Co-condensed silicon quantum dot oil-displacing agent as well as preparation method and application thereof
By using a method for preparing co-condensed silicon quantum dot oil displacement agents, the problem of poor stability of traditional oil displacement agents in high-temperature, low-permeability reservoirs and heavy oil extraction has been solved, enabling efficient oil recovery in complex reservoir environments, reducing costs, and meeting environmental protection requirements.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-04-10
AI Technical Summary
Traditional oil displacement agents have poor stability and insufficient adaptability in high-temperature, low-permeability reservoirs and heavy oil extraction scenarios, resulting in low oil production efficiency and high costs, making it difficult to meet the high-efficiency development needs of modern oilfields.
A method for preparing co-condensed silicon quantum dot oil displacement agent is adopted, which involves pre-hydrolyzing and hydrothermally condensing dodecyltrimethoxysilane and 3-aminopropyltrimethoxysilane under acidic conditions to form functionalized silicon quantum dots with covalently linked silicon-oxygen framework structures, simplifying the synthesis process and improving stability.
The prepared co-condensed silicon quantum dot oil displacement agent is stable at high temperatures, adapts to complex reservoir environments, reduces oil-water interfacial tension, and improves oil production efficiency. It is particularly suitable for low-permeability reservoirs and heavy oil extraction, reducing costs and meeting environmental protection requirements.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of petrochemical industry, and particularly relates to a co-condensation silicon quantum dot oil displacement agent and a preparation method and application thereof. BACKGROUND
[0002] In oilfield development operations, traditional oil displacement technology is facing multiple real challenges such as low recovery rate, high operation cost and environmental pollution hazards, which have become key bottlenecks restricting efficient development of oilfields. From the aspect of oil displacement agent, traditional products generally take chemical surfactants as core functional components. Although such surfactants can realize oil displacement effect by reducing oil-water interfacial tension and promoting oil-water phase separation, the performance of the surfactants is extremely sensitive to key parameters such as temperature and salinity in the oil reservoir environment, and under high temperature fluctuation or high salinity conditions, the surfactants are prone to structural changes or performance degradation, which directly leads to a significant decrease in the stability of the surfactants in complex oil reservoir environments. At the same time, in order to maintain the performance of the oil displacement agent, a large amount of external energy is often required for oil reservoir temperature control and salinity adjustment, further increasing the development cost. More importantly, in the face of special development scenarios such as high-temperature oil reservoirs, low-permeability reservoirs and heavy oil exploitation, the adaptability of traditional oil displacement agents is particularly poor: they are prone to decomposition and failure in high-temperature environments, prone to adsorption and plugging in low-permeability reservoirs, and lack the ability to emulsify and carry high-viscosity heavy oil, ultimately leading to difficulty in improving oil recovery efficiency and failing to meet the development needs of modern oilfields in terms of scale and efficiency.
[0003] Quantum dot oil displacement agents, with the advantage of nanoscale of 1-10 nm, have high efficiency in reducing oil-water interfacial tension and strong environmental stability, and not only have low dosage, but also can adapt to low-permeability reservoirs and heavy oil development scenarios. Carbon-based and silicon-based quantum dots, which are the main types of quantum dots, do not contain heavy metals and are low-toxic and easy-to-degrade, which not only improve oil recovery efficiency and reduce development cost, but also meet the green environmental protection demand, and are new efficient materials for responding to the development challenges of complex oil reservoirs. However, the traditional method for preparing functionalized quantum dots is complicated and has low grafting efficiency.
[0004] Therefore, there is an urgent need for a quantum dot oil displacement agent that is easy to prepare, has self-adaptability under complex temperature change conditions, good stability, is environmentally friendly and has a simple synthesis method. SUMMARY
[0005] In order to overcome the above-mentioned defects of the prior art, the present application aims to provide a co-condensation silicon quantum dot oil displacement agent and a preparation method and application thereof, the preparation method comprising the following steps: firstly, pre-hydrolyzing dodecyltrimethoxysilane (DTMS) in a mixed solution of water and ethanol with acetic acid being added dropwise; secondly, self-condensing the dodecyltrimethoxysilane (DTMS) and 3-aminopropyltrimethoxysilane (APTMS) through a hydrothermal method; and finally, preparing the co-condensation silicon quantum dot oil displacement agent through dialysis and freeze-drying.
