Emulsifier for oil-based petroleum drilling fluid and preparation method thereof

Abstract

The invention discloses an emulsifier for oil-based petroleum drilling fluid and a preparation method of the emulsifier, and belongs to the technical field of petroleum drilling, the emulsifier comprises an emulsion A and an emulsion B, the weight ratio of the emulsion A to the emulsion B is (1.5-2): 1, the emulsion A is formed by mixing a polyesteramide emulsion and a polyamide emulsion, and the preparation method comprises the following steps: preparing the emulsion A, preparing the emulsion B and preparing the emulsion B; the emulsion A and the emulsion B are mixed and cooled to form the emulsifier, and the emulsion A and the emulsion B are mixed, so that when the emulsion formed by the technical scheme is used, the emulsion has relatively high high-temperature and high-pressure resistance, the filter vector of the drilling fluid is reduced, the suspension stability and the flowability of the drilling fluid are improved, and the emulsion has the effects of high emulsification and high wettability; according to the present invention, the oil-based petroleum drilling fluid has characteristics of high viscosity, high stability during use, easy use in the oil-based petroleum drilling fluid, simple process during preparation, and easy large-scale production.

Description

Technical Field

[0001] The invention relates to an emulsifier, in particular to an emulsifier for oil-based petroleum drilling fluid and a preparation method thereof, belonging to the technical field of petroleum drilling. Background Art

[0002] Emulsifier for oil-based petroleum drilling fluid is a special chemical treatment agent, which is mainly used to promote two immiscible liquids (such as oil and water) to form a uniformly mixed emulsion. Emulsifier for oil-based petroleum drilling fluid plays a vital role in drilling operations. The correct selection and use of emulsifiers are of great significance to improving drilling efficiency, reducing costs, and protecting the environment. The components of emulsifiers for oil-based petroleum drilling fluid are complex and diverse. The selection and ratio of these components need to be determined according to the specific needs of the drilling fluid and the working environment.

[0003] For example, the Chinese invention patent with the announcement number CN116948613A discloses an emulsifier for oil-based drilling fluid and its preparation method. The preparation method of an emulsifier for oil-based drilling fluid of the invention comprises the following steps: S1, subjecting the fatty acid regenerated from waste cooking oil to amidation reaction with polyethylene polyamine; S2, subjecting the product of the amidation reaction in step S1 to amidation reaction with compound A; the compound A is selected from one or any combination of dicarboxylic acid compounds, polycarboxylic acid compounds, and acid anhydride compounds. The preparation method of the emulsifier for oil-based drilling fluid of the invention uses fatty acid regenerated from waste cooking oil as the basic raw material, has more superior environmental protection and economy, and the prepared emulsifier, when used in oil-based drilling fluid, can improve the rheological properties of high-density oil-based drilling fluid, reduce the viscosity and shear force of high-density oil-based drilling fluid, speed up the drilling speed, and prevent the occurrence of complicated downhole situations such as leakage.

[0004] Another example is a Chinese invention patent with the announcement number CN118956358A, which discloses an emulsifier for oil-based drilling fluid and a preparation method thereof; the preparation method of the emulsifier for oil-based drilling fluid comprises the following steps: after nitrogen is passed through the mixed vegetable oil fatty acid for deoxygenation, the organic amine and the mixed vegetable oil fatty acid are dissolved in a solvent for reaction, and then an acid anhydride is added for acylation reaction; white oil is added for complete reaction, and the oil-based drilling fluid emulsifier is obtained after cooling to room temperature. The emulsifier is environmentally friendly, has a simple preparation method, has excellent temperature resistance and emulsification properties, and can stabilize the oil-water interface in the drilling fluid system, prevent oil-water separation, and thus maintain the long-term stability of the performance of the oil-based drilling fluid.

[0005] However, when in use, the high temperature resistance is poor. During high temperature drilling, the performance of the emulsifier is greatly reduced, which reduces the suspension stability and fluidity of the drilling fluid, increases the filtration vector of the drilling fluid, and is not convenient for stable use. Summary of the invention

[0006] The purpose of the present invention is to provide an emulsifier for oil-based petroleum drilling fluid and a preparation method thereof in order to solve the above-mentioned problems, which can improve the high temperature resistance during use and increase the suspension stability and fluidity of the drilling fluid.

