Silicon oxide-oil phase shell-core structure solid powder, pressure flooding agent and preparation thereof

Abstract

The invention discloses silicon oxide-oil phase shell-core structure solid powder, a pressure flooding agent and preparation thereof. The silicon oxide-oil phase shell-core structure solid powder is based on an alkyl glycoside surfactant. When a pressure flooding agent prepared from the silicon oxide-oil phase shell-core structure solid powder is used for fracturing, the fracture forming capacity and the drainage assisting and oil displacing effect of fracturing fluid can be further improved. In addition, the raw materials for preparing the pressure flooding agent are green and environment-friendly, the safety index is high, the preparation method is simple, the good fracturing oil displacement effect is achieved, and the fracturing performance of fracturing fluid cannot be affected in the fracturing process. The pressure flooding agent disclosed by the invention can be used as an efficient oil displacement agent for fracturing to solve the problem of research and development of reservoir transformation key fluid in the'pressure-injection-production 'integrated operation of a low-permeability-tight oil reservoir, and has a good market prospect.

Description

Technical Field

[0001] The invention relates to silicon oxide-oil phase core-shell structure solid powder, a pressure driving agent and preparation thereof. Background Art

[0002] With increasing exploration and development, low-permeability reservoirs have garnered widespread attention for their abundant reserves (accounting for approximately 60% of total reserves). Over half of these reserves are found in ultra-low permeability reservoirs with permeabilities ranging from 1 to 10 mD. However, these reservoirs often exhibit poor physical properties, low porosity and permeability, and harbor natural microfractures, small microscopic pore throats, and complex pore structures. This makes waterflooding difficult, resulting in low recovery rates and limited water injection. To address the "high-pressure underinjection" problem in ultra-low permeability reservoirs and improve development effectiveness, hydraulic fracturing and acidizing for plugging and augmented injection have been widely used. However, these measures generally suffer from short-term effectiveness, limited reach, and high costs. Furthermore, they struggle to address deeper issues such as formation fluid flow difficulties, large displacement pressure differentials, and high initial start-up pressure gradients caused by low reservoir permeability, making them difficult to meet the actual production needs of oilfields. Summary of the Invention

[0003] In order to at least partially solve the above-mentioned technical problems existing in the prior art, an embodiment of the present invention provides a pressure displacement agent to further improve the fracture-forming ability and the drainage and oil displacement effect of the fracturing fluid.

[0004] As a first aspect of the present invention, it relates to a silicon oxide-oil phase core-shell structure solid powder, wherein the solid powder is based on an alkyl glycoside surfactant.

[0005] In one or some possible embodiments, the solid powder comprises the following raw materials, calculated by mass: 0.3 to 0.7 parts of an alkyl glycoside surfactant, 3.5 to 5 parts of an oil phase, 40 to 43 parts of ethanol, 2 to 4 parts of aqueous ammonia, 2 to 3 parts of a silane coupling agent, 0.2 to 0.35 parts of a polyoxyethylene polyoxypropylene ether block polyether, and deionized water.

[0006] In one or some possible embodiments, the alkyl glycoside surfactant is as shown in formula (I):

[0007]

[0008] In formula (I), R is selected from C8 to C 16 One of the alkyl fatty chains.

[0009] In one or some possible embodiments, the alkyl glycoside surfactant is selected from one or more C8-C16 alkyl glycoside surfactants.

[0010] In one or some possible embodiments, the oil phase is selected from one or more of kerosene, n-hexane or industrial white oil.

[0011] In one or some possible embodiments, the silane coupling agent is selected from one or more of vinyltrichlorosilane, vinyltriethoxysilane, vinyltriacetoxysilane or ethyl orthosilicate.

[0012] In one or some possible embodiments, the polyoxyethylene polyoxypropylene ether block polyether is selected from one or more of polyether F127, polyether F68 or polyether F108.

