Dispersion stabilizer for improving dispersion stability of organic soil for ultralow-temperature drilling fluid as well as preparation method and application of dispersion stabilizer

Abstract

The invention provides a dispersion stabilizer for improving dispersion stability of organic soil for ultralow-temperature drilling fluid as well as a preparation method and application of the dispersion stabilizer. The dispersion stabilizer is prepared from N-lauryl diethanolamine, a carboxylic acid compound and a polyene polyamine compound; the carboxylic acid compound is one of adipic acid or azelaic acid; the polyene polyamine compound is one of polyoxyethylene diamine, diethylenetriamine or tetraethylenepentamine. The dispersion stabilizer provided by the invention can effectively improve the dispersion performance of organic soil in base oil and the colloid performance of drilling fluid under an ultralow temperature condition.

Description

Technical Field

[0001] The invention relates to a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid, a preparation method and application thereof, and belongs to the technical field of polar drilling. Background Art

[0002] Organic soil is one of the important additives in Antarctic drilling fluid, which has a significant effect on improving the ultra-low temperature rheological properties of drilling fluid. However, due to the special base oil used in Antarctic drilling fluid, which is usually an oil with very low viscosity, the organic soil has poor dispersion under ultra-low temperature conditions, and thus the ultra-low temperature rheological properties of drilling fluid cannot be significantly improved. Therefore, it is of great significance to develop a treatment agent that can significantly improve the dispersion of organic soil under ultra-low temperature conditions.

[0003] In deep oil and gas drilling, scholars have developed an additive to improve the dispersion stability of organic soil for drilling fluid. Chinese patent document CN103773324A discloses a method for improving the gelation rate of organic soil in oil-based drilling fluid mud, which mainly develops a polar activator, the main component of which includes one of esters, alcohols or ketones. Studies have found that this activator can keep the colloid rate of organic soil in base oil (standing for 24 hours) above 95%, and the dispersion performance is good. Chinese patent document CN101948116A discloses a method for improving the dispersibility of organic soil, which is mainly by adding polyol fatty acid esters to a system composed of non-polar alkane organic solvents (such as gas-to-oil, paraffin oil) and organic soil to improve the dispersion performance of organic soil and the colloidal stability of the system. Polyol fatty acid esters include Span series and glyceride series. Studies have shown that it can effectively improve the dispersion performance of organic soil and can also significantly shorten the dispersion time of organic soil in non-polar solvents, thereby reducing costs.

[0004] At present, in the field of polar drilling research, there is no report on the low-temperature dispersion stability of organic soil. Therefore, it is urgent to invent a method to improve the ultra-low temperature dispersion stability of organic soil, so as to improve the ultra-low temperature dispersion performance and colloid properties of drilling fluid, thereby improving drilling efficiency. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid, and its preparation method and application. The dispersion stabilizer of the present invention can effectively improve the dispersion performance of organic soil in base oil and the colloid performance of drilling fluid under ultra-low temperature conditions.

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

[0007] A dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid. The dispersion stabilizer is prepared from N-lauryl diethanolamine, a carboxylic acid compound and a polyene polyamine compound; the carboxylic acid compound is one of adipic acid or azelaic acid; the polyene polyamine compound is one of polyoxyethylene diamine, diethylene triamine or tetraethylene pentamine.

[0008] Preferably, according to the present invention, the average molecular weight of the polyoxyethylene diamine is 1000-2000; the structural formula of the polyoxyethylene diamine is shown in the following formula I:

[0009]

[0010] According to the present invention, the preparation method of the above-mentioned dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid comprises the following steps:

[0011] (1) adding a carboxylic acid compound to N-lauryldiethanolamine, stirring and mixing uniformly, passing nitrogen to deoxygenate, heating to a reaction temperature, adding concentrated sulfuric acid, reacting, and obtaining a first reaction product;

[0012] (2) Under stirring conditions, polyene-polyamine compounds are continuously added to the first reaction product, and after stirring evenly, nitrogen is introduced to deoxygenate and react to obtain a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid.

