Preparation method and application of high-temperature-resistant inorganic modified bentonite

Abstract

The invention relates to a preparation method and application of high-temperature-resistant inorganic modified bentonite. The method comprises the following steps: firstly, treating bentonite and sepiolite composite clay through a microwave-assisted hydrogen peroxide method, and improving the dispersity of minerals by utilizing a large amount of oxygen generated by decomposing hydrogen peroxide in a microwave field; then metal oxide nanoparticles are added into the suspension of the composite clay mineral, and sepiolite and metal oxide are used for synergistically modifying bentonite, so that the high-temperature tolerance of the material at 250 DEG C is improved, and the material can be used as a slurry making agent in water-based drilling fluid. No organic reagent is used, and related products have good thermal stability.

Description

Technical Field

[0001] The technical solution of this invention relates to the field of preparing functional pulping agents from non-metallic minerals, specifically to a method for preparing and applying high-temperature resistant inorganic modified bentonite. Background Technology

[0002] Bentonite is a commonly used material in water-based drilling fluid formulations, serving to adjust drilling fluid density, carry cuttings, and improve fluid viscosity. However, as drilling depth increases, the temperature of the drilling fluid also rises, causing the bentonite structure to be damaged. At this point, the viscosity and filtration loss of the drilling mud fail to meet operational requirements. Therefore, developing high-temperature resistant bentonite-based mud additives is crucial for ensuring the safe operation of deep well drilling.

[0003] Currently, the main methods to improve the high-temperature resistance of bentonite are compounding with organic polymers and surface organic modification, but these methods usually involve complex processes, high costs, and high environmental risks. CN119463826A discloses a method for preparing palygorskite-bentonite compound slurry by mechanical crushing. Although this method is simple and low-cost, the material has insufficient dispersibility, with a filtration loss of 19.6 ml after heat treatment at 180℃, which cannot meet the requirements for use under ultra-high temperature conditions of 250℃. A Turkish university reported a MgO-modified bentonite-based slurry, which had a filtration loss of 19.2 ml after heat treatment at 180℃, also failing to meet the requirements for use under ultra-high temperature conditions of 250℃ (Applied Clay Science, 2010, 48:398-404).

[0004] Since the improvement of bentonite's high-temperature slurry-making performance by using mineral compounding or metal oxide as a single modification method is limited and cannot meet the requirements of use under ultra-high temperature drilling conditions, it is of great significance to develop a multi-source composite bentonite-based slurry agent and its preparation method that can meet the drilling conditions of 250℃. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of current technologies by providing a method for preparing and applying high-temperature resistant inorganic modified bentonite. This method first treats bentonite and sepiolite composite clay using a microwave-assisted hydrogen peroxide method, utilizing the large amount of oxygen generated by the decomposition of hydrogen peroxide in the microwave field to improve the dispersibility of the minerals. Subsequently, metal oxide nanoparticles are added to the suspension of the composite clay minerals, utilizing the synergistic modification of bentonite by sepiolite and metal oxides, thereby improving the material's high-temperature resistance at 250℃. This allows it to be used as a mud-forming agent in water-based drilling fluids. The method used in this invention does not use organic reagents, and the related products exhibit good thermal stability.

[0006] The technical solution adopted by this invention to solve this technical problem is:

[0007] A method for preparing high-temperature resistant inorganic modified bentonite, the method comprising the following steps:

[0008] (1) Immerse the mixed powder of sepiolite and bentonite in an aqueous solution of hydrogen peroxide, stir for 1-3 hours and then sonicate for 0.5-2 hours; place the centrifuged solid in a microwave reactor and irradiate with microwave for 8-15 minutes to obtain composite clay mineral powder.

[0009] The mass ratio of sepiolite to bentonite is 1:20 to 1:100.

[0010] The mass concentration of the hydrogen peroxide aqueous solution is 10-30%.

[0011] (2) Disperse the mineral powder obtained in step (1) in deionized water, add metal oxide nanoparticle powder, stir for 0.5-1h and sonicate for 0.5-1h, then load the above suspension into a reaction vessel and transfer it to a microwave reactor. The microwave emission power is 300-500W and the treatment time is 1-3h.

[0012] The mass ratio of the metal oxide nanoparticles to the composite clay mineral powder is between 1:100 and 1:300.

[0013] Metal oxides refer to one or more of MgO, TiO2, Fe2O3, ZnO, Al2O3, and ZrO2.

[0014] (3) After the above suspension is cooled, centrifuge it, discard the supernatant, and place the remaining solid in a freeze dryer. After drying, the high-temperature resistant bentonite-based slurry agent is obtained.

[0015] The freeze-drying temperature is -70℃ to -20℃, and the drying time is 12 to 72 hours.

[0016] The microwave transmission power in step (1) is 300-500W.

