A lubricant, its method of manufacture and use

Abstract

The present application relates to a kind of lubricant and its preparation method and use, the raw material of the lubricant includes by mass percentage: natural vegetable oil 60-70%;Polyhydric alcohol 10-20%;Surfactant 5-10%;Extreme pressure antiwear agent 5-15%.The lubricant provided by the present application can meet the operation requirement under the temperature condition above 180 DEG C, while having good salt resistance, can effectively reduce friction resistance, improve rate of penetration, shorten drilling cycle, meet the requirements of environmental protection.

Description

Technical Field

[0001] This invention relates to the field of water-based drilling fluid treatment agents, specifically to a lubricant, its preparation method, and its uses. Background Technology

[0002] Currently, drilling technology is developing towards deep and ultra-deep wells, due to ultra-high density (≥2.30 g / cm³). 3 The combined effects of high temperature (≥180℃) and extreme humidity make the selection of drilling fluid treatment agents extremely difficult. Currently, there is a lack of water-based drilling fluid treatment agents with high temperature and salt resistance, resulting in issues such as substandard quality, high production costs, and the inability to achieve large-scale production. This is especially true when the density of the drilling system increases to 2.0 g / cm³. 3 At these temperatures, its rheological properties and wall-forming properties are difficult to control, and it cannot meet the requirements for high-temperature operations above 180°C.

[0003] With the increasing drilling intensity of extended reach wells, horizontal wells, and deep and ultra-deep wells, the conflict between lubrication and downhole safety is becoming increasingly prominent. During directional or horizontal sliding drilling, frictional resistance is high and pressure buildup is severe, especially when the drilling fluid density is high (e.g., 2.0 g / cm³). 3 When the density and temperature of the drilling fluid system are high, its rheological properties and lubricity are difficult to control, which can easily lead to drilling accidents. During the drilling of deep and ultra-deep wells, drilling fluids are easily contaminated by salt and calcium intrusion, resulting in severe stuck pipe problems, which in turn leads to frequent downhole accidents and prolongs the drilling cycle. When the density and temperature of the drilling fluid system are high, conventional lubricants can easily increase the system's complexity, making it difficult to achieve the required lubrication effect.

[0004] Therefore, it is necessary to develop a lubricant with high temperature and salt resistance, improve extreme pressure anti-wear ability, reduce lubrication coefficient, and not change the rheological properties of the system. Summary of the Invention

[0005] To address the above problems, the present invention aims to provide a lubricant, its preparation method, and its uses. Compared with the prior art, the lubricant provided by the present invention can meet the operational requirements under temperature conditions above 180°C, while also having good salt resistance, effectively reducing frictional resistance, increasing mechanical drilling speed, shortening drilling cycle, and meeting environmental protection requirements.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a lubricant, wherein the raw materials of the lubricant, by weight percentage, comprise:

[0008]

[0009] The lubricant provided by this invention modifies natural plant oil with polyols to improve its flash point, thermal stability and viscosity index. Through the synergistic effect of the modified natural plant oil, surfactant and extreme pressure anti-wear agent, a denser hydrophobic film can be formed, thereby improving its anti-wear and lubrication effect, and making it more resistant to high temperature and salt, which meets the requirements of environmental protection.

[0010] The natural plant oil has a mass percentage content of 60-70%, for example, it can be 60%, 62%, 64%, 66%, 68% or 70%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0011] The mass percentage of the polyol is 10-20%, for example, it can be 10%, 12%, 14%, 16%, 18% or 20%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] The surfactant has a mass percentage content of 5-10%, for example, it can be 5%, 6%, 7%, 8%, 9% or 10%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] The extreme pressure anti-wear agent has a mass percentage content of 5-15%, for example, it can be 5%, 6%, 8%, 10%, 12%, 14% or 15%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] Preferably, the natural vegetable oil includes rapeseed oil.

[0015] Preferably, the polyol includes any one or a combination of at least two of ethylene glycol, 1,2-propanediol, 1,4-butanediol or 1,6-hexanediol.