[0007] The present invention achieves the above-mentioned purpose through the following technical scheme: an emulsifier for oil-based petroleum drilling fluid and a preparation method thereof, comprising emulsion A and emulsion B, wherein the weight ratio of the emulsion A to the emulsion B is 1.5-2:1, the emulsion A is formed by mixing a polyester amide emulsion and a polyamide emulsion, and the polyester amide emulsion and the polyamide emulsion are formulated in a weight ratio of 1.2-1.5:1, and by mixing the emulsion A and the emulsion B, the high temperature and high pressure resistance during use is improved, the thermal stability is improved, and the suspension stability and fluidity of the drilling fluid are guaranteed.

[0008] Preferably, in order to improve the wettability and dispersibility of the emulsifier and reduce the oil-water interfacial tension, the emulsion B is made of ingredients including white oil, erucic acid, calcium stearate, fatty alcohol polyoxyethylene ether, glyceryl stearate, cetearyl alcohol, and sorbitol polyether.

[0009] Preferably, in order to better exert the emulsifying performance, the ingredients in the emulsion B are mixed according to a weight ratio of 220-280 parts of the white oil, 60-75 parts of the erucic acid, 55-65 parts of the calcium stearate, 80-110 parts of the fatty alcohol polyoxyethylene ether, 10-22 parts of the glyceryl stearate, 30-45 parts of the cetearyl alcohol and 35-48 parts of the sorbitan polyether.

[0010] When preparing, the method is as follows:

[0011] S1, preparing the emulsion A;

[0012] S2, preparing the emulsion B;

[0013] S3, mixing the emulsion A with the emulsion B;

[0014] S4. Cooling the obtained mixture to form an emulsifier.

[0015] Preferably, in order to facilitate the preparation of the emulsion A, in step S1, when preparing the emulsion A, the polyester amide emulsion and the polyamide emulsion in a weight ratio of 1.2-1.5:1 are injected into the interior of the reactor, heated to 60-80 degrees Celsius in a water bath, and stirred at a stirring speed of 200-350 revolutions per minute for 15-30 minutes. After the stirring is completed, it is allowed to stand for 30-60 minutes. During the standing, it is in a heat preservation state, and after the standing is completed, it is naturally cooled to room temperature to obtain the emulsion A.

[0016] Preferably, in order to facilitate the preparation of the emulsion B, in step S2, when preparing the emulsion B, the erucic acid and the calcium stearate are injected into the white oil, and dissolved and stirred. During stirring, the temperature is controlled at 45-60 degrees Celsius, the rotation speed during stirring is controlled at 300-350 rpm, and sufficient mixing is carried out. The stirring time is controlled at 5-10 minutes. After the mixing is completed, the fatty alcohol polyoxyethylene ether, the cetearyl alcohol and the sorbitan polyether are added, and after the addition, the temperature is raised to 75-85 degrees Celsius, and stirring is continued. During stirring, the rotation speed is controlled at 220-300 rpm and 60-110 rpm, and the two stirring speeds are used alternately. The alternating interval time is 1-3 minutes, and the total stirring time is controlled at 20-30 minutes. During stirring, the glyceryl stearate is added dropwise.

[0017] Preferably, in order to improve the performance of the emulsion B, after the glyceryl stearate is added dropwise, the emulsion is kept warm and allowed to stand at a temperature of 55-70 degrees Celsius for 30-60 minutes, and then cooled naturally to form the emulsion B.

[0018] Preferably, in order to produce the fatty alcohol polyoxyethylene ether and the sorbitol polyether, the fatty alcohol polyoxyethylene ether is produced by reacting fatty alcohol and ethylene oxide, and the sorbitol polyether is produced by reacting sorbitol and ethylene oxide.

