Lubricant with modified silicon carbide particle structure coated with resin material for drilling fluid as well as preparation method and application of lubricant

Abstract

The invention provides a lubricant with a modified silicon carbide particle structure coated with a resin material for a drilling fluid as well as a preparation method and application of the lubricant, and belongs to the technical field of lubricants for oil field drilling fluids. The preparation method of the lubricant comprises the following steps: adding pretreated nano SiC particles, hydroxyethyl acrylate, dodecyl acrylate and a silane coupling agent into base oil, then adding a chain transfer agent, stirring, and then adding an initiator for reaction; after the reaction is finished, filtering, washing and drying to obtain modified nano SiC particles; and adding the modified nano SiC particles into the fluorocarbon resin solution, heating for reaction, drying and grinding to obtain the fluorocarbon resin. The invention develops a novel efficient lubricant material for the drilling fluid, and the lubricant material not only can greatly reduce the flow resistance of the drilling fluid and the friction resistance coefficient of a filter cake and slow down the wear of a drilling tool, but also has excellent wear resistance and corrosion resistance, and can effectively improve the drilling efficiency and prolong the service life of a drill bit.

Description

Technical Field

[0001] The invention relates to a lubricant with a resin material coated modified silicon carbide particle structure for drilling fluid, a preparation method and application thereof, and belongs to the technical field of lubricants for oilfield drilling fluid. Background Art

[0002] During the drilling process, there are three main types of friction: direct dry friction without any medium between the drill string and the well wall, boundary friction caused by the boundary film effect between the drill string and the well wall, and flow friction caused by the circulation process of the drilling fluid. In order to reduce friction, a variety of lubricants for drilling fluids have been developed one after another. Commonly used drilling fluid lubricants mainly include liquid lubricants and solid lubricants. Commonly used liquid lubricants mainly include mineral oil lubricants, vegetable oil lubricants, polymer alcohol lubricants and sulfonated tall oil lubricants; solid lubricants mainly include modified graphite, carbon balls, soft metals, alkaline earth metal fluorides and soft oxides.

[0003] However, with the increasing number of wells with complex structures such as horizontal wells, extended reach wells and cluster wells in drilling projects, the drawbacks of existing conventional drilling fluid lubricants in extremely complex environments have become increasingly prominent. Chinese patent document CN109439296A discloses a drilling fluid lubricant and its preparation method and application, which is composed of nanographite, fatty acid ester, surfactant, phosphate ester and water. However, the lubricant can only achieve uniform lubrication of all positions, and has the same effect on high friction and low friction areas, and cannot be adapted and adjusted according to different formations and drilling conditions. U.S. patent document US7250390B2 discloses a high-efficiency lubricant for drilling fluid prepared with sorbitol and ricinoleic acid as raw materials. The lubricant solves the foaming problem of ester lubricants and can achieve the effect of improving the rheology of drilling fluid and reducing filtration loss. European patent document EP2036963 (A1) discloses an oligoglycerol fatty acid ester obtained from an acid component, preferably a fatty acid compound (I), a dicarboxylic acid, a dimer, an oligomer, or a hydroxy fatty acid, and its polyol component, which is an oligoglycerol or an oligoglycerol alkoxy ester, can be used as a lubricating additive in an oil-based drilling fluid, but fatty acid ester lubricants are prone to failure in high temperature and high salt environments.

[0004] At present, lubricants for drilling fluids have gradually failed to meet the needs of complex wells for lubricants for drilling fluids, which has seriously affected the drilling speed and accelerated the wear rate of the drill bit. With the continuous increase in well depth, complex accident problems such as high friction and high torque during drilling have brought new challenges to safe and efficient deep-layer drilling. Therefore, in view of the difficulties faced by the exploration and development of deep and ultra-deep oil and gas, such as torque resistance and large wear of drill tools, the development of a new type of efficient lubricant for drilling fluids is one of the important means to solve this problem. For this reason, the present invention is proposed. Summary of the invention

[0005] In view of the shortcomings of the existing technology, especially the problems faced by complex wells such as large friction torque, severe wear of drill tools, and high risk of stuck drill tools in the current deep, ultra-deep and offshore oil and gas drilling and production processes, the present invention provides a lubricant with a modified silicon carbide particle structure coated with a resin material for drilling fluid, and its preparation method and application. The present invention has developed a new high-efficiency lubricant material for drilling fluid. The lubricant material of the present invention can not only greatly reduce the flow resistance of the drilling fluid and the friction coefficient of the filter cake, slow down the wear of the drill tool, but also has excellent wear and corrosion resistance, which can effectively improve the drilling efficiency and extend the service life of the drill bit.