[0016] Preferably, the mass ratio of the natural plant oil to the polyol is (3-7):1, for example, it can be 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1 or 7:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] In this invention, by optimizing the mass ratio of natural plant oil to polyol, the modification effect of polyol on natural plant oil can be further enhanced, thereby further improving the salt resistance and high temperature resistance.

[0018] Preferably, the surfactant includes a nonionic surfactant.

[0019] Preferably, the nonionic surfactant includes any one or a combination of at least two of alkylolamide, fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, or C13 isopropanolamide.

[0020] Preferably, the extreme pressure anti-wear agent comprises any one or a combination of at least two of sodium metaborate, potassium metaborate, or potassium triborate, and more preferably a combination of sodium metaborate and potassium metaborate, a combination of sodium metaborate and potassium triborate, or a combination of potassium metaborate and potassium triborate.

[0021] In this invention, it is preferred to use two extreme pressure anti-wear agents in combination, which can prevent or reduce wear on metal surfaces under moderate load conditions. Compared with using a single extreme pressure anti-wear agent, the combination of two extreme pressure anti-wear agents can obtain a more stable physical adsorption film and chemical adsorption film, further improving extreme pressure and anti-wear properties.

[0022] In a second aspect, the present invention provides a method for preparing a lubricant as described in the first aspect of the present invention, the method comprising the following steps:

[0023] (1) Mix natural plant oil, polyol and surfactant, and then react to obtain a modified intermediate;

[0024] (2) The modified intermediate obtained in step (1) and the extreme pressure anti-wear agent are mixed to obtain a lubricant.

[0025] The preparation method provided by the present invention involves first mixing natural plant oil, surfactant and polyol, and then reacting to obtain a modified intermediate with good flash point and stability. Then, the modified intermediate is mixed with extreme pressure anti-wear agent to obtain a lubricant with good salt resistance and high temperature resistance.

[0026] Preferably, the reaction in step (1) is carried out under heating conditions.

[0027] In this invention, there are no special limitations on the heating method; for example, it can be water bath heating.

[0028] Preferably, the reaction temperature is 30-50°C, for example, it can be 30°C, 32°C, 34°C, 36°C, 38°C, 40°C, 42°C, 44°C, 46°C, 48°C or 50°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the reaction time is 1-3 hours, for example, it can be 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours or 3 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the reaction is first stirred.

[0031] Preferably, the first stirring speed is 800-1000 rpm, for example, it can be 800 rpm, 820 rpm, 840 rpm, 860 rpm, 880 rpm, 900 rpm, 920 rpm, 940 rpm, 960 rpm, 980 rpm or 1000 rpm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0032] Preferably, the mixing in step (2) is followed by a second stirring.

[0033] Preferably, the temperature of the second stirring is 30-50°C, for example, it can be 30°C, 32°C, 34°C, 36°C, 38°C, 40°C, 42°C, 44°C, 46°C, 48°C or 50°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] Preferably, the second stirring time is 1-3 hours, for example, it can be 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours or 3 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] Preferably, the second stirring speed is 800-1000 rpm, for example, it can be 800 rpm, 820 rpm, 840 rpm, 860 rpm, 880 rpm, 900 rpm, 920 rpm, 940 rpm, 960 rpm, 980 rpm or 1000 rpm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0036] As a preferred embodiment of the second aspect of the present invention, the preparation method includes the following steps:

[0037] (1) Mix natural plant oil, polyol and surfactant, and then react at 30-50℃ for 1-3h. During the reaction, the mixture is stirred at 800-1000rpm to obtain a modified intermediate.

[0038] (2) The modified intermediate and extreme pressure anti-wear agent obtained in step (1) are mixed and stirred for 1-3 hours at a speed of 800-1000 rpm and a temperature of 30-50℃ to obtain a lubricant.

[0039] Thirdly, the present invention provides a use of the lubricant as described in the first aspect of the present invention, the lubricant being used in oil drilling.

