An oil-based drilling fluid and a method of making

Abstract

The application provides an oil-based drilling fluid and a preparation method thereof. The oil-based drilling fluid comprises the following components in parts by weight: 9-12 parts of fatty acid amide; 9-12 parts of alkanolamide; 9-15 parts of alkalinity regulator; 3-12 parts of organic clay; 3-12 parts of flow pattern regulator; 12-15 parts of nano plugging agent; 15-18 parts of filtrate reducer; 340-1400 parts of barite; 30-60 parts of inorganic chlorides aqueous solution; and 240-270 parts of oil. The oil-based drilling fluid has excellent rheological stability, emulsification stability, sedimentation stability and filtrate reduction stability in an ultrahigh temperature environment.

Description

Technical Field

[0001] This invention relates to an oil-based drilling fluid and its preparation method, belonging to the technical field of oil-based drilling fluids for petroleum drilling. Background Technology

[0002] Deep and / or ultra-deep oil and gas have become important alternative energy sources globally. However, the bottom hole temperature of deep and / or ultra-deep oil and gas is extremely high, which places higher demands on wellbore working fluid treatment agents and treatment systems. Therefore, it is necessary to study oil-based drilling fluids that can withstand ultra-high temperatures. Summary of the Invention

[0003] This invention provides an oil-based drilling fluid that exhibits excellent rheological stability, emulsification stability, sedimentation stability, and filtration loss reduction stability under ultra-high temperature conditions.

[0004] This invention provides a method for preparing an oil-based drilling fluid. This method can produce the aforementioned oil-based drilling fluid, and it is simple to operate and suitable for widespread application.

[0005] This invention provides an oil-based drilling fluid, comprising the following components by weight:

[0006] 9-12 parts of fatty acid amides;

[0007] 9-12 parts of alkanolamide;

[0008] 9-15 parts alkalinity adjuster;

[0009] 3-12 parts organic soil;

[0010] 3-12 parts of flow pattern regulator;

[0011] 12-15 parts of nano-blocking agent;

[0012] 15-18 parts of filtration loss reducer;

[0013] Barite 340-1400 parts;

[0014] 30-60 parts of an aqueous solution of inorganic chloride salts;

[0015] 240-270 parts oil.

[0016] The oil-based drilling fluid described above comprises, by weight, the following components:

[0017] 10-11 parts of fatty acid amide;

[0018] 10-11 parts of alkanolamide;

[0019] 11-13 parts alkalinity adjuster;

[0020] 4.5-10.5 parts organic soil;

[0021] Flow pattern regulator 4.5-10.5 parts;

[0022] 13-14 parts of nano-blocking agent;

[0023] 16-17 parts of filtration loss reducer;

[0024] Barite 340-1400 parts;

[0025] 30-60 parts of an aqueous solution of inorganic chloride salts;

[0026] 240-270 parts oil.

[0027] In the oil-based drilling fluid described above, the mass ratio of unsaturated fatty acid, tallow-based propylene diamine, diphenylethylenediamine, diethylenetriamine, and salicylic acid in the fatty acid amide is (80-140):(20-50):(25-50):(10-35):(50-75).

[0028] In the oil-based drilling fluid described above, the mass ratio of unsaturated fatty acid, diethanolamine, propylene dithiol, 2-dibutylamine-4,6-dithiol and sulfonic acid in the alkanolamide is (60-100):(10-40):(10-40):(10-30):(60-100).

[0029] The oil-based drilling fluid described above, wherein the alkalinity adjuster is selected from at least one of sodium hydroxide, potassium hydroxide, calcium oxide, and magnesium oxide; and / or,

[0030] The filtration loss reducer is selected from at least one of oxidized asphalt, organic lignite, and humic acid amide resin.

[0031] In the oil-based drilling fluid described above, the mass ratio of bentonite, n-octyltriethoxysilane, aminopropyltriethoxysilane, and dioctadecyldimethylammonium chloride in the organic soil is (100-180):(25-50):(5-20):(10-30).