[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions: The present application provides a preparation method of a co-condensation silicon quantum dot oil displacement agent, comprising the following steps: The dodecyltrimethoxysilane is added dropwise into a mixed solution of water and ethanol with acetic acid, and pre-hydrolysis is carried out at room temperature to obtain a silanol solution; The silanol solution and the 3-aminopropyltrimethoxysilane are mixed, and a hydrothermal condensation reaction is carried out under the protection of nitrogen to form a silicon quantum dot oligomer, and then cooling, dialysis and freeze-drying are sequentially carried out to obtain a functionalized silicon quantum dot powder; The functionalized silicon quantum dot powder is dissolved in deionized water, and an ultrasonic wave is used to obtain a co-condensation silicon quantum dot oil displacement agent.
[0007] In an embodiment, the volume ratio of water to ethanol in the mixed solution of water and ethanol is 3:2.
[0008] In an embodiment, the pH value of the mixed solution of water and ethanol is adjusted by acetic acid, and the pH value of the mixed solution of water and ethanol is 4; the pre-hydrolysis time is 1 h.
[0009] In an embodiment, the volume ratio of the dodecyltrimethoxysilane to the 3-aminopropyltrimethoxysilane is 0.1-0.4:1.
[0010] In an embodiment, the volume ratio of the dodecyltrimethoxysilane to the 3-aminopropyltrimethoxysilane is 0.3:1.
[0011] In an embodiment, the temperature of the hydrothermal condensation reaction is 70℃, and the time is 4 hours.
[0012] In an embodiment, the dialysis is carried out using a dialysis bag with a molecular weight cut-off of 1000 Da, and the time is 24 hours; the freeze-drying temperature is-50℃, and the time is 24 hours.
[0013] The application provides a co-condensation silicon quantum dot oil displacement agent prepared by a preparation method of the co-condensation silicon quantum dot oil displacement agent.
[0014] In an embodiment, the co-condensation silicon quantum dot oil displacement agent comprises functionalized silicon quantum dots, the particle size distribution of the functionalized silicon quantum dots is 1-10 nm, the surface of the functionalized silicon quantum dots is provided with dodecyl and amino groups, and the functionalized silicon quantum dots have a silicon-oxygen skeleton structure formed by silicon atoms and oxygen atoms connected by a covalent bond.
[0015] The application provides an application of the co-condensation silicon quantum dot oil displacement agent prepared by the preparation method of the co-condensation silicon quantum dot oil displacement agent in oil exploitation.
[0016] Compared with the prior art, the application has the following beneficial effects: The application provides a preparation method of a co-condensation silicon quantum dot oil displacement agent, and since a hydroxyl group in a water molecule replaces an alkoxy group in silane under acidic conditions, the silane is easily hydrolyzed to generate silanol, and the silanol will be positively charged by adsorbing a proton under acidic conditions, so that electrostatic repulsion is generated between silanol molecules and the silanol molecules are not easy to condense. By using this characteristic, DTMS is dropped into a water and ethanol mixture (acetic acid is used to adjust pH=4) at room temperature, and the silanol is obtained by pre-hydrolysis through rapid stirring; the silanol solution is poured into a flask containing the water and ethanol mixture and stirring is started, and APTMS is slowly added dropwise, the amino group in the structure of the APTMS is protonated to provide an alkaline condition, and the alkaline condition is deprotonated to promote condensation, and then an oligomer containing a siloxyl group is formed, and a large amount of water and ethanol mixture can extremely dilute the reaction environment to prevent the silanol molecules from colliding with each other to form a colloid, and rapid stirring can make the silanol molecules fully contact with each other to condense to form the oligomer; and after dialysis and freeze-drying, a functionalized quantum dot powder is obtained. The functionalized silicon quantum dot powder is dissolved in deionized water to obtain a silicon quantum dot oil displacement agent. The preparation method only needs one step of water bath method to prepare the surface-modified silicon quantum dot, the synthesis method is simple, raw materials are easy to obtain, and the cost is low; the amino group (-NH2) of the APTMS is protonated to -NH3 + in the water and ethanol mixed solvent, the electrostatic repulsion is used to prevent the quantum dots from gathering, and the alkaline environment is formed to promote the condensation between the silanols after hydrolysis. The surface modification group is covalently linked with the quantum dot core, and compared with the electrostatic adsorption and the surface modification after the synthesis of the quantum dots, the surface modification is more stable. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 FIG. 1 is an infrared spectrum of the co-condensation silicon quantum dot oil displacement agent prepared in Embodiment 3 of the application; Figure 2 FIG. 2 is a particle size distribution diagram of the co-condensation silicon quantum dot oil displacement agent prepared in Embodiment 3 of the application; Figure 3 The contact angle of the silicon quantum dot oil displacement agent in Example 3 of the present application at different concentrations; Figure 4 The interfacial tension of the silicon quantum dot in Example 3 of the present application. DETAILED DESCRIPTION
[0018] To enable persons skilled in the art to understand the features and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used herein have their usual meanings understood by those skilled in the art of the present application, and in the event of a conflict, the definitions in the specification shall prevail.
