057] Example 4 A lubricant and its preparation method are provided, the only difference from Example 1 being that low-sulfur isobutylene sulfide (sulfur content 1.0 wt%) is replaced with the same mass of isobutylene sulfide (sulfur content 1.5 wt%).

[0058] Example 5 A lubricant and its preparation method are provided, the only difference from Example 1 being that the preparation method of the lubricant does not include the gradient dispersion step.

[0059] Specifically, the method for preparing the lubricant includes the following steps: (1) Take 48 kg of methyl palmitate and dehydrate it at 80℃ and -0.095 MPa; (2) Add 22 kg of modified organic molybdenum complex (molybdenum content 9 wt%), 15 kg of low sulfur sulfide isobutylene (sulfur content 1.0 wt%), and 6.5 kg of nano WS2, and disperse ultrasonically (40 kHz / 1.5 h). (3) Add 4 kg of benzotriazole octyl ester and react at 120°C for 2 h under a nitrogen atmosphere; (4) Cool down to 60°C, add 3.5 kg of sorbitan monooleate, and emulsify at 5000 rpm for 40 min; (5) Vacuum filtration yields a light green viscous liquid, which is the lubricant.

[0060] Example 6 A lubricant and its preparation method are provided, the only difference from Example 1 being that the preparation method of the emulsifier does not include a high-temperature stabilization step.

[0061] Specifically, the method for preparing the lubricant includes the following steps: (1) Take 48 kg of methyl palmitate and dehydrate it at 80℃ and -0.095 MPa; (2) Add 22 kg of modified organic molybdenum complex (molybdenum content 9 wt%) and shear at 2000 rpm for 30 min; (3) Add 15 kg of low-sulfur isobutylene (sulfur content 1.0 wt%) and 6.5 kg of nano WS2, and disperse ultrasonically (40 kHz / 1.5 h). (4) Add 4 kg of benzotriazole octyl ester, cool to 60°C, add 3.5 kg of sorbitan monooleate, and emulsify at 5000 rpm for 40 min; (5) Vacuum filtration yields a light green viscous liquid, which is the lubricant.

[0062] Comparative Example 1 A lubricant and its preparation method are provided, the only difference from Example 1 being that the modified organic molybdenum complex is replaced with the same number of parts by weight of ammonium thiomolybdate.

[0063] Specifically, the method for preparing the lubricant includes the following steps: (1) Take 48 kg of methyl palmitate and dehydrate it at 80℃ and -0.095 MPa; (2) Add 22 kg of modified ammonium thiomolybdate and shear at 2000 rpm for 30 min; (3) Add 15 kg of low-sulfur isobutylene (sulfur content 1.0 wt%) and 6.5 kg of nano WS2, and disperse ultrasonically (40 kHz / 1.5 h). (4) Add 4 kg of benzotriazole octyl ester and react at 120°C for 2 h under a nitrogen atmosphere; (5) Cool down to 60°C, add 3.5 kg of sorbitan monooleate, and emulsify at 5000 rpm for 40 min; (6) Vacuum filtration yields a light green viscous liquid, which is the lubricant.

[0064] Comparative Example 2 A lubricant and its preparation method are provided, the only difference from Example 1 being that the nano-tungsten disulfide has a weight fraction of 0 parts.

[0065] Comparative Example 3 A lubricant and its preparation method are provided, the only difference from Example 1 being that the weight of the low-sulfur isobutylene is 0 parts.

[0066] Application Example 1-6, Comparison with Application Example 1-3 A method for preparing an oil-based drilling fluid is provided. The method for preparing the organic drilling fluid includes the following steps: 243 mL of No. 3 white oil is poured into a high-speed stirring cup; 8.55 g of MOEMUL (purchased from CNOOC Oilfield Services Limited) and 7.15 g of MOCOAT (purchased from CNOOC Oilfield Services Limited) as the primary emulsifier for oil-based drilling fluid are weighed and added to the high-speed stirring cup, and stirred at 10000 r / min for 5 min; 46 mL of a pre-prepared 25% CaCl2 aqueous solution is slowly poured in under stirring conditions, and stirred at 10000 r / min for 20 min; then 8.00 g of organic clay for oil-based drilling fluid preparation is added, and stirred at 10000 r / min for 20 min; 15.00 g of filtration reducer and 6.00 g of calcium oxide are added to the oil-based drilling fluid, and stirred at 10000 r / min for 10 min; then 400 g of barite is added, and stirred at 10000 r / min for 10 min. The mixture is stirred at high speed for 20 minutes, and then the lubricants described in Examples 1-7 and Comparative Examples 1-3 are added to obtain the oil-based drilling fluid. The mass percentage of the lubricant in the oil-based drilling fluid is 1%.

[0067] Comparative Application Example 4 An oil-based drilling fluid and its preparation method are provided, the only difference from Application Example 1 being that the oil-based drilling fluid is a base slurry without added lubricant.

[0068] Specifically, the preparation method of the organic drilling fluid includes the following steps: Measure 243 mL of No. 3 white oil and pour it into a high-speed stirring cup; weigh 8.55 g of MOEMUL (purchased from CNOOC Oilfield Services Limited) and 7.15 g of MOCOAT (purchased from CNOOC Oilfield Services Limited) as the main emulsifier for oil-based drilling fluid and add them to the high-speed stirring cup; stir at 10000 r / min for 5 min; slowly pour in 46 mL of a pre-prepared 25% CaCl2 aqueous solution under stirring conditions; stir at 10000 r / min for 20 min; then add 8.00 g of organic clay for oil-based drilling fluid preparation; stir at 10000 r / min for 20 min; add 15.00 g of filtration reducer and 6.00 g of calcium oxide for oil-based drilling fluid; stir at 10000 r / min for 10 min; then add 400 g of barite; stir at 10000 r / min for 20 min. The oil-based drilling fluid was obtained after min.