[0032] In the oil-based drilling fluid described above, the mass ratio of trimeric fatty acid, polyetheramine, nano-silica, and silane coupling agent in the flow pattern regulator is (100-150):(50-90):(1-10):(2-15).

[0033] In the oil-based drilling fluid described above, the mass ratio of carbon nanotubes, styrene, acrylamide, N-vinylpyrrolidone, and allyltriethoxysilane in the nano-plugging agent is (2-10):(30-60):(25-75):(30-60):(5-15).

[0034] In the oil-based drilling fluid described above, the density of the barite is greater than or equal to 4.30 g / cm³. 3 ; and / or,

[0035] The inorganic chloride aqueous solution contains 15-35% inorganic chloride by mass; and / or,

[0036] The oil is selected from at least one of diesel, gas-derived oil, and white oil.

[0037] The present invention provides a method for preparing the oil-based drilling fluid as described above, comprising: mixing fatty acid amide, alkanolamide, alkalinity regulator, organic clay, flow pattern regulator, nano-plugging agent, filtration loss reducer, barite, inorganic chloride aqueous solution and oil to obtain the oil-based drilling fluid.

[0038] The oil-based drilling fluid of the present invention is composed of special components. The synergistic effect of the components enables the oil-based drilling fluid to have excellent rheological stability, emulsification stability, sedimentation stability and filtration loss reduction stability in ultra-high temperature environments. This can avoid complex downhole situations during deep well and / or ultra-deep well drilling, thereby improving drilling efficiency and safety.

[0039] The method for preparing the oil-based drilling fluid of the present invention can produce the above-mentioned oil-based drilling fluid. The preparation method is simple to operate and suitable for widespread application. Detailed Implementation

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] A first aspect of the present invention provides an oil-based drilling fluid, wherein it comprises the following components in parts by weight:

[0042] 9-12 parts of fatty acid amides;

[0043] 9-12 parts of alkanolamide;

[0044] 9-15 parts alkalinity adjuster;

[0045] 3-12 parts organic soil;

[0046] 3-12 parts of flow pattern regulator;

[0047] 12-15 parts of nano-blocking agent;

[0048] 15-18 parts of filtration loss reducer;

[0049] Barite 340-1400 parts;

[0050] 30-60 parts of an aqueous solution of inorganic chloride salts;

[0051] 240-270 parts oil.

[0052] This invention does not impose any particular limitation on fatty acid amides, alkanolamides, alkalinity regulators, organoclay, flow pattern regulators, nano-blocking agents, filtration loss reducers, barite, inorganic chloride salt aqueous solutions, and oils. The materials can be selected from those commonly used in the art, such as fatty acid amides, alkanolamides, alkalinity regulators, organoclay, flow pattern regulators, nano-blocking agents, filtration loss reducers, barite, inorganic chloride salt aqueous solutions, and oils.

[0053] The oil-based drilling fluid of this invention is composed of specific amounts of fatty acid amides, alkanolamides, alkalinity regulators, organic clay, flow pattern regulators, nano-plugging agents, filtration loss reducers, barite, inorganic chloride salt aqueous solutions, and oil. This oil-based drilling fluid exhibits excellent rheological stability, emulsification stability, sedimentation stability, and filtration loss reduction stability under ultra-high temperature environments, thus better maintaining wellbore stability. It effectively solves the problem of performance instability of oil-based drilling fluids under ultra-high temperature conditions (200-260℃), with a salt water intrusion resistance of up to 50% and a cuttings intrusion resistance of over 50%, meeting the actual drilling needs of deep / ultra-deep oil and gas wells.

[0054] In this invention, the weight proportions of each component can be further selected in order to further improve the rheological stability, emulsification stability, sedimentation stability and filtration loss reduction stability of oil-based drilling fluid.

