Ultralow-temperature drilling fluid emulsifier for polar region drilling as well as preparation method and application of ultralow-temperature drilling fluid emulsifier

Abstract

The invention provides an ultralow-temperature drilling fluid emulsifier for polar region drilling as well as a preparation method and application of the ultralow-temperature drilling fluid emulsifier. The preparation method of the emulsifier comprises the following steps: uniformly mixing an amino acid derivative and dodecylbenzene sulfonic acid, adding a catalyst, and reacting to obtain a first reaction product; uniformly mixing the first reaction product with alcohol ether organic matters, adding a catalyst, and reacting to obtain the ultralow-temperature drilling fluid emulsifier for polar region drilling. The emulsifier provided by the invention can solve the problem of poor stability of the drilling fluid emulsion under an ultralow temperature condition, and can also improve the ultralow temperature rheological property of the drilling fluid. The emulsifier disclosed by the invention is applied to ultralow-temperature drilling fluid for polar region drilling, and can improve the strength of an oil-water interface through hydrogen-bond interaction with emulsified liquid drops at the oil-water interface, so that the stability of the drilling fluid emulsion under a low-temperature condition is greatly improved, and the rheological property of the drilling fluid under the low-temperature condition is improved.

Description

Technical Field

[0001] The invention relates to an ultra-low temperature drilling fluid emulsifier for polar drilling, a preparation method and application thereof, and belongs to the technical field of polar drilling. Background Art

[0002] Antarctica holds countless scientific mysteries and rich resources. Currently, the proven oil reserves in Antarctica are approximately (7.95-15.90)×10 9 m 3 , natural gas reserves are about (3-5)×10 12 m 3 . However, existing drilling technology cannot efficiently meet the needs of exploring the above resources. Drilling fluid plays a very important role in drilling projects. At present, existing drilling fluid technology cannot be used in the harsh low-temperature environment and complex subglacial geological environment conditions in Antarctica. They often exhibit problems such as insufficient low-temperature resistance, poor rheological properties and high costs, and thus cannot meet the needs of efficient drilling in the Antarctic region. Antarctic oil-in-water emulsion drilling fluid is prepared with water as the dispersed phase and oil as the continuous phase, and an appropriate amount of emulsifiers, density regulators and inorganic salts are added. The oil-in-water emulsion droplets in this drilling fluid can effectively improve the low-temperature rheological properties of the drilling fluid, and it has the advantage of low cost. However, this emulsified drilling fluid belongs to a thermodynamically unstable system, and the existing emulsifiers cannot effectively improve the emulsion stability of the drilling fluid under ultra-low temperature conditions.

[0003] Currently, numerous reports have been published on the development of high-temperature-resistant drilling fluid emulsifiers, demonstrating significant results. For example, Chinese patent document CN118792021A discloses a high-temperature-resistant emulsifier for oil-based drilling fluids and its preparation method. This invention uses fatty acids, organic amines, alkylbenzenesulfonic acids, and anhydrides as raw materials to prepare an emulsifier capable of withstanding temperatures of 260°C. This emulsifier imparts excellent rheological properties to the drilling fluid system, with an emulsion breaking voltage exceeding 800V, a water loss under high temperature and high pressure of less than 5mL, and a thin and tough mud cake, demonstrating excellent high-temperature emulsification resistance. Chinese patent document CN117264610A discloses a high-temperature-resistant emulsifier for oil-based drilling fluids and its preparation method. This invention uses amino acids, diethylenetriamine, chlorosulfonic acid, and calcium dodecylbenzenesulfonate as primary raw materials to prepare an oil-based drilling fluid emulsifier. A 5% emulsifier stabilizes the emulsion breaking voltage of the drilling fluid at 260°C above 900V after aging, demonstrating excellent temperature stability. Chinese patent document CN105315973A discloses a modified fatty acid primary emulsifier for high-temperature-resistant oil-based drilling fluids and its preparation method. This invention primarily uses dibasic acid anhydride, fatty acid, and epichlorohydrin as raw materials. Studies have shown that this emulsifier can achieve a demulsification voltage of 399V after aging the drilling fluid at 220°C. It exhibits strong emulsification and high-temperature resistance, while also reducing high-temperature and high-pressure fluid loss in oil-based drilling fluids.

