An organic clay for high-temperature-resistant synthetic-based drilling fluid and a preparation method thereof

Abstract

The application provides an organic soil for high-temperature-resistant synthetic base drilling fluid and a preparation method thereof, and comprises the following raw materials in parts by weight: purified Na-based bentonite and methyl bentonite 50-75 parts; 1-octadecene trimethyl ammonium chloride 15-30 parts; intercalation aid 1-10 parts; and water 1000-1500 parts. The organic soil for high-temperature-resistant synthetic base drilling fluid has high-temperature resistance and good viscosity increasing and shearing effects, can improve the viscosity and shearing force and high-temperature stability of the synthetic base drilling fluid, and thus solves the problems of barite sedimentation and poor rock carrying capacity caused by low viscosity and shearing force of the drilling fluid during drilling of deep and ultra-deep wells.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of petroleum chemical industry, relates to the technical field of organic clay for drilling fluid, and particularly relates to an organic bentonite for high-temperature-resistant oil-based drilling fluid and a preparation method thereof. BACKGROUND

[0002] Bentonite is a hydrous clay mineral mainly containing montmorillonite, and its molecular formula is Na x (H2O)4(Al 2-X Mg 0.83 )Si4O 10 )(OH)2. It is used in various fields due to its special properties such as swelling, binding, adsorption, catalysis, thixotropy, suspension and cation exchange. Bentonite resources are very rich in China, ranking second in the world only after the United States, but the deep processing and utilization thereof are far less than those abroad, and the research work on the deep processing and utilization of bentonite has just been carried out in recent years. Organic bentonite is one of the fine products of the deep processing of bentonite. Organic bentonite is widely used in the fields of oil drilling, paint, ink, high-temperature lubricating grease, cosmetics, casting and pesticide as anti-settling agent, thickening agent, tackifier and suspending agent due to its hydrophobic and lipophilic characteristics, good dispersibility, solubility and emulsification in organic solvents.

[0003] Organic bentonite is the most basic lipophilic colloid in oil-based drilling fluid, which can not only improve the viscosity and shear force of the mud, but also reduce the filtration loss of the oil-based drilling fluid, so that the organic clay is an indispensable additive in the oil-based drilling fluid. The organic clay mainly plays a role in increasing viscosity and shear in the drilling fluid, and the performance thereof will directly affect the rheological property and rock-carrying capacity of the drilling fluid. The organic bentonite can also enhance the stability of the synthetic base emulsion to a certain extent and play the role of solid emulsifier. The preparation method of the organic clay on the market generally uses cationic surfactants and highly dispersed hydrophilic clay to produce ion exchange and adsorption, and the combination will decompose at high temperatures, so that the organic clay has poor temperature resistance. Therefore, the preparation of the organic clay for high-temperature-resistant oil-based drilling fluid is studied. SUMMARY

[0004] The present application aims to provide an organic clay for high-temperature-resistant synthetic base drilling fluid and a preparation method thereof.

[0005] The method can greatly improve the temperature resistance and rheological property of the organic bentonite for drilling fluid, and the organic bentonite with excellent performance is invented, and the temperature resistance can reach 200℃.

[0006] The main technical scheme of the present application is that the organic clay for high-temperature-resistant synthetic base drilling fluid comprises the following raw materials in parts by weight:

[0007] purified sodium bentonite-potassium bentonite mixture 50-75 parts

[0008] primary intercalation agent 15-30 parts

[0009] intercalation aid 1-10 parts

[0010] water 1000-1500 parts.

[0011] Generally, the primary intercalation agent is 1-octadecene trimethyl ammonium chloride.

[0012] The intercalation aid is polyvinyl alcohol [C2H4O]n with a molecular weight of 300-5000, which is used to improve the adsorption stability of quaternary ammonium salt on clay and weaken the desorption of quaternary ammonium salt at high temperature.

[0013] The application provides a preparation method of organic soil for high-temperature-resistant synthetic-based drilling fluid, characterized by the following steps: dispersing a purified sodium bentonite-potassium bentonite mixture in deionized water to obtain a stable suspension; performing a primary intercalation reaction on the suspension under the action of an initiator with a primary intercalation agent and an intercalation aid to obtain a primary intercalation material; performing a secondary intercalation reaction on the primary intercalation material and the intercalation aid to obtain a secondary intercalation material; and drying, crushing and sieving the secondary intercalation material to obtain the organic soil for high-temperature-resistant synthetic-based drilling fluid.

[0014] Preferably, the purified sodium bentonite-potassium bentonite mixture is dispersed in deionized water and stirred at a high speed to obtain a stable suspension, and the pH value of the suspension is adjusted to 7-8.

[0015] The primary intercalation reaction is performed at 60-80°C for 1-2 hours to obtain an organic soil material liquid, and the organic soil material liquid is subjected to pressure filtration and water removal to obtain the primary intercalation material.