[0019] Preferably, in order to facilitate mixing the emulsion A and the emulsion B, in step S3, when the emulsion A and the emulsion B are mixed, the emulsion A and the emulsion B are injected into a stirring device at a weight ratio of 1.5-2:1, and the temperature is raised to 60-80 degrees Celsius and stirred. The stirring speed is controlled at 120-250 revolutions per minute. After stirring for 10-20 minutes, the emulsion is kept warm and allowed to stand for 30-50 minutes. Then, step S4 is performed. In step S4, when cooling, step-by-step cooling is adopted, and the cooling rate is controlled at a rate of 1-2 degrees Celsius per minute to cool to room temperature to obtain an emulsifier for oil-based petroleum drilling fluid.

[0020] Beneficial effects:

[0021] By mixing emulsion A and emulsion B, the emulsion formed by the technical solution has high high temperature and high pressure resistance when in use, reduces the filtration vector of the drilling fluid, and improves the suspension stability and fluidity of the drilling fluid. It has the effects of high emulsification and high wettability, improves the stability when in use, and is convenient for use in oil-based petroleum drilling fluid. In addition, the process is simple during preparation, which is convenient for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a composition ratio diagram of the present invention.

[0023] Figure 2 A flow chart was prepared for the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1

[0026] See also Figure 1-Figure 2As shown, an emulsifier for oil-based petroleum drilling fluid and a preparation method thereof, comprising emulsion A and emulsion B, wherein the weight ratio of emulsion A to emulsion B is 1.5:1, emulsion A is prepared by mixing polyester amide emulsion and polyamide emulsion, and the polyester amide emulsion and polyamide emulsion are prepared by mixing at a weight ratio of 1.2:1, and by mixing emulsion A and emulsion B, the high temperature and high pressure resistance during use is improved, and the thermal stability is improved, thereby ensuring the suspension stability and fluidity of the drilling fluid, and the components of emulsion B include white oil, erucic acid, calcium stearate, fatty alcohol polyoxyethylene ether, glycerol stearate, cetearyl alcohol, and sorbitol polyether, and the components in emulsion B are mixed at a weight ratio of 220 parts of white oil, 60 parts of erucic acid, 55 parts of calcium stearate, 80 parts of fatty alcohol polyoxyethylene ether, 10 parts of glycerol stearate, 30 parts of cetearyl alcohol, and 35 parts of sorbitol polyether.

[0027] When preparing, the method is as follows:

[0028] S1. preparing emulsion A;

[0029] S2, preparing emulsion B;

[0030] S3, mixing emulsion A and emulsion B;

[0031] S4. Cooling the obtained mixture to form an emulsifier.

[0032] As a technical optimization solution of the present invention, Figure 2As shown, in step S1, when preparing emulsion A, a polyester amide emulsion and a polyamide emulsion in a weight ratio of 1.2:1 are injected into the interior of a reactor, heated to 60 degrees Celsius in a water bath, and stirred at a stirring speed of 200 revolutions per minute for 15 minutes. After the stirring is completed, the mixture is allowed to stand for 30 minutes in a heat preservation state, and after the standing is completed, the mixture is naturally cooled to room temperature to obtain emulsion A. In step S2, emulsion B is subjected to During the preparation, erucic acid and calcium stearate are injected into the white oil, dissolved and stirred. During the stirring, the temperature is controlled at 45 degrees Celsius, the speed during stirring is controlled at 300 revolutions per minute, and the stirring time is controlled at 5 minutes. After the mixing is completed, fatty alcohol polyoxyethylene ether, cetearyl alcohol and sorbitol polyether are added, and after the addition, the temperature is raised to 75 degrees Celsius, and stirring is continued. The rotation speed during stirring is controlled at 220 revolutions per minute and 60 revolutions per minute. The stirring speed is alternated, the alternating interval time is 1 minute, the total stirring time is controlled to be 20 minutes, and while stirring, glyceryl stearate is added dropwise, after the glyceryl stearate is added dropwise, the mixture is kept warm and allowed to stand, the temperature of the warming is controlled at 55 degrees Celsius, and the mixture is allowed to stand for 30 minutes, and then the temperature is naturally lowered to form emulsion B, the fatty alcohol polyoxyethylene ether is generated by reacting fatty alcohol and ethylene oxide, and the sorbitol polyether is generated by reacting sorbitol and ethylene oxide. In step S3, emulsion A and emulsion B are mixed. When mixing with B, emulsion A and emulsion B in a weight ratio of 1.5:1 are injected into a stirring device, and the temperature is raised to 60 degrees Celsius and stirred. The stirring speed is controlled at 120 revolutions per minute. After stirring for 10 minutes, the mixture is kept warm and allowed to stand for 30 minutes. Then, step S4 is performed. In step S4, when cooling, step-by-step cooling is adopted. The cooling rate is controlled at a rate of 1 degree Celsius per minute to cool to room temperature to obtain an emulsifier for oil-based petroleum drilling fluid.