[0004] However, there are no reports on low-temperature drilling fluid emulsifiers suitable for the Antarctic region. Therefore, it is urgent to develop ultra-low-temperature drilling fluid emulsifiers suitable for the Antarctic region to improve the emulsion stability and rheological properties of drilling fluids under ultra-low temperature conditions. Summary of the Invention

[0005] To address the shortcomings of the prior art, the present invention provides an ultra-low-temperature drilling fluid emulsifier for polar drilling, as well as its preparation method and application. The emulsifier of the present invention not only addresses the poor stability of drilling fluid emulsions under ultra-low temperature conditions, but also improves the ultra-low temperature rheological properties of drilling fluids. When applied to ultra-low-temperature drilling fluids for polar drilling, the emulsifier of the present invention can enhance the oil-water interface strength through hydrogen bonding with emulsified droplets at the oil-water interface, significantly improving the stability of the drilling fluid emulsion under low-temperature conditions and the rheological properties of the drilling fluid under low-temperature conditions.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] A method for preparing an ultra-low temperature drilling fluid emulsifier for polar drilling comprises the following steps:

[0008] (1) uniformly mixing the amino acid derivative and dodecylbenzenesulfonic acid, adding a catalyst, and reacting to obtain a first reaction product;

[0009] (2) The first reaction product is mixed evenly with an alcohol ether organic matter, a catalyst is added, and an ultra-low temperature drilling fluid emulsifier for polar drilling is obtained through reaction.

[0010] According to the present invention, preferably, in step (1), the amino acid derivative is one of 16-aminohexadecanoic acid, 12-aminododecanoic acid or 10-aminodecanoic acid, preferably 16-aminohexadecanoic acid.

[0011] Preferably, according to the present invention, in step (1), the molar ratio of dodecylbenzenesulfonic acid to the amino acid derivative is 1.05:1.1-1.3.

[0012] According to the present invention, preferably, in step (1), the catalyst is an alkaline catalyst, preferably sodium hydroxide; the mass of the catalyst is 0.5-1.0% of the total mass of the amino acid derivative and dodecylbenzenesulfonic acid.

[0013] According to the preferred embodiment of the present invention, in step (1), the reaction temperature is 80-100° C.; the reaction time is 3-5 h; and the reaction is carried out under stirring conditions of 300-350 r / min.

[0014] According to the present invention, preferably, in step (2), the alcohol ether organic compound is one of diethylene glycol monobutyl ether or ethylene glycol monoethyl ether, preferably diethylene glycol monobutyl ether.

[0015] According to the preferred embodiment of the present invention, in step (2), the molar amount of the alcohol ether organic compound is 0.8 to 1.1 times the molar amount of dodecylbenzenesulfonic acid.

[0016] According to the present invention, preferably, in step (2), the catalyst is one of concentrated sulfuric acid with a mass concentration of 98 wt% or p-toluenesulfonic acid, preferably concentrated sulfuric acid with a mass concentration of 98 wt%.

[0017] According to the preferred embodiment of the present invention, in step (2), the mass of the catalyst is 1.0 to 1.5% of the mass of the alcohol ether organic substance.

[0018] According to a preferred embodiment of the present invention, in step (2), the reaction temperature is 120-150° C., the reaction time is 4-6 hours, and the reaction is carried out under protective gas protection and stirring at 300-350 rpm. The protective gas is nitrogen or argon.

[0019] An ultra-low temperature drilling fluid emulsifier for polar drilling is prepared by the above method.

[0020] The application of the above-mentioned ultra-low temperature drilling fluid emulsifier for polar drilling in polar drilling fluid.

[0021] According to the present invention, preferably, the polar region is Antarctica.

[0022] According to the present invention, preferably, the mass of the emulsifier is 1-5% of the mass of the drilling fluid.

