Organoclay compositions for oil-based drilling fluids and organoclays for oil-based drilling fluids and methods of making the same

Abstract

The application relates to the technical field of drilling fluids, and discloses an organic clay composition for oil-based drilling fluid and an organic clay for oil-based drilling fluid and a preparation method thereof. The mixture comprises sodium-based montmorillonite, an intercalation aid, a main intercalation agent, a secondary intercalation agent and water, wherein the intercalation aid is a long-chain quaternary ammonium salt, the main intercalation agent is a long-chain alcohol and / or a long-chain acid, and the secondary intercalation agent is a long-chain diol; the temperature resistance of the organic clay for oil-based drilling fluid can reach 260 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of drilling fluid technology, specifically relating to an organic soil composition for oil-based drilling fluid and an organic soil for oil-based drilling fluid, and a method for preparing the same. Background Technology

[0002] Organoclases are the most widely used rheology control agents in oil-based drilling fluids. Due to their good oleophilicity and large interlayer spacing, organoclases can control the rheological behavior of oil-based drilling fluids by dispersing and swelling in the base oil. However, at high temperatures, organoclase modifiers are prone to desorption and dissociation, and emulsifiers are prone to demulsification. Existing drilling fluid treatment agents and drilling fluid systems can no longer fully meet the needs of ultra-deep well drilling technology. Therefore, the development of organoclases for high-temperature resistant oil-based drilling fluids is urgently needed.

[0003] In actual drilling operations, organic soils are oleophilic colloidal materials obtained by organically modifying montmorillonite. The basic structural unit of montmorillonite consists of two layers of tetrahedral silica sheets sandwiching a layer of octahedral silica sheets, making it a typical layered silicate clay mineral. Due to isomorphic substitution, the crystal layers of montmorillonite carry a certain amount of structural negative charge. To maintain electroneutrality, an equal amount of cations can be adsorbed between the layers. Conventional organic soils are generally modified from montmorillonite through a single intercalation and adsorption of long-chain quaternary ammonium salts. 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.

[0004] CN113336238B discloses a method for preparing an organo-bentonite for high-temperature resistant water-in-oil drilling fluid. The method comprises, by weight, 50-75 parts purified sodium-based bentonite; 15-30 parts 1-octadecenetrimethylammonium chloride; 1-10 parts chelating agent (fatty alcohol polyoxyethylene ether); and 1000-1500 parts water. This organo-bentonite uses 1-octadecenetrimethylammonium chloride as an intercalating agent and simultaneously introduces a chelating agent. The resulting organo-bentonite can significantly improve the temperature resistance and rheological properties of the organo-bentonite for drilling fluid; however, the temperature resistance can only reach 240℃.

[0005] CN102827591A discloses an organic bentonite and its preparation method, wherein the organic bentonite contains: 100 parts of sodium bentonite, 25-40 parts of quaternary ammonium salt, 8-10 parts of alkylphenol polyoxyethylene ether or 1-3 parts of fatty acid triol ester.

[0006] CN103773324B discloses a method for improving the gelation rate of organic clay in oil-based drilling fluid mud. The method includes adding organic clay to oil-based drilling fluid base oil to obtain a mixed system, and then adding an activator to the mixed system. The organic clay content is 0.5-15% by weight, and the amount of activator is 5-30% by weight of organic clay. The organic clay is bentonite modified with organic ammonium or organic amine. All organic ammoniums are dodecyltrimethyl chloride / ammonium bromide, dodecyldimethylbenzyl chloride / ammonium bromide, and bis(dodecylmethylmethylbenzyl chloride / ammonium bromide); the organic amines are dodecyloctadecyl primary amine, secondary amine, and tertiary amine.

[0007] CN104017549B discloses an organic soil for formulating high yield value oil-based drilling fluid and its preparation method. The organic soil is formed by reacting montmorillonite, an alkyl quaternary ammonium salt cationic surfactant, a quaternary ammonium salt cationic surfactant with a strong polar group, and an anionic surfactant with a long-chain alkyl group. The alkyl quaternary ammonium salt cationic surfactant is a single or double long-chain alkyl quaternary ammonium salt cationic surfactant with 14-22 carbon atoms. The quaternary ammonium salt cationic surfactant with a strong polar group has one or more of amide, hydroxyl, or ester groups in its molecular structure. The anionic surfactant with a long-chain alkyl group is a fatty acid, fatty acid salt, alkyl sulfonic acid, or alkyl sulfonate with a carbon chain of 12-18 carbons.