[0033] Example 2

[0034] See also Figure 1-Figure 2As shown, an emulsifier for oil-based petroleum drilling fluid and a preparation method thereof, comprising emulsion A and emulsion B, wherein the weight ratio of emulsion A to emulsion B is 1.8:1, emulsion A is prepared by mixing polyester amide emulsion and polyamide emulsion, and the polyester amide emulsion and polyamide emulsion are prepared by mixing at a weight ratio of 1.3:1, and by mixing emulsion A and emulsion B, the high temperature and high pressure resistance during use is improved, and the thermal stability is improved, thereby ensuring the suspension stability and fluidity of the drilling fluid, and the components of emulsion B include white oil, erucic acid, calcium stearate, fatty alcohol polyoxyethylene ether, glycerol stearate, cetearyl alcohol, and sorbitol polyether, and the components in emulsion B are mixed at a weight ratio of 250 parts of white oil, 70 parts of erucic acid, 60 parts of calcium stearate, 95 parts of fatty alcohol polyoxyethylene ether, 15 parts of glycerol stearate, 35 parts of cetearyl alcohol, and 42 parts of sorbitol polyether.

[0035] During the preparation, the method is the same as that of Example 1, and the difference from Example 1 is that in step S1, when preparing emulsion A, a polyester amide emulsion and a polyamide emulsion in a weight ratio of 1.3:1 are injected into the interior of the reactor, heated to 70 degrees Celsius in a water bath, and stirred at a stirring speed of 300 revolutions per minute for 25 minutes. After the stirring is completed, the mixture is allowed to stand for 40 minutes, and is kept warm during the standing. After the standing is completed, the mixture is naturally cooled to room temperature. Emulsion A is obtained. In step S2, when preparing emulsion B, erucic acid and calcium stearate are injected into the white oil, and dissolved and stirred. During stirring, the temperature is controlled at 50 degrees Celsius, the rotation speed during stirring is controlled at 320 revolutions per minute, and sufficient mixing is performed. The stirring time is controlled at 8 minutes. After the mixing is completed, fatty alcohol polyoxyethylene ether, cetearyl alcohol and sorbitol polyether are added, and after the addition, the temperature is raised to 80 degrees Celsius, and stirring is continued. The rotation speed during stirring is controlled at 250 revolutions per minute. and 80 rpm, the two stirring speeds are used alternately, the alternating interval time is 2 minutes, the total stirring time is controlled to be 25 minutes, and during the stirring, glyceryl stearate is added dropwise, after the glyceryl stearate is added dropwise, the mixture is kept warm and allowed to stand, the temperature of the warming is controlled at 60 degrees Celsius, the mixture is allowed to stand for 40 minutes, and then the temperature is naturally lowered to form emulsion B, the fatty alcohol polyoxyethylene ether is generated by reacting fatty alcohol and ethylene oxide, the sorbitol polyether is generated by reacting sorbitol and ethylene oxide, and in step S3, the emulsion When liquid A and emulsion B are mixed, emulsion A and emulsion B are injected into a stirring device at a weight ratio of 1.8:1, and the temperature is raised to 70 degrees Celsius and stirred. The stirring speed is controlled at 200 revolutions per minute. After stirring for 15 minutes, the mixture is kept warm and allowed to stand for 40 minutes. Then, step S4 is performed. In step S4, when cooling, step-by-step cooling is adopted. The cooling rate is controlled to be 1.5 degrees Celsius per minute to cool to room temperature, thereby obtaining an emulsifier for oil-based petroleum drilling fluid.