[0013] As a second aspect of the present invention, a method for preparing the above-mentioned silicon oxide-oil phase core-shell structure solid powder comprises the following steps:

[0014] S1. Add an alkyl glycoside surfactant, an oil phase, and a portion of deionized water in order according to the formula, stir at 30°C to 50°C for 2 to 3 hours, and perform ultrasonic emulsification to obtain an intermediate product 1;

[0015] S2. Add ethanol, ammonia water and the remaining deionized water in order according to the formula, mix at 30°C to 50°C for 30 to 60 minutes, add silane coupling agent dropwise to the mixed solution, and stir at room temperature for 30 to 60 minutes to obtain intermediate product 2;

[0016] S3. Maintaining the temperature at 30° C. to 50° C., under stirring, add the intermediate product 2 obtained in S2 dropwise to the intermediate product 1 obtained in S1. After the addition is complete, add polyoxyethylene polyoxypropylene ether block polyether, mix for 24 to 30 hours, raise the temperature to 100 to 120° C., and react for 24 to 32 hours to obtain an oil-phase microsphere dispersion with a siliceous shell based on an emulsion template;

[0017] S4. After washing the dispersion of oil-phase microspheres with a siliceous shell based on an emulsion template obtained in S3, drying and crushing the dispersion at 60-100° C., a solid powder of a silica-oil-phase core-shell structure based on an alkyl glycoside surfactant is obtained.

[0018] In one or some possible embodiments, in S1, the ultrasonic emulsification conditions are set as: ultrasonic power 300-500w, ultrasonic time 30-45min.

[0019] In one or some possible embodiments, in S4, the cleaning method of the oil-phase microsphere dispersion with a siliceous shell obtained in S3 is centrifugal cleaning, and the conditions of the centrifugal cleaning are set to: a centrifugal speed of 6000-8000 r / min.

[0020] As a third aspect of the present invention, it relates to the use of the above-mentioned silicon oxide-oil phase core-shell structure solid powder in the preparation of pressure-driven fluid.

[0021] As a fourth aspect of the present invention, it relates to a pressure-displacing agent, which comprises the above-mentioned silicon oxide-oil phase core-shell structure solid powder.

[0022] In one or some possible embodiments, the pressure-displacing agent comprises the following raw materials, calculated by weight: 0.3 to 1 parts of a silicon oxide-oil phase core-shell structure solid powder based on an alkyl glycoside surfactant, and 99.7 to 99 parts of slick water.

[0023] In one or some possible embodiments, the viscosity of the slippery water does not exceed 10 mPa·s.

[0024] As a fifth aspect of the present invention, it relates to a method for preparing the above-mentioned pressure-displacing agent, wherein the method comprises mixing the above-mentioned constituent raw materials according to the above-mentioned formula to prepare the pressure-displacing agent.

[0025] When the pressure-displacement agent (also known as a "fracture-displacement agent") of the present invention is used for fracturing, the outer shell of the silica-oil phase core-shell structure continuously wears away as it passes through pore throats and rough surfaces during the high-speed migration of the fracture-matrix. As the fracture size changes, the core-shell structure is unevenly stressed, the degree of wear increases, and the siliceous shell cracks more, releasing the internal oil core. The cracked siliceous shell can serve as a micro-fracture proppant to support the fracture, thereby further improving the fracture-forming ability of the fracturing fluid. At the same time, the oil phase released after the rupture of the siliceous shell and the coated alkyl glycoside surfactant can achieve efficient oil washing and imbibition, improving the drainage-assisted oil displacement effect, and will not affect the fracturing performance of the fracturing fluid. Therefore, it can be used as an efficient fracturing degreasing agent for low-permeability and tight oil reservoirs.

[0026] The pressure displacement agent of the present invention is green, environmentally friendly, pollution-free and free of potential safety hazards. After entering the formation, the silicon shell is broken and the drainage and oil displacement effect is adjusted by changes in its own interface properties.

[0027] The raw materials used to prepare the pressure-displacement agent of the present invention are environmentally friendly, have a high safety index, are simple to prepare, and exhibit good fracturing and oil-displacing effects. During the fracturing process, the fracturing performance of the fracturing fluid itself is not affected. The pressure-displacement agent of the present invention can be used as a highly efficient fracturing oil-displacing agent to address the challenges of developing key fluids for reservoir reconstruction in integrated "pressure-injection-production" operations in low-permeability and tight oil reservoirs, and has promising market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The graph is a graph showing the change in recovery rate over time of the pressure displacement agents of Examples 1 to 3 and the comparative example in the core model flooding test. DETAILED DESCRIPTION

[0029] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0030] In the description of the present invention, it should be noted that the terms “include”, “including”, “have”, “contain”, etc. are all open terms, which mean including but not limited to.