[0008] CN114539992A discloses an improved organo-attapulgite for oil-based drilling fluids and its preparation method. The improved organo-attapulgite for oil-based drilling fluids is prepared by weight of the following components: 100 parts attapulgite, 8-80 parts quaternary ammonium salt, and 0.08-40 parts anionic surfactant.

[0009] The above-disclosed technical solutions all use long-chain quaternary ammonium salts as modifiers to modify montmorillonite into organic clay. When evaluated below 150°C, this type of organic clay has a high colloid content and good shearing and thickening effects, but its performance deteriorates significantly after exceeding 180°C.

[0010] Therefore, it is of great significance to research and develop an organic clay for high-temperature resistant oil-based drilling fluids. Summary of the Invention

[0011] The purpose of this invention is to overcome the problem of poor temperature resistance of organic soil in the prior art, and to provide an organic soil composition for oil-based drilling fluid, an organic soil for oil-based drilling fluid, and a method for preparing the same, wherein the temperature resistance of the organic soil for oil-based drilling fluid can reach 260℃.

[0012] To achieve the above objectives, a first aspect of the present invention provides an organic clay composition for oil-based drilling fluids, wherein the mixture comprises: sodium-based montmorillonite, an intercalation aid, a primary intercalation agent, a secondary intercalation agent, and water, wherein the intercalation aid is a long-chain quaternary ammonium salt, the primary intercalation agent is a long-chain alcohol and / or a long-chain acid, and the secondary intercalation agent is a long-chain diol.

[0013] A second aspect of the present invention provides a method for preparing organic clay for oil-based drilling fluids using the aforementioned composition, wherein the method comprises:

[0014] (1) Sodium-based montmorillonite, water and intercalation aid are brought into contact and mixed to obtain a first mixture;

[0015] (2) The first mixture and the main intercalating agent are brought into contact for a second mixing to obtain a second mixture;

[0016] (3) The second mixture and the secondary intercalating agent are brought into contact for a third mixing to obtain a third mixture;

[0017] (4) The third mixture is cooled, filtered, washed, dried, crushed and sieved to obtain organic soil for oil-based drilling fluid.

[0018] A third aspect of the present invention provides an organic clay for oil-based drilling fluid prepared by the aforementioned method.

[0019] Through the above technical solution, using the method of the present invention, with sodium-based montmorillonite as the base material, preferably with purified sodium-based montmorillonite as the base material, firstly, long-chain quaternary ammonium salts are used to expand the interlayer spacing of montmorillonite, and then long-chain alcohols (or acids) and long-chain diols are used in sequence for intercalation modification, which greatly improves the temperature resistance of organic soil. At 260℃, it still has a high colloidal content and good viscosity-enhancing and shear-lifting effects, which can meet the drilling application requirements of deep wells, ultra-deep wells, and complex wells. Detailed Implementation

[0020] The endpoints and any values ​​of the ranges disclosed herein 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0021] As previously stated, the first aspect of the present invention provides an organic clay composition for oil-based drilling fluids, wherein the mixture comprises: sodium-based montmorillonite, an intercalation aid, a primary intercalation agent, a secondary intercalation agent, and water, wherein the intercalation aid is a long-chain quaternary ammonium salt, the primary intercalation agent is a long-chain alcohol and / or a long-chain acid, and the secondary intercalation agent is a long-chain diol.

[0022] The inventors of this invention discovered that long-chain quaternary ammonium salts, as intercalation aids, can effectively penetrate the interlayer space of montmorillonite, increasing the interlayer spacing to a certain extent, providing space for the main intercalating agent to enter, and improving intercalation efficiency. The main intercalating agent uses long-chain alcohols or long-chain acids, whose hydroxyl and carboxyl groups can react with the silicon-oxygen bonds between montmorillonite layers, chemically connecting the intercalating agent and montmorillonite, making the intercalating agent stable and less prone to desorption. The secondary intercalating agent uses long-chain diols, whose hydroxyl groups can react with the interlayer silicon-oxygen bonds to form chemical bonds, connecting adjacent montmorillonite layers, improving the interlayer stability of montmorillonite, and preventing it from loosening and collapsing at high temperatures. The combined effect of the main and secondary intercalating agents greatly improves the temperature resistance of the resulting organic soil.