[0040] The lubricant provided by this invention is used in drilling fluid systems and can form a dense hydrophobic film. It has good compatibility with various drilling fluid systems, can effectively reduce frictional resistance, increase mechanical drilling speed, shorten drilling cycle, and does not change the rheology and stability of drilling fluid.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The lubricant provided by the present invention modifies natural plant oil with polyols and combines the synergistic effect of surfactants and extreme pressure anti-wear agents to improve the lubricant’s resistance to salt and high temperature, and has good stability, which can meet the construction requirements of deep wells and ultra-deep wells.

[0043] (2) The lubricant provided by the present invention can form a dense hydrophobic film and has good compatibility with a variety of drilling fluid systems. It can effectively reduce frictional resistance, increase mechanical drilling speed, shorten drilling cycle, and does not change the rheology and stability of drilling fluid.

[0044] (3) The raw materials used in the lubricant provided by the present invention are non-toxic and harmless, with low cost, and have both good environmental protection and economy. Attached Figure Description

[0045] Figure 1 This is the thermogravimetric curve of the lubricant described in Embodiment 1 of the present invention. Detailed Implementation

[0046] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0047] Example 1

[0048] This embodiment provides a lubricant, the raw materials of which include:

[0049]

[0050] The mass ratio of rapeseed oil to polyol (ethylene glycol) is 7:1.

[0051] This embodiment also provides a method for preparing the above-mentioned lubricant, the method comprising the following steps:

[0052] (1) Mix rapeseed oil, ethylene glycol and alkylolamide, put them into a three-necked flask equipped with a stirrer and a thermometer, and then carry out the reaction in a water bath at 30°C for 2 hours. During the reaction, the first stirring is carried out at a speed of 1000 rpm to obtain the modified intermediate.

[0053] (2) Add sodium metaborate and potassium metaborate to the modified intermediate obtained in step (1), and stir for 2 hours at a speed of 1000 rpm and a temperature of 30°C to obtain a lubricant.

[0054] The thermogravimetric curve of the lubricant obtained in this embodiment is shown in the figure below. Figure 1 As shown, from Figure 1 It can be seen that the molecular chain decomposition temperature of the lubricant provided by the present invention is 390℃, which shows good thermal stability; and the weight of the sample tends to stabilize after 470℃, indicating that it has basically decomposed completely, thus exhibiting good high-temperature resistance.

[0055] Example 2

[0056] This embodiment provides a lubricant, the raw materials of which include:

[0057]

[0058] The mass ratio of rapeseed oil to polyols (ethylene glycol and 1,2-propanediol) is 4.7:1.

[0059] This embodiment also provides a method for preparing the above-mentioned lubricant, the method comprising the following steps:

[0060] (1) Mix rapeseed oil, ethylene glycol, 1,2-propanediol, fatty alcohol polyoxyethylene ether and alkyl alcohol amide, and put them into a three-necked flask equipped with a stirrer and a thermometer. Then, the mixture is placed in a water bath at 30°C and reacted for 2 hours. During the reaction, the mixture is stirred at 1000 rpm to obtain a modified intermediate.

[0061] (2) Add sodium metaborate and potassium metaborate to the modified intermediate obtained in step (1), and stir for 2 hours at a speed of 1000 rpm and a temperature of 30°C to obtain a lubricant.

[0062] Example 3

[0063] This embodiment provides a lubricant, the raw materials of which include:

[0064]

[0065]

[0066] The mass ratio of rapeseed oil to polyols (ethylene glycol and 1,2-propanediol) is 4.3:1.

[0067] This embodiment also provides a method for preparing the above-mentioned lubricant, the method comprising the following steps:

[0068] (1) Mix rapeseed oil, ethylene glycol, 1,2-propanediol and alkylolamide, and put them into a three-necked flask equipped with a stirrer and a thermometer. Then, the mixture is placed in a water bath at 40°C and reacted for 2 hours. During the reaction, the mixture is stirred at 900 rpm to obtain a modified intermediate.

[0069] (2) Add potassium metaborate and potassium triborate to the modified intermediate obtained in step (1), and stir for 2 hours at a speed of 900 rpm and a temperature of 40°C to obtain a lubricant.

[0070] Example 4

[0071] This embodiment provides a lubricant, the raw materials of which include:

[0072]

[0073] The mass ratio of rapeseed oil to polyols (ethylene glycol and 1,2-propanediol) is 4.3:1.

