Organic soil as well as preparation method and application thereof

Abstract

The invention relates to the field of drilling fluid, and discloses organic soil as well as a preparation method and application thereof. The organic soil comprises the following components in parts by weight: 50-80 parts of Na-montmorillonite, 10-30 parts of long-chain quaternary ammonium salt and 5-15 parts of a silane coupling agent. According to the organic soil provided by the invention, the long-chain quaternary ammonium salt is introduced as a primary intercalator and can effectively enter the interlayer space of the Na-montmorillonite to increase the interlayer space, and the silane coupling agent is introduced as a secondary intercalator and is connected with two adjacent layers of montmorillonite by using a Si-O chemical bond, so that the connection between the long-chain quaternary ammonium salt and the Na-montmorillonite is firmer, and the stability of the organic soil is improved. Further, the stability, the tackifying and shear-improving effects, the suspension performance and the high-temperature resistance of the organic soil are improved; according to the preparation method of the organic soil, the operation conditions and the technological process are simplified, the reaction conditions are mild, and industrial production is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of drilling fluid, and in particular to an organic soil and a preparation method and application thereof. Background Art

[0002] At present, the number of deep wells, ultra-deep wells and complex wells in various countries around the world is increasing, which puts higher requirements on the temperature resistance of drilling fluids. Organic clay is the most widely used rheology control agent in oil-based drilling fluids. Due to its good lipophilicity and large interlayer spacing, organic clay controls the rheological behavior of oil-based drilling fluids by dispersing and swelling in the base oil. At present, the organic clay used in actual drilling operations is an oleophilic colloidal material obtained by organically modifying montmorillonite.

[0003] The basic structural unit of montmorillonite is composed of two layers of silicon-oxygen tetrahedral sheets with a layer of silicon-oxygen octahedral sheets in the middle. It is a typical 2:1 type layered silicate clay mineral. Due to isomorphous substitution in the structure of montmorillonite, its crystal layers carry a certain amount of structural negative charge. In order to maintain electrical neutrality, the montmorillonite layers can adsorb an equal amount of cations. Conventional organic soil is generally made of montmorillonite modified by long-chain quaternary ammonium salt intercalation adsorption. The quaternary ammonium salt and montmorillonite layers are mainly connected by charge interaction. Under high temperature conditions, the adsorbed long-chain quaternary ammonium salt modifier is easy to disperse and desorb, resulting in the failure of the organic soil.

[0004] CN103773324A discloses a method for improving the gelation rate of organic soil in oil-based drilling fluid mud. The organic soil is prepared by bentonite modified by organic ammonium or organic amine. When evaluated below 150°C, the colloid rate is high and the shear and viscosity increasing effect is good. However, after exceeding 180°C, the performance deteriorates significantly.

[0005] CN113336238A discloses a method for preparing organic soil for high temperature resistant oil-in-water drilling fluid, wherein 1-octadecenetrimethylammonium chloride is used as an intercalating agent and a chelating agent is introduced at the same time. The obtained organic soil has a good viscosity-increasing and shear-enhancing effect at high temperature, but an initiator needs to be added during the reaction process and the chelating agent has a high cost.

[0006] Therefore, there is an urgent need to develop an organic soil with a simple preparation method, low cost and good temperature resistance. Summary of the invention

[0007] The purpose of the present invention is to overcome the problems of poor stability, viscosity-enhancing and shear-improving effects, suspension performance and high temperature resistance of organic soil in the prior art, and to provide an organic soil and a preparation method and application thereof.

[0008] In order to achieve the above object, the first aspect of the present invention provides an organic soil, wherein the organic soil comprises: 50-80 parts by weight of sodium montmorillonite, 10-30 parts by weight of long-chain quaternary ammonium salt and 5-15 parts by weight of silane coupling agent.

[0009] A second aspect of the present invention provides a method for preparing organic soil, wherein the method comprises the following steps:

[0010] 1) mixing sodium montmorillonite and water for the first time, adding a long-chain quaternary ammonium salt and adjusting the pH to obtain a primary intercalation mixture;

[0011] 2) mixing the silane coupling agent, ethanol and the primary intercalation mixed solution for a second time to obtain a secondary intercalation mixed solution;

[0012] 3) Treating the secondary intercalation mixed solution to obtain organic soil.