[0055] In some embodiments of the present invention, the oil-based drilling fluid comprises the following components by weight:

[0056] 10-11 parts of fatty acid amide;

[0057] 10-11 parts of alkanolamide;

[0058] 11-13 parts alkalinity adjuster;

[0059] 4.5-10.5 parts organic soil;

[0060] Flow pattern regulator 4.5-10.5 parts;

[0061] 13-14 parts of nano-blocking agent;

[0062] 16-17 parts of filtration loss reducer;

[0063] Barite 340-1400 parts;

[0064] 30-60 parts of an aqueous solution of inorganic chloride salts;

[0065] 240-270 parts oil.

[0066] Furthermore, the present invention can further improve the rheological stability, emulsification stability, sedimentation stability and filtration loss reduction stability of oil-based drilling fluids by further selecting the components.

[0067] In some embodiments of the present invention, the mass ratio of unsaturated fatty acid, tallow propylene diamine, diphenylethylenediamine, diethylenetriamine and salicylic acid in the fatty acid amide is (80-140):(20-50):(25-50):(10-35):(50-75).

[0068] Furthermore, in the fatty acid amide, the mass ratio of unsaturated fatty acid, tallow propylene diamine, diphenylethylenediamine, diethylenetriamine and salicylic acid is (100-120):(30-40):(35-40):(20-25):(60-65).

[0069] The unsaturated fatty acids involved in this invention may be selected from at least one of arachidic acid, soybean oleic acid, olive oil, and tea oil.

[0070] In some embodiments of the present invention, fatty acid amides can be prepared by a method including the following steps:

[0071] Unsaturated fatty acids, tartrate-based propylene diamine, diphenylethylene diamine, and diethylenetriamine were subjected to an amidation reaction at 175℃-195℃ for 6-8 hours. Salicylic acid was then added at 180℃-205℃, and the reaction was continued with excess amine for 2-4 hours to obtain fatty acid amides.

[0072] In some embodiments of the present invention, the mass ratio of unsaturated fatty acid, diethanolamine, propylene dithiol, 2-dibutylamine-4,6-dithiol and sulfonic acid in the alkanolamide is (60-100):(10-40):(10-40):(10-30):(60-100).

[0073] In some embodiments of the present invention, alkanolamides can be prepared by a method including the following steps:

[0074] Unsaturated fatty acids, diethanolamine, propylene dithiol, and 2-dibutylamine-4,6-dithiol were subjected to an amidation reaction at 95℃-125℃ for 10-16 h. Sulfonic acid was then added at 150℃-185℃, and the reaction was continued with excess amine for 1-4 h to obtain alkanolamide.

[0075] In some embodiments of the present invention, the alkalinity adjuster is selected from at least one of sodium hydroxide, potassium hydroxide, calcium oxide, and magnesium oxide.

[0076] Furthermore, the alkalinity regulator can be calcium oxide.

[0077] In some embodiments of the present invention, the filtration loss reducing agent is selected from at least one of oxidized asphalt, organic lignite, and humic acid amide resin.

[0078] Furthermore, the filtration loss reducer can be selected from oxidized bitumen and / or organic lignite. Even further, the filtration loss reducer can be selected from oxidized bitumen.

[0079] In some embodiments of the present invention, the mass ratio of bentonite, n-octyltriethoxysilane, aminopropyltriethoxysilane and dioctadecyldimethylammonium chloride in the organic soil is (100-180):(25-50):(5-20):(10-30).

[0080] Furthermore, in the organic soil, the mass ratio of bentonite, n-octyltriethoxysilane, aminopropyltriethoxysilane and dioctadecyldimethylammonium chloride is (130-150):(30-40):(10-15):(20-25).

[0081] In some embodiments of the present invention, organic soil can be prepared by a method including the following steps:

[0082] Bentonite, n-octyltriethoxysilane and aminopropyltriethoxysilane were subjected to surface grafting reaction at 45℃-65℃ for 1-3 hours. Then, dioctadecyldimethylammonium chloride was added at room temperature to carry out the second step of intercalation modification reaction for 0.5-2 hours to obtain organic soil.

[0083] In some embodiments of the present invention, the mass ratio of trimeric fatty acid, polyetheramine, nano-silica and silane coupling agent in the flow pattern regulator is (100-150):(50-90):(1-10):(2-15).