[0031] The present invention will be further described below with reference to specific examples, but the scope of protection of the present invention is not limited by the following examples. Unless otherwise specified, the sources of materials mainly involved in the examples are conventional commercial products.

[0032] Example 1

[0033] The composition of the silica-oil phase core-shell structure oil displacement agent for fracturing based on an alkyl glycoside surfactant of this embodiment is as follows: 0.3 parts of silica-oil phase core-shell structure solid powder based on a glycoside surfactant and 99.7 parts of slick water; the above two substances are thoroughly stirred and mixed to prepare the silica-oil phase core-shell structure oil displacement agent based on an alkyl glycoside surfactant;

[0034] The preparation method of the silica-oil phase core-shell structure solid powder based on glycoside surfactant is as follows:

[0035] S1. To 30 g of deionized water, 0.5 g of a dodecyl glycoside surfactant and 4 g of n-hexane (as the oil phase) were added in sequence. The mixture was stirred at 30° C. for 2 h and ultrasonically emulsified for 30 min to obtain a milky white suspension, which was intermediate product 1.

[0036] S2. At 30° C., 40 g of ethanol, 19.7 g of deionized water, and 3 g of aqueous ammonia were mixed and stirred for 30 min. 2.5 g of ethyl orthosilicate (as a silane coupling agent) was added dropwise to the mixed solution and stirred at room temperature for 30 min to obtain intermediate product 2.

[0037] S3. Add intermediate product 2 dropwise to intermediate product 1 at 30° C. while stirring. After the addition is complete, add 0.3 g of F127 (polyoxyethylene polyoxypropylene ether block polyether), maintain the temperature at a constant temperature for 24 h, raise the temperature to 100° C., and maintain the temperature for another 24 h to obtain an oil-phase microsphere dispersion with a siliceous shell based on an emulsion template;

[0038] S4. The dispersion of oil-phase microspheres with a siliceous shell based on an emulsion template obtained in S3 was centrifugally washed at a rate of 6000 r / min, dried and crushed at 60°C to obtain a solid powder of a silica oil-phase core-shell structure based on a dodecyl glycoside surfactant with a particle size of 52 nm.

[0039] Example 2

[0040] The composition of the silica-oil phase core-shell structure oil displacement agent for fracturing based on an alkyl glycoside surfactant of this embodiment is as follows: 0.5 parts of silica-oil phase core-shell structure solid powder based on an alkyl glycoside surfactant and 99.5 parts of slick water; the above two substances are thoroughly stirred and mixed to prepare the silica-oil phase core-shell structure oil displacement agent based on an alkyl glycoside surfactant;

[0041] The preparation method of the silica-oil phase core-shell structure solid powder based on alkyl glycoside surfactant is as follows:

[0042] S1. To 28.55 g of deionized water, 0.3 g of a hexadecyl glycoside surfactant and 3.5 g of n-hexane (as the oil phase) were added in sequence. The mixture was stirred at 30° C. for 2 h and ultrasonically emulsified for 40 min to obtain a milky white suspension, which was intermediate product 1.

[0043] S2. At 40° C., 40 g of ethanol, 22.4 g of deionized water, and 2 g of aqueous ammonia were mixed and stirred for 30 min. 3 g of vinyltrichlorosilane (as a silane coupling agent) was added dropwise to the mixed solution, and the mixture was stirred at room temperature for 40 min to obtain intermediate product 2.

[0044] S3. Add intermediate product 2 dropwise to intermediate product 1 at 40° C. while stirring. After the addition is complete, add 0.25 g of F68 (polyoxyethylene polyoxypropylene ether block polyether), maintain the temperature at a constant temperature for 28 h, raise the temperature to 100° C., and maintain the temperature for 30 h to obtain an oil-phase microsphere dispersion with a siliceous shell based on an emulsion template;

[0045] S4. The dispersion of oil-phase microspheres with a siliceous shell based on an emulsion template obtained in S3 was centrifugally washed at a rate of 6000 r / min, dried and crushed at 80°C to obtain a solid powder of a silica oil-phase core-shell structure based on a hexadecyl glycoside surfactant with a particle size of 53 nm.