[0013] Preferably according to the present invention, the molar ratio of N-lauryldiethanolamine to the carboxylic acid compound in step (1) is (1-1.2):1.

[0014] Preferably, according to the present invention, the stirring rate in step (1) is 300-400 r / min, and the stirring time is 10-15 min.

[0015] Preferably, according to the present invention, in step (1), the time for deoxygenation by nitrogen is 10-30 minutes.

[0016] Preferably, according to the present invention, the mass fraction of the concentrated sulfuric acid in step (1) is 98%; the mass of the concentrated sulfuric acid added is 0.5-1% of the total mass of N-lauryldiethanolamine and the carboxylic acid compound.

[0017] Preferably, according to the present invention, the reaction temperature in step (1) is 120-140° C., and the reaction time is 3-5 h.

[0018] Preferably according to the present invention, the molar ratio of the polyene polyamine compound to the carboxylic acid compound in step (2) is 2-2.3:1.

[0019] Preferably, according to the present invention, the stirring speed in step (2) is 300-400 r / min; and the time for nitrogen deoxygenation is 5-15 min.

[0020] Preferably, according to the present invention, the reaction temperature in step (2) is 170-190° C., and the reaction time is 4-6 h.

[0021] According to the present invention, the application of the above-mentioned dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid in polar formation drilling fluid is used to improve the dispersion stability of organic soil in ultra-low temperature drilling fluid; preferably, the polar region is Antarctica and the ultra-low temperature is -45°C.

[0022] According to a preferred embodiment of the present invention, the method for improving the dispersion stability of organic soil in ultra-low temperature drilling fluid is: adding a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid to the ultra-low temperature drilling fluid, and the mass ratio of the dispersion stabilizer to the organic soil is 1-3:3.

[0023] According to the present invention, the dispersion stabilizer makes the colloidal rate of the organic soil at -45°C 81.5-85.2%, the contact angle 14.4°-17.4°, the number of particles 3504-3667, and the average particle size 32.96-33.45 μm.

[0024] The technical features and beneficial effects of the present invention are as follows:

[0025] 1. The preparation method of the present invention is simple, and the obtained dispersion stabilizer is safe, environmentally friendly, and has no irritating odor.

[0026] 2. The monomers used in the dispersion stabilizer prepared by the present invention are optimally combined in specific types and specific proportions, and their combined effect achieves the excellent effect of the present invention.

[0027] 3. The dispersing stabilizer in the present invention is prepared from three monomers: N-lauryl diethanolamine, carboxylic acid compounds and polyene polyamine compounds. The molecular structure of the dispersing stabilizer is composed of a polar part and a non-polar part, which is similar to a non-ionic surfactant. It can interact with organic soil through multiple strong polar groups, thereby changing the connection mode of organic soil particles in the base oil, thereby improving the ultra-low temperature dispersion performance of organic soil in the base oil under ultra-low temperature conditions.

[0028] 4. The molar ratio of the carboxylic acid compound to the polyene polyamine compound in the present invention needs to be appropriate. If the ratio is too low, the number of amide groups generated is limited, which may lead to an insignificant improvement in the dispersibility of the organic soil; if the ratio is too high, the unreacted polyene polyamine will affect the molecular spatial structure of the product, thereby affecting its performance. DETAILED DESCRIPTION

[0029] The present invention will be further described below by means of specific examples, but is not limited thereto.

[0030] The experimental methods described in the examples are conventional methods unless otherwise specified; the reagents and materials used are commercially available unless otherwise specified.

[0031] The mass fraction of concentrated sulfuric acid used in the embodiments and comparative examples is 98%.