[0023] The technical features and beneficial effects of the present invention are as follows:

[0024] 1. The preparation method of the emulsifier of the present invention is simple, and the obtained emulsifier is safe, environmentally friendly, and has no irritating odor.

[0025] 2. The emulsifier of the present invention is prepared using dodecylbenzenesulfonic acid, an amino acid derivative, and an alcohol ether as reactive monomers. The reaction is divided into two stages: the first stage, in which the sulfonic acid groups in the dodecylbenzenesulfonic acid react with the amine groups in the amino acid derivative to form amide groups through an amidation reaction; the second stage, in which the carboxyl groups in the product of the first stage react with the hydroxyl groups in the alcohol ether to form the emulsifier through an esterification reaction. The prepared emulsifier has highly polar groups such as ester, ether, and amide groups. When used to emulsify drilling fluid, it can enhance the oil-water interface strength by hydrogen bonding with droplets at the oil-water interface. This significantly improves the low-temperature stability and low-temperature rheological properties of the drilling fluid emulsion.

[0026] 3. The monomers used to prepare the emulsifier of the present invention are optimally combined with a specific type and a specific ratio, combined with a specific amount and type of catalyst, and work together to achieve the excellent effects of the present invention. The molar ratio of the amino acid derivative to dodecylbenzenesulfonic acid in the present invention needs to be suitable. If the ratio is too high, the unreacted amino acid derivative will affect the effective adsorption of the emulsifier at the oil-water interface, thereby affecting the degree of improvement in the stability of the low-temperature drilling fluid emulsion. At the same time, the amount of catalyst added is also directly related to the reaction product conversion rate. If the amount of catalyst added is too low, it will result in a low reaction product conversion rate, thereby affecting the emulsification effect of the low-temperature drilling fluid. The amount of the alcohol ether organic compound of the present invention, the type of reactive monomer and catalyst, etc. also need to be suitable. If not suitable, the emulsification effect on the low-temperature drilling fluid will be reduced. DETAILED DESCRIPTION

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

[0028] The experimental methods described in the examples are conventional methods unless otherwise specified; the reagents and materials used are commercially available unless otherwise specified.

[0029] Example 1

[0030] A method for preparing an ultra-low temperature drilling fluid emulsifier for polar drilling comprises the following steps:

[0031] (1) adding dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid in a molar ratio of 1.05:1.2 into a reaction kettle, mixing and dispersing them uniformly, heating to 90° C., adding sodium hydroxide (the mass of sodium hydroxide is 0.8% of the total mass of dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid), and dispersing them thoroughly;

[0032] (2) the reaction system was stirred at a speed of 350 r / min and kept at 90° C. for 4 h to obtain a first reaction product;

[0033] (3) uniformly mixing the first reaction product and diethylene glycol monobutyl ether, and passing nitrogen for 20 minutes to maintain the reaction system in a nitrogen environment; wherein the molar amount of diethylene glycol monobutyl ether added is 1.1 times the molar amount of dodecylbenzenesulfonic acid;

[0034] (4) The reaction system was heated to 135° C., concentrated sulfuric acid with a mass concentration of 98 wt% (the mass of the concentrated sulfuric acid was 1.3% of the mass of diethylene glycol monobutyl ether) was added, a condenser was added above the flask, and the mixture was kept at a constant temperature of 135° C. for 5 h under a stirring speed of 350 r / min, and then cooled to room temperature to obtain an emulsifier.

[0035] Example 2

[0036] A method for preparing an ultra-low temperature drilling fluid emulsifier for polar drilling comprises the following steps:

[0037] (1) adding dodecylbenzenesulfonic acid and 12-aminododecanoic acid in a molar ratio of 1.05:1.2 into a reactor, mixing and dispersing them uniformly, heating to 90° C., adding sodium hydroxide (the mass of sodium hydroxide is 0.8% of the total mass of dodecylbenzenesulfonic acid and 12-aminododecanoic acid), and dispersing them fully;

[0038] (2) the reaction system was stirred at a speed of 350 r / min and kept at 90° C. for 4 h to obtain a first reaction product;