[0013] The third aspect of the present invention provides the use of the above-mentioned organic soil in drilling fluid.

[0014] Through the above technical solution, the present invention provides an organic soil and its preparation method and application to achieve the following beneficial effects:

[0015] (1) The organosilicon provided by the present invention can effectively enter the interlayer of sodium-based montmorillonite by introducing a long-chain quaternary ammonium salt as a primary intercalation agent to increase the interlayer distance, and can also introduce a silane coupling agent as a secondary intercalation agent to connect two adjacent layers of montmorillonite by utilizing its Si-O chemical bond, thereby making the connection between the long-chain quaternary ammonium salt and the sodium-based montmorillonite more firmly, thereby improving the stability of the organosilicon, the viscosity-increasing and shear-increasing effect (at 240° C., the apparent viscosity is 13-15 mPa·s, the plastic viscosity is 8.5-9.5 mPa·s and the dynamic shear force is 4.5-5.5 Pa), the suspension performance (the colloid rate at room temperature is 88-94%, and the colloid rate after aging at 240° C. is 75-81%), and the high temperature resistance performance reaches 240° C.;

[0016] (2) The method for preparing the organic soil provided by the present invention simplifies the operating conditions and process flow, has mild reaction conditions, and is convenient for industrial production. DETAILED DESCRIPTION

[0017] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0018] The first aspect of the present invention provides an organic soil, wherein the organic soil comprises: 50-80 parts by weight of sodium montmorillonite, 10-30 parts by weight of a long-chain quaternary ammonium salt and 5-15 parts by weight of a silane coupling agent.

[0019] Furthermore, the organic soil comprises: 60-70 parts by weight of sodium montmorillonite, 15-25 parts by weight of long-chain quaternary ammonium salt and 8-12 parts by weight of silane coupling agent.

[0020] In the present invention, when the sodium montmorillonite, the long-chain quaternary ammonium salt and the silane coupling agent meet the above ranges, the prepared organic soil has good rheological properties and high temperature stability in the oil-based drilling fluid system, and still has good viscosity-increasing and shear-enhancing effects at 240°C.

[0021] According to the present invention, the long-chain quaternary ammonium salt is selected from n-alkyl trimethyl ammonium chloride and / or n-alkyl trimethyl ammonium bromide, wherein n represents the carbon number, which is 12-18.

[0022] In the present invention, the long-chain quaternary ammonium salt acts as a primary intercalation agent, which can effectively enter the interlayers of sodium-based montmorillonite, increase the interlayer distance, improve the solubility of montmorillonite in oil-based solvents, and further improve its rheological properties in oil-based drilling fluids.

[0023] According to the present invention, the silane coupling agent is selected from at least one of m-alkyltrimethoxysilane, γ-aminopropyltriethoxysilane and γ-methacryloxypropyltrimethoxysilane, wherein m represents the carbon number, which is 12, 14 or 16.

[0024] In the present invention, the silane coupling agent is used as a secondary intercalation agent to connect two adjacent layers of montmorillonite using its Si-O chemical bond, while making the connection between the long-chain quaternary ammonium salt and the sodium-based montmorillonite more firmly, which can effectively improve the problem of easy desorption of ionic bonds, thereby enhancing the high-temperature stability of the organic montmorillonite.

[0025] A second aspect of the present invention provides a method for preparing organic soil, wherein the method comprises the following steps:

[0026] 1) mixing sodium montmorillonite and water for the first time, adding a long-chain quaternary ammonium salt and adjusting the pH to obtain a primary intercalation mixture;

[0027] 2) mixing the silane coupling agent, ethanol and the primary intercalation mixed solution for a second time to obtain a secondary intercalation mixed solution;

[0028] 3) Treating the secondary intercalation mixed solution to obtain organic soil.

[0029] According to the present invention, in step 1), the first mixing process comprises: stirring at 75-80° C. for 10-30 min.