[0023] According to the present invention, the mixture comprises, by weight, 50 parts of sodium montmorillonite, 1-10 parts of intercalation aid, 11-30 parts of primary intercalation agent, 2.5-20 parts of secondary intercalation agent, and 1000-1500 parts of water; preferably, by weight, the mixture comprises, 50 parts of sodium montmorillonite, 3-8 parts of intercalation aid, 15-30 parts of primary intercalation agent, 10-15 parts of secondary intercalation agent, and 1000-1500 parts of water.

[0024] In this invention, if the amount of intercalation aid is too large, it will cause the intercalation aid to occupy too many reaction sites on the montmorillonite surface, thereby affecting the intercalation reaction effect of the subsequent primary and secondary intercalation agents; if the amount of intercalation aid is too small, it will lead to insufficient intercalation reaction, small interlayer spacing of montmorillonite, and reduced reaction effect of the subsequent intercalation agents.

[0025] In this invention, if the amount of the primary intercalating agent is too large, it will affect the intercalation efficiency of the secondary intercalating agent and cause waste of the intercalating agent; if the amount of the primary intercalating agent is too small, it will result in fewer chemical bonds being formed between the intercalating agent and montmorillonite, and insufficient temperature resistance of montmorillonite.

[0026] In this invention, if the amount of secondary intercalating agent is too large, it will lead to waste of intercalating agent; if the amount of secondary intercalating agent is too small, it will lead to insufficient temperature resistance of montmorillonite.

[0027] According to the present invention, the intercalation aid is alkyltrimethylammonium chloride and / or alkyltrimethylammonium bromide; preferably, the alkyl group is one or more of 12-18 carbon atoms; more preferably, the alkyl group is one or more of 12, 14, 16 and 18 carbon atoms.

[0028] According to the present invention, the primary intercalating agent is selected from one or more of n-tetradecanoic acid, n-hexadecanoic acid, n-octadecanoic acid, n-tetradecanoic acid, and n-octadecanoic acid.

[0029] According to the present invention, the secondary intercalating agent is selected from one or more of 1,14-tetradecanediol, 1,16-hexadecanediol, and 1,18-octadecanediol.

[0030] In this invention, preferably, the sodium-based montmorillonite is purified sodium-based montmorillonite. Purification refers to the purification of sodium-based montmorillonite using a hydrocyclone separation method. The parameters of the purified sodium-based montmorillonite include: cation exchange capacity of 125-135 mmol / g, swelling capacity of 90-100 mL / g, gel value >500 mL / (15 g), and montmorillonite content of 90-95% by weight. Preferably, in the embodiments and / or comparative examples of this invention, the cation exchange capacity is 130 mmol / g, the swelling capacity is 94 mL / g, the gel value is >500 mL / (15 g), and the montmorillonite content is 92.5% by weight. Furthermore, it should be noted that the volume of the gel formed by mixing bentonite and water in a certain proportion and adding an appropriate amount of magnesium oxide is called the gel value. It is expressed in milliliters as the volume of gel formed from 15 grams of sample.

[0031] In this invention, sodium-based montmorillonite was purchased from Beidou Qiming (Beijing) Energy Saving Technology Service Co., Ltd.

[0032] A second aspect of the present invention provides a method for preparing organic clay for oil-based drilling fluids using the aforementioned composition, wherein the method comprises:

[0033] (1) Sodium-based montmorillonite, water and intercalation aid are brought into contact and mixed to obtain a first mixture;

[0034] (2) The first mixture and the main intercalating agent are brought into contact for a second mixing to obtain a second mixture;

[0035] (3) The second mixture and the secondary intercalating agent are brought into contact for a third mixing to obtain a third mixture;

[0036] (4) The third mixture is cooled, filtered, washed, dried, crushed and sieved to obtain organic soil for oil-based drilling fluid.

[0037] According to the present invention, the conditions for the first mixing include: a temperature of 75-80°C, a time of 1.5-2.5 h, and a pH value of weak alkalinity; preferably, the pH value is 7-8; preferably, the conditions for the first mixing include: mixing sodium montmorillonite and water first, and then mixing with the intercalation aid; preferably, the conditions for the first mixing include: mixing sodium montmorillonite and water first, and then mixing with the intercalation aid for 1.5-2.5 h.

[0038] According to the present invention, the conditions for the second mixing include: a temperature of 85-90°C, a time of 2-4 hours, and an acidic pH value; preferably, the pH value is 2-3.