[0016] The secondary intercalation reaction is performed for 30-120 minutes at 60-80°C between the primary intercalation material and the intercalation aid to obtain the secondary intercalation material, which is dried at 60-80°C for 3-5 hours, cooled to room temperature, crushed and sieved through a 200-mesh sieve to obtain the organic soil for high-temperature-resistant synthetic-based drilling fluid.

[0017] The initiator is one or more of cerium ammonium nitrate, potassium persulfate and ammonium persulfate.

[0018] The equipment used for mixing and stirring in the primary intercalation reaction is a reaction kettle with a heating, stirring and cooling system, and the equipment used for pressure filtration is a plate-and-frame filter press.

[0019] Both the primary intercalation reaction and the secondary intercalation reaction are performed by wet heating.

[0020] The application provides the organic soil for the high-temperature-resistant synthetic-based drilling fluid, adopts 1-octadecene trimethyl ammonium chloride as a primary intercalation agent, and adds an intercalation aid to perform primary intercalation on a mixture of sodium-based soil and potassium-based soil under the action of an initiator, one of the Pi bonds of C=C double bonds in the 1-octadecene trimethyl ammonium chloride and the intercalation aid is broken to combine with part of Al atoms in the purified mixture of sodium-based soil and potassium-based soil to generate a firm sigma bond, and finally a copolymer organic soil product with chemical bonds and ionic bonds is formed.

[0021] The application has the following advantages:

[0022] The obtained organic soil for the high-temperature-resistant synthetic-based drilling fluid is resistant to high temperature, has good viscosity increasing and cutting effect, and can improve the viscosity and cutting force and high-temperature stability of the synthetic-based drilling fluid, thereby solving the problems of barite sedimentation and poor rock carrying capacity caused by low viscosity and cutting force of the drilling fluid during the drilling of deep and ultra-deep wells.

[0023] The two sigma bonds generated by breaking one of the Pi bonds of C=C double bonds in the intercalation reaction quaternary ammonium salt and the intercalation aid under certain conditions perform intercalation reaction with the purified mixture of sodium-based soil and potassium-based soil to form a copolymer with chemical bonds and ionic bonds, the layered structure intercalation aid is added twice under certain conditions to form the organic soil with dispersed small crystal flake distribution, the organic soil has good high-temperature resistance, and thus the lipophilic organic bentonite is prepared, and the organic bentonite can be well dispersed in the high-temperature oil-based drilling fluid. DETAILED DESCRIPTION

[0024] The application will be described in detail below with reference to the examples.

[0025] In the following examples, the intercalation aid is polyvinyl alcohol [C2H4O]n with a molecular weight of 300-5000; and the initiator is one or more of cerium ammonium nitrate, potassium persulfate and ammonium persulfate.

[0026] The equipment used for the mixing and stirring operation in the primary intercalation reaction is a reaction kettle with a heating, stirring and cooling system, and the equipment used for the pressure filtration is a plate and frame filter press. The primary intercalation reaction and the secondary intercalation reaction are both wet heating.

[0027] Example 1

[0028] A mixture of 50 parts of sodium bentonite and potassium bentonite was dispersed in 700 parts of deionized water, and stirred at high speed to obtain a stable suspension. The pH of the suspension was adjusted to 7-8, and the suspension was prepared for use. 20 parts of 1-octadecene trimethyl ammonium chloride was dissolved in 300 parts of deionized water, and stirred to obtain a clear and transparent solution a for use. 3 parts of intercalation aid was dissolved in 200 parts of deionized water, and stirred to obtain a clear and transparent solution b for use. The initiator, solution a and solution b were rapidly added to the suspension under high speed stirring, and reacted at 75°C for 1.5 hours. 5 parts of intercalation aid was continuously added, and reacted for 1 hour. The product was cooled to room temperature, and deionized water was repeatedly added to remove residual Cl- from the product. The product was filtered, and the prepared organic bentonite was vacuum dried at 70°C, crushed and sieved through a 200 mesh screen to obtain the organic bentonite product.

[0029] Example 2

[0030] A mixture of 60 parts of sodium bentonite and potassium bentonite was dispersed in 800 parts of deionized water, and stirred at high speed to obtain a stable suspension. The pH of the suspension was adjusted to 7-8, and the suspension was prepared for use. 22 parts of 1-octadecene trimethyl ammonium chloride was dissolved in 200 parts of deionized water, and stirred to obtain a clear and transparent solution a for use. 4 parts of intercalation aid was dissolved in 100 parts of deionized water, and stirred to obtain a clear and transparent solution b for use. The initiator, solution a and solution b were rapidly added to the suspension under high speed stirring, and reacted at 70°C for 1.5 hours. 5 parts of intercalation aid was continuously added, and reacted for 1 hour. The product was cooled to room temperature, and deionized water was repeatedly added to remove residual Cl- from the product. The product was filtered, and the prepared organic bentonite was vacuum dried at 75°C, crushed and sieved through a 200 mesh screen to obtain the organic bentonite product.