[0074] This embodiment also provides a method for preparing the above-mentioned lubricant, the method comprising the following steps:

[0075] (1) Mix rapeseed oil, ethylene glycol, 1,2-propanediol, fatty alcohol polyoxyethylene ether and alkyl alcohol amide, and put them into a three-necked flask equipped with a stirrer and a thermometer. Then, the mixture is placed in a water bath at 40°C and reacted for 2 hours. During the reaction, the mixture is stirred at 900 rpm to obtain a modified intermediate.

[0076] (2) Add sodium metaborate and potassium metaborate to the modified intermediate obtained in step (1), and stir for a second time for 1 hour at a speed of 900 rpm and a temperature of 40°C to obtain a lubricant.

[0077] Example 5

[0078] This embodiment provides a lubricant, the raw materials of which include:

[0079]

[0080] The mass ratio of rapeseed oil to polyols (ethylene glycol and 1,2-propanediol) is 3:1.

[0081] This embodiment also provides a method for preparing the above-mentioned lubricant, the method comprising the following steps:

[0082] (1) Mix rapeseed oil, 1,4-butanediol, 1,2-propanediol, fatty alcohol polyoxyethylene ether and alkyl alcohol amide, and put them into a three-necked flask equipped with a stirrer and a thermometer. Then, the mixture is placed in a water bath at 50°C and reacted for 2 hours. During the reaction, the mixture is stirred at 800 rpm to obtain a modified intermediate.

[0083] (2) Add sodium metaborate and potassium metaborate to the modified intermediate obtained in step (1), and stir for 2 hours at a speed of 800 rpm and a temperature of 50°C to obtain a lubricant.

[0084] Example 6

[0085] This embodiment provides a lubricant, the raw materials of which include:

[0086]

[0087]

[0088] The mass ratio of rapeseed oil to polyols (ethylene glycol and 1,2-propanediol) is 3:1.

[0089] This embodiment also provides a method for preparing the above-mentioned lubricant, the method comprising the following steps:

[0090] (1) Mix rapeseed oil, 1,4-butanediol, 1,2-propanediol, alkylphenol polyoxyethylene ether and C13 isopropanol amide, and put them into a three-necked flask equipped with a stirrer and a thermometer. Then, the mixture was placed in a water bath at 60°C for 2 hours. During the reaction, the mixture was stirred at 800 rpm to obtain a modified intermediate.

[0091] (2) Add sodium metaborate and potassium metaborate to the modified intermediate obtained in step (1), and stir for a second time for 1 hour at a speed of 800 rpm and a temperature of 60°C to obtain a lubricant.

[0092] Example 7

[0093] This embodiment provides a lubricant, which differs from that in Example 1 only in that the mass of ethylene glycol is 35g and the mass ratio of rapeseed oil to polyol (ethylene glycol) is 2:1.

[0094] This embodiment also provides a method for preparing the above-mentioned lubricant. The preparation method is the same as in Example 1, except that the amount of ethylene glycol added is adjusted according to the above content.

[0095] Example 8

[0096] This embodiment provides a lubricant, which differs from that in Example 1 only in that the mass of ethylene glycol is 7g and the mass ratio of rapeseed oil to polyol (ethylene glycol) is 10:1.

[0097] This embodiment also provides a method for preparing the above-mentioned lubricant. The preparation method is the same as in Example 1, except that the amount of ethylene glycol added is adjusted according to the above content.

[0098] Example 9

[0099] This embodiment provides a lubricant that differs from that in Embodiment 1 only in that it uses only one extreme pressure anti-wear agent, namely, potassium metaphosphate is replaced with an equal mass of sodium metaphosphate.

[0100] This embodiment also provides a method for preparing the above-mentioned lubricant, which is the same as in Example 1 except that potassium metaphosphate is replaced with an equal mass of sodium metaphosphate.

[0101] Comparative Example 1

[0102] This comparative example provides a lubricant that differs from Example 1 only in that it does not contain ethylene glycol.