[0032] Example 1

[0033] A method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid comprises the following steps:

[0034] (1) adding azelaic acid to N-lauryldiethanolamine (CAS No.: 1541-67-9), stirring for 15 min at a stirring rate of 340 r / min, mixing evenly, and passing nitrogen for 20 min; wherein the molar ratio of N-lauryldiethanolamine to azelaic acid is 1.05:1;

[0035] (2) heating the reaction system to 130° C., adding concentrated sulfuric acid (the added mass is 0.8% of the total mass of N-lauryldiethanolamine and azelaic acid), and reacting at 130° C. for 4 hours to obtain a first reaction product;

[0036] (3) adding diethylenetriamine to the above system at a stirring rate of 340 r / min and 130° C., stirring for 10 min and then passing nitrogen for 10 min; wherein the molar ratio of diethylenetriamine to azelaic acid is 2.1:1;

[0037] (4) The temperature is raised to 180° C. and the reaction is carried out at a constant temperature of 180° C. for 4 hours. After the reaction is completed, the reaction is naturally cooled to room temperature to obtain a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid.

[0038] Example 2

[0039] A method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid is as described in Example 1, except that tetraethylenepentamine is used instead of diethylenetriamine in step (3), and other conditions are the same as in Example 1.

[0040] Example 3

[0041] A method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid is as described in Example 1, except that the molar ratio of diethylenetriamine to azelaic acid in step (3) is 2.3:1.

[0042] Comparative Example 1

[0043] A method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid is as described in Example 3, except that the reaction temperature in step (4) is changed from 180°C to 150°C, and the other conditions are the same as in Example 3.

[0044] Comparative Example 2

[0045] A method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid is as described in Example 3, except that the reaction time in step (2) is changed from 4 hours to 2 hours, and the other conditions are the same as in Example 3.

[0046] Comparative Example 3

[0047] A method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid is as described in Example 3, except that the molar ratio of diethylenetriamine to azelaic acid in step (3) is 2.6:1, and other conditions are the same as in Example 3.

[0048] Comparative Example 4

[0049] A method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid is as described in Example 3, except that in step (1), azelaic acid is replaced by phthalic acid, and other conditions are the same as in Example 3.

[0050] Comparative Example 5

[0051] A method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid is as described in Example 3, except that diethylenetriamine is replaced by benzylamine in step (3), and other conditions are the same as in Example 3.

[0052] Test Example 1

[0053] The dispersion stabilizers in Examples 1-3 and Comparative Examples 1-5 were evaluated for colloid ratio, contact angle, number of particles, and average particle size.

[0054] (1) Sample preparation:

[0055] The drilling fluid base fluid is composed as follows: first, 4# aviation kerosene and 5# white oil are prepared into a base oil in a volume ratio of 7:3, with a total of 25 mL; secondly, 120F type organic clay (produced by Shanghai Wanzhao Fine Chemical Co., Ltd.) is added in an amount of 3% by mass of the base oil to prepare a drilling fluid base fluid; the dispersion stabilizers in the embodiments or comparative examples are added to the drilling fluid base fluid respectively, and the added amount is 2% by mass of the drilling fluid base fluid, and the mixture is fully stirred on a high-speed stirrer (rotating speed of 5000 r / min) for 30 minutes to obtain a drilling fluid sample; and its performance at -45°C is tested.

[0056] (2) Test method:

[0057] Colloid 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 (-45°C) and let it stand for 24 hours to calculate the colloid rate, colloid rate = (lower volume / total volume) * 100%.

[0058] Contact angle test: The mica sheet was immersed in the above-mentioned drilling fluid, frozen in a DW-40 ultra-low temperature constant temperature box (temperature is -45°C) for 24 hours, and then the contact angle size was tested using a contact angle meter, using a 5.0 μL oil droplet as a probe. Each sample was measured three times and the average value was recorded.

[0059] Particle number and average particle size: The prepared drilling fluid to be tested was stirred for 15 minutes on a high-speed stirrer at a stirring rate of 600r / min to fully disperse it. Then the drilling fluid to be tested was placed in a low-temperature cooling circulation pump (the temperature was set to -45°C), and the particle number and average particle size of the solid phase particles in the drilling fluid were measured using the Particle Track G600 focused beam reflectometer from Mettler, Switzerland.

[0060] The colloid rate, contact angle, particle number and average particle size were measured. The test results are shown in Table 1.