[0019] Theories or mechanisms described and disclosed herein, whether correct or not, should not be considered limiting the scope of the present application, i.e., the present application can be practiced without relying on any particular theory or mechanism.
[0020] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents and concentrations, are for the sake of brevity and convenience. Therefore, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).
[0021] In this document, unless otherwise specified, "comprise", "include", "contain", "have" or similar words encompass the meaning of "consist of" and "consist essentially of", for example, "A comprises a" encompasses the meaning of "A comprises a and other" and "A comprises only a".
[0022] In this document, for the sake of brevity, all possible combinations of the technical features in each embodiment or example are not described. Therefore, as long as the combinations of the technical features do not conflict, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope of the present specification.
[0023] The present application provides a co-condensation silicon quantum dot oil displacement agent and a preparation method and application thereof, In one aspect, a preparation method of a co-condensation silicon quantum dot oil displacement agent is provided, comprising the following steps: Dropping dodecyltrimethoxysilane (DTMS) into a mixture of water and ethanol with pH value of 4, pre-hydrolysis is carried out under stirring at room temperature to obtain a silanol solution; wherein the volume ratio of water to ethanol in the mixture of water and ethanol is 3:2; in the pre-hydrolysis step, acetic acid is used to adjust the pH value of the mixture of water and ethanol to 4; in the pre-hydrolysis step, the dropping amount of DTMS is 0.1ml to 0.4ml, and the dropping amount of APTMS is 1ml, and further preferably, the dropping amount of DTMS is 0.3ml.
[0024] Mixing the silanol solution with 3-aminopropyltrimethoxysilane (APTMS) and heating to 70℃ under nitrogen protection for 4 hours to form a silicon quantum dot oligomer through hydrothermal condensation; Cooling the obtained solution to room temperature, dialyzing with a dialysis bag with a molecular weight cut-off of 1000Da for 24 hours to remove unreacted raw materials to obtain a purified silicon quantum dot solution; Freeze-drying the purified silicon quantum dot solution at -50℃ for 24 hours to obtain a functionalized silicon quantum dot powder; Dissolving the functionalized silicon quantum dot powder in deionized water and ultrasonic treatment for 20 minutes to obtain a silicon quantum dot oil displacement agent.
[0025] In another aspect, a co-condensation silicon quantum dot oil displacement agent is provided, which is prepared by the above preparation method, and the oil displacement agent comprises functionalized silicon quantum dots with a particle size distribution in the range of 1-10 nm, and has dodecyl and amino groups on the surface, which are connected by covalent bonds to form a silicon-oxygen skeleton structure. The oil displacement agent can reduce the oil-water interfacial tension, and the interfacial tension gradually decreases with time under the condition of 60℃.
[0026] The oil displacement agent shows the following characteristic absorption peaks in infrared spectrum: a wide peak at 3500 cm -1 corresponding to residual H2O and Si-OH, peaks at 2937 cm -1 and 2876 cm -1 corresponding to propyl chains in APTMS, a peak at 1661 cm -1 corresponding to -NH2 groups, double peaks at 1100 cm -1 corresponding to Si-O-Si skeleton, and a peak at 700 cm -1 corresponding to Si-C bond.
[0027] In still another aspect, a co-condensation silicon quantum dot oil displacement agent is provided, which is suitable for use in oil exploitation, especially as an oil displacement agent in high-temperature oil reservoirs, low-permeability reservoirs or heavy oil exploitation.