[0046] Example 3

[0047] The composition of the silica-oil phase core-shell structure oil displacement agent for fracturing based on an alkyl glycoside surfactant of this embodiment is as follows: 0.7 parts of silica-oil phase core-shell structure solid powder based on an alkyl glycoside surfactant and 99.3 parts of slick water; the above two substances are thoroughly stirred and mixed to prepare the silica-oil phase core-shell structure oil displacement agent based on an alkyl glycoside surfactant;

[0048] The preparation method of the silica-oil phase core-shell structure solid powder based on alkyl glycoside surfactant is as follows:

[0049] S1. To 35.5 g of deionized water, 0.5 g of an octaalkyl glycoside surfactant and 4.5 g of kerosene (as the oil phase) were added in sequence. The mixture was stirred at 30° C. for 3 h and ultrasonically emulsified for 45 min to obtain a milky white suspension, which was intermediate product 1.

[0050] S2. At 50° C., 42 g of ethanol, 11.3 g of deionized water, and 4 g of aqueous ammonia were mixed and stirred for 40 min. 2 g of vinyltriacetoxysilane (silane coupling agent) was added dropwise to the mixed solution and stirred at room temperature for 40 min to obtain intermediate product 2.

[0051] S3. Add intermediate product 2 dropwise to intermediate product 1 at 50° C. while stirring. After the addition is completed, add 0.2 g of F108 (polyoxyethylene polyoxypropylene ether block polyether), react at a constant temperature for 30 h, then raise the temperature to 120° C. and maintain for 24 h to obtain an oil-phase microsphere dispersion with a siliceous shell based on an emulsion template;

[0052] S4. The dispersion of oil-phase microspheres with a siliceous shell based on an emulsion template obtained in S3 was centrifugally washed at a rate of 8000 r / min, dried and crushed at 100°C to obtain a solid powder of a silica oil-phase core-shell structure based on an octaalkyl glycoside surfactant with a particle size of 55 nm.

[0053] Example 4

[0054] The mass composition of the silica-oil phase core-shell structure oil displacement agent for fracturing based on an alkyl glycoside surfactant of this embodiment is as follows: 1 part of silica-oil phase core-shell structure solid powder based on an alkyl glycoside surfactant and 99 parts of slick water; the above two substances are thoroughly stirred and mixed to prepare the silica-oil phase core-shell structure oil displacement agent based on an alkyl glycoside surfactant;

[0055] The preparation method of the silica-oil phase core-shell structure solid powder based on alkyl glycoside surfactant is as follows:

[0056] S1. To 32 g of deionized water, 0.7 g of a decanyl glycoside surfactant and 5 g of industrial white oil (as the oil phase) were added in sequence. The mixture was stirred at 30° C. for 2 h and ultrasonically emulsified for 30 min to obtain a milky white suspension, which was intermediate product 1.

[0057] S2. At 30° C., 43 g of ethanol, 14.95 g of deionized water, and 2 g of aqueous ammonia were mixed and stirred for 60 min. 2 g of butyl orthosilicate (as a silane coupling agent) was added dropwise to the mixed solution and stirred at room temperature for 60 min to obtain intermediate product 2.

[0058] S3. Add intermediate product 2 dropwise to intermediate product 1 at 30° C. while stirring. After the addition is completed, add 0.35 g of F127 (polyoxyethylene polyoxypropylene ether block polyether), react at a constant temperature for 30 h, then raise the temperature to 120° C. and maintain for 30 h to obtain an oil-phase microsphere dispersion with a siliceous shell based on an emulsion template;

[0059] S4. The dispersion of oil-phase microspheres with a siliceous shell based on an emulsion template obtained in S3 was centrifugally washed at a rate of 8000 r / min, dried and crushed at 100°C to obtain a solid powder of a silica oil-phase core-shell structure based on a decanyl glycoside surfactant with a particle size of 59 nm.

[0060] The above examples 1 to 4 were tested as follows:

[0061] Test-Compatibility Test

[0062] Refer to the relevant standards recorded in SY / T 7627-2021 Technical Requirements for Water-Based Fracturing Fluids, specifically including: measuring 200 ml of the pressure displacement agent and slick water prepared in Examples 1 to 4 respectively, using slick water as a blank control group (i.e., blank sample), placing the beakers in a water bath at room temperature, sealing them for 2 hours, and comparing and observing the phenomena in the five beakers.