[0030] According to the present invention, in step 1), the mass ratio of the sodium montmorillonite, water and long-chain quaternary ammonium salt is (5-8):(100-150):(1-3).

[0031] According to the present invention, in step 1), the pH of the primary intercalation mixture is 7-8.

[0032] According to the present invention, the pH is adjusted with a 0.01-0.1 mol / L hydrochloric acid solution.

[0033] According to the present invention, in step 2), the mass volume ratio of the silane coupling agent to ethanol is (5-15) g: (50-100) mL.

[0034] According to the present invention, in step 2), the second mixing process comprises: stirring at 75-80° C. for 1-3 hours.

[0035] According to the present invention, in step 3), the treatment process includes: cooling, filtering, washing, drying, crushing and screening.

[0036] According to the present invention, the cooling process includes: naturally cooling to room temperature.

[0037] According to the present invention, the room temperature is 25-35°C.

[0038] According to the present invention, the washing process comprises: repeatedly washing the organic soil with water.

[0039] In the present invention, the purpose of the washing is to remove Br - and Cl - .

[0040] According to the present invention, the drying conditions include: a temperature of 80-100° C. and a time of 6-10 h.

[0041] According to the present invention, the sieving conditions include: 100-300 mesh sieve.

[0042] The third aspect of the present invention provides the use of the above-mentioned organic soil in drilling fluid.

[0043] The present invention will be described in detail below by way of examples. In the following examples,

[0044] Sodium montmorillonite was purchased from Zhejiang Fenghong New Materials Co., Ltd., model BP-188;

[0045] Long-chain quaternary ammonium salts were purchased from Sinopharm Group;

[0046] Silane coupling agent was purchased from MACKLIN;

[0047] The raw materials used in the examples and comparative examples are all commercially available.

[0048] Example 1

[0049] 1) 65 g of sodium montmorillonite and 1200 g of deionized water were stirred at 77° C. for 20 min, 20 g of hexadecyltrimethylammonium chloride and 0.5 mol / L hydrochloric acid solution were added to adjust the pH to 7.5, and stirred for 1.5 h to obtain a primary intercalation mixture;

[0050] 2) Add 10 g of dodecyltrimethoxysilane and 70 mL of ethanol to the primary intercalation mixture, and stir at 77° C. for 2 h to obtain a secondary intercalation mixture;

[0051] 3) The secondary intercalation mixture was naturally cooled to room temperature, repeatedly washed with deionized water, filtered, dried at 100° C. for 8 h, crushed and sieved with a 200-mesh sieve to obtain organic soil A1.

[0052] Example 2

[0053] 1) 60 g of sodium montmorillonite and 1300 g of deionized water were stirred at 78° C. for 25 min, 25 g of tetradecyltrimethylammonium chloride and 0.7 mol / L hydrochloric acid solution were added to adjust the pH to 8, and stirred for 1.7 h to obtain a primary intercalation mixture;

[0054] 2) Add 8 g of tetradecyltrimethoxysilane and 85 mL of ethanol to the primary intercalation mixture, and stir at 78° C. for 2 h to obtain a secondary intercalation mixture;

[0055] 3) The secondary intercalation mixture was naturally cooled to room temperature, repeatedly washed with deionized water, filtered, dried at 110° C. for 7 h, crushed and sieved with a 250-mesh sieve to obtain organic soil A2.

[0056] Example 3

[0057] 1) 70 g of sodium montmorillonite and 1100 g of deionized water were stirred at 76° C. for 15 min, 15 g of dodecyltrimethylammonium chloride and 0.3 mol / L hydrochloric acid solution were added to adjust the pH to 7, and stirred for 1.3 h to obtain a primary intercalation mixture;

[0058] 2) Add 12 g of hexadecyltrimethoxysilane and 65 mL of ethanol to the primary intercalation mixture, and stir at 76° C. for 2 h to obtain a secondary intercalation mixture;

[0059] 3) The secondary intercalation mixture was naturally cooled to room temperature, repeatedly washed with deionized water, filtered, dried at 90° C. for 9 h, crushed and sieved with a 150-mesh sieve to obtain organic soil A3.