[0069] Test methods The oil-based drilling fluids from Application Examples 1-6 and Comparative Application Examples 1-4 were placed in an aging tank and aged at 220°C for 16 hours in a hot rolling furnace. After the drilling fluids were removed and cooled, their lubrication coefficient, extreme pressure film strength, demulsification voltage, and apparent viscosity change rate were determined according to the methods specified in GB / T 16783.2, EP extreme pressure lubrication tester, and GB / T18420.2-2009 Marine Oil Exploration and Development Pollutants - Biotoxicity Part 2: Test Methods.

[0070] The test results are shown in Table 1.

[0071] Table 1 The test results show that: (1) As can be seen from Application Examples 1-6, the present invention has prepared a high-temperature stable and environmentally friendly oil-based drilling fluid lubricant by designing the components of the lubricant.

[0072] Application Example 1 is the best application example of the present invention. After adding lubricant, the lubricity of the oil-based drilling fluid after hot rolling aging at 220°C is greatly improved, and the lubricity coefficient decreases from 0.15 to 0.07, a decrease rate of 53.3%; the extreme pressure film strength increases from 540 N to 980 N, an increase rate of 81.4%; the apparent viscosity change rate is only 3.8%, which has little impact on the rheology of the oil-based drilling fluid; the biotoxicity LC50 is greater than 15000 mg / L, which meets the discharge standards for marine non-aqueous drilling fluids, and its environmental performance is good.

[0073] (2) By comparing Example 1 and Example 4, it can be seen that the present invention further improves the performance of the lubricant by further limiting the sulfur content of the sulfurized olefin.

[0074] A comparison of Examples 1 and 5-6 shows that the present invention further improves the performance of the lubricant by further defining the preparation method of the lubricant.

[0075] (3) By comparing Example 1 with Comparative Examples 1-3, it can be seen that the performance of the lubricant is significantly worse when any one of the modified organic molybdenum complex, sulfurized olefin and nano tungsten disulfide is missing.

[0076] In summary, this invention, through the design of lubricant components, prepares an oil-based drilling fluid lubricant with good high-temperature stability and environmental friendliness.

[0077] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A lubricant, characterized in that, The lubricant comprises the following components: palm oil-based compounds, modified organic molybdenum complexes, sulfurized olefins, and nano-tungsten disulfide.

2. The lubricant according to claim 1, characterized in that, The modified organomolybdenum complex was prepared by a complexation reaction of ammonium thiomolybdate and C16-C18 fatty acid amides. Preferably, the modified organic molybdenum complex has a molybdenum content of 8 wt%-10 wt%.

3. The lubricant according to claim 1 or 2, characterized in that, The sulfur content of sulfurized olefins is ≤1.2wt%.

4. The lubricant according to any one of claims 1-3, characterized in that, The average particle size of the nano-tungsten dioxide is ≤100 nm; Preferably, the specific surface area of ​​the nano-tungsten dioxide is ≥150 m². 2 / g; Preferably, the interlayer spacing of the nano-tungsten dioxide is 0.80-0.85 nm; Preferably, the lubricant comprises the following components in parts by weight: 45-60 parts of palm oil-based compound, 15-25 parts of modified organic molybdenum complex, 10-18 parts of sulfurized olefin, and 5-8 parts of nano-tungsten disulfide.

5. The lubricant according to any one of claims 1-4, characterized in that, The lubricant also includes a high-temperature stabilizer. Preferably, the high-temperature stabilizer includes benzotriazole high-temperature stabilizers; Preferably, the high-temperature stabilizer is 3-5 parts by weight, based on 45-60 parts by weight of the palm oil-based compound; Preferably, the lubricant further comprises a bio-based emulsifier; Preferably, the HLB value of the bio-based emulsifier is 8-10; Preferably, the bio-based emulsifier is 2-4 parts by weight, based on 45-60 parts by weight of the palm oil-based compound; Preferably, the palm oil-based compound includes methyl palmitate.

6. A method for preparing a lubricant as described in any one of claims 1-5, characterized in that, The preparation method includes the following steps: (1) Mix and disperse the palm oil-based compound with the modified organomolybdenum complex; (2) Add sulfurized olefins and nano-tungsten disulfide, and disperse; (3) Add a high-temperature stabilizer and heat to 115-125℃ for 1.5-2.5 h; (4) After cooling to 55-65℃, add bio-based emulsifier and shear emulsify to obtain the lubricant.

7. The preparation method according to claim 6, characterized in that, Step (1) further includes a pretreatment step before mixing the palm oil-based compound with the modified organic molybdenum complex. The pretreatment method includes heating the palm oil-based compound to 75-85°C and dehydrating it under vacuum. Preferably, the dispersion in step (1) includes shear dispersion; Preferably, the shear dispersion rate is 1800-2200 rpm; Preferably, the shear dispersion time is 25-35 min.

8. The preparation method according to claim 6 or 7, characterized in that, The dispersion in step (2) includes ultrasonic dispersion; Preferably, the frequency of the ultrasonic dispersion is 35-45 kHz; Preferably, the ultrasonic dispersion time is 1-2 hours.

9. The preparation method according to any one of claims 6-8, characterized in that, Step (4) after shear emulsification also includes a post-processing step, the post-processing method of which includes vacuum filtration.

10. The use of a lubricant as described in any one of claims 1-5 in an oil-based drilling fluid.

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