[0017] The microwave processing temperature in step (2) is between 150°C and 220°C.

[0018] The high-temperature resistant inorganic modified bentonite prepared by the method is used as a slurry-forming agent in water-based drilling fluids resistant to temperatures above 250°C.

[0019] Specifically, the steps include the following:

[0020] (1) Under stirring at 1000-1500 rpm / min, the high-temperature resistant bentonite-based slurrying agent and anhydrous Na2CO3 were added to deionized water and stirred for 30-60 min to obtain a suspension.

[0021] For every 300-400 ml of deionized water, add 20-30 g of high-temperature resistant bentonite-based slurrying agent and 15-20 g of anhydrous Na2CO3.

[0022] (2) Add 1-2g of sodium carboxymethyl cellulose thickener to the suspension obtained in step (1) at a stirring speed of 1800-2000rpm / min and continue stirring for 1-2h.

[0023] (3) Transfer the suspension obtained in step (2) to a sealed container at 20-30°C and let it stand for 16-24 hours to obtain a water-based drilling fluid resistant to temperatures above 250°C.

[0024] The preparation method of the above-mentioned high-temperature resistant bentonite-based slurry agent involves raw materials, reagents and equipment other than sepiolite and bentonite, all of which are obtained through known means, and the operation process is mastered by those skilled in the art.

[0025] The beneficial effects of this invention are as follows: Compared with the prior art, this invention has the following outstanding substantive features and significant progress:

[0026] (1) The present invention uses sepiolite and metal oxide nanoparticles as compounding agents. The raw / auxiliary materials used are inexpensive and have excellent performance, resulting in good economic and social benefits.

[0027] (2) The method provided by the present invention does not require the use of organic reagents and has low environmental risk.

[0028] (3) The preparation method of the present invention is simple, has low production cost, and uses abundant raw materials, making it easy to scale up production and use.

[0029] (4) Compared with the modified bentonite-based slurry agent published in CN119463826A and Applied Clay Science (2010,48:398-404), the product prepared by this invention has better thermal stability. Its filtration loss after hot rolling at 250℃ is only 12.5ml, which meets the requirements for use. Attached Figure Description

[0030] Figure 1 The filtration loss of water-based drilling fluid prepared with the inorganic modified bentonite-based slurry agent prepared in Example 1, Comparative Example 1, and Comparative Example 2 after hot rolling at 250°C for 30 minutes. Detailed Implementation

[0031] The sepiolite described in the following examples is produced in Lingshou County, Hebei Province, and is used after being processed using the method disclosed in CN200910070297.8; the bentonite is sodium-based bentonite sold by Xinjiang Zhongfei Xiazijie Bentonite Co., Ltd.; but it is not limited to these.

[0032] Example 1

[0033] 10g of sepiolite and 500g of bentonite were weighed and immersed in 2L of 20% (w / w) H2O2 aqueous solution. The mixture was stirred for 2h and then sonicated for 1h (frequency 40kHz). After centrifugation (4000rpm, 15min), the solid was transferred to a microwave reactor and irradiated at 400W power for 12min to obtain composite clay mineral powder. The obtained composite clay mineral powder was dispersed in 1.5L of deionized water, and 2.55g of Al2O3 nanoparticles with a particle size of 50nm were added (composite clay mineral powder:Al2O3 = 200:1). The mixture was stirred for 40min and then sonicated for 30min (40kHz). The suspension was transferred to a reaction vessel and treated in a microwave reactor at 400W power and 180℃ for 2h. After cooling, the supernatant was discarded by centrifugation (4000rpm, 15min). The solid was placed in a freeze dryer and dried at -50℃ for 48h to finally obtain high-temperature resistant bentonite-based slurry powder.

[0034] Comparative Example 1

[0035] The other steps are the same as in Example 1, except that "weighing 10g of sepiolite and 500g of bentonite and immersing them in 2L of 20% H2O2 aqueous solution" is changed to "weighing 510g of bentonite and immersing them in 2L of 20% H2O2 aqueous solution".

[0036] Comparative Example 2

[0037] The other steps are the same as in Example 1, except that "weighing 10g of sepiolite and 500g of bentonite and immersing them in 2L of 20% H2O2 aqueous solution" is changed to "weighing 10g of sepiolite and 500g of bentonite and immersing them in 2L of deionized water".