[0028] The method first pre-hydrolyzes dodecyltrimethoxysilane (DTMS) into silanol under acidic conditions, and then mixes the silanol with 3-aminopropyltrimethoxysilane (APTMS) in a diluted water-ethanol mixture, uses the alkaline environment provided by the protonation of the amino group of APTMS to perform a one-step hydrothermal condensation reaction, and finally obtains functionalized silicon quantum dot powder through dialysis and freeze-drying. The present application realizes the synthesis and surface functionalization of quantum dots in one step, and the method is simple and the raw materials are easy to obtain. The prepared silicon quantum dots have a particle size of 1-10 nm, and the surface is covalently bonded with a dodecyl long chain and an amino group at the same time, so that the silicon quantum dots have hydrophilic-lipophilic self-adaptive characteristics under the condition of oil reservoir temperature change, can effectively reduce the oil-water interfacial tension, and have good stability in complex oil reservoir environments such as high temperature and high salt, and are suitable for improving the recovery of crude oil, especially the exploitation of low-permeability reservoirs and heavy oil.
[0029] The application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the application and not to limit the scope of the application. Furthermore, it should be understood that those skilled in the art can make various modifications or changes to the application after reading the content of the present application, and these equivalent forms also fall within the scope defined by the appended claims.
[0030] The following examples use conventional apparatus in the art. The experimental methods in the following examples, unless otherwise specified, are usually carried out according to conventional conditions, or according to the conditions recommended by the manufacturer. Various raw materials are used in the following examples, unless otherwise specified, and conventional commercially available products are used, which are conventional specifications in the art. In the specification of the present application and the following examples, unless otherwise specified, “%” means weight percent, “parts” means weight parts, and the ratio means weight ratio.
[0031] Example 1 A co-condensation silicon quantum dot oil displacement agent and a preparation method thereof, comprising the following steps: (1) DTMS pre-hydrolysis: using the characteristics that silane is easy to hydrolyze but not easy to condense under acidic conditions, 30 ml of deionized water and 20 ml of ethanol are added to a 100 ml beaker, the beaker is ultrasonicated in an ultrasonic instrument for 10 min, then acetic acid is added dropwise to adjust the pH value to 4, the beaker is placed on a magnetic chain stirrer at room temperature, the stirring speed is adjusted to the center vortex appears, 0.1 ml of DTMS is added dropwise to the vortex, and the pre-hydrolysis is carried out for 1 h under rapid stirring.
[0032] (2) Hydrolyzed DTMS and APTMS hydrothermal condensation: 30 ml of water and 20 ml of ethanol are added to a 250 ml three-necked flask and placed in a heat collecting magnetic stirrer, the flask is stirred vigorously, and then the pre-hydrolysis solution is poured into the flask, 1 ml of APTMS is added dropwise into the flask, nitrogen gas is used to heat to 70℃, and the reaction is carried out for 4 h.
[0033] (3) The reaction solution obtained is cooled to room temperature and dialyzed with a dialysis bag (molecular weight cut-off 1000 Da) for 24 hours to remove unreacted raw materials. The purified silicon quantum dot solution is collected and freeze-dried at -50°C for 24 hours to obtain functionalized silicon quantum dot solids.
[0034] (4) 0.1 g of functionalized silicon quantum dot powder is weighed with an analytical balance and dissolved in 100 ml of deionized water, and a silicon quantum dot oil displacement agent solution is obtained by ultrasonic treatment for 20 min.
[0035] Example 2 A co-condensed silicon quantum dot oil displacement agent and a preparation method thereof, comprising the following steps: (1) DTMS pre-hydrolysis: taking advantage of the characteristics that silane is easy to hydrolyze but not easy to condense under acidic conditions, 30 ml of deionized water and 20 ml of ethanol are added to a 100 ml beaker, the beaker is ultrasonically treated in an ultrasonic instrument for 10 min, then acetic acid is added dropwise to adjust the pH value to 4, the beaker is placed on a magnetic chain stirrer at room temperature, the stirring speed is adjusted to the center vortex appears, 0.2 ml of DTMS is added dropwise to the vortex, and the pre-hydrolysis is carried out for 1 h with rapid stirring.
[0036] (2) Hydrolyzed DTMS and APTMS hydrothermal condensation: 30 ml of water and 20 ml of ethanol are added to a 250 ml three-necked flask and placed in a heat collecting magnetic stirrer, the flask is stirred vigorously, then the pre-hydrolysis solution is poured into the flask, 1 ml of APTMS is added dropwise into the flask, the temperature is raised to 70°C by nitrogen blowing, and the reaction is carried out for 4 h.