[0084] Furthermore, in the flow pattern regulator, the mass ratio of trimeric fatty acid, polyetheramine, nano-silica and silane coupling agent is (120-130):(60-80):(4-6):(5-10).

[0085] The silane coupling agent of the present invention can be a silane coupling agent containing unsaturated hydrocarbon groups.

[0086] In some embodiments of the present invention, flow pattern regulators can be prepared by a method including the following steps:

[0087] Nano-silica and unsaturated chain silane coupling agent are subjected to sol-gel reaction at 45℃-65℃ for 1-3 hours. Trimeric fatty acid and polyetheramine are added at room temperature, and the temperature is raised to 150℃ for the second amidation reaction for 2-6 hours to obtain flow pattern regulator.

[0088] In some embodiments of the present invention, the mass ratio of carbon nanotubes, styrene, acrylamide, N-vinylpyrrolidone and allyltriethoxysilane in the nano-blocking agent is (2-10):(30-60):(25-75):(30-60):(5-15).

[0089] Furthermore, in the nano-blocking agent, the mass ratio of carbon nanotubes, styrene, acrylamide, N-vinylpyrrolidone and allyltriethoxysilane is (4-6):(40-50):(40-50):(40-50):(8-12).

[0090] In some embodiments of the present invention, nano-blocking agents can be prepared by a method including the following steps:

[0091] Carbon nanotubes and allyltriethoxysilane were surface modified at 25℃-55℃ for 1-3 hours. Styrene, acrylamide and N-vinylpyrrolidone were added at room temperature, and the temperature was raised to 45℃ for polymerization for 2-5 hours to obtain a nano-blocking agent.

[0092] In some embodiments of the present invention, the density of barite is greater than or equal to 4.30 g / cm³. 3 .

[0093] In some embodiments of the present invention, the inorganic chloride aqueous solution contains 15-35% by mass of inorganic chloride.

[0094] In this invention, the inorganic chloride salt can be selected from alkali metal chlorides and / or alkaline earth metal chlorides. For example, the inorganic chloride salt can be selected from at least one of sodium chloride, calcium chloride, and potassium chloride.

[0095] In some embodiments of the present invention, the oil is selected from at least one of diesel oil, gas-derived oil, and white oil.

[0096] When the oil is white oil, it can be No. 3 white oil and / or No. 5 white oil. The relevant parameters for No. 3 white oil are: flash point of 220℃, kinematic viscosity at 40℃ of 3 mm² / s, and specific gravity of 0.85; the relevant parameters for No. 5 white oil are: flash point of 220℃, kinematic viscosity at 40℃ of 3.5 mm² / s. 2 / s, specific gravity is 0.85.

[0097] A second aspect of the present invention provides a method for preparing the above-mentioned oil-based drilling fluid, comprising: mixing fatty acid amide, alkanolamide, alkalinity regulator, organic clay, flow pattern regulator, nano-plugging agent, filtration loss reducer, barite, inorganic chloride aqueous solution and oil to obtain the oil-based drilling fluid.

[0098] In this invention, the oil-based drilling fluid of this invention can be obtained by mixing specific amounts of the above-mentioned raw materials. Specifically, the preparation method of the oil-based drilling fluid of this invention includes:

[0099] At a stirring speed of 11,000 rpm, fatty acid amides and alkanolamides were added to the oil and stirred for 20 min. Then, organic clay was added and stirred for 10 min. A flow pattern regulator was added and stirred for 10 min. An inorganic chloride salt aqueous solution was added and stirred for 20 min. A nano-plugging agent was added and stirred for 10 min. An alkalinity regulator was added and stirred for 10 min. A filtration loss reducer was added and stirred for 10 min. Finally, barite was added and stirred for 30 min to obtain an oil-based drilling fluid.

[0100] The method for preparing the oil-based drilling fluid of the present invention can produce the above-mentioned oil-based drilling fluid. The preparation method is simple to operate and suitable for widespread application.