[0063] Test 2: Viscosity test

[0064] The viscosity of the pressure-displacing agent before and after sealing was measured with reference to the relevant standards described in GB / T 10247-2008 Viscosity Measurement Method.

[0065] The test results of Test 1 and Test 2 are recorded in Table 1 below.

[0066] Table 1 Performance test results of blank sample and pressure-displacement agent prepared in Examples 1 to 4

[0067]

[0068] It can be seen from the performance test results in Table 1 that the pressure displacement agent prepared in the embodiment of the present invention has a lower viscosity. Therefore, when performing oil displacement operations, the required injection pressure is also lower, and it is easier to enter the low-permeability-dense core.

[0069] The inventors further conducted the following tests on the pressure-displacement agents prepared in Examples 1 to 4 and blank slick water. The following tests were all performed in accordance with the relevant standards described in SY / T 5370-2018 Surface and interfacial tension determination method:

[0070] Test 3 Surface tension test

[0071] The surface tension between the silica-oil core-shell structure displacement agent based on alkyl glycoside surfactant and crude oil was measured using a Krüss K100 surface tension meter and the ring method.

[0072] Test 4: Interfacial tension test

[0073] The interfacial tension between the silica-oil phase core-shell structure displacement agent based on alkyl glycoside surfactant and crude oil was measured using a TX-500 spinning drop interfacial tension meter, including: maintaining a rotation speed of 6000 r / min and a time interval of 1 minute to measure the interfacial tension between the crude oil and the agent.

[0074] The test results of Tests 3 and 4 are recorded in Table 2 below.

[0075] Table 2 Performance test results of blank sample and pressure-displacement agent prepared in Examples 1 to 4

[0076] system Temperature (℃) Surface tension (mN / m) Interfacial tension (mN / m) Blank 25.1 32.8 3.65 Example 1 25.2 27.6 1.7 Example 2 25.0 27.4 1.45 Example 3 25.4 27.4 1.46 Example 4 25.2 28.2 1.54

[0077] Finally, the inventors conducted a core model flooding test using the pressure displacement agents prepared in Examples 1 to 3 above as an example and a blank sample as a comparative example. The test was performed in accordance with the relevant standards described in Q / SH 0578-2014 for determination of oil recovery, specifically including:

[0078] Place the core in the core holder, apply confining pressure to the core to 10MPa, evacuate the core and saturate the core with clean water. Secondly, all the saturated crude oil is discharged to the outlet to establish a bound water environment. During the process, the confining pressure is continuously adjusted to maintain it at a simulated formation environment pressure. Then, the pressure-displacing agent prepared in Examples 1 to 3, the comparative example and the entire displacement system are placed in a constant temperature box respectively, the inlet end of the core holder is closed, and the pressure-displacing agent prepared in Examples 1 to 3 and the comparative example are respectively injected into the core holder at the outlet end with a constant flow metering pump, and the outlet end of the core holder is opened. Part of the crude oil is extracted by relying on the model's own pressure, and the recovery rate is calculated. The change of the recovery rate over time is shown in FIG. Figure 1 shown.

[0079] Depend on Figure 1It can be seen that the recovery rate of Example 1 is as high as 54.9%, the recovery rate of Example 2 is as high as 50.3%, and the recovery rate of Example 3 is as high as 45.8%. The recovery rate of the blank sample is only 28.7%. Compared with the comparative example, the recovery rate is increased by at least 17 percentage points. This is because the pressure-displacement agent prepared by the present invention has a smaller particle size and lower interfacial tension. Therefore, it can be shown that the pressure-displacement agent of the present invention can significantly improve the crude oil recovery rate and achieve good mining effect.

[0080] Although the present invention has been described in considerable detail and with particularity with respect to several embodiments, it is not intended to limit the present invention to any of these details or embodiments or any particular embodiment, so as to effectively encompass the intended scope of the present invention. In addition, the present invention has been described above with respect to embodiments foreseen by the inventors for the purpose of providing a useful description, and those insubstantial modifications of the present invention that are not currently foreseen may still represent equivalent modifications of the present invention.

[0081] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0082] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A silicon oxide-oil phase core-shell structure solid powder, characterized in that: The solid powder is based on an alkyl glycoside surfactant.