[0036] Example 3

[0037] See also Figure 1-Figure 2As shown, an emulsifier for oil-based petroleum drilling fluid and a preparation method thereof, including emulsion A and emulsion B, wherein the weight ratio of emulsion A to emulsion B is 2:1, emulsion A is formed by mixing polyester amide emulsion and polyamide emulsion, and the polyester amide emulsion and polyamide emulsion are prepared in a weight ratio of 1.5:1, and by mixing emulsion A and emulsion B, the high temperature and high pressure resistance during use is improved, and the thermal stability is improved, thereby ensuring the suspension stability and fluidity of the drilling fluid, and the components of emulsion B include white oil, erucic acid, calcium stearate, fatty alcohol polyoxyethylene ether, glycerol stearate, cetearyl alcohol, and sorbitol polyether, and the components in emulsion B are mixed in a weight ratio of 280 parts of white oil, 75 parts of erucic acid, 65 parts of calcium stearate, 110 parts of fatty alcohol polyoxyethylene ether, 22 parts of glycerol stearate, 45 parts of cetearyl alcohol, and 48 parts of sorbitol polyether.

[0038] During the preparation, the method is the same as that of Example 1, and the difference from Example 1 is that in step S1, when preparing emulsion A, a polyester amide emulsion and a polyamide emulsion in a weight ratio of 1.5:1 are injected into the interior of the reactor, heated to 80 degrees Celsius in a water bath, and stirred at a stirring speed of 350 revolutions per minute for 30 minutes. After the stirring is completed, the mixture is allowed to stand for 60 minutes, and is kept warm during the standing. After the standing is completed, the mixture is naturally cooled to room temperature. Emulsion A is obtained. In step S2, when preparing emulsion B, erucic acid and calcium stearate are injected into the white oil, and dissolved and stirred. During stirring, the temperature is controlled at 60 degrees Celsius, the rotation speed during stirring is controlled at 350 revolutions per minute, and sufficient mixing is performed. The stirring time is controlled at 10 minutes. After the mixing is completed, fatty alcohol polyoxyethylene ether, cetearyl alcohol and sorbitol polyether are added, and after the addition, the temperature is raised to 85 degrees Celsius, and stirring is continued. The rotation speed during stirring is controlled at 300 revolutions per minute. The two stirring speeds are alternately used at 100 rpm and 110 rpm, with an alternating interval of 3 minutes, and the total stirring time is controlled to be 30 minutes. During the stirring, glyceryl stearate is added dropwise. After the glyceryl stearate is added dropwise, the mixture is kept warm and allowed to stand for 60 minutes at a temperature of 70 degrees Celsius, and then cooled naturally to form emulsion B. The fatty alcohol polyoxyethylene ether is generated by reacting fatty alcohol and ethylene oxide, and the sorbitol polyether is generated by reacting sorbitol and ethylene oxide. In step S3 When emulsion A and emulsion B are mixed, emulsion A and emulsion B are injected into a stirring device in a weight ratio of 2:1, and the temperature is raised to 80 degrees Celsius and stirred. The stirring speed is controlled at 250 revolutions per minute. After stirring for 20 minutes, the mixture is kept warm and allowed to stand for 50 minutes. Then, step S4 is performed. In step S4, when cooling, step-by-step cooling is adopted. The cooling rate is controlled to be 2 degrees Celsius per minute to cool to room temperature to obtain an emulsifier for oil-based petroleum drilling fluid.

[0039] The emulsifiers obtained in Examples 1 to 3 were subjected to performance tests.

[0040] The emulsifiers obtained in Examples 1 to 3 were added to the oil-based drilling fluid, and the fluid was placed in a roller heating furnace at 220 degrees Celsius for 24 hours. The demulsification voltage and filtration loss before and after the hot rolling were tested.

[0041]

[0042] Combined with the data, it can be concluded that the emulsifier obtained by the present technical solution is superior to some emulsifier products on the market in terms of high temperature resistance and stability, and has higher high temperature and high pressure resistance.

[0043] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0044] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An emulsifier for oil-based petroleum drilling fluid, characterized in that: It comprises emulsion A and emulsion B, wherein the weight ratio of emulsion A to emulsion B is 1.5-2:1, the emulsion A is formed by mixing polyester amide emulsion and polyamide emulsion, and the polyester amide emulsion and polyamide emulsion are formulated in a weight ratio of 1.2-1.5:

1.