[0039] According to the present invention, the conditions for the third mixing include: a temperature of 85-90°C, a time of 4-5 hours, and an acidic pH value; preferably, the pH value is 2-3.

[0040] According to the present invention, a hydrochloric acid solution of 0.01 mol / L to 0.1 mol / L is used to adjust the pH.

[0041] In this invention, deionized water is used for repeated washing to remove Br. - and Cl - Use silver nitrate to test the clear supernatant until no white precipitate is produced.

[0042] According to the present invention, the drying conditions include a temperature of 100-105°C and a time of 16-18 hours.

[0043] According to the present invention, the material can be pulverized or passed through a 200-mesh sieve.

[0044] According to a particularly preferred embodiment of the present invention, a method for providing organic clay for oil-based drilling fluids includes:

[0045] (1) Mix purified sodium montmorillonite with water, stir at 75-80℃ for 30 min, add intercalation aid, adjust pH to 7-8, and continue stirring for 1.5 h to obtain a mixture;

[0046] (2) Add the primary intercalating agent to the mixture, adjust the pH to 2-3, stir at 85-90℃ for 2 hours, then add the secondary intercalating agent, maintain the temperature and continue stirring for 4 hours to obtain the intercalation mixture;

[0047] (3) Cool the intercalation mixture, filter, wash, dry, crush and sieve to obtain organic soil for oil-based drilling fluid.

[0048] A third aspect of the present invention provides an organic clay for oil-based drilling fluid prepared by the aforementioned method.

[0049] The present invention will be described in detail below through embodiments.

[0050] In the following examples and comparative examples:

[0051] (1) Method for determining colloidal content at room temperature:

[0052] Add 200 mL of No. 0 diesel oil to a high-speed stirring cup, place it in a water bath, and bring the temperature to 30℃±1℃. While stirring at 11000 r / min, add 4.0 g (accurate to 0.01 g) of organic soil sample and stir at high speed for 10 min to obtain organic soil test solution. Pour the organic soil test solution into a stoppered graduated cylinder to 100 mL, and start a stopwatch to record the volume V of the free oil in the upper part after 90 min.

[0053] Calculate the colloid content J, % using the following formula:

[0054]

[0055] (2) Method for determining the colloidal content after aging:

[0056] The above organic soil test solution was poured into a high-temperature aging tank and aged at 180℃ and 240℃ for 16 hours. After aging, it was cooled to room temperature and stirred at high speed at 11000r / min for 10 minutes. Then it was poured into a stoppered graduated cylinder to 100mL. At the same time, a stopwatch was started to record the volume V of the free oil in the upper part at 90 minutes. The colloid ratio was calculated according to the above formula (1).

[0057] (3) Methods for determining the properties of organic soil suspensions:

[0058] Under normal temperature conditions: 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. During the stirring process, ensure that there is no sample adhering to the cup wall and keep the temperature of the test solution between 25℃ and 30℃. After stirring, use a six-speed rotational viscometer to measure the stable readings of the viscometer at 600 r / min, 300 r / min and 3 r / min at 50℃±1℃, and calculate the apparent viscosity, plastic viscosity and dynamic shear force.

[0059] After aging at 260℃: the prepared test solution was placed in a high-temperature aging tank and put into a roller heating furnace. After aging at 260℃ for 16 hours, it was taken out and stirred at high speed at 11000r / min for 20 minutes. After stirring, the apparent viscosity, plastic viscosity and dynamic shear force were measured and calculated.

[0060] Alkyltrimethylammonium chloride and / or alkyltrimethylammonium bromide were purchased from Sigma-Aldrich.

[0061] Tetradecanoic acid, hexadecanoic acid, octadecanoic acid and octadecanoic acid were purchased from Aladdin;

[0062] 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, and 1,18-octadecanediol were purchased from Meredith.

[0063] Example 1

[0064] This embodiment illustrates the organic clay for oil-based drilling fluids prepared using the method of the present invention.

[0065] (1) Weigh 50g of purified sodium montmorillonite, add 1000mL of deionized water, stir at 80℃ for 30min, add 5g of cetyltrimethylammonium chloride, adjust the pH to 7.5 with hydrochloric acid, and continue stirring for 1.5h to obtain a mixture;

[0066] (2) Add 20g of n-hexadecyl alcohol, adjust the pH to 2.5, stir at 90℃ for 2h, then add 5g of 1,16-hexadecanediol, keep the temperature and continue stirring for 4h to obtain the intercalation mixture;

[0067] (3) Cool the intercalation mixture to room temperature, and repeatedly wash and filter it with deionized water to remove Cl. - The supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 105℃ for 16 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #1.