[0103] This comparative example also provides a method for preparing the above-mentioned lubricant, wherein ethylene glycol is not added in the mixing step (1), and the rest is the same as in Example 1.

[0104] Comparative Example 2

[0105] This comparative example provides a lubricant that differs from Example 1 only in that it does not contain alkylolamide.

[0106] This comparative example also provides a method for preparing the above-mentioned lubricant, wherein no alkylolamide is added in the mixing step (1), and the rest is the same as in Example 1.

[0107] Comparative Example 3

[0108] This comparative example provides a lubricant that differs from Example 1 only in that it does not contain sodium metaborate and potassium metaborate.

[0109] This comparative example also provides a method for preparing the above-mentioned lubricant. The preparation method is as follows: after obtaining the modified intermediate in step (1), the mixture is stirred at 1000 rpm and 30°C for 2 hours. The rest is the same as in Example 1.

[0110] (I) Environmental impact assessment:

[0111] Using BOD5 / COD DrThe ratio evaluation method was used for determination; the BOD5 determination method was based on HJ505-2009 "Determination of Five-Day Biochemical Oxygen Demand (BOD5) in Water - Dilution and Inoculation Methods", and COD... Dr Based on HJ 828-2017 "Determination of Chemical Oxygen Demand in Water - Dichromate Method"; the evaluation criteria are based on SY / T6787-2010 "Technical Requirements for Environmental Protection of Water-Soluble Oilfield Chemicals" and SYff 6788-2020 "Evaluation Methods for Environmental Protection of Water-Soluble Oilfield Chemicals". Specific evaluation criteria are shown in Table 1, where Y represents BOD5 / COD. Dr The ratio of .

[0112] Table 1

[0113] <![CDATA[BOD5 / COD Dr ]]> Y≥0.05 0.01≤Y≥0.05 Y＜0.01 Biodegradable easy Difficult Disaster

[0114] The evaluation results of Examples 1-6 are shown in Table 2.

[0115] Table 2

[0116] <![CDATA[BOD5(mg / L)]]> <![CDATA[COD Dr (mg / L)]]> <![CDATA[BOD5 / COD Dr ]]> Example 1 56.3 970.6 0.058 Example 2 60.4 990.1 0.061 Example 3 64.9 968.6 0.067 Example 4 68.7 1108 0.062 Example 5 67.4 1298 0.052 Example 6 71.6 1351 0.053

[0117] As can be seen from the data in Table 2, the Y values ​​of the lubricating oils provided in Examples 1-6 are in the range of 0.052-0.067, all ≥0.05, indicating that they are easily biodegradable and meet environmental protection requirements.

[0118] (II) Evaluation of Lubrication Performance

[0119] A. The Influence of Lubricants on the Lubricating Performance of Drilling Fluid Systems

[0120] Freshwater and seawater drilling fluid systems were selected for study. The freshwater drilling fluid system was formulated as follows: 400 mL water, 8 g sodium bentonite (OCMA), 0.8 g soda ash (Na2CO3), 2 g shearing and filtration loss reducer (KJAN), 2 g high-temperature resistant modified natural polymer (PFT-601), and 168 g barite, with a density of 1.2 g / cm³. 3 The formulation of the brine-based drilling fluid system is as follows: 400 mL water, 12 g KCl, 8 g sodium bentonite (OCMA), 0.8 g soda ash (Na2CO3), 8 g salt-resistant filtration loss reducer (BZ-KLS), and 310 g barite, with a density of 1.5 g / cm³. 3 .

[0121] Using freshwater drilling fluid system and seawater drilling fluid system as base slurry, the lubricants obtained in Examples 1-6 were added to the base slurry according to different mass addition amounts to obtain sample slurry. The base slurry and sample slurry were aged at 150℃ for 16h. Then, the lubrication coefficient f and lubrication coefficient reduction rate R of the base slurry and sample slurry were measured by extreme pressure lubrication instrument. The results are shown in Tables 3 and 4.