2. The emulsifier for oil-based petroleum drilling fluid according to claim 1, characterized in that: The emulsion B is made of ingredients including white oil, erucic acid, calcium stearate, fatty alcohol polyoxyethylene ether, glyceryl stearate, cetearyl alcohol, and sorbitol polyether.

3. The emulsifier for oil-based petroleum drilling fluid according to claim 2, characterized in that: The ingredients in the emulsion B are mixed according to a weight ratio of 220-280 parts of the white oil, 60-75 parts of the erucic acid, 55-65 parts of the calcium stearate, 80-110 parts of the fatty alcohol polyoxyethylene ether, 10-22 parts of the glyceryl stearate, 30-45 parts of the cetearyl alcohol and 35-48 parts of the sorbitan polyether.

4. A method for preparing an emulsifier for oil-based petroleum drilling fluid, characterized in that: The method for preparing the oil-based petroleum drilling fluid emulsifier according to any one of claims 1 to 3 is as follows: S1, preparing the emulsion A; S2, preparing the emulsion B; S3, mixing the emulsion A with the emulsion B; S4. Cooling the obtained mixture to form an emulsifier.

5. The method for preparing an oil-based petroleum drilling fluid emulsifier according to claim 4, characterized in that: In step S1, when preparing the emulsion A, the polyester amide emulsion and the polyamide emulsion in a weight ratio of 1.2-1.5:1 are injected into the interior of the reactor, heated in a water bath to 60-80 degrees Celsius, and stirred at a stirring speed of 200-350 revolutions per minute for 15-30 minutes. After stirring, the mixture is allowed to stand for 30-60 minutes in a heat preservation state. After standing, the mixture is naturally cooled to room temperature to obtain the emulsion A.

6. The method for preparing an emulsifier for oil-based petroleum drilling fluid according to claim 4, characterized in that: In step S2, when preparing the emulsion B, the erucic acid and the calcium stearate are injected into the white oil, and dissolved and stirred. During stirring, the temperature is controlled at 45-60 degrees Celsius, the rotation speed during stirring is controlled at 300-350 rpm, and sufficient mixing is carried out. The stirring time is controlled at 5-10 minutes. After the mixing is completed, the fatty alcohol polyoxyethylene ether, the cetearyl alcohol and the sorbitol polyether are added. After the addition, the temperature is raised to 75-85 degrees Celsius, and stirring is continued. During stirring, the rotation speed is controlled at 220-300 rpm and 60-110 rpm. The two stirring speeds are used alternately, and the alternating interval time is 1-3 minutes. The total stirring time is controlled at 20-30 minutes, and during stirring, the glyceryl stearate is added dropwise.

7. The method for preparing an oil-based petroleum drilling fluid emulsifier according to claim 6, characterized in that: After the glyceryl stearate is added dropwise, the mixture is kept warm and allowed to stand at a temperature of 55-70 degrees Celsius for 30-60 minutes, and then cooled naturally to form the emulsion B.

8. The method for preparing an oil-based petroleum drilling fluid emulsifier according to claim 7, characterized in that: The fatty alcohol polyoxyethylene ether is produced by reacting fatty alcohol and ethylene oxide, and the sorbitol polyether is produced by reacting sorbitol and ethylene oxide.

9. The method for preparing an oil-based petroleum drilling fluid emulsifier according to claim 1, characterized in that: In step S3, when the emulsion A and the emulsion B are mixed, the emulsion A and the emulsion B are injected into a stirring device at a weight ratio of 1.5-2:1, and the temperature is raised to 60-80 degrees Celsius and stirred. The stirring speed is controlled at 120-250 revolutions per minute. After stirring for 10-20 minutes, the mixture is kept warm and allowed to stand for 30-50 minutes. Then, step S4 is performed. In step S4, when cooling, step-by-step cooling is adopted. The cooling rate is controlled at a rate of 1-2 degrees Celsius per minute to cool to room temperature, so as to obtain an emulsifier for oil-based petroleum drilling fluid.

Images