[0068] Example 2

[0069] This embodiment illustrates the organic clay for oil-based drilling fluids prepared using the method of the present invention.

[0070] (1) Weigh 50g of purified sodium montmorillonite, add 1000mL of deionized water, stir at 80℃ for 30min, add 5g of cetyltrimethylammonium chloride, adjust the pH to 7.5 with hydrochloric acid, and continue stirring for 1.5h to obtain a mixture;

[0071] (2) Add 20g of n-hexadecyl alcohol, adjust the pH to 2.5, stir at 90℃ for 2h, then add 10g of 1,16-hexadecanediol, keep the temperature and continue stirring for 4h to obtain the intercalation mixture;

[0072] (3) Cool the intercalation mixture to room temperature, and repeatedly wash and filter it with deionized water to remove Cl. - The supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 105℃ for 16 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #2.

[0073] Example 3

[0074] This embodiment illustrates the organic clay for oil-based drilling fluids prepared using the method of the present invention.

[0075] (1) Weigh 50g of purified sodium montmorillonite, add 1000mL of deionized water, stir at 80℃ for 30min, add 5g of cetyltrimethylammonium chloride, adjust the pH to 7.5 with hydrochloric acid, and continue stirring for 1.5h to obtain a mixture;

[0076] (2) Add 20g of hexadecanoic acid, adjust the pH to 2.5, stir at 90℃ for 2h, then add 5g of 1,16-hexadecanediol, keep the temperature and continue stirring for 4h to obtain the intercalation mixture;

[0077] (3) Cool the intercalation mixture to room temperature, and repeatedly wash and filter it with deionized water to remove Cl. - The supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 105℃ for 16 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #3.

[0078] Example 4

[0079] This embodiment illustrates the organic clay for oil-based drilling fluids prepared using the method of the present invention.

[0080] (1) Weigh 50g of purified sodium montmorillonite, add 1000mL of deionized water, stir at 80℃ for 30min, add 5g of tetradecyltrimethylammonium chloride, adjust the pH to 7.5 with hydrochloric acid, and continue stirring for 1.5h to obtain a mixture;

[0081] (2) Add 20g of n-tetradecanediol, adjust the pH to 2.5, stir at 90℃ for 2h, then add 5g of 1,14-tetradecanediol, and continue stirring at the temperature for 4h to obtain the intercalation mixture;

[0082] (3) Cool the intercalation mixture to room temperature, and repeatedly wash and filter it with deionized water to remove Cl. - The supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 105℃ for 16 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #4.

[0083] Example 5

[0084] This embodiment illustrates the organic clay for oil-based drilling fluids prepared using the method of the present invention.

[0085] (1) Weigh 50g of purified sodium montmorillonite, add 1000mL of deionized water, stir at 80℃ for 30min, add 5g of tetradecyltrimethylammonium chloride, adjust the pH to 7.5 with hydrochloric acid, and continue stirring for 1.5h to obtain a mixture;

[0086] (2) Add 20g of n-tetradecanediol, adjust the pH to 2.5, stir at 90℃ for 2h, then add 10g of 1,14-tetradecanediol, keep the temperature and continue stirring for 4h to obtain the intercalation mixture;

[0087] (3) Cool the intercalation mixture to room temperature, and repeatedly wash and filter it with deionized water to remove Cl. -The supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 105℃ for 16 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #5.

[0088] Example 6

[0089] This embodiment illustrates the organic clay for oil-based drilling fluid prepared using the method of the present invention.

[0090] (1) Weigh 50g of purified sodium montmorillonite, add 1000mL of deionized water, stir at 80℃ for 30min, add 5g of tetradecyltrimethylammonium chloride, adjust the pH to 7.5 with hydrochloric acid, and continue stirring for 1.5h to obtain a mixture;

[0091] (2) Add 20g of tetradecanoic acid, adjust the pH to 2.5, stir at 90℃ for 2h, then add 5g of 1,14-tetradecanediol, keep the temperature and continue stirring for 4h to obtain the intercalation mixture;

[0092] (3) Cool the intercalation mixture to room temperature, and repeatedly wash and filter it with deionized water to remove Cl. - The supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 105℃ for 16 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #6.

[0093] Example 7

[0094] This embodiment illustrates the organic clay for oil-based drilling fluid prepared using the method of the present invention.