[0031] Example 3

[0032] A mixture of 65 parts of sodium bentonite and potassium bentonite was dispersed in 800 parts of deionized water, and stirred at high speed to obtain a stable suspension. The pH of the suspension was adjusted to 7-8, and the suspension was prepared for use. 24.8 parts of 1-octadecene trimethyl ammonium chloride was dissolved in 200 parts of deionized water, and stirred to obtain a clear and transparent solution a for use. 2 parts of intercalation aid was dissolved in 100 parts of deionized water, and stirred to obtain a clear and transparent solution b for use. The initiator, solution a and solution b were rapidly added to the suspension under high speed stirring, and reacted at 70°C for 1.5 hours. 6 parts of intercalation aid was continuously added, and reacted for 1 hour. The product was cooled to room temperature, and deionized water was repeatedly added to remove residual Cl- from the product. The product was filtered, and the prepared organic bentonite was vacuum dried at 70°C, crushed and sieved through a 200 mesh screen to obtain the organic bentonite product.

[0033] Example 4

[0034] A mixture of 70 parts of sodium bentonite and potassium bentonite was dispersed in 1500 parts of deionized water, and stirred at high speed to obtain a stable suspension. The pH of the suspension was adjusted to 7-8, and the suspension was prepared for use. 26 parts of 1-octadecene trimethyl ammonium chloride was dissolved in 200 parts of deionized water, and stirred to obtain a clear and transparent solution a, which was prepared for use. 5 parts of intercalation aid was dissolved in 100 parts of deionized water, and stirred to obtain a clear and transparent solution b, which was prepared for use. The initiator, solution a and solution b were rapidly added to the suspension under high speed stirring, and reacted at 70°C for 1.5 hours. Then, 5 parts of the prepared intercalation aid was continuously added, and reacted for 1 hour. The product was cooled to room temperature, washed repeatedly with deionized water, filtered, dried at 75°C under vacuum, pulverized and sieved through a 200 mesh screen, to obtain the organic bentonite product.

[0035] Example 5

[0036] A mixture of 85 parts of sodium bentonite and potassium bentonite was dispersed in 800 parts of deionized water, and stirred at high speed to obtain a stable suspension. The pH of the suspension was adjusted to 7-8, and the suspension was prepared for use. 28 parts of 1-octadecene trimethyl ammonium chloride was dissolved in 200 parts of deionized water, and stirred to obtain a clear and transparent solution a, which was prepared for use. 3 parts of intercalation aid was dissolved in 100 parts of deionized water, and stirred to obtain a clear and transparent solution b, which was prepared for use. The initiator, solution a and solution b were rapidly added to the suspension under high speed stirring, and reacted at 70°C for 1.5 hours. Then, 7 parts of the prepared intercalation aid was continuously added, and reacted for 1 hour. The product was cooled to room temperature, washed repeatedly with deionized water, filtered, dried at 75°C under vacuum, pulverized and sieved through a 200 mesh screen, to obtain the organic bentonite product.

[0037] Example 6

[0038] A mixture of 65 parts of sodium bentonite and potassium bentonite was dispersed in 800 parts of deionized water, and stirred at high speed to obtain a stable suspension. The pH of the suspension was adjusted to 7-8, and the suspension was prepared for use. 25 parts of 1-octadecene trimethyl ammonium chloride was dissolved in 200 parts of deionized water, and stirred to obtain a clear and transparent solution a, which was prepared for use. 2 parts of intercalation aid was dissolved in 100 parts of deionized water, and stirred to obtain a clear and transparent solution b, which was prepared for use. The initiator, solution a and solution b were rapidly added to the suspension under high speed stirring, and reacted at 70°C for 2 hours. Then, 7 parts of the prepared intercalation aid was continuously added, and reacted for 0.5 hour. The product was cooled to room temperature, washed repeatedly with deionized water, filtered, dried at 75°C under vacuum, pulverized and sieved through a 200 mesh screen, to obtain the organic bentonite product.

[0039] Example 7

[0040] A mixture of 70 parts of sodium bentonite and potassium bentonite was dispersed in 800 parts of deionized water under high-speed stirring to obtain a stable suspension, and the pH value of the suspension was adjusted to 7-8 for standby use; 25 parts of 1-octadecene trimethyl ammonium chloride was dissolved in 200 parts of deionized water under stirring to form a clear and transparent solution a for standby use. 6 parts of intercalation aid was dissolved in 100 parts of deionized water under stirring, heated to 80℃, and reacted for 10 minutes to form a clear and transparent solution b for standby use. Under high-speed stirring, solution a and solution b were rapidly added to the suspension, and reacted at 70℃ for 2 hours, and then 3 parts of prepared intercalation aid was continuously added under stirring for 0.5 hours. The product was cooled to room temperature, washed repeatedly with deionized water, filtered, and then dried at 75℃ under vacuum, crushed, and sieved through a 200-mesh screen to obtain the organic bentonite product.