[0038] The temperature resistance performance of the above-described embodiments and comparative products was evaluated:

[0039] Measure 300-400 ml of deionized water and add it to a mixing cup. While stirring (1200 rpm / min), add 22.5 g of high-temperature bentonite-based slurrying agent and 17 g of anhydrous Na2CO3, and continue stirring for 30 min. Then increase the speed to 1800 rpm / min and add 1-2 g of sodium carboxymethyl cellulose to the suspension, continuing stirring for 1.5 h. Transfer the resulting suspension to a constant temperature curing chamber and cure it at 25℃ in a sealed environment for 16 h. After curing, transfer the suspension to an aging tank, purge with nitrogen to 1.0 MPa for 30 s, then place the aging tank in a roller heating furnace and hot-roll at 250℃ for 30 min. After cooling to room temperature, determine the drilling fluid filtration loss using a threaded cup cap type permeability plugging instrument as specified in GB / 29170-2012. The test results are as follows: Figure 1 As shown.

[0040] from Figure 1 As can be seen from the data, the filtration loss of Example 1 was only 12.5 ml, which is significantly better than that of commercially available OCMA grade bentonite; at the same time, its filtration loss was also significantly lower than that of Comparative Examples 1 and 2, indicating that this modification method significantly enhances the high temperature resistance of bentonite.

[0041] Example 2

[0042] The other steps are the same as in Example 1, except that "weighing 10g of sepiolite and 500g of bentonite" is replaced with "weighing 10g of sepiolite and 800g of bentonite"; the filtration loss of the water-based drilling fluid prepared with the obtained material is close to that in Example 1.

[0043] Example 3

[0044] The other steps are the same as in Example 1, except that "adding 2.55g of Al2O3 nanoparticles with a particle size of 50nm" is replaced with "adding 1.7g of Al2O3 nanoparticles with a particle size of 50nm"; the filtration loss of the water-based drilling fluid prepared with the obtained material is close to that of Example 1.

[0045] Example 4

[0046] The other steps are the same as in Example 1, except that "treatment in a microwave reactor at 400W power and 180°C for 2 hours" is replaced with "treatment in a microwave reactor at 500W power and 220°C for 2 hours"; the filtration loss of the water-based drilling fluid prepared with the obtained material is close to that in Example 1.

[0047] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

[0048] Matters not covered in this invention are common knowledge.

Claims

1. A method for preparing high-temperature resistant inorganic modified bentonite, characterized in that, The method includes the following steps: (1) Immerse the mixed powder of sepiolite and bentonite in an aqueous solution of hydrogen peroxide, stir for 1-3 hours and then sonicate for 0.5-2 hours; place the centrifuged solid in a microwave reactor and irradiate with microwave for 8-15 minutes to obtain composite clay mineral powder. The mass ratio of sepiolite to bentonite is 1:20 to 1:

100. (2) Disperse the mineral powder obtained in step (1) in deionized water, add metal oxide nanoparticle powder, stir for 0.5-1h and sonicate for 0.5-1h, then load the above suspension into a reaction vessel and transfer it to a microwave reactor. The microwave emission power is 300-500W and the treatment time is 1-3h. The mass ratio of the metal oxide nanoparticles to the composite clay mineral powder is between 1:100 and 1:

300. (3) After the above suspension is cooled, centrifuge it, discard the supernatant, and freeze-dry the remaining solid to obtain the high-temperature resistant bentonite-based slurry agent. The freeze-drying temperature is -70℃ to -20℃, and the drying time is 12 to 72 hours.

2. The preparation method of high-temperature resistant inorganic modified bentonite as described in claim 1, characterized in that, The mass concentration of the hydrogen peroxide aqueous solution is 10-30%.

3. The preparation method of high-temperature resistant inorganic modified bentonite as described in claim 1, characterized in that, Metal oxides refer to one or more of MgO, TiO2, Fe2O3, ZnO, Al2O3, and ZrO2.

4. The preparation method of high-temperature resistant inorganic modified bentonite as described in claim 1, characterized in that, The microwave transmission power in step (1) is 300-500W.

5. The preparation method of high-temperature resistant inorganic modified bentonite as described in claim 1, characterized in that, The microwave processing temperature in step (2) is between 150°C and 220°C.

6. The application of the high-temperature resistant inorganic modified bentonite prepared by the method described in claim 1, characterized in that, It is used as a slurry-forming agent in water-based drilling fluids that can withstand temperatures above 250°C.

7. The application as described in claim 6, characterized by comprising the following steps: (1) Under stirring at 1000-1500 rpm / min, the high-temperature resistant bentonite-based slurrying agent and anhydrous Na2CO3 were added to deionized water and stirred for 30-60 min to obtain a suspension. in, Add 20-30g of high-temperature resistant bentonite-based slurrying agent and 15-20g of anhydrous Na2CO3 to every 300-400ml of deionized water; (2) Add 1-2g of sodium carboxymethyl cellulose thickener to the suspension obtained in step (1) at a stirring speed of 1800-2000rpm / min and continue stirring for 1-2h. (3) Transfer the suspension obtained in step (2) to a sealed container at 20-30°C and let it stand for 16-24 hours to obtain a water-based drilling fluid resistant to temperatures above 250°C.

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