[0060] Example 4

[0061] 1) 50 g of sodium montmorillonite and 1500 g of deionized water were stirred at 80° C. for 10 min, 30 g of octadecyltrimethylammonium chloride and 0.1 mol / L hydrochloric acid solution were added to adjust the pH to 7, and stirred for 2 h to obtain a primary intercalation mixture;

[0062] 2) Add 5 g of γ-aminopropyltriethoxysilane and 100 mL of ethanol to the primary intercalation mixture, and stir at 80° C. for 2 h to obtain a secondary intercalation mixture;

[0063] 3) The secondary intercalation mixture was naturally cooled to room temperature, repeatedly washed with deionized water, filtered, dried at 120° C. for 6 h, crushed and sieved with a 300-mesh sieve to obtain organic soil A4.

[0064] Example 5

[0065] 1) 80 g of sodium montmorillonite and 1000 g of deionized water were stirred at 75° C. for 30 min, 10 g of hexadecyltrimethylammonium chloride and 1 mol / L hydrochloric acid solution were added to adjust the pH to 8, and stirred for 1 h to obtain a primary intercalation mixture;

[0066] 2) adding 15 g of γ-methacryloxypropyltrimethoxysilane and 50 mL of ethanol to the primary intercalation mixture, stirring at 75° C. for 2 h to obtain a secondary intercalation mixture;

[0067] 3) The secondary intercalation mixture was naturally cooled to room temperature, repeatedly washed with deionized water, filtered, dried at 80° C. for 10 h, crushed and sieved with a 100-mesh sieve to obtain organic soil A5.

[0068] Comparative Example 1

[0069] The method of Example 1 is followed, except that the mass ratio of sodium montmorillonite to hexadecyltrimethylammonium chloride is 1:1, to obtain organic soil D1.

[0070] Comparative Example 2

[0071] The method of Example 1 was followed except that dodecyltrimethoxysilane was not added.

[0072] Test Example 1

[0073] The colloid rate of the organic soil in the above embodiments and comparative examples was tested.

[0074] The test method of colloid rate is as follows:

[0075] Method for determining the colloid rate at room temperature: add 200mL of No. 0 diesel oil to a high-stirring cup, put it in a water bath, make the temperature reach 30℃±1℃, add 4.0g (accurate to 0.01g) of organic soil sample while stirring at a speed of 11000r / min, stir at high speed for 10min to obtain the organic soil test solution. Pour the organic soil test solution into a stoppered measuring cylinder to 100mL, start the stopwatch at the same time, and record the volume V of the upper free oil at 90min.

[0076] Calculate the colloid rate J, % by the following formula:

[0077]

[0078] Method for determining the colloid rate after aging: Pour the above organic soil test solution into a high-temperature aging tank and age it at 180°C and 240°C for 16 hours. After aging, cool it to room temperature and stir it at a high speed of 11000r / min for 10 minutes. Then pour it into a stoppered measuring cylinder to 100mL, start a stopwatch at the same time, and record the volume V of the free oil in the upper part at 90 minutes. Calculate the colloid rate according to formula (1).

[0079] The results are shown in Table 1.

[0080] Table 1

[0081] serial number Room temperature colloid rate / % Colloid rate after aging at 180℃ / % Colloid rate after aging at 240℃ / % A1 93 90 81 A2 94 87 80 A3 92 86 79 A4 91 85 77 A5 88 83 75 D1 80 70 60 D2 85 40 5

[0082] As shown in Table 1, the colloid rate of the organic soil prepared by the present invention in diesel at room temperature is higher than that of the comparative agent, the colloid effect is excellent, and the suspension performance is excellent. From the results after aging at 180°C and 220°C, it can be seen that the colloid rate of the organic soil prepared in the embodiment decreases slightly, and the temperature resistance is excellent.

[0083] Test Example 2

[0084] The suspension performance of the organic soil in the above examples and comparative examples was tested.