[0101] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0102] Example 1

[0103] The oil-based drilling fluid of this embodiment is prepared by a method including the following steps:

[0104] Take 240g of diesel fuel, add 10.5g of fatty acid amide and 10.5g of alkanolamide at a stirring speed of 11000 rpm, stir at high speed for 10 min, then add 10.5g of organic clay and stir at high speed for 10 min. Add 10.5g of flow modifier and stir at high speed for 10 min. Add 60g of 25wt% CaCl2 aqueous solution and stir at high speed for 20 min. Add 12g of calcium oxide and stir at high speed for 10 min. Add 14g of nano-sealing agent and stir at high speed for 10 min. Add 17g of oxidized asphalt and stir at high speed for 10 min. Finally, add 340g of fuel with a density of 4.30g / cm³. 3 The barite was stirred for 30 minutes to obtain a density of 1.6 g / cm³. 3 Oil-based drilling fluids;

[0105] Fatty acid amides are prepared by the following method:

[0106] Unsaturated fatty acids, taurate-based propylene diamine, diphenylethylene diamine, and diethylenetriamine were added to a three-necked flask in a mass ratio. The temperature was raised to 175°C and reacted for 4 hours. Then the temperature was raised to 195°C and reacted for 2 hours. When the temperature was lowered to 80°C, salicylic acid was added in a mass ratio and reacted for 4 hours to obtain the final product, fatty acid amide.

[0107] The mass ratio of unsaturated fatty acids, tallow-based propylene diamine, diphenylethylenediamine, diethylenetriamine, and salicylic acid is 110:35:37.5:22.5:62.5;

[0108] Alkylamides are prepared by the following method:

[0109] Unsaturated fatty acids, diethanolamine, propylene dithiol, and 2-dibutylamine-4,6-dithiol were added to a three-necked flask in a mass ratio. The temperature was raised to 165°C and reacted for 6 hours. The temperature was then lowered to 120°C, and sulfonic acid was added in a mass ratio. The reaction was continued for 4 hours to obtain the final product, alkanolamide.

[0110] The mass ratio of unsaturated fatty acids, diethanolamine, propylene dithiol, 2-dibutylamine-4,6-dithiol, and sulfonic acid is 80:25:25:20:80.

[0111] Organic soil is prepared by the following method:

[0112] First, a certain mass of bentonite is added to water and stirred and dispersed. Then, n-octyltriethoxysilane and aminopropyltriethoxysilane are added according to the mass ratio. The temperature is raised to 50°C and the reaction is carried out for 4 hours. Then, dioctadecyldimethylammonium chloride is added and the mixture is stirred for another 2 hours to obtain the final product, organo-earth.

[0113] The mass ratio of bentonite, n-octyltriethoxysilane, aminopropyltriethoxysilane, and dioctadecyldimethylammonium chloride is 140:35:17.5:22.5.

[0114] The flow pattern regulator was prepared by the following method:

[0115] First, nano-silica and silane coupling agent are added to an alcohol-water mixture solution with a mass ratio of 30:70. The pH is adjusted to 10 using ammonia water, and the mixture is stirred continuously for 4 hours. The temperature is then raised to 150°C, and polyetheramine D230 is added according to the mass ratio. The mixture is reacted for 3 hours, and then trimeric fatty acids are added according to the mass ratio. The mixture is reacted for 2 hours, and the temperature is lowered to obtain the final product, a flow pattern regulator.

[0116] The mass ratio of trimeric fatty acid, polyetheramine D230, nano-silica, and silane coupling agent is 125:70:5:7.5.

[0117] The nano-blocking agent was prepared by the following method:

[0118] First, carbon nanotubes were dispersed in a 50:50 ethanol-water mixture. Allyltriethoxysilane was added according to the mass ratio, and the pH was adjusted to 10 with ammonia. The reaction was carried out at room temperature for 2 hours. Then, styrene, acrylamide and N-vinylpyrrolidone were added according to the mass ratio, the temperature was raised to 50°C, and the reaction was carried out for 3 hours to obtain the final product, a nano-blocking agent.