[0006] The technical solution of the present invention is as follows: A method for preparing a lubricant with a modified silicon carbide particle structure coated with a resin material for drilling fluid comprises the following steps: (1) adding nano-SiC particles to a mixed solvent of ethyl acetate and butyl acetate, stirring evenly, and then performing ultrasonic dispersion to obtain a nano-SiC dispersion; filtering and drying to obtain pretreated nano-SiC particles; (2) adding the pretreated nano-SiC particles obtained in step (1), hydroxyethyl acrylate, lauryl acrylate and a silane coupling agent to a base oil, then adding a chain transfer agent, stirring, and then adding an initiator to react; after the reaction is completed, filtering, washing and drying to obtain modified nano-SiC particles; (3) Adding the modified nano-SiC particles obtained in step (2) into a fluorocarbon resin solution, heating to react, drying and grinding to obtain a lubricant with a resin material-coated modified silicon carbide particle structure for drilling fluid.

[0007] Preferably, according to the present invention, the mass ratio of ethyl acetate to butyl acetate in the mixed solvent in step (1) is 1:1-2; and the mass ratio of the mixed solvent to the nano-SiC particles is 10-40:1.

[0008] Preferably, according to the present invention, the stirring speed in step (1) is 200-300 r / min; the ultrasonic dispersion time is 6-12 h; and the drying is performed at 60-75° C. to constant weight.

[0009] Preferably, according to the present invention, the mass ratio of the pretreated nano-SiC particles, hydroxyethyl acrylate and dodecyl acrylate in step (2) is 1:6-20:1-4.

[0010] Preferably, according to the present invention, the silane coupling agent in step (2) is one or more of vinyl trimethoxy silane, vinyl triethoxy silane, vinyl triisopropoxy silane, γ-methacryloxypropyl methyl dimethoxy silane, γ-methacryloxypropyl trimethoxy silane, and vinyl tri (β-methoxyethoxy) silane; the mass ratio of the silane coupling agent to the pretreated nano-SiC particles is 1:4-20.

[0011] According to the present invention, the base oil in step (2) is white oil, and more preferably 5 ＃ White oil or 7 ＃ White oil; the mass ratio of the base oil to the pretreated nano-SiC particles is 20-100:1.

[0012] Preferably, according to the present invention, the chain transfer agent in step (2) is one of dodecyl mercaptan, trichloroethylene and 2-mercaptopropanol; and the mass ratio of the chain transfer agent to the pretreated nano-SiC particles is 1-5:100.

[0013] Preferably, according to the present invention, the stirring temperature in step (2) is 80-120°C, more preferably 90°C, the stirring time is 50-70min, and the stirring speed is 400-500r / min; the stirring is carried out under a nitrogen atmosphere.

[0014] Preferably, according to the present invention, the initiator in step (2) is one of azobisisobutyronitrile and potassium persulfate; and the mass ratio of the initiator to the pretreated nano-SiC particles is 1-5:100.

[0015] Preferably, according to the present invention, the reaction temperature in step (2) is 70-80°C, and the reaction time is 6-8h; the reaction is carried out under a nitrogen atmosphere, and the stirring rate during the reaction is 400-500r / min.

[0016] Preferably, in step (2), the washing is performed by washing with anhydrous ethanol for 3-5 times; and the drying is performed at 65-85° C. for 4-6 hours.

[0017] Preferably, according to the present invention, the fluorocarbon resin solution in step (3) is obtained by adding fluorocarbon resin to dioctyl azelaic acid and subjecting to ultrasonic treatment for 5-7 hours; the mass ratio of the fluorocarbon resin to dioctyl azelaic acid is 1:1-20; there are no specific requirements for the fluorocarbon resin, and ordinary commercially available products can be used, such as RF-301 solvent-based two-component fluorocarbon resin or RF-302 solvent-based two-component fluorocarbon resin produced by Fuxin Ruifeng Fluorochemical Co., Ltd.

