High temperature resistant organic clay for drilling fluid and its preparation method
By compounding sodium-based montmorillonite, attapulgite, long-chain quaternary ammonium salt, and chelating agents, the interlayer spacing is increased and the montmorillonite layers are connected by chemical bonds. This solves the problem of performance degradation of organic soil under high temperature conditions and achieves high-efficiency drilling fluid performance above 200℃.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2023-10-27
- Publication Date
- 2026-05-26
AI Technical Summary
Existing organic soils have poor high-temperature resistance under high-temperature conditions, which leads to a decline in drilling fluid performance.
A compounding method using sodium-based montmorillonite, attapulgite, long-chain quaternary ammonium salt, and chelating agents was adopted. Through primary and secondary intercalation modification, the interlayer spacing was increased and the montmorillonite layers were connected by chemical bonds, thereby improving the high-temperature resistance.
The prepared organic soil maintains a high colloid content and good viscosity-enhancing and shearing effect at temperatures above 200℃, thus improving the high-temperature resistance of the drilling fluid.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of drilling fluid technology, specifically relating to an organic soil for high-temperature resistant drilling fluid and its preparation method. Background Technology
[0002] Drilling fluid is a general term for various circulating fluids that fulfill the needs of drilling operations through multiple functions. Different drilling depths place different demands on drilling fluid performance. This is because, with increased well depth, the bottom of the well is under high temperature and pressure conditions, the drilling section is long and includes large sections of open hole, and many complex formations must be drilled through. Therefore, the operating conditions are much harsher than in ordinary wells, thus placing higher demands on the performance of drilling fluids (especially high-temperature resistance). Organoclase is the most widely used rheology control agent in oil-based drilling fluids. Due to its good oleophilicity and large interlayer spacing, organoclase controls the rheological behavior of oil-based drilling fluids by dispersing and expanding in the base oil. Currently, the organoclase used in actual drilling operations is an oleophilic colloidal material obtained by organically modifying montmorillonite. The basic structural unit of montmorillonite consists of a 2:1 layered structure composed of two layers of silicon-oxygen tetrahedral sheets sandwiching a layer of aluminum-oxygen octahedral sheets, making it a typical layered cassiterite clay mineral. Due to isomorphous substitution, the montmorillonite crystal layers carry a certain amount of structural negative charge. To maintain electroneutrality, the interlayers of montmorillonite can adsorb an equal amount of cations. Conventional organic soils are generally modified from montmorillonite through a single intercalation adsorption of long-chain quaternary ammonium salts. These organic soils exhibit high colloidal content and good shearing and viscosity-enhancing effects below 150℃, but their performance deteriorates significantly above 180℃. The quaternary ammonium salt and montmorillonite layers are mainly connected through charge interactions. Under high-temperature conditions, the adsorbed long-chain quaternary ammonium salt modifier is easily dispersed and desorbed, leading to the failure of the organic soil and severely affecting the overall performance of the drilling fluid. Therefore, effectively improving the high-temperature resistance of organic soils is crucial for improving the high-temperature resistance of drilling fluids. Summary of the Invention
[0003] To address the technical problem of poor high-temperature resistance of organic soil for high-temperature drilling fluids in the prior art, this invention proposes a high-temperature resistant organic soil for drilling fluids and its preparation method, so as to achieve high-temperature resistance of organic soil above 200℃, while having a high colloid content and good viscosity-enhancing and shearing effect at this temperature.
[0004] To achieve the above objectives, the following technical solution is adopted:
[0005] One aspect of this invention provides an organic clay for high-temperature drilling fluid, comprising the following components by weight: 50-80 parts of sodium montmorillonite, 10-30 parts of attapulgite, 10-30 parts of long-chain quaternary ammonium salt, and 5-15 parts of chelating agent.
[0006] Furthermore, the long-chain quaternary ammonium salt is one of n-alkyltrimethylammonium chloride or n-alkyltrimethylammonium bromide, wherein n = 12-18.
[0007] Furthermore, the chelating agent is one of n-alkyltrimethylphosphine chloride or n-alkyltrimethylphosphine bromide, wherein n = (12, 14 or 16).