[0119] The mass ratio of carbon nanotubes, styrene, acrylamide, N-vinylpyrrolidone, and allyltriethoxysilane is 5:45:45:45:10.

[0120] Example 2

[0121] The oil-based drilling fluid of this embodiment is prepared by a method including the following steps:

[0122] Take 240 mL of diesel oil, add 10.5 g of fatty acid amide and 10.5 g of alkanolamide at a stirring speed of 11000 rpm, stir at high speed for 10 min, then add 9 g of organic clay and stir at high speed for 10 min, add 9 g of flow modifier and stir at high speed for 10 min, then add 60 mL of 25 wt% CaCl2 aqueous solution and stir at high speed for 20 min, then add 12 g of calcium oxide and stir at high speed for 10 min, then add 14 g of nano-sealing agent and stir at high speed for 10 min, then add 17 g of oxidized asphalt and stir at high speed for 10 min, finally add 470 g of asphalt with a density of 4.30 g / cm³. 3 The barite was stirred for 30 minutes to obtain a density of 1.8 g / cm³. 3 Oil-based drilling fluids;

[0123] The compositions of the alkanolamide, organoclay, flow modifier, and nano-blocking agent are the same as in Example 1.

[0124] Example 3

[0125] The oil-based drilling fluid of this embodiment is prepared by a method including the following steps:

[0126] Take 255 mL of diesel oil, add 10.5 g of fatty acid amide and 10.5 g of alkanolamide at a stirring speed of 11000 rpm, stir at high speed for 10 min, then add 7.5 g of organic clay, stir at high speed for 10 min, add 7.5 g of flow modifier, stir at high speed for 10 min, add 45 mL of 25 wt% CaCl2 aqueous solution, stir at high speed for 20 min, add 12 g of calcium oxide, stir at high speed for 10 min, add 14 g of nano-sealing agent, stir at high speed for 10 min, then add 17 g of oxidized asphalt, stir at high speed for 10 min, and finally add 630 g of asphalt with a density of 4.30 g / cm³. 3 Barite, stirred for 30 minutes, yielded a density of 2 g / cm³. 3 Oil-based drilling fluids;

[0127] The compositions of the alkanolamide, organoclay, flow modifier, and nano-blocking agent are the same as in Example 1.

[0128] Example 4

[0129] The oil-based drilling fluid of this embodiment is prepared by a method including the following steps:

[0130] Take 255 mL of diesel oil, add 10.5 g of fatty acid amide and 10.5 g of alkanolamide at a stirring speed of 11000 rpm, stir at high speed for 10 min, then add 7.5 g of organic clay, stir at high speed for 10 min, add 7.5 g of flow modifier, stir at high speed for 10 min, add 45 mL of 25 wt% CaCl2 aqueous solution, stir at high speed for 20 min, add 12 g of calcium oxide, stir at high speed for 10 min, add 14 g of nano-sealing agent, stir at high speed for 10 min, then add 17 g of oxidized asphalt, stir at high speed for 10 min, and finally add 820 g of asphalt with a density of 4.30 g / cm³. 3 The barite was stirred for 30 minutes to obtain a density of 2.2 g / cm³. 3 Oil-based drilling fluids;

[0131] The compositions of the alkanolamide, organoclay, flow modifier, and nano-blocking agent are the same as in Example 1.

[0132] Example 5

[0133] The oil-based drilling fluid of this embodiment is prepared by a method including the following steps:

[0134] Take 270 mL of diesel oil, add 10.5 g of fatty acid amide and 10.5 g of alkanolamide at a stirring speed of 11000 rpm, stir at high speed for 10 min, then add 6 g of organic clay and stir at high speed for 10 min, add 6 g of flow modifier and stir at high speed for 10 min, then add 60 mL of 25 wt% CaCl2 aqueous solution and stir at high speed for 20 min, then add 12 g of calcium oxide and stir at high speed for 10 min, then add 14 g of nano-sealing agent and stir at high speed for 10 min, then add 17 g of oxidized asphalt and stir at high speed for 10 min, finally add 1050 g of asphalt with a density of 4.30 g / cm³. 3 The barite was stirred for 30 minutes to obtain a density of 2.4 g / cm³. 3 Oil-based drilling fluids;

[0135] The compositions of the alkanolamide, organoclay, flow modifier, and nano-blocking agent are the same as in Example 1.