[0018] Preferably, according to the present invention, the mass ratio of the modified nano-SiC particles to the fluorocarbon resin solution in step (3) is 1:40-120.

[0019] According to a preferred embodiment of the present invention, the heating in step (3) is heating to 320-400°C, more preferably 360°C; the heating reaction time is 6-8h; and the drying is drying at 60-70°C for 18-30h.

[0020] The present invention also provides a lubricant with a resin material coated modified silicon carbide particle structure for drilling fluid, which is prepared by the above-mentioned preparation method.

[0021] According to the present invention, the lubricant with a modified silicon carbide particle structure coated with a drilling fluid resin material is used in the drilling fluid and is used as a lubricant in the drilling process to achieve the drilling goal of reducing drag and increasing speed; preferably, the specific application is as follows: at the beginning of the drilling operation, a lubricant with a modified silicon carbide particle structure coated with a drilling fluid resin material with a mass concentration of 0.2-1.2wt% is added to the drilling fluid.

[0022] The technical features and beneficial effects of the present invention are as follows: 1. Aiming at the problems of large friction and torque, severe wear of drilling tools and other problems faced by complex wells such as long horizontal wells in deep and ultra-deep oil and gas exploitation, the present invention provides a lubricant for drilling fluid lubricant with a coated structure, which has the advantage of greatly reducing the lubrication coefficient by adding a small amount. The lubricant of the present invention can effectively reduce the friction and torque of the drilling tool during drilling, reduce the wear of the drill bit, and improve the drilling efficiency.

[0023] 2. The lubricant of the present invention uses modified nano silicon carbide particles as the core and is coated with fluorocarbon resin materials, which can form a dense fluorocarbon resin film on the surface of the nano silicon carbide particles, greatly improving the lubrication performance and wear resistance of the material, and can play a role for a long time, avoiding material failure under slight wear. At the same time, fluorocarbon resin has the characteristics of high corrosion resistance. As a shell coating, the lubricant material can be protected from formation fluids, ensuring effective function. Its non-adhesive properties also improve the output rate of material preparation to a certain extent, and it is not easy to adhere.

[0024] 3. The lubricant of the present invention is a nanometer silicon carbide particle obtained by modifying silicon carbide particles with hydroxyethyl acrylate and dodecyl acrylate as the core. Hydroxyethyl acrylate (HEA) is a polar acrylate, and its terminal hydroxyl group can enhance the adsorption capacity of the polymer on the surface of the drill tool, and can also form a polymer film on the metal surface. Dodecyl acrylate is a long-chain acrylate, which can expand the adsorption area of ​​the polymer on the solid surface and enhance the strength of the lubricating film. In the high friction area of ​​the lubricant material of the present invention, after the outer fluorocarbon resin material is damaged, the internal modified silicon carbide material is exposed and adsorbed on the surface of the drill tool, thereby improving the efficiency of the lubricant. The fluorocarbon resin material is used as the lubricant shell, and the fluorocarbon resin-coated modified silicon carbide particle lubricant material can withstand a temperature of 220°C. However, the lubricant obtained by coating unmodified silicon carbide particles with resin, or the modified silicon carbide particles that are not coated, has poor performance.

[0025] 4. In the preparation method of the present invention, the mass ratio of fluorocarbon resin and nano-SiC particles needs to be appropriate. If it is not appropriate, the coating effect is not good, thereby reducing the performance of the lubricant material. The preparation method of the present invention as a whole, each step and each condition work together to achieve the excellent effect of the present invention.

[0026] 5. The lubricant preparation method of the present invention is simple, the reaction conditions are relatively mild, it has excellent adaptability to extremely complex well conditions, has the prospect of large-scale industrial production, and shows great potential for the exploitation of oil and gas in deep, ultra-deep, and deep-water marine complex structure wells. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to specific embodiments, but is not limited thereto.

[0028] Meanwhile, the experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents, materials and equipment described are all commercially available unless otherwise specified.

[0029] The fluorocarbon resin used in the examples is RF-301 solvent-based two-component fluorocarbon resin produced by Fuxin Ruifeng Fluorine Chemical Co., Ltd.