[0008] Another aspect of the present invention provides a method for preparing organic clay for high-temperature drilling fluid, comprising the following steps:
[0009] (1) Weigh out sodium-based montmorillonite, attapulgite, long-chain quaternary ammonium salt and chelating agent according to the weight parts;
[0010] (2) Mix the weighed sodium montmorillonite and attapulgite with water, stir at 75-85℃ for 8-15 min, add the weighed long-chain quaternary ammonium salt, stir and adjust the pH to 7-8, and continue stirring for 0.5-2 h to obtain a first-intercalation mixture.
[0011] (3) Add ethanol and the weighed chelating agent to the primary intercalation mixture and continue stirring at 75-85℃ for 2 hours to obtain the secondary intercalation mixture;
[0012] (4) The secondary intercalation mixture is cooled, filtered, washed, dried, crushed and sieved to obtain high-temperature resistant drilling fluid organic soil.
[0013] Furthermore, in step (2), the mixing ratio of sodium montmorillonite, attapulgite and water by weight is (50-80) parts: (10-30) parts: (1000-1500) parts.
[0014] Furthermore, in step (2), the solution used to adjust the pH is a hydrochloric acid solution.
[0015] Furthermore, in step (3), the ratio of ethanol to chelating agent by weight is (50-100) parts: (5-15) parts.
[0016] Furthermore, in step (4), the washing process is as follows: repeatedly wash with deionized water until the supernatant is tested with silver nitrate and no white precipitate is found.
[0017] Furthermore, in step (4), the drying temperature is 80-100℃ and the drying time is 8-12h.
[0018] Furthermore, in step (4), a 200-mesh sieve is used for sieving.
[0019] The beneficial effects of this invention are:
[0020] This invention uses a compound of montmorillonite and attapulgite as a modifying material to prevent the single layered structure of montmorillonite from discontinuing at high temperatures, thus affecting the high-temperature resistance of the organic soil. Then, a long-chain quaternary ammonium salt is used as a primary intercalating agent to effectively penetrate the interlayers of montmorillonite, increasing the interlayer spacing. Next, a chelating agent is used as a secondary intercalating agent to connect adjacent montmorillonite layers using chemical bonds. Simultaneously, the primary intercalating agent and the montmorillonite are further connected to improve the problem of easy ionic bond desorption. This results in an organic soil for high-temperature drilling fluids, with a high temperature resistance exceeding 200℃. At this temperature, the organic soil also exhibits a high colloidal content and good viscosity-enhancing and shear-lifting effects. Detailed Implementation
[0021] The present application will now be clearly and completely described in conjunction with the technical solutions of the embodiments. Obviously, the described embodiments are merely some embodiments of the present application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.
[0022] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0023] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0024] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0025] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0026] Example 1
[0027] Weigh 40g of sodium montmorillonite and 10g of attapulgite, add them to 1000mL of deionized water and mix well. Stir at 80℃ for 10min, then add 15g of dodecyltrimethylammonium chloride, stir and adjust the pH to 7 with 0.01mol / L hydrochloric acid. Continue stirring for 1.5h to obtain a first-intercalation mixture.
[0028] Add 5g of cetyltrimethoxyphosphine chloride and 50mL of ethanol to the primary intercalation mixture, and continue stirring at 80℃ for 2h to obtain the secondary intercalation mixture.
[0029] The secondary intercalation mixture was cooled to room temperature, repeatedly washed and filtered with deionized water, and the supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 100℃ for 10 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #1.
[0030] Example 2
[0031] Weigh 40g of sodium montmorillonite and 10g of attapulgite, add them to 1000mL of deionized water and mix well. Stir at 80℃ for 10min, then add 15g of tetradecyltrimethylammonium bromide, stir and adjust the pH to 7 with 0.01mol / L hydrochloric acid. Continue stirring for 1.5h to obtain a first-intercalation mixture.
[0032] Add 5g of cetyltrimethoxyphosphine chloride and 50mL of ethanol to the primary intercalation mixture, and continue stirring at 80℃ for 2h to obtain the secondary intercalation mixture.
[0033] The secondary intercalation mixture was cooled to room temperature, repeatedly washed and filtered with deionized water, and the supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 100℃ for 10 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #2.
[0034] Example 3
[0035] Weigh 40g of sodium montmorillonite and 10g of attapulgite, add them to 1000mL of deionized water and mix well. Stir at 80℃ for 10min, then add 15g of hexadecyltrimethylammonium chloride, stir and adjust the pH to 7 with 0.01mol / L hydrochloric acid. Continue stirring for 1.5h to obtain a first-intercalation mixture.