[0039] (3) uniformly mixing the first reaction product and diethylene glycol monobutyl ether, and passing nitrogen for 20 minutes to maintain the reaction system in a nitrogen environment; wherein the molar amount of diethylene glycol monobutyl ether added is 1.1 times the molar amount of dodecylbenzenesulfonic acid;

[0040] (4) The reaction system was heated to 135° C., concentrated sulfuric acid with a mass concentration of 98 wt% (the mass of the concentrated sulfuric acid was 1.3% of the mass of diethylene glycol monobutyl ether) was added, a condenser was added above the flask, and the mixture was kept at a constant temperature of 135° C. for 5 h under a stirring speed of 350 r / min, and then cooled to room temperature to obtain an emulsifier.

[0041] Example 3

[0042] A method for preparing an ultra-low temperature drilling fluid emulsifier for polar drilling comprises the following steps:

[0043] (1) adding dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid in a molar ratio of 1.05:1.1 into a reactor, mixing and dispersing them uniformly, heating to 90° C., adding sodium hydroxide (the mass of sodium hydroxide is 0.8% of the total mass of dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid), and dispersing them thoroughly;

[0044] (2) the reaction system was stirred at a speed of 350 r / min and kept at 90° C. for 4 h to obtain a first reaction product;

[0045] (3) uniformly mixing the first reaction product and diethylene glycol monobutyl ether, and passing nitrogen for 20 minutes to maintain the reaction system in a nitrogen environment; wherein the molar amount of diethylene glycol monobutyl ether added is 1.1 times the molar amount of dodecylbenzenesulfonic acid;

[0046] (4) The reaction system was heated to 135° C., concentrated sulfuric acid with a mass concentration of 98 wt% (the mass of the concentrated sulfuric acid was 1.3% of the mass of diethylene glycol monobutyl ether) was added, a condenser was added above the flask, and the mixture was kept at a constant temperature of 135° C. for 5 h under a stirring speed of 350 r / min, and then cooled to room temperature to obtain an emulsifier.

[0047] Example 4

[0048] A method for preparing an ultra-low temperature drilling fluid emulsifier for polar drilling comprises the following steps:

[0049] (1) adding dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid in a molar ratio of 1.05:1.2 into a reaction kettle, mixing and dispersing them uniformly, heating to 90° C., adding sodium hydroxide (the mass of sodium hydroxide is 0.8% of the total mass of dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid), and dispersing them thoroughly;

[0050] (2) the reaction system was stirred at 350 r / min and kept at 90° C. for 3 h to obtain a first reaction product;

[0051] (3) uniformly mixing the first reaction product and diethylene glycol monobutyl ether, and passing nitrogen for 20 minutes to maintain the reaction system in a nitrogen environment; wherein the molar amount of diethylene glycol monobutyl ether added is 1.1 times the molar amount of dodecylbenzenesulfonic acid;

[0052] (4) The reaction system was heated to 135° C., concentrated sulfuric acid with a mass concentration of 98 wt% (the mass of the concentrated sulfuric acid was 1.3% of the mass of diethylene glycol monobutyl ether) was added, a condenser was added above the flask, and the mixture was kept at a constant temperature of 135° C. for 5 h under a stirring speed of 350 r / min, and then cooled to room temperature to obtain an emulsifier.

[0053] Example 5

[0054] A method for preparing an ultra-low temperature drilling fluid emulsifier for polar drilling comprises the following steps:

[0055] (1) adding dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid in a molar ratio of 1.05:1.2 into a reaction kettle, mixing and dispersing them uniformly, heating to 90° C., adding sodium hydroxide (the mass of sodium hydroxide is 0.8% of the total mass of dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid), and dispersing them thoroughly;

[0056] (2) the reaction system was stirred at a speed of 350 r / min and kept at 90° C. for 4 h to obtain a first reaction product;

[0057] (3) uniformly mixing the first reaction product and diethylene glycol monobutyl ether, and passing nitrogen for 20 minutes to maintain the reaction system in a nitrogen environment; wherein the molar amount of diethylene glycol monobutyl ether added is 1.1 times the molar amount of dodecylbenzenesulfonic acid;

[0058] (4) The reaction system was heated to 120° C., concentrated sulfuric acid with a mass concentration of 98 wt% (the mass of the concentrated sulfuric acid was 1.3% of the mass of diethylene glycol monobutyl ether) was added, a condenser was added above the flask, and the mixture was kept at a constant temperature of 120° C. for 5 h under a stirring speed of 350 r / min, and then cooled to room temperature to obtain an emulsifier.