[0030] Example 1 A method for preparing a lubricant with a modified silicon carbide particle structure coated with a resin material for drilling fluid comprises the following steps: (1) Pretreatment of nano-SiC particles 5 g of nano-SiC particles (particle size of 40-50 nm) were added to 100 g of a mixed solvent (the mixed solvent was obtained by mixing ethyl acetate and butyl acetate in a mass ratio of 1:1), first stirred and mixed evenly at a stirring speed of 300 r / min, and then ultrasonically dispersed for 12 hours to obtain a nano-SiC dispersion; then filtered and dried at 75°C to constant weight to obtain pretreated nano-SiC particles.

[0031] (2) Modification of Nano-SiC Particles Weigh 5 g of pretreated nano-SiC particles, 50 g of hydroxyethyl acrylate, 10 g of dodecyl acrylate and 1 g of silane coupling agent (a combination of vinyl trimethoxysilane and vinyl triethoxysilane, with a mass ratio of 1:1), mix and stir evenly, and then dissolve in 300 g of base oil (7 ＃ white oil); then add 0.2g of chain transfer agent dodecyl mercaptan and bubble with nitrogen; under nitrogen atmosphere, stir at 90°C and 500r / min for 60min; then add 0.2g of azobisisobutyronitrile and react at 75°C for 8h, with a stirring speed of 500r / min during the reaction; after the reaction is completed, cool naturally to room temperature; filter, wash the reaction product with anhydrous ethanol for 3 times, and dry at 65°C for 4h to obtain modified nano-SiC particles.

[0032] (3) Coating of modified nano-SiC particles Add fluorocarbon resin to dioctyl azelaic acid, and ultrasonically treat for 6 hours to form a uniform fluorocarbon resin solution, wherein the mass ratio of fluorocarbon resin to dioctyl azelaic acid is 1:10; put 1 part by weight of modified nano-SiC particles into a beaker, and then add 80 parts by weight of fluorocarbon resin solution, and heat on an electric furnace at 360°C for 6 hours, and stir the mixture with a stirrer to gradually volatilize the dioctyl azelaic acid and gradually deposit the fluorocarbon resin on the surface of the modified nano-SiC particles; dry the heated and stirred mixture at 65°C for 24 hours; and obtain a lubricant with a modified silicon carbide particle structure coated with a resin material for drilling fluid after screening and grinding.

[0033] Example 2 A method for preparing a lubricant having a modified silicon carbide particle structure coated with a resin material for drilling fluid is as described in Example 1, except that the amount of fluorocarbon resin solution added in step (3) is 40 parts by weight.

[0034] Example 3 A method for preparing a lubricant having a modified silicon carbide particle structure coated with a resin material for drilling fluid is as described in Example 1, except that the amount of fluorocarbon resin solution added in step (3) is 120 parts.

[0035] Example 4 A method for preparing a lubricant having a modified silicon carbide particle structure coated with a resin material for drilling fluid is as described in Example 1, except that in step (2), the initiator is replaced by potassium persulfate.

[0036] Comparative Example 1 A method for preparing a lubricant for drilling fluid is as described in steps (1)-(2) of Example 1, without coating in step (3).

[0037] Comparative Example 2 A method for preparing a lubricant for drilling fluid is as described in Example 1, except that in step (2), 5 g of pretreated nano-SiC particles, 20 g of hydroxyethyl acrylate, 5 g of dodecyl acrylate and 0.5 g of silane coupling agent are used.

[0038] Test example Lubrication performance is the primary factor in evaluating whether the drilling fluid lubricant meets the use conditions. According to the SY / T 6094-1994 "Evaluation Procedure for Lubricants for Drilling Fluids" and GB / T 16783.1-2006 "Field Test of Drilling Fluids in the Petroleum and Natural Gas Industry", the extreme pressure lubrication instrument is used to measure the lubrication performance of the base slurry after adding lubricants of different concentrations. When the lubrication coefficient is smaller or the lubrication coefficient reduction rate is greater, the lubricant's friction and drag reduction performance is better. Drilling fluid lubrication coefficient formula reference:

[0039] Where: R-lubrication coefficient reduction rate, %; η0-lubrication coefficient without adding lubricant; η1-lubrication coefficient with adding lubricant.