[0037] (3) The reaction solution obtained is cooled to room temperature and dialyzed with a dialysis bag (molecular weight cut-off 1000 Da) for 24 hours to remove unreacted raw materials. The purified silicon quantum dot solution is collected and freeze-dried at -50°C for 24 hours to obtain functionalized silicon quantum dot solids.
[0038] (4) 0.1 g of functionalized silicon quantum dot powder is weighed with an analytical balance and dissolved in 100 ml of deionized water, and a silicon quantum dot oil displacement agent solution is obtained by ultrasonic treatment for 20 min.
[0039] Example 3 A co-condensed silicon quantum dot oil displacement agent and a preparation method thereof, comprising the following steps: (1) DTMS pre-hydrolysis: taking advantage of the characteristics that silane is easy to hydrolyze but not easy to condense under acidic conditions, 30 ml of deionized water and 20 ml of ethanol are added to a 100 ml beaker, the beaker is ultrasonically treated in an ultrasonic instrument for 10 min, then acetic acid is added dropwise to adjust the pH value to 4, the beaker is placed on a magnetic chain stirrer at room temperature, the stirring speed is adjusted to the center vortex appears, 0.2 ml of DTMS is added dropwise to the vortex, and the pre-hydrolysis is carried out for 1 h with rapid stirring.
[0040] (2) Hydrothermal condensation of hydrolyzed DTMS with APTMS: 30 ml of water and 20 ml of ethanol were added to a 250 ml three-necked flask and placed in a heat collecting magnetic stirrer. After the pre-hydrolysis solution was poured into the flask, 1 ml of APTMS was added dropwise into the flask. After the temperature was raised to 70°C by nitrogen blowing, the reaction was carried out for 4 h.
[0041] (3) The reaction solution was cooled to room temperature and dialyzed for 24 h using a dialysis bag (molecular weight cut-off 1000 Da) to remove unreacted raw materials. The purified silicon quantum dot solution was collected and freeze-dried at -50°C for 24 h to obtain functionalized silicon quantum dot solids.
[0042] (4) 0.1 g of functionalized silicon quantum dot powder was weighed using an analytical balance and dissolved in 100 ml of deionized water. Ultrasonic treatment was performed for 20 min to obtain a silicon quantum dot oil displacement agent solution.
[0043] Example 4 A co-condensed silicon quantum dot oil displacement agent and a method for preparing the same, comprising the following steps: (1) DTMS pre-hydrolysis: 30 ml of deionized water and 20 ml of ethanol were added to a 100 ml beaker and ultrasonically treated for 10 min. Then, 0.4 ml of DTMS was added dropwise into the beaker while the beaker was placed on a magnetic chain stirrer at room temperature. The stirring speed was adjusted to the center vortex appeared. The pre-hydrolysis was carried out for 1 h.
[0044] (2) Hydrothermal condensation of hydrolyzed DTMS with APTMS: 30 ml of water and 20 ml of ethanol were added to a 250 ml three-necked flask and placed in a heat collecting magnetic stirrer. After the pre-hydrolysis solution was poured into the flask, 1 ml of APTMS was added dropwise into the flask. After the temperature was raised to 70°C by nitrogen blowing, the reaction was carried out for 4 h.
[0045] (3) The reaction solution was cooled to room temperature and dialyzed for 24 h using a dialysis bag (molecular weight cut-off 1000 Da) to remove unreacted raw materials. The purified silicon quantum dot solution was collected and freeze-dried at -50°C for 24 h to obtain functionalized silicon quantum dot solids.
[0046] (4) 0.1 g of functionalized silicon quantum dot powder was weighed using an analytical balance and dissolved in 100 ml of deionized water. Ultrasonic treatment was performed for 20 min to obtain a silicon quantum dot oil displacement agent solution.
[0047] Performance characterization In order to evaluate the performance of the co-condensed silicon quantum dot oil displacement agent, the structure of the functionalized silicon quantum dots prepared in Example 3 was analyzed using an infrared spectrometer, and the results are shown in Figure 1 Figure 1 It can be seen that the wide peak at 3500 is derived from residual H2O and Si-OH, the peaks at 2937 and 2876 are derived from the propyl chain in APTMS, indicating that the organic part has not been removed during the synthesis, the peak at 1661 is derived from the -NH2 group, and the double peaks at about 1100 are derived from the Si-O-Si skeleton, and the Si-C absorption peak appears at about 700.