[0136] Example 6

[0137] The oil-based drilling fluid of this embodiment is prepared by a method including the following steps:

[0138] Take 270 mL of diesel oil, add 10.5 g of fatty acid amide and 10.5 g of alkanolamide at a stirring speed of 11000 rpm, stir at high speed for 10 min, then add 4.5 g of organic clay, stir at high speed for 10 min, add 4.5 g of flow modifier, stir at high speed for 10 min, add 30 mL of 25 wt% CaCl2 aqueous solution, stir at high speed for 20 min, add 12 g of calcium oxide, stir at high speed for 10 min, add 14 g of nano-sealing agent, stir at high speed for 10 min, then add 17 g of oxidized asphalt, stir at high speed for 10 min, and finally add 1400 g of asphalt with a density of 4.30 g / cm³. 3 The barite was stirred for 30 minutes to obtain a density of 2.6 g / cm³. 3 Oil-based drilling fluids;

[0139] The compositions of the alkanolamide, organoclay, flow modifier, and nano-blocking agent are the same as in Example 1.

[0140] Experimental Example 1

[0141] The rheological properties, emulsification stability, and filtration loss reduction of the oil-based drilling fluids in Examples 1-5 before and after ultra-high temperature aging are shown in Table 1. The specific test methods include:

[0142] Oil-based drilling fluid is placed in an aging tank and aged at 260℃ for 16 hours (48 hours or 72 hours). After cooling to room temperature, the tank is opened and the sedimentation of the drilling fluid is examined using a glass rod. The results are as follows: hard sedimentation indicates severe barite sedimentation, preventing the freely falling glass rod from reaching the bottom of the aging tank; soft sedimentation indicates a density difference exists within the drilling fluid in the aging tank, resulting in weaker barite sedimentation, allowing the glass rod to slowly reach the bottom; no sedimentation indicates no density difference between the top and bottom of the drilling fluid after aging.

[0143] The drilling fluid in the aging tank was stirred at 12,000 rpm for 10 minutes, then heated to 65°C. The scale readings at 600 rpm, 300 rpm, 6 rpm (Φ6 / ), and 3 rpm (Φ3) were measured using a ZNN-D6 six-speed rotational viscometer. The rheological parameters of the drilling fluid were calculated according to the following formula:

[0144] Apparent viscosity: AV = 1 / 2 × 600 r / min (reading) mPa.s

[0145] Plastic viscosity: PV = 600 r / min (reading) - 300 r / min (reading) mPa·s

[0146] Dynamic shear force: YP = 1 / 2 × (300 r / min (reading) – PV) Pa.

[0147] The high-temperature, high-pressure filtration loss (FL) of drilling fluid is determined according to GB / T 16783.2. HTHP) and demulsification voltage (ES).

[0148] Table 1 Performance of Oil-Based Drilling Fluids of Different Densities

[0149]

[0150] As can be seen from Table 1, the oil-based drilling fluid in the embodiments of the present invention has excellent high-temperature rheological stability, emulsification stability and reduced filtration loss.

[0151] Experimental Example 2

[0152] The resistance of the oil-based drilling fluid in Example 1 to salt water intrusion was tested according to GB / T 16783.2, and the results are shown in Table 2.

[0153] Table 2 Evaluation of Saltwater Intrusion Resistance of Oil-Based Drilling Fluid in Example 1

[0154]

[0155]

[0156] As can be seen from Table 2, the oil-based drilling fluid in Example 1 of the present invention has excellent resistance to salt water intrusion, with a resistance of up to 50%.

[0157] Experimental Example 3

[0158] The resistance to cuttings erosion of the oil-based drilling fluid in Example 1 was tested according to GB / T 16783.2, and the results are shown in Table 3.