[0095] (1) Weigh 50g of purified sodium montmorillonite, add 1000mL of deionized water, stir at 80℃ for 30min, add 5g of octadecyltrimethylammonium chloride, adjust the pH to 7.5 with hydrochloric acid, and continue stirring for 1.5h to obtain a mixture;

[0096] (2) Add 20g of n-octadecyl alcohol, adjust the pH to 2.5, stir at 90℃ for 2h, then add 5g of 1,18-octadecanediol, keep the temperature and continue stirring for 4h to obtain the intercalation mixture;

[0097] (3) Cool the intercalation mixture to room temperature, and repeatedly wash and filter it with deionized water to remove Cl. - The supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 105℃ for 16 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #7.

[0098] Example 8

[0099] This embodiment illustrates the organic clay for oil-based drilling fluid prepared using the method of the present invention.

[0100] (1) Weigh 50g of purified sodium montmorillonite, add 1000mL of deionized water, stir at 80℃ for 30min, add 5g of octadecyltrimethylammonium chloride, adjust the pH to 7.5 with hydrochloric acid, and continue stirring for 1.5h to obtain a mixture;

[0101] (2) Add 20g of octadecanoic acid, adjust the pH to 2.5, stir at 90℃ for 2h, then add 5g of 1,18-octadecanediol, and continue stirring at the temperature for 4h to obtain the intercalation mixture;

[0102] (3) Cool the intercalation mixture to room temperature, and repeatedly wash and filter it with deionized water to remove Cl. - The supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 105℃ for 16 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #8.

[0103] Example 9

[0104] This embodiment illustrates the organic clay for oil-based drilling fluid prepared using the method of the present invention.

[0105] (1) Weigh 50g of purified sodium montmorillonite, add 1000mL of deionized water, stir at 80℃ for 30min, add 5g of dodecyltrimethylammonium chloride, adjust the pH to 7.5 with hydrochloric acid, and continue stirring for 1.5h to obtain a mixture;

[0106] (2) Add 20g of n-dodecyl alcohol, adjust the pH to 2.5, stir at 90℃ for 2h, then add 5g of 1,12-dodecanediol, and continue stirring at the temperature for 4h to obtain the intercalation mixture;

[0107] (3) Cool the intercalation mixture to room temperature, and repeatedly wash and filter it with deionized water to remove Cl. - The supernatant was tested with silver nitrate until no white precipitate was formed. It was then dried at 105℃ for 16 hours, followed by pulverization through a 200-mesh sieve to obtain organic soil #9.

[0108] Comparative Example 1

[0109] Commercially available samples were used, specifically HR-A (Zhejiang Fenghong New Materials Co., Ltd.), which is organic soil.

[0110] Comparative Example 2

[0111] Organo-soil was prepared using the same method as in Example 1, except that the main intercalating agent, n-hexadecyl alcohol, was not added.

[0112] As a result, organic soil D2# was prepared.

[0113] Comparative Example 3

[0114] Organic soil was prepared using the same method as in Example 1, except that the secondary intercalating agent 1,16-hexadecanediol was not added.

[0115] As a result, organic soil D3# was prepared.

[0116] Comparative Example 4

[0117] Organo-soil was prepared using the same method as in Example 1, except that “20g of n-hexadecyl alcohol” in Example 1 was changed to “10g of n-hexadecyl alcohol”.

[0118] As a result, organic soil D4# was prepared.

[0119] Comparative Example 5

[0120] Organo-soil was prepared using the same method as in Example 1, except that “5g of 1,16-hexadecanediol” in Example 1 was changed to “2g of 1,16-hexadecanediol”.

[0121] As a result, organic soil D5# was prepared.

[0122] Comparative Example 6

[0123] Organo-soil was prepared using the same method as in Example 1, except that “n-hexadecyl alcohol” in Example 1 was replaced with “n-dodecanol”.

[0124] As a result, organic soil D6# was prepared.

[0125] Test Example 1

[0126] The samples prepared in the examples and comparative examples were subjected to (1) room temperature colloid content determination and (2) aging colloid content determination. The results are shown in Table 1.

[0127] Table 1

[0128]

[0129]

[0130] As shown in Table 1, the organic soil prepared by the method of this invention has a higher colloid content in diesel fuel at room temperature than commercially available organic soil, and the overall gelation effect is very good. Looking at the results after aging at 180℃ and 260℃, the colloid content of the organic soil prepared in the examples decreased slightly, and its temperature resistance was better than that of commercially available samples.