[0059] Example 6

[0060] A method for preparing an ultra-low temperature drilling fluid emulsifier for polar drilling comprises the following steps:

[0061] (1) Dodecylbenzenesulfonic acid and 10-aminodecanoic acid were added to a reactor at a molar ratio of 1.05:1.2, mixed thoroughly and dispersed evenly, heated to 90° C., and then sodium hydroxide (the mass of sodium hydroxide was 0.8% of the total mass of dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid) was added and dispersed thoroughly;

[0062] (2) the reaction system was stirred at a speed of 350 r / min and kept at 90° C. for 4 h to obtain a first reaction product;

[0063] (3) uniformly mixing the first reaction product and diethylene glycol monobutyl ether, and passing nitrogen for 20 minutes to maintain the reaction system in a nitrogen environment; wherein the molar amount of diethylene glycol monobutyl ether added is 1.1 times the molar amount of dodecylbenzenesulfonic acid;

[0064] (4) The reaction system was heated to 135° C., concentrated sulfuric acid with a mass concentration of 98 wt% (the mass of the concentrated sulfuric acid was 1.3% of the mass of diethylene glycol monobutyl ether) was added, a condenser was added above the flask, and the mixture was kept at a constant temperature of 135° C. for 5 h under a stirring speed of 350 r / min, and then cooled to room temperature to obtain an emulsifier.

[0065] Example 7

[0066] A method for preparing an ultra-low temperature drilling fluid emulsifier for polar drilling comprises the following steps:

[0067] (1) adding dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid in a molar ratio of 1.05:1.2 into a reaction kettle, mixing and dispersing them uniformly, heating to 90° C., adding sodium hydroxide (the mass of sodium hydroxide is 0.8% of the total mass of dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid), and dispersing them thoroughly;

[0068] (2) the reaction system was stirred at a speed of 350 r / min and kept at 90° C. for 4 h to obtain a first reaction product;

[0069] (3) uniformly mixing the first reaction product with ethylene glycol monoethyl ether, and flowing nitrogen for 20 minutes to maintain the reaction system in a nitrogen environment; wherein the molar amount of ethylene glycol monoethyl ether added is 1.1 times the molar amount of dodecylbenzenesulfonic acid;

[0070] (4) The reaction system was heated to 135° C., concentrated sulfuric acid with a mass concentration of 98 wt% (the mass of concentrated sulfuric acid was 1.3% of the mass of ethylene glycol monoethyl ether) was added, a condenser was placed above the flask, and the mixture was kept at 135° C. for 5 h under a stirring speed of 350 r / min, and then cooled to room temperature to obtain an emulsifier.

[0071] Example 8

[0072] A method for preparing an ultra-low temperature drilling fluid emulsifier for polar drilling comprises the following steps:

[0073] (1) adding dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid in a molar ratio of 1.05:1.2 into a reaction kettle, mixing and dispersing them uniformly, heating to 90° C., adding sodium hydroxide (the mass of sodium hydroxide is 0.8% of the total mass of dodecylbenzenesulfonic acid and 16-aminohexadecanoic acid), and dispersing them thoroughly;

[0074] (2) the reaction system was stirred at a speed of 350 r / min and kept at 90° C. for 4 h to obtain a first reaction product;

[0075] (3) uniformly mixing the first reaction product and diethylene glycol monobutyl ether, and flowing nitrogen for 20 minutes to maintain the reaction system in a nitrogen environment; wherein the molar amount of diethylene glycol monobutyl ether added is 0.8 times the molar amount of dodecylbenzenesulfonic acid;

[0076] (4) The reaction system was heated to 135° C., concentrated sulfuric acid with a mass concentration of 98 wt% (the mass of the concentrated sulfuric acid was 1.3% of the mass of diethylene glycol monobutyl ether) was added, a condenser was added above the flask, and the mixture was kept at a constant temperature of 135° C. for 5 h under a stirring speed of 350 r / min, and then cooled to room temperature to obtain an emulsifier.