[0061] Table 1 Dispersion performance test

[0062] sample Colloid rate / % Contact angle (°) Number of particles Average particle size / μm Base fluid 12.6％ 22.8° 3165 37.25 Example 1 85.2％ 14.4° 3667 32.96 Example 2 83.3％ 16.2° 3522 33.45 Example 3 81.5％ 17.4° 3504 33.28 Comparative Example 1 68.2％ 20.6° 3416 33.95 Comparative Example 2 71.6％ 20.8° 3437 33.67 Comparative Example 3 75.0％ 20.1° 3485 33.56 Comparative Example 4 67.2％ 21.2° 3378 34.69 Comparative Example 5 72.8％ 20.4° 3449 33.62

[0063] It can be seen from the data in Table 1 that the drilling fluid dispersing stabilizer prepared by the present invention has good lipophilicity and can reduce the contact angle of the organic soil for drilling fluid from 22.8° to 14.4°; in addition, the average particle size of the organic soil can also be reduced from 37.25 μm to 32.96 μm, and the number of particles can be increased from 3165 to 3667. Under -45°C conditions, the colloid rate after standing for 24 hours can still reach more than 81.5%, which shows that the dispersing stabilizer can significantly improve the dispersing stability of the organic soil for drilling fluid under ultra-low temperature conditions.

[0064] In summary, the method of improving the dispersion stability of organic soil for ultra-low temperature drilling fluid of the present invention can meet the needs of polar drilling.

[0065] 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, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0066] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0067] In addition, 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 dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid, characterized in that: The dispersion stabilizer is prepared from N-lauryl diethanolamine, a carboxylic acid compound and a polyene polyamine compound; the carboxylic acid compound is one of adipic acid or azelaic acid; the polyene polyamine compound is one of polyoxyethylene diamine, diethylene triamine or tetraethylene pentamine.

2. The dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid according to claim 1, characterized in that: The average molecular weight of the polyoxyethylene diamine is 1000-2000.

3. The method for preparing the dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid according to claim 1, comprising the following steps: (1) adding a carboxylic acid compound to N-lauryldiethanolamine, stirring and mixing uniformly, passing nitrogen to deoxygenate, heating to a reaction temperature, adding concentrated sulfuric acid, reacting, and obtaining a first reaction product; (2) Under stirring conditions, polyene-polyamine compounds are continuously added to the first reaction product, and after stirring evenly, nitrogen is introduced to deoxygenate and react to obtain a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid.

4. The method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid according to claim 3, characterized in that: The molar ratio of N-lauryldiethanolamine to the carboxylic acid compound in step (1) is (1-1.2):

1.

5. The method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid according to claim 3, characterized in that: The stirring rate in step (1) is 300-400 r / min, the stirring time is 10-15 min, and the nitrogen deoxygenation time is 10-30 min.

6. The method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid according to claim 3, characterized in that: The mass fraction of the concentrated sulfuric acid in step (1) is 98%; the mass of the concentrated sulfuric acid added is 0.5-1% of the total mass of N-lauryldiethanolamine and the carboxylic acid compound; The reaction temperature is 120-140° C., and the reaction time is 3-5 h.

7. The method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid according to claim 3, characterized in that: The molar ratio of the polyene polyamine compound to the carboxylic acid compound in step (2) is 2-2.3:

1.

8. The method for preparing a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid according to claim 3, characterized in that: The stirring speed in step (2) is 300-400 r / min; the nitrogen deoxygenation time is 5-15 min; The reaction temperature is 170-190° C., and the reaction time is 4-6 hours.

9. Use of the dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid according to claim 1 or 2 in polar formation drilling fluid, characterized in that: Used to improve the dispersion stability of organic soil in ultra-low temperature drilling fluid; preferably, the polar region is Antarctica, and the ultra-low temperature is -45°C.

10. The use according to claim 9, characterized in that: The method for improving the dispersion stability of organic soil in ultra-low temperature drilling fluid is: adding a dispersion stabilizer for improving the dispersion stability of organic soil for ultra-low temperature drilling fluid to the ultra-low temperature drilling fluid, wherein the mass ratio of the dispersion stabilizer to the organic soil is 1-3:3.

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