[0122] The method for calculating the lubrication coefficient f is as follows: Where CF represents the correction factor;

[0123] The method for calculating the lubrication coefficient reduction rate R is as follows: Where K0 represents the lubrication coefficient of the base slurry, and K1 represents the lubrication coefficient of the sample slurry;

[0124] The calculation methods for the correction factor CF include:

[0125] Step 1: Clean the block, ring, and all parts of the instrument that come into contact with the sample with detergent or soap, and thoroughly wash and dry them with distilled water; do not let the slider and slip ring touch at first, i.e., do not apply pressure to the torque wrench; start the instrument and run it at 300 r / min for 15 minutes, then adjust the speed to 60 r / min, with a deviation of ±5 r / min;

[0126] Step 2: After the rotation speed stabilizes, turn off the power and adjust the torque wrench to zero; fill the sample cup with distilled water and immerse the block and ring in it, turn on the instrument, run it idle for 5 minutes, and check again whether the tachometer and torque meter are properly adjusted; then adjust the torque wrench value to 16.95 N·m (150 PSI), and adjust the tachometer to 60 r / min. Then remove the torque meter, i.e., do not apply pressure. At this time, the motor is running idle. Increase the distance between the ring and the block, and then adjust the zero adjustment knob to zero.

[0127] Step 3: At the standard speed (60 r / min), quickly adjust the torque wrench dial reading to 16.95 N·m (150 PSI) and run the instrument for 5 minutes; the torque gauge reading should be within the range of 28-48. Record the instrument reading for later use.

[0128] Table 3

[0129]

[0130] Table 4

[0131]

[0132]

[0133] The following points can be observed from the data in Tables 3 and 4:

[0134] ①As the amount of lubricant added increases, the extreme pressure lubrication coefficient of drilling fluid decreases significantly.

[0135] ② When the amount of lubricant added is 1%, the lubrication coefficient reduction rate of both freshwater drilling fluid system and seawater drilling fluid system reaches more than 70%.

[0136] ③ When the lubricant addition amount is 2%, the lubrication coefficient reduction rate of both drilling fluid systems reaches over 80%, demonstrating good lubrication performance. After adding the lubricant, the density of the drilling fluid system remains essentially unchanged, indicating that the lubricant provided by this invention will not cause drilling fluid foaming, which is beneficial for on-site construction.

[0137] B. Lubricating properties of freshwater-based drilling fluids of different densities

[0138] The selected water-based drilling fluid system formulation is as follows: 400 mL water, 12 g sodium bentonite (PRT), 1.2 g soda ash (Na2CO3), 4 g filtration loss reducer (GJL), and 4 g high-temperature resistant modified natural polymer (PFT-601), barite, with a density of 1.2 g / cm³. 3 1.5g / cm 3 1.8g / cm 3 and 2.0g / cm 3 The amounts of barite added were 105g, 263g, 420g, and 525g, respectively.

[0139] Using the above-mentioned water-based drilling fluids of different densities as the base slurry, the lubricating fluids obtained in Examples 1-4 were added to freshwater drilling fluids of different densities according to different mass addition amounts to obtain sample slurries. The lubrication coefficient f and lubrication coefficient reduction rate R of the base slurry and the sample slurry were measured using an extreme pressure lubrication instrument. The results are shown in Table 5. The test method is the same as the test method in (II) Lubrication Performance Evaluation A.

[0140] Table 5

[0141]

[0142]

[0143] As can be seen from Table 5, at a lower density, i.e., a density of 1.5 g / cm³, 3 When the lubricant addition amount is 1%, the lubrication coefficient reduction rate reaches over 75%; when the density is high, i.e., 2.0 g / cm³... 3 When the amount of lubricant added is 2%, the lubrication coefficient reduction rate reaches more than 79%.

[0144] (III) Evaluation of Salt Resistance

[0145] The selected base slurry formulation includes: 400 mL distilled water, 0.8 g anhydrous sodium carbonate, and 20 g bentonite (PRT), with different mass fractions of sodium chloride added, namely 4%, 8%, 15%, and 30% sodium chloride. Among them, the base slurry with a NaCl concentration of 4% simulates the NaCl concentration in seawater; the base slurries with NaCl concentrations of 8% and 15% simulate the upper limit of salt resistance of most salt- and calcium-resistant water-based drilling fluid lubricants currently available; and the base slurry with a NaCl concentration of 30% simulates the saturated NaCl concentration.