[0077] Comparative Example 1

[0078] A method for preparing a drilling fluid emulsifier is as described in Example 1, except that in step (1), the molar ratio of dodecylbenzenesulfonic acid to 16-aminohexadecanoic acid is changed from 1.05:1.2 to 1.05:1.8; the other steps and conditions are the same as in Example 1.

[0079] Comparative Example 2

[0080] A method for preparing a drilling fluid emulsifier is as described in Example 1, except that the reaction temperature in step (4) is changed from 135° C. to 110° C.; the other steps and conditions are the same as in Example 1.

[0081] Comparative Example 3

[0082] A method for preparing a drilling fluid emulsifier is as described in Example 1, except that the reaction time in step (4) is changed from 5 hours to 2 hours; the other steps and conditions are the same as in Example 1.

[0083] Comparative Example 4

[0084] A laboratory-made amide emulsifier (HDA) was prepared by mixing palmitic acid and diethylenetriamine at a molar ratio of 2.05:1, stirring in an oil bath at 165°C for 4 hours to obtain the HDA.

[0085] Comparative Example 5

[0086] A method for preparing a drilling fluid emulsifier is as described in Example 1, except that steps (3) and (4) are omitted and the first reaction product is used as the emulsifier; the other steps and conditions are the same as those in Example 1.

[0087] Test Example 1

[0088] The emulsifiers in Examples 1-8 and Comparative Examples 1-5 were tested for emulsification rate, demulsification voltage, interfacial tension and rheological properties.

[0089] (1) Preparation of drilling fluid emulsion:

[0090] First, the emulsifier was added to the jet fuel and stirred for 10 minutes to fully dissolve it. Subsequently, a 30% CaCl₂ aqueous solution was added to the system and stirred for 25-30 minutes on a high-speed blender to form an emulsion (the mass of the emulsifier was 3% of the total mass of the jet fuel and CaCl₂ aqueous solution, i.e., the mass of the drilling fluid). The volume ratio of the jet fuel to the CaCl₂ aqueous solution was 9:1. The performance of the emulsion was tested at -35°C.

[0091] (2) Test method:

[0092] Emulsification rate test: Pour a certain amount of prepared drilling fluid into a colorimetric tube, then place the colorimetric tube in a low-temperature constant temperature box (-35℃) and let it stand for 16 hours to calculate the emulsification rate.

[0093] Where: V1---total volume, mL;

[0094] V2---the volume of the upper clear liquid, mL;

[0095] Rheological test: Pour a certain amount of prepared emulsion into the test slurry cup, use a low-temperature rheometer to test the 600r and 300r readings at -35°C, and then calculate the relevant rheological parameters.

[0096] Interfacial tension testing: First, an emulsifier was added to aviation kerosene to create a low-density phase (the mass of the emulsifier was 3% of the mass of the aviation kerosene). The inorganic salt CaCl2 was added to deionized water to create a high-density phase (a 30% CaCl2 aqueous solution). Next, each was frozen at -35°C for 16 hours. Finally, the interfacial tension was measured using a DCAT21 interfacial tension meter (Dataphysics, Germany). The instrument has an accuracy of ±0.001 mN / m.

[0097] Demulsification voltage test: First, the prepared emulsion was placed in an ultra-low temperature constant temperature oven (-35°C) for 16 hours and then stirred for 20-25 minutes using a high-speed stirrer (500 rpm). Next, the demulsification voltage of the frozen emulsion was measured using a DWY-2 electrical stability tester (Jiaonan Analytical Instrument Factory, Qingdao, China). Each sample was tested three times, and the average of the three tests was used as the experimental value.