2. The silicon oxide-oil phase core-shell structure solid powder according to claim 1, characterized in that: The solid powder comprises the following raw materials by weight: 0.3 to 0.7 parts of an alkyl glycoside surfactant, 3.5 to 5 parts of an oil phase, 40 to 43 parts of ethanol, 2 to 4 parts of aqueous ammonia, 2 to 3 parts of a silane coupling agent, 0.2 to 0.35 parts of a polyoxyethylene polyoxypropylene ether block polyether, and deionized water.

3. The silicon oxide-oil phase core-shell structure solid powder according to claim 2, characterized in that The alkyl glycoside surfactant is shown in formula (I): In formula (I), R is selected from C8 to C 16 One of the alkyl fatty chains.

4. The silicon oxide-oil phase core-shell structure solid powder according to claim 3, characterized in that The alkyl glycoside surfactant is selected from C8~C 16 One or more of the alkyl glycoside surfactants.

5. The silicon oxide-oil phase core-shell structure solid powder according to claim 2, characterized in that: The oil phase is selected from one or more of kerosene, n-hexane or industrial white oil.

6. The silicon oxide-oil phase core-shell structure solid powder according to claim 2, characterized in that: The silane coupling agent is selected from one or more of vinyl trichlorosilane, vinyl triethoxysilane, vinyl triacetoxysilane or ethyl orthosilicate.

7. The silicon oxide-oil phase core-shell structure solid powder according to claim 2, characterized in that: The polyoxyethylene polyoxypropylene ether block polyether is selected from one or more of polyether F127, polyether F68 or polyether F108.

8. A method for preparing the silicon oxide-oil phase core-shell structure solid powder according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: S1. Add an alkyl glycoside surfactant, an oil phase, and a portion of deionized water in order according to the formula, stir at 30°C to 50°C for 2 to 3 hours, and perform ultrasonic emulsification to obtain an intermediate product 1; S2. Add ethanol, ammonia water and the remaining deionized water in order according to the formula, mix at 30°C to 50°C for 30 to 60 minutes, add silane coupling agent dropwise to the mixed solution, and stir at room temperature for 30 to 60 minutes to obtain intermediate product 2; S3. Maintaining the temperature at 30° C. to 50° C., under stirring, add the intermediate product 2 obtained in S2 dropwise to the intermediate product 1 obtained in S1. After the addition is complete, add polyoxyethylene polyoxypropylene ether block polyether, mix for 24 to 30 hours, raise the temperature to 100 to 120° C., and react for 24 to 32 hours to obtain an oil-phase microsphere dispersion with a siliceous shell based on an emulsion template; S4. After washing the dispersion of oil-phase microspheres with a siliceous shell based on an emulsion template obtained in S3, drying and crushing the dispersion at 60-100° C., a solid powder of a silica-oil-phase core-shell structure based on an alkyl glycoside surfactant is obtained.

9. The method according to claim 8, characterized in that In S1, the ultrasonic emulsification conditions are set as: ultrasonic power 300-500w, ultrasonic time 30-45min.

10. The method according to claim 8, characterized in that In S4, the method for washing the oil-phase microsphere dispersion with a siliceous shell obtained in S3 is centrifugal washing, and the conditions for the centrifugal washing are set to: a centrifugal speed of 6000-8000 r / min.

11. Use of the silicon oxide-oil phase core-shell structure solid powder according to any one of claims 1 to 7 in the preparation of a pressure-displacing agent.

12. A pressure-displacing agent, characterized in that: The pressure-displacing agent comprises the silicon oxide-oil phase core-shell structure solid powder according to any one of claims 1 to 7.

13. The pressure-displacing agent according to claim 12, characterized in that: The composition comprises the following raw materials in parts by mass: 0.3 to 1 parts of silicon oxide-oil phase core-shell structure solid powder based on alkyl glycoside surfactant and 99.7 to 99 parts of slick water.

14. The pressure-displacing agent according to claim 13, characterized in that The viscosity of the slippery water does not exceed 10 mPa·s.

15. A method for preparing the pressure-displacing agent according to claims 12 to 14, characterized in that: The method comprises mixing the component raw materials according to the formula to prepare the pressure-displacing agent.

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