[0085] The test method for suspension performance is as follows:

[0086] Add 340mL of No. 0 diesel and 12.0g of Span 80 (accurate to 0.01g, the same below) into a high-stirring cup, stir at 11000r / min for 10min, then add 60mL of water, continue stirring for 10min, add 16.0g of organic soil sample while stirring, and stir at high speed for 20min. During the stirring process, ensure that there is no sample adhesion to the cup wall and the test liquid temperature is kept at 25℃-30℃. After stirring, use a six-speed rotary viscometer to measure the stable readings of the viscometer at 600r / min, 300r / min and 3r / min at 50℃±1℃, and calculate the apparent viscosity, plastic viscosity and dynamic shear force.

[0087] The prepared test liquid is loaded into a high-temperature aging tank, placed in a roller heating furnace, and taken out after rolling aging at 240°C for 16 hours. It is stirred at a high speed of 11000r / min for 20 minutes. After stirring, the apparent viscosity, plastic viscosity, and dynamic shear force are measured and calculated.

[0088] The results are shown in Table 2.

[0089] Table 2

[0090]

[0091]

[0092] As shown in Table 2, the organic soil prepared in the present invention has good temperature resistance in the oil-based system and reaches 240°C, and has excellent comprehensive performance.

[0093] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. An organic soil, characterized in that: The organic soil comprises: 50-80 parts by weight of sodium montmorillonite, 10-30 parts by weight of long-chain quaternary ammonium salt and 5-15 parts by weight of silane coupling agent.

2. The organic soil according to claim 1, wherein The long-chain quaternary ammonium salt is selected from n-alkyl trimethyl ammonium chloride and / or n-alkyl trimethyl ammonium bromide, wherein n represents the carbon number, which is 12-18.

3. The organic soil according to claim 1 or 2, wherein The silane coupling agent is selected from at least one of m-alkyltrimethoxysilane, γ-aminopropyltriethoxysilane and γ-methacryloxypropyltrimethoxysilane, wherein m represents the carbon number, which is 12, 14 or 16.

4. A method for preparing organic soil, characterized in that: The method comprises the following steps: 1) mixing sodium montmorillonite and water for the first time, adding a long-chain quaternary ammonium salt and adjusting the pH to obtain a primary intercalation mixture; 2) mixing the silane coupling agent, ethanol and the primary intercalation mixed solution for a second time to obtain a secondary intercalation mixed solution; 3) Treating the secondary intercalation mixed solution to obtain organic soil.

5. The preparation method according to claim 4, wherein In step 1), the first mixing process includes: stirring at 75-80° C. for 10-30 min; Preferably, the mass ratio of the sodium montmorillonite, water and long-chain quaternary ammonium salt is (5-8):(100-150):(1-3); Preferably, the pH of the primary intercalation mixture is 7-8.

6. The preparation method according to claim 4 or 5, wherein: In step 1), the long-chain quaternary ammonium salt is selected from n-alkyltrimethylammonium chloride and / or n-alkyltrimethylammonium bromide, wherein n represents the carbon number, which is 12-18.

7. The preparation method according to any one of claims 4 to 6, characterized in that: In step 2), the silane coupling agent is selected from at least one of m-alkyltrimethoxysilane, γ-aminopropyltriethoxysilane and γ-methacryloxypropyltrimethoxysilane, wherein m represents the carbon number, which is 12, 14, or 16; Preferably, the mass ratio of the silane coupling agent to ethanol is (5-15):(50-100); Preferably, the second mixing process comprises: stirring at 75-80° C. for 1-3 hours.

8. The preparation method according to any one of claims 4 to 6, wherein: In step 3), the treatment process includes: cooling, filtering, washing, drying, crushing and screening.

9. The preparation method according to claim 8, wherein: The washing process comprises: repeatedly washing the organic soil with water; Preferably, the drying conditions include: temperature of 80-120°C and time of 6-10h; Preferably, the sieving conditions include: 100-300 mesh sieve.

10. Use of the organosoil according to claims 1 to 3 or the organosoil prepared by the preparation method according to any one of claims 4 to 9 in drilling fluid.

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