[0040] 5% base slurry formula: 500 parts of water + 25 parts of bentonite for drilling fluid + 1 part of anhydrous sodium carbonate, hydrated for 24 hours.

[0041] Different weight percentages of lubricants prepared in the examples or comparative examples were added to 500 mL of base slurry, stirred at 8000 rpm for 10 min, and then transferred to a high-temperature roller heating furnace and hot rolled at 220° C. for 16 h. The lubrication coefficient of the above experimental slurry before and after aging was tested using an EP-1 extreme pressure lubrication instrument, and the test results are shown in Table 1.

[0042] Table 1 Lubrication coefficient after adding lubricants prepared in Example 1 in different proportions

[0043] Table 2 Lubrication coefficient after adding lubricants prepared in Example 2 in different proportions

[0044] Table 3 Lubrication coefficient after adding lubricants prepared in Example 3 in different proportions

[0045] Table 4 Lubrication coefficient after adding lubricants prepared in Example 4 in different proportions

[0046] It can be seen from Tables 1-4 that after high-temperature aging at 220°C, the lubrication coefficient of the material prepared in the embodiment of the present invention does not change much, and the lubricant still has excellent lubrication ability after aging at 220°C. However, in Embodiments 1-3, due to the addition of different amounts of fluorocarbon resin, the coating effect and the thickness of the coating layer are affected, thereby affecting the reduction rate of the lubrication coefficient of the material; in Embodiment 4, the lubrication coefficient changes less overall.

[0047] Table 5 Lubrication coefficient after adding lubricants prepared in Comparative Example 1 in different proportions

[0048] It can be seen from Table 5 that the uncoated modified nano-SiC particles in Comparative Example 1 can reduce the lubrication coefficient to a certain extent, and the lubrication coefficient reduction rate is between 20% and 45%; however, the high temperature of 220°C has little effect on it, and the lubrication coefficient fluctuates slightly after high-temperature aging, but overall, the uncoated modified SiC material can still withstand a temperature of 220°C, but the lubrication coefficient reduction rate is much lower than that of the coated material.

[0049] Table 6 Lubrication coefficient after adding lubricants prepared in Comparative Example 2 in different proportions

[0050] It can be seen from Table 6 that in Comparative Example 2, the mass ratio of nano-SiC is too large, and it is difficult to achieve uniform coating of the pretreated nano-SiC particles with the fluorocarbon resin, resulting in reduced lubrication performance and a reduced lubrication coefficient.

[0051] Table 7 Lubrication coefficient after adding different proportions of lubricant (RY-828)

[0052] Table 8 Lubrication coefficient after adding different proportions of lubricant (vegetable oil RH-1)

[0053] It can be seen from Table 7-8 that lubricant RY-828 and vegetable oil RH-1 have a higher lubricity coefficient reduction rate before aging, but their temperature resistance is poor. After aging, the lubricity coefficient decreases significantly.

[0054] In summary, it can be seen that the lubricant of the present invention can effectively reduce the friction and torque of the drill bit during the drilling process, reduce drill bit wear, improve drilling efficiency, and effectively solve the problems of large friction and torque, severe wear of drill bits and other complex structure wells such as long horizontal wells in deep and ultra-deep oil and gas production. It has the advantage of greatly reducing the lubrication coefficient by adding a small amount.