[0036] Add 5g of cetyltrimethoxyphosphine chloride and 50mL of ethanol to the primary intercalation mixture, and continue stirring at 80℃ for 2h to obtain the secondary intercalation mixture.
[0037] The secondary intercalation mixture was cooled to room temperature, repeatedly washed and filtered with deionized water, and the supernatant was tested with silver nitrate until no white precipitate was produced. It was then dried at 100℃ for 10 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #3.
[0038] Example 4
[0039] Weigh 35g of sodium montmorillonite and 15g of attapulgite, add them to 1000mL of deionized water and mix well. Stir at 80℃ for 10min, then add 10g of hexadecyltrimethylammonium chloride, stir and adjust the pH to 7 with 0.01mol / L hydrochloric acid. Continue stirring for 1.5h to obtain a first-intercalation mixture.
[0040] Add 10g of cetyltrimethoxyphosphine chloride and 50mL of ethanol to the primary intercalation mixture, and continue stirring at 80℃ for 2h to obtain the secondary intercalation mixture.
[0041] The secondary intercalation mixture was cooled to room temperature, repeatedly washed and filtered with deionized water, and the supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 100℃ for 10 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #4.
[0042] Example 5
[0043] Weigh 40g of sodium montmorillonite and 10g of attapulgite, add them to 1000mL of deionized water and mix well. Stir at 80℃ for 10min, then add 15g of hexadecyltrimethylammonium chloride, stir and adjust the pH to 7 with 0.01mol / L hydrochloric acid. Continue stirring for 1.5h to obtain a first-intercalation mixture.
[0044] Add 5g of cetyltrimethoxyphosphine chloride and 50mL of ethanol to the primary intercalation mixture, and continue stirring at 80℃ for 2h to obtain the secondary intercalation mixture.
[0045] The secondary intercalation mixture was cooled to room temperature, repeatedly washed and filtered with deionized water, and the supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 100℃ for 10 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #5.
[0046] Example 6
[0047] Weigh 40g of sodium montmorillonite and 10g of attapulgite, add them to 1000mL of deionized water and mix well. Stir at 80℃ for 10min, then add 15g of octadecyltrimethylammonium chloride, stir and adjust the pH to 7 with 0.01mol / L hydrochloric acid. Continue stirring for 1.5h to obtain a first-intercalation mixture.
[0048] Add 5g of cetyltrimethoxyphosphine chloride and 50mL of ethanol to the primary intercalation mixture, and continue stirring at 80℃ for 2h to obtain the secondary intercalation mixture.
[0049] The secondary intercalation mixture was cooled to room temperature, repeatedly washed and filtered with deionized water, and the supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 100℃ for 10 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #6.
[0050] Example 7
[0051] Weigh 40g of sodium montmorillonite and 10g of attapulgite, add them to 1000mL of deionized water and mix well. Stir at 80℃ for 10min, then add 15g of octadecyltrimethylammonium chloride, stir and adjust the pH to 7 with 0.01mol / L hydrochloric acid. Continue stirring for 1h to obtain a first-intercalation mixture.
[0052] Add 5g of cetyltrimethoxyphosphine chloride and 50mL of ethanol to the primary intercalation mixture, and continue stirring at 80℃ for 2h to obtain the secondary intercalation mixture.
[0053] The secondary intercalation mixture was cooled to room temperature, repeatedly washed and filtered with deionized water, and the supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 100℃ for 10 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #7.
[0054] Example 8
[0055] Weigh 40g of sodium montmorillonite and 10g of attapulgite, add them to 1000mL of deionized water and mix well. Stir at 75℃ for 15min, then add 15g of octadecyltrimethylammonium chloride, stir and adjust the pH to 7.5 with 0.01mol / L hydrochloric acid. Continue stirring for 2h to obtain a first-intercalation mixture.
[0056] Add 5g of cetyltrimethoxyphosphine chloride and 50mL of ethanol to the primary intercalation mixture, and continue stirring at 75℃ for 2h to obtain the secondary intercalation mixture.
[0057] The secondary intercalation mixture was cooled to room temperature, repeatedly washed and filtered with deionized water, and the supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 90℃ for 10 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #8.
[0058] Example 9
[0059] Weigh 40g of sodium montmorillonite and 10g of attapulgite, add them to 1000mL of deionized water and mix well. Stir at 85℃ for 10min, then add 15g of octadecyltrimethylammonium chloride, stir and adjust the pH to 8 with 0.01mol / L hydrochloric acid. Continue stirring for 1h to obtain a first-intercalation mixture.