[0041] The sample prepared in the above example was subjected to performance detection and compared with the same type of product on the market.

[0042] Sample Name Apparent Viscosity (AV) / mPa-s Plastic Viscosity (PV) / mPa-s Yield Point (YP) / Pa Blank Sample 3.8 3.6 0.2 Sample 1 15.0 9.0 6 Sample 2 14.0 9.0 5 Sample 3 14.0 8.0 6 Sample 4 11.5 7.0 4 Sample 5 19.5 12.0 7.5 Sample 6 16 12 4 Sample 7 18. 13 5 YH-918 (Domestic) 10 8.5 1.5

[0043] It can be seen from the detection results that the sample obtained by the method of the present application has significantly better performance than the products on the domestic market.

[0044] The viscosity and shear performance of the organic soil for synthetic-based drilling fluid obtained in the example was determined for sample 5:

[0045] The emulsion formula is: synthetic base oil + 4% solid emulsifier + 3% organic soil + 5% fluid loss additive + 20% CaCl2 brine + barite

[0046]

[0047] Through the heat-resistant rolling experiment detection, after the organic soil of the present example was added to the synthetic-based drilling fluid, the drilling fluid system obtained had good rheological properties, and after high-temperature heat rolling at 200℃, the apparent viscosity and dynamic shear force were basically unchanged, and the performance was stable, indicating that the organic soil prepared in the example had good thermal stability.

Claims

1. An organoclay for use in a high temperature resistant synthetic base drilling fluid, characterized in that The purified sodium bentonite-potassium bentonite mixture comprises the following raw materials by weight: The purified sodium bentonite-potassium bentonite mixture 50-75 parts The primary intercalation agent 15-30 parts The intercalation aid 1-10 parts Water 1000-1500 parts The primary intercalation agent is 1-octadecene trimethyl ammonium chloride; and the intercalation aid is polyvinyl alcohol [C2H4O]n with a molecular weight of 300-5000.

2. The method for preparing high-temperature resistant synthetic drilling fluid organic clay according to claim 1, characterized in that: The purified sodium bentonite-potassium bentonite mixture is dispersed in deionized water to obtain a stable suspension; the primary intercalation agent and the intercalation aid are subjected to a primary intercalation reaction with the suspension under the action of an initiator to obtain a primary intercalation material; the primary intercalation material and the intercalation aid are subjected to a secondary intercalation reaction to obtain a secondary intercalation material; and the secondary intercalation material is dried, crushed and sieved to obtain the organic soil for high-temperature-resistant synthetic-based drilling fluid.

3. The method for preparing high-temperature resistant synthetic drilling fluid organic clay according to claim 2, characterized in that: The purified sodium bentonite-potassium bentonite mixture is dispersed in deionized water and stirred at high speed to obtain a stable suspension, and the pH value of the suspension is adjusted to 7-8.

4. The method for preparing high-temperature resistant synthetic drilling fluid organic clay according to claim 2, characterized in that: The primary intercalation reaction is stirred at 60-80°C for 1-2 hours to obtain an organic soil slurry, and the organic soil slurry is subjected to pressure filtration and water removal to obtain the primary intercalation material.

5. The method for preparing high-temperature resistant synthetic drilling fluid organic clay according to claim 2, characterized in that: The secondary intercalation reaction: the primary intercalation material and the intercalation aid are reacted for 30-120 minutes at a temperature of 60-80°C to obtain the secondary intercalation material, which is dried at 60-80°C for 3-5 hours, cooled to room temperature, crushed and sieved through a 200-mesh screen to obtain the organic soil for high-temperature-resistant synthetic-based drilling fluid.

6. The method for preparing high-temperature resistant synthetic drilling fluid organic clay according to claim 2, characterized in that: The initiator is one or more of cerium ammonium nitrate, potassium persulfate and ammonium persulfate.

7. The method for preparing high-temperature resistant synthetic drilling fluid organic clay according to claim 4, characterized in that: The equipment used for mixing and stirring in the primary intercalation reaction is a reaction kettle with heating, stirring and cooling systems, and the equipment used for pressure filtration is a plate-and-frame filter press.

8. The method for preparing high-temperature resistant synthetic drilling fluid organic clay according to claim 4 or 5, characterized in that: Both the primary intercalation reaction and the secondary intercalation reaction are wet heating.

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