[0146] The base slurries with different sodium chloride concentrations were added to the lubricating fluid obtained in Example 2 at a mass addition rate of 2% to obtain sample slurries. The obtained sample slurries were then subjected to hot rolling aging. The method was as follows: the sample slurries were poured into an aging tank, placed in a roller heating furnace, heated to 180°C, and continuously hot rolled for 16 hours. The rheological properties of the base slurry, the sample slurry before hot rolling, and the sample slurry after hot rolling were tested using a ZNN-D6 six-speed rotational viscometer, including the initial and final shear values ​​(Gel), apparent viscosity (AV), plastic viscosity (PV), dynamic shear force (YP), and other rheological parameters of the drilling fluid. The results are shown in Table 6. The lubrication coefficient f and the lubrication coefficient reduction rate R were measured using an extreme pressure lubrication instrument. The results are shown in Table 6. The test method is the same as the test method in (II) Lubrication Performance Evaluation A.

[0147] Table 6

[0148]

[0149]

[0150] The following points can be observed from Table 6:

[0151] ①As the salt concentration increases, the lubrication coefficient decreases by more than 70% before aging.

[0152] ②After aging, as the salt concentration increases, the lubrication coefficient decreases by more than 89%, therefore the lubricant provided by this invention has good salt resistance.

[0153] ③ The lubricant provided by this invention can reduce the AV and YP values ​​of the base slurry after addition; it produces less foam and has a small density change value.

[0154] In summary, the lubricant provided by this invention has excellent salt resistance.

[0155] (IV) Evaluation of high temperature resistance

[0156] The base slurry formulation includes: 400 mL water, 20 g sodium bentonite (PRT), 2 g anhydrous sodium carbonate, 8 g lignite resin (SPNH), 8 g high-temperature and salt-resistant filtration loss reducer (HG-RS), 8 g sulfonated phenolic resin (SMP), 0.4 g cutting agent (KJAN), and 250 g barite, with a density of 1.5 g / cm³. 3 .

[0157] The lubricants from Examples 1, 3-9, and Comparative Examples 1-3 were added to the base slurry at a mass addition rate of 3% to obtain sample slurries. The sample slurries were aged at 150℃, 180℃, 200℃, and 220℃ for 16 hours, respectively. The rheological properties, including plastic viscosity (PV) and shear force (YP), of the base slurry, the sample slurry before aging, and the sample slurry after aging at different temperatures were tested using a ZNN-D6 six-speed rotational viscometer. The filtration loss (API) of the base slurry, the sample slurry before aging, and the sample slurry after aging at different temperatures was tested using a triple-stage fluid loss meter. The lubrication coefficient f was determined using an extreme pressure lubricator. The test methods were the same as those in (II) Lubrication Performance Evaluation A. The results are shown in Table 7.

[0158] Table 7

[0159]

[0160]

[0161]

[0162] The following points can be observed from Table 7:

[0163] ① As can be seen from the data of Examples 1 and 3-6, after adding lubricant to the base slurry at a mass addition amount of 3%, the rheological properties of the drilling fluid remain basically unchanged, and the filtration loss decreases and the lubrication coefficient decreases. This indicates that the lubricant provided by the present invention has good temperature resistance and its temperature resistance can reach 220℃.

[0164] ② A comparison between Examples 7-8 and Example 1 shows that the only difference between Examples 7-8 and Example 1 is that the mass ratio of rapeseed oil to polyol is not within the preferred range of this invention. The results show that the filtration loss in Example 1 is significantly lower than that in Examples 7-8, and the lubrication coefficient and plastic viscosity in Example 1 are significantly lower than those in Examples 7-8. Therefore, it can be seen that this invention preferably controls the mass ratio of rapeseed oil to polyol within a specific range, which can further reduce frictional resistance and improve compatibility with drilling fluid, avoid affecting the performance of drilling fluid, and avoid excessive viscosity of drilling fluid.