[0060] Add 5g of cetyltrimethoxyphosphine chloride and 50mL of ethanol to the primary intercalation mixture, and continue stirring at 85℃ for 2h to obtain the secondary intercalation mixture.
[0061] The secondary intercalation mixture was cooled to room temperature, repeatedly washed and filtered with deionized water, and the supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 90℃ for 10 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #9.
[0062] Comparative Example 1
[0063] Weigh 50g of sodium montmorillonite and add it to 1000mL of deionized water. Mix well and stir at 80℃ for 10min. Then add 15g of hexadecyltrimethylammonium chloride, stir, and adjust the pH to 7 with 0.01mol / L hydrochloric acid. Continue stirring for 1.5h to obtain a first-intercalation mixture.
[0064] Add 5g of cetyltrimethoxyphosphine chloride and 50mL of ethanol to the primary intercalation mixture, and continue stirring at 80℃ for 2h to obtain the secondary intercalation mixture.
[0065] The secondary intercalation mixture was cooled to room temperature, repeatedly washed and filtered with deionized water, and the supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 100℃ for 10 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil pair #1.
[0066] The difference between Comparative Example 1 and Example 3 above is that no attapulgite clay was added.
[0067] Comparative Example 2
[0068] Weigh 40g of sodium montmorillonite and 10g of attapulgite, add them to 1000mL of deionized water and mix well. Stir at 80℃ for 10min, then add 15g of hexadecyltrimethylammonium chloride, stir and adjust the pH to 7 with 0.01mol / L hydrochloric acid. Continue stirring for 1.5h to obtain the intercalation mixture.
[0069] The intercalation mixture was cooled to room temperature, repeatedly washed and filtered with deionized water, and the supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 100℃ for 10 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil pair #2.
[0070] The difference between Comparative Example 2 and Example 3 above is that hexadecyltrimethoxyphosphine chloride was not used for secondary intercalation modification.
[0071] Comparative Example 3
[0072] Weigh 40g of sodium montmorillonite and 10g of attapulgite, add them to 1000mL of deionized water and mix well. Stir at 80℃ for 10min, then add 15g of hexadecyltrimethylammonium chloride, stir and adjust the pH to 7 with 0.01mol / L hydrochloric acid. Continue stirring for 1.5h to obtain a first-intercalation mixture.
[0073] Add 5g of cetyltrimethylammonium chloride and 50mL of ethanol to the primary intercalation mixture, and continue stirring at 80℃ for 2h to obtain the secondary intercalation mixture.
[0074] The secondary intercalation mixture was cooled to room temperature, repeatedly washed and filtered with deionized water, and the supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 100℃ for 10 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil pair #3.
[0075] The difference between Comparative Example 3 and Example 2 above is that the secondary intercalating agent "hexadecyltrimethoxyphosphine chloride" is replaced with "hexadecyltrimethylammonium chloride".
[0076] Comparative Example 4
[0077] The organic soil is commercially available with the model number YH-918, and is designated as #4.
[0078] Performance testing
[0079] To compare the performance of the organic soils obtained in the various embodiments and comparative examples, the suspension performance of the organic soils obtained in the above embodiments and comparative examples was tested. The test methods are as follows:
[0080] Prepare the test solution:
[0081] Add 340 mL of No. 0 diesel oil and 12.0 g of Span 80 (accurate to 0.01 g, the same below) to a high-speed stirring cup. Stir at 11000 r / min for 10 min, then add 60 mL of water and continue stirring for 10 min. While stirring, add 16.0 g of organic soil sample and stir at high speed for 20 min to obtain the test solution. During the stirring process, ensure that no sample adheres to the cup wall and maintain the temperature of the test solution between 25℃ and 30℃.
[0082] room temperature test
[0083] A six-speed rotational viscometer was used to test the stable readings of the test liquid at 600 r / min, 300 r / min, and 3 r / min, and the apparent viscosity, plastic viscosity, and dynamic shear force of the test liquid were calculated. The test temperature was 50 ± 1℃.