[0048] The particle size of the oil displacement agent of the silicon quantum dots prepared in Example 3 was analyzed by using a nanoparticle size potential instrument, and the results are shown in Figure 2 From Figure 2 It can be seen that the particle size of the oil displacement agent of the silicon quantum dots prepared by the present application is within 1-10 nm, which is an important characteristic of the silicon quantum dot material, indicating the successful preparation of the silicon quantum dots.
[0049] The contact angle of the oil displacement agent of the silicon quantum dots prepared in Example 3 with the lipophilic glass plate at different preparation concentrations was tested, and the specific test method refers to the Technical Specification for Oil Displacement Agent for Oil Field Fracturing (Q / SY 8023-2023), and the results are shown in Figure 3 From Figure 3 It can be seen that the oil displacement agent molecules gradually become lipophilic with the increase of the concentration, which helps to improve the distribution and flow of the oil.
[0050] The interfacial tension of the oil displacement agent of the silicon quantum dots prepared in Example 3 at 60℃ was tested, and the results are shown in Figure 4 From Figure 4 It can be seen that with the increase of the preparation concentration, the oil-water interfacial tension of the oil displacement agent of the silicon quantum dots first decreases and then increases, and the minimum value is obtained at the preparation concentration of 0.3%, which can effectively improve the recovery rate of crude oil, especially in low permeability and complex reservoir environments.
[0051] The above content only illustrates the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the present application.
Claims
1. A method for preparing a co-condensed silicon quantum dot oil displacement agent, characterized in that, Includes the following steps: Dodecyltrimethoxysilane was added dropwise to an acidic mixture of water and ethanol, and pre-hydrolyzed by stirring at room temperature to obtain a silanol solution. A silanol solution was mixed with 3-aminopropyltrimethoxysilane and heated under nitrogen protection to carry out a hydrothermal condensation reaction to form silicon quantum dot oligomers. Then, the mixture was cooled, dialyzed and freeze-dried in sequence to obtain functionalized silicon quantum dot powder. Functionalized silicon quantum dot powder was dissolved in deionized water and ultrasonically prepared to obtain a co-condensed silicon quantum dot oil displacement agent.
2. The method for preparing the co-condensed silicon quantum dot oil displacement agent according to claim 1, characterized in that, The volume ratio of water to ethanol in the water-ethanol mixture is 3:
2.
3. The method for preparing the co-condensed silicon quantum dot oil displacement agent according to claim 1, characterized in that, The pH of the water-ethanol mixture is adjusted using acetic acid, and the pH of the water-ethanol mixture is 4; the pre-hydrolysis time is 1 hour.
4. The method for preparing the co-condensed silicon quantum dot oil displacement agent according to claim 1, characterized in that, The volume ratio of dodecyltrimethoxysilane to 3-aminopropyltrimethoxysilane is 0.1~0.4:
1.
5. The method for preparing the co-condensed silicon quantum dot oil displacement agent according to claim 4, characterized in that, The volume ratio of dodecyltrimethoxysilane to 3-aminopropyltrimethoxysilane is 0.3:
1.
6. The method for preparing the co-condensed silicon quantum dot oil displacement agent according to claim 1, characterized in that, The hydrothermal condensation reaction was carried out at a temperature of 70°C for 4 hours.
7. The method for preparing the co-condensed silicon quantum dot oil displacement agent according to claim 1, characterized in that, The dialysis was performed using a dialysis bag with a molecular weight cutoff of 1000 Da for 24 hours; the freeze-drying was performed at a temperature of -50°C for 24 hours.
8. A co-condensed silicon quantum dot oil displacement agent, characterized in that, It is prepared by the method described in any one of claims 1 to 7 for the preparation of co-condensed silicon quantum dot oil displacement agent.
9. The co-condensed silicon quantum dot oil displacement agent according to claim 8, characterized in that, The co-condensed silicon quantum dot oil displacement agent comprises functionalized silicon quantum dots with a particle size distribution of 1-10 nm. The surface of the functionalized silicon quantum dots has dodecyl and amino groups, and the functionalized silicon quantum dots have a silicon-oxygen framework structure formed by silicon atoms and oxygen atoms connected by covalent bonds.
10. The application of a co-condensed silicon quantum dot oil displacement agent prepared by the method described in any one of claims 1 to 7 in oil extraction.