[0165] ③ As can be seen from the comparison between Example 9 and Example 1, the only difference between Example 9 and Example 1 is that only one extreme pressure anti-wear agent is used. The filtration loss in Example 1 is significantly lower than that in Example 9, and the lubrication coefficient and plastic viscosity in Example 1 are significantly lower than those in Example 9. Therefore, it can be seen that the present invention preferably uses a combination of two extreme pressure anti-wear agents, which can further reduce frictional resistance and improve compatibility with drilling fluid.

[0166] ④ A comparison of Comparative Examples 1-3 and Example 1 shows that the only difference between Comparative Examples 1-3 and Example 1 is that ethylene glycol, alkylolamide, and extreme pressure anti-wear agent are not added respectively. The filtration loss in Example 1 is significantly lower than that in Comparative Examples 1-3, and the lubrication coefficient and plastic viscosity in Example 1 are significantly lower than those in Comparative Examples 1-3. It can be seen that the lubricant system provided by the present invention can significantly reduce frictional resistance and has good compatibility with drilling fluid.

[0167] In summary, the lubricant provided by this invention can form a dense hydrophobic film in drilling fluid systems, and has good compatibility with various drilling fluid systems. It can effectively reduce frictional resistance, increase mechanical drilling speed, shorten drilling cycle, and does not change the rheological properties and stability of the drilling fluid.

[0168] 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 raw materials of the lubricant, by weight percentage, include: 60-70% natural plant oil; Polyols 10-20%; Surfactant 5-10%; Extreme pressure anti-wear agent 5-15%; The mass ratio of the natural plant oil to the polyol is (3-7):1; The extreme pressure anti-wear agent is a combination of sodium metaborate and potassium metaborate, a combination of sodium metaborate and potassium triborate, or a combination of potassium metaborate and potassium triborate.

2. The lubricant according to claim 1, characterized in that, The natural plant oils include rapeseed oil.

3. The lubricant according to claim 1, characterized in that, The polyols include any one or a combination of at least two of ethylene glycol, 1,2-propanediol, 1,4-butanediol, or 1,6-hexanediol.

4. The lubricant according to claim 1, characterized in that, The surfactants include nonionic surfactants.

5. The lubricant according to claim 4, characterized in that, The nonionic surfactant includes any one or a combination of at least two of alkylolamides, fatty alcohol polyoxyethylene ethers, alkylphenol polyoxyethylene ethers, or C13 isopropanolamides.

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 natural plant oil, polyol and surfactant, and then react to obtain a modified intermediate; (2) The modified intermediate obtained in step (1) and the extreme pressure anti-wear agent are mixed to obtain a lubricant.

7. The preparation method according to claim 6, characterized in that, The reaction described in step (1) is carried out under heating conditions.

8. The preparation method according to claim 6, characterized in that, The reaction temperature is 30-50℃.

9. The preparation method according to claim 6, characterized in that, The reaction time is 1-3 hours.

10. The preparation method according to claim 6, characterized in that, The reaction is first stirred.

11. The preparation method according to claim 10, characterized in that, The first stirring speed is 800-1000 rpm.

12. The preparation method according to claim 6, characterized in that, After mixing in step (2), a second stirring is performed.

13. The preparation method according to claim 12, characterized in that, The temperature of the second stirring is 30-50℃.

14. The preparation method according to claim 12, characterized in that, The second stirring time is 1-3 hours.

15. The preparation method according to claim 12, characterized in that, The second stirring speed is 800-1000 rpm.

16. The preparation method according to claim 6, characterized in that, The preparation method includes the following steps: (1) Mix natural plant oil, polyol and surfactant, and then react at 30-50℃ for 1-3h. During the reaction, the mixture is stirred at 800-1000rpm to obtain the modified intermediate. (2) The modified intermediate and extreme pressure anti-wear agent obtained in step (1) are mixed and stirred for 1-3 hours at a speed of 800-1000 rpm and a temperature of 30-50℃ to obtain a lubricant.

17. Use of the lubricant as described in any one of claims 1-5, characterized in that, The lubricant is used in oil drilling.

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