Claims

1. A method for preparing a lubricant having a modified silicon carbide particle structure coated with a resin material for drilling fluid, characterized in that: The steps include: (1) adding nano-SiC particles to a mixed solvent of ethyl acetate and butyl acetate, stirring evenly, and then performing ultrasonic dispersion to obtain a nano-SiC dispersion; filtering and drying to obtain pretreated nano-SiC particles; the mass ratio of ethyl acetate to butyl acetate in the mixed solvent is 1:1-2; the mass ratio of the mixed solvent to the nano-SiC particles is 10-40:1; (2) adding the pretreated nano-SiC particles obtained in step (1), hydroxyethyl acrylate, lauryl acrylate and a silane coupling agent to a base oil, then adding a chain transfer agent, stirring, and then adding an initiator to react; after the reaction is completed, filtering, washing, and drying to obtain modified nano-SiC particles; the mass ratio of the pretreated nano-SiC particles, hydroxyethyl acrylate and lauryl acrylate is 1:6-20:1-4; the silane coupling agent is vinyl trimethoxysilane, vinyl triethoxysilane, ... One or more of alkenyl triisopropoxy silane, γ-methacryloxypropyl methyl dimethoxy silane, γ-methacryloxypropyl trimethoxy silane, and vinyl tri(β-methoxyethoxy) silane, wherein the mass ratio of the silane coupling agent to the pretreated nano-SiC particles is 1:4-20; the base oil is white oil; the chain transfer agent is one of dodecyl mercaptan, trichloroethylene, and 2-mercaptopropanol, and the mass ratio of the chain transfer agent to the pretreated nano-SiC particles is 1-5:100; (3) adding the modified nano-SiC particles obtained in step (2) into a fluorocarbon resin solution, heating to react, drying and grinding to obtain a lubricant having a modified silicon carbide particle structure coated with a resin material for drilling fluid; The fluorocarbon resin solution is obtained by adding fluorocarbon resin to dioctyl azelate and subjecting it to ultrasonic treatment. The mass ratio of the fluorocarbon resin to the dioctyl azelate is 1:1-20, and the mass ratio of the modified nano-SiC particles to the fluorocarbon resin solution is 1:40-120. The heating is performed to 320-400°C.

2. The method for preparing a lubricant having a modified silicon carbide particle structure coated with a resin material for drilling fluid according to claim 1, characterized in that: The stirring speed in step (1) is 200-300 r / min; the ultrasonic dispersion time is 6-12 h; and the drying is performed at 60-75° C. to constant weight.

3. The method for preparing a lubricant having a modified silicon carbide particle structure coated with a resin material for drilling fluid according to claim 1, characterized in that: The white oil in step (2) is 5 ＃ White oil or 7 ＃ White oil; the mass ratio of the base oil to the pretreated nano-SiC particles is 20-100:

1.

4. The method for preparing a lubricant having a modified silicon carbide particle structure coated with a resin material for drilling fluid according to claim 1, characterized in that: The stirring temperature in step (2) is 80-120° C., the stirring time is 50-70 min, and the stirring speed is 400-500 r / min; the stirring is carried out under a nitrogen atmosphere.

5. The method for preparing a lubricant having a modified silicon carbide particle structure coated with a resin material for drilling fluid according to claim 1, characterized in that: The initiator in step (2) is one of azobisisobutyronitrile and potassium persulfate; the mass ratio of the initiator to the pretreated nano-SiC particles is 1-5:

100.

6. The method for preparing a lubricant having a modified silicon carbide particle structure coated with a resin material for drilling fluid according to claim 1, characterized in that: The reaction temperature in step (2) is 70-80°C, and the reaction time is 6-8h; the reaction is carried out under a nitrogen atmosphere, and the stirring rate during the reaction is 400-500r / min; The washing is performed by washing with anhydrous ethanol for 3-5 times; and the drying is performed at 65-85° C. for 4-6 hours.

7. The method for preparing a lubricant having a modified silicon carbide particle structure coated with a resin material for drilling fluid according to claim 1, characterized in that: The ultrasonic treatment time in step (3) is 5-7h.

8. The method for preparing a lubricant having a modified silicon carbide particle structure coated with a resin material for drilling fluid according to claim 1, characterized in that: The heating in step (3) is heating to 360°C; the heating reaction time is 6-8h; and the drying is drying at 60-70°C for 18-30h.

9. A lubricant with a modified silicon carbide particle structure coated with a resin material for drilling fluid, characterized in that: The preparation method is described in any one of claims 1 to 8.

10. The lubricant with modified silicon carbide particle structure coated with resin material for drilling fluid as claimed in claim 9 is used in drilling fluid as a lubricant in the drilling process to achieve the drilling goal of reducing drag and increasing speed, characterized in that: The specific application is as follows: at the beginning of the drilling operation, a lubricant having a modified silicon carbide particle structure coated with a drilling fluid resin material with a mass concentration of 0.2-1.2wt% is added to the drilling fluid.

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