[0159] Table 3 Evaluation of Cuttings Resistance of Oil-Based Drilling Fluid in Example 1

[0160] 0% rock cuttings 55 48 7 7 / 6 10% rock cuttings 58 50 8 8 / 7 20% rock cuttings 61 52 9 9 / 8 30% rock cuttings 66 54 12 12 / 10 40% rock cuttings 79 61 18 17 / 15 50% rock cuttings 96 72 24 24 / 22

[0161] As can be seen from Table 3, the oil-based drilling fluid of this invention has excellent resistance to cuttings intrusion, with a resistance of over 50%.

[0162] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. An oil-based drilling fluid, characterized in that, The following components are included in parts by weight: 9-12 parts of fatty acid amides; 9-12 parts of alkanolamide; 9-15 parts alkalinity adjuster; 3-12 parts organic soil; 3-12 parts of flow pattern regulator; 12-15 parts of nano-blocking agent; 15-18 parts of filtration loss reducer; Barite 340-1400 parts; 30-60 parts of an aqueous solution of inorganic chloride salts; 240-270 parts oil; In the flow pattern regulator, the mass ratio of trimeric fatty acid, polyetheramine, nano-silica and silane coupling agent is (100-150):(50-90):(1-10):(2-15).

2. The oil-based drilling fluid according to claim 1, characterized in that, The following components are included in parts by weight: 10-11 parts of fatty acid amide; 10-11 parts of alkanolamide; 11-13 parts alkalinity adjuster; 4.5-10.5 parts organic soil; Flow pattern regulator 4.5-10.5 parts; 13-14 parts of nano-blocking agent; 16-17 parts of filtration loss reducer; Barite 340-1400 parts; 30-60 parts of an aqueous solution of inorganic chloride salts; 240-270 parts oil.

3. The oil-based drilling fluid according to claim 1 or 2, characterized in that, In the fatty acid amide, the mass ratio of unsaturated fatty acid, tallow propylene diamine, diphenylethylene diamine, diethylenetriamine and salicylic acid is (80-140):(20-50):(25-50):(10-35):(50-75).

4. The oil-based drilling fluid according to claim 1 or 2, characterized in that, In the alkanolamide, the mass ratio of unsaturated fatty acid, diethanolamine, propylene dithiol, 2-dibutylamine-4,6-dithiol and sulfonic acid is (60-100):(10-40):(10-40):(10-30):(60-100).

5. The oil-based drilling fluid according to claim 1 or 2, characterized in that, The alkalinity adjuster is selected from at least one of sodium hydroxide, potassium hydroxide, calcium oxide, and magnesium oxide; and / or, The filtration loss reducer is selected from at least one of oxidized asphalt, organic lignite, and humic acid amide resin.

6. The oil-based drilling fluid according to claim 1 or 2, characterized in that, In the organic soil, the mass ratio of bentonite, n-octyltriethoxysilane, aminopropyltriethoxysilane and dioctadecyldimethylammonium chloride is (100-180):(25-50):(5-20):(10-30).

7. The oil-based drilling fluid according to claim 1 or 2, characterized in that, In the nano-blocking agent, the mass ratio of carbon nanotubes, styrene, acrylamide, N-vinylpyrrolidone and allyltriethoxysilane is (2-10):(30-60):(25-75):(30-60):(5-15).

8. The oil-based drilling fluid according to claim 1 or 2, characterized in that, The density of the barite is greater than or equal to 4.30 g / cm³. 3 ; and / or, The inorganic chloride aqueous solution contains 15-35% inorganic chloride by mass; and / or, The oil is selected from at least one of diesel, gas-derived oil, and white oil.

9. A method for preparing the oil-based drilling fluid according to any one of claims 1-8, characterized in that, include: The oil-based drilling fluid is obtained by mixing fatty acid amides, alkanolamides, alkalinity regulators, organic clay, flow pattern regulators, nano-plugging agents, filtration loss reducers, barite, inorganic chloride salt aqueous solutions, and oil.

Images