[0084] 200℃ Aging Resistance Test
[0085] The prepared test solution was placed in a high-temperature aging tank and then placed in a roller furnace. After aging at 200℃ for 16 hours, it was removed and stirred at 11000 r / min for 20 minutes to obtain the aged test solution. A six-speed rotational viscometer was used to test the stable readings of the test solution at 600 r / min, 300 r / min, and 3 r / min, and the apparent viscosity, plastic viscosity, and dynamic shear force of the aged test solution were calculated. The test temperature was 50 ± 1℃.
[0086] The aging test results at room temperature and 200°C for the above embodiments and comparative examples are shown in the table below.
[0087]
[0088]
[0089] The experimental data from the examples in the table above show that the organic soil prepared by the method of the present invention has good suspension ability in the oil-based system, and the overall suspension performance is not significantly affected after aging at 200℃, indicating that it has good resistance to high-temperature aging at 200℃.
[0090] The test data from Examples 3 and 4 and Comparative Example 1 show that adding a certain amount of attapulgite can effectively improve the thermal stability of organic soil compared to not adding attapulgite. However, when the amount of attapulgite added increases, the rheological properties of the organic soil decrease because attapulgite cannot promote the intercalation modification of bentonite.
[0091] As can be seen from the test data of Example 3 and Comparative Example 2, even with the addition of attapulgite to the raw materials, the rheological properties and thermal stability of the organic soil obtained by simply using hexadecyltrimethylammonium chloride for one-time intercalation modification are reduced.
[0092] As can be seen from the test data of Example 3 and Comparative Example 3, when the secondary intercalating agent in Example 3 is replaced with hexadecyltrimethylammonium chloride, the rheological properties of the organic clay increase, while its resistance to high temperature of 200°C decreases.
[0093] Finally, a comparison of the test data of each embodiment with those of commercially available organic soil shows that the organic soil prepared by the method of the present invention has excellent overall performance, and still has a high colloid content and good adhesion-enhancing and shearing effect after aging at 200℃.
[0094] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.
[0095] The preparation method of high-temperature resistant drilling fluid organic soil provided in the embodiments of this application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A type of organic soil for high-temperature drilling fluid, characterized in that: By weight, it comprises the following components: 50-80 parts of sodium montmorillonite, 10-30 parts of attapulgite, 10-30 parts of long-chain quaternary ammonium salt, and 5-15 parts of chelating agent; wherein the chelating agent is one of n-alkyltrimethylphosphine chloride or n-alkyltrimethylphosphine bromide, wherein n=12, 14 or 16. The long-chain quaternary ammonium salt is one of n-alkyltrimethylammonium chloride or n-alkyltrimethylammonium bromide, wherein n=12-18; The method for preparing the high-temperature resistant drilling fluid organic soil includes the following steps: (1) Weigh out sodium-based montmorillonite, attapulgite, long-chain quaternary ammonium salt and chelating agent according to the weight parts; (2) Weigh out sodium montmorillonite and attapulgite and mix them with water. Stir at 75-85℃ for 8-15 min, then add weighed long-chain quaternary ammonium salt, stir and adjust the pH to 7-8, and continue stirring for 0.5-2 h to obtain a first-intercalation mixture. (3) Add ethanol and the weighed chelating agent to the primary intercalation mixture and continue stirring at 75-85℃ for 2 hours to obtain the secondary intercalation mixture; (4) The secondary intercalation mixture is cooled, filtered, washed, dried, crushed and sieved to obtain high-temperature resistant drilling fluid organic soil.
2. The high-temperature resistant organic soil for drilling fluid according to claim 1, characterized in that: In step (2), the mixing ratio of sodium montmorillonite, attapulgite and water by weight is 50-80 parts: 10-30 parts: 1000-1500 parts.
3. The high-temperature resistant organic soil for drilling fluid according to claim 1, characterized in that: In step (2), the solution used to adjust the pH is a hydrochloric acid solution.
4. The high-temperature resistant organic soil for drilling fluid according to claim 1, characterized in that: In step (3), the ratio of ethanol to chelating agent by weight is 50-100 parts: 5-15 parts.
5. The high-temperature resistant organic soil for drilling fluid according to claim 1, characterized in that: In step (4), the washing process is as follows: wash repeatedly with deionized water until the supernatant is tested with silver nitrate and no white precipitate is found.
6. The high-temperature resistant organic soil for drilling fluid according to claim 1, characterized in that: In step (4), the drying temperature is 80-100℃ and the drying time is 8-12h.
7. The high-temperature resistant organic soil for drilling fluid according to claim 1, characterized in that: In step (4), a 200-mesh sieve is used for sieving.