[0098] The emulsification rate, interfacial tension, demulsification voltage and rheological properties were measured. The test results are shown in Table 1.

[0099] Table 1 Performance test of drilling fluid emulsifier at -35℃

[0100]

[0101] The data in Table 1 show that the ultra-low-temperature drilling fluid emulsifier prepared by the present invention has good emulsification and rheological properties. The emulsion containing the emulsifier has good emulsion stability at -35°C, with an emulsification rate still exceeding 79.2% after standing for 16 hours and an interfacial tension below 2.05 mN / m. Furthermore, the emulsion has good rheological properties, with a plastic viscosity below 20.0 mPa.s at -35°C and a dynamic shear force of up to 3.0 Pa.

[0102] In summary, the ultra-low temperature drilling fluid emulsifier for polar drilling of the present invention can meet the needs of polar drilling.

[0103] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0104] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0105] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing an ultra-low temperature drilling fluid emulsifier for polar drilling, comprising the steps of: (1) uniformly mixing the amino acid derivative and dodecylbenzenesulfonic acid, adding a catalyst, and reacting to obtain a first reaction product; (2) The first reaction product is mixed evenly with an alcohol ether organic matter, a catalyst is added, and an ultra-low temperature drilling fluid emulsifier for polar drilling is obtained through reaction.

2. The method for preparing the ultra-low temperature drilling fluid emulsifier for polar drilling according to claim 1, characterized in that: In step (1), the amino acid derivative is one of 16-aminohexadecanoic acid, 12-aminododecanoic acid or 10-aminodecanoic acid, preferably 16-aminohexadecanoic acid.

3. The method for preparing the ultra-low temperature drilling fluid emulsifier for polar drilling according to claim 1, characterized in that: In step (1), the molar ratio of dodecylbenzenesulfonic acid to the amino acid derivative is 1.05:1.1-1.

3.

4. The method for preparing the ultra-low temperature drilling fluid emulsifier for polar drilling according to claim 1, characterized in that: In step (1), one or more of the following conditions are included: i. The catalyst is an alkaline catalyst, preferably sodium hydroxide; the mass of the catalyst is 0.5 to 1.0% of the total mass of the amino acid derivative and dodecylbenzenesulfonic acid; ii. The reaction temperature is 80-100° C.; the reaction time is 3-5 h; and the reaction is carried out under stirring conditions of 300-350 r / min.

5. The method for preparing the ultra-low temperature drilling fluid emulsifier for polar drilling according to claim 1, characterized in that: In step (2), the alcohol ether organic compound is one of diethylene glycol monobutyl ether or ethylene glycol monoethyl ether, preferably diethylene glycol monobutyl ether.

6. The method for preparing the ultra-low temperature drilling fluid emulsifier for polar drilling according to claim 1, characterized in that: In step (2), the molar amount of the alcohol ether organic compound is 0.8 to 1.1 times the molar amount of dodecylbenzenesulfonic acid.

7. The method for preparing the ultra-low temperature drilling fluid emulsifier for polar drilling according to claim 1, characterized in that: In step (2), one or more of the following conditions are included: i. The catalyst is one of concentrated sulfuric acid or p-toluenesulfonic acid with a mass concentration of 98 wt%, preferably concentrated sulfuric acid with a mass concentration of 98 wt%; ii. The mass of the catalyst is 1.0-1.5% of the mass of the alcohol ether organic substance; iii. The reaction temperature is 120-150° C.; the reaction time is 4-6 hours; the reaction is carried out under protective gas protection and stirring at 300-350 r / min; the protective gas is nitrogen or argon.

8. An ultra-low temperature drilling fluid emulsifier for polar drilling, prepared by the method according to any one of claims 1 to 7.

9. Use of the ultra-low temperature drilling fluid emulsifier for polar drilling as claimed in claim 8 in polar drilling fluid.

10. The use according to claim 9, characterized in that The polar region is Antarctica; the mass of the emulsifier is 1-5% of the mass of the drilling fluid.

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