[0131] Test Example 2

[0132] The samples prepared in the examples and comparative examples were subjected to (3) organic soil suspension properties after aging at room temperature and 260℃. The apparent viscosity, plastic viscosity and dynamic shear force were measured. The results are shown in Table 2.

[0133] Table 2

[0134]

[0135]

[0136] As can be seen from Table 2 above, the organic soil synthesized in the examples exhibits good suspension ability in oil-based systems and a temperature resistance of up to 260℃. Its overall performance is significantly superior to commercially available products.

[0137] In summary, this invention utilizes long-chain quaternary ammonium salts to expand the interlayer spacing of montmorillonite, and sequentially performs intercalation modification with long-chain alcohols (or acids) and long-chain diols to develop a high-temperature resistant organic soil for oil-based drilling fluids, which can meet the drilling application requirements of deep wells, ultra-deep wells, and complex wells.

[0138] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An organo-soil composition for oil-based drilling fluids, characterized in that, The mixture comprises: sodium montmorillonite, an intercalation aid, a primary intercalation agent, a secondary intercalation agent, and water, wherein the intercalation aid is a long-chain quaternary ammonium salt, the primary intercalation agent is a long-chain alcohol and / or a long-chain acid, and the secondary intercalation agent is a long-chain diol.

2. The composition according to claim 1, wherein, The mixture comprises, by weight: 50 parts sodium montmorillonite, 1-10 parts intercalation aid, 11-30 parts primary intercalation agent, 2.5-20 parts secondary intercalation agent, and 1000-1500 parts water. Preferably, the mixture comprises, by weight, 50 parts sodium montmorillonite, 3-8 parts intercalation aid, 15-30 parts primary intercalation agent, 5-15 parts secondary intercalation agent, and 1000-1500 parts water.

3. The composition according to claim 1 or 2, wherein, The intercalation aid is alkyltrimethylammonium chloride and / or alkyltrimethylammonium bromide; Preferably, the alkyl group is one or more alkyl groups having 12-18 carbon atoms; More preferably, the alkyl group is one or more alkyl groups having 12, 14, 16 and 18 carbon atoms; And / or, the primary intercalating agent is selected from one or more of n-tetradecanoic acid, n-hexadecanoic acid, n-octadecanoic acid, and n-octadecanoic acid; And / or, the secondary intercalating agent is selected from one or more of 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, and 1,18-octadecanediol.

4. The composition according to claim 1 or 2, wherein, The sodium-based montmorillonite is purified sodium-based montmorillonite obtained by hydrocyclone separation.

5. The composition according to claim 1 or 2, wherein, The purified sodium-based montmorillonite has a montmorillonite content of 90-95% by weight.

6. A method for preparing organic clay for oil-based drilling fluids using the composition according to any one of claims 1-5, characterized in that, The method includes: (1) Sodium-based montmorillonite, water and intercalation aid are brought into contact and mixed to obtain a first mixture; (2) The first mixture and the main intercalating agent are brought into contact for a second mixing to obtain a second mixture; (3) The second mixture and the secondary intercalating agent are brought into contact for a third mixing to obtain a third mixture; (4) The third mixture is cooled, filtered, washed, dried, crushed and sieved to obtain organic soil for oil-based drilling fluid.

7. The method according to claim 6, wherein, The conditions for the first mixing include: a temperature of 75-80°C, a time of 1.5-2.5 h, and a pH value of weak alkalinity; preferably, the pH value is 7-8. Preferably, the conditions for the first mixing include: first contacting and mixing sodium montmorillonite and water, and then mixing with the intercalation aid; Preferably, the conditions for the first mixing include: mixing sodium montmorillonite and water first for 0.5-1 h, and then mixing with the intercalation aid for 1.5-2.5 h.

8. The method according to claim 6, wherein, The conditions for the second mixing include: a temperature of 85-90℃ and a time of 2-4 hours; And / or, the conditions for the second mixing also include: an acidic pH value; preferably, a pH value of 2-3.

9. The method according to claim 6, wherein, The conditions for the third mixing include: a temperature of 85-90℃ and a time of 4-5 hours; And / or, the conditions for the third mixture further include: an acidic pH value; preferably, a pH value of 2-3.

10. An organic clay for oil-based drilling fluid prepared by the method according to any one of claims 6-9.

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