Slow-release oil-soluble quantum dot tracer as well as preparation method and application thereof
By preparing slow-release oil-soluble quantum dot tracers, the problem of chemical tracers being unable to achieve slow release and high-precision monitoring in oil field development was solved, and efficient differentiation and long-term stable monitoring of oil well fluid production were achieved, reducing production costs.
Patent Information
- Application Number
- CN202510761693.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-09
- Publication Date
- 2025-09-12
AI Technical Summary
Existing chemical tracers cannot achieve slow-release performance and high-precision liquid production monitoring in oilfield development, and it is difficult to distinguish the differences in liquid production in different horizontal well sections.
A method for preparing a slow-release oil-soluble quantum dot tracer is adopted. By adding a morphology regulator, cadmium oxide, and selenium powder into a molten eutectic salt system, and combining functional ligands and resin curing agents, a quantum dot tracer with a narrow excitation wavelength half-peak width is prepared.
It realizes long-term tracing of oil well production fluid, improves monitoring accuracy, can effectively distinguish the differences in fluid production in different horizontal well sections, and reduce production costs.
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Figure CN120624005A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of nanomaterials, and in particular relates to a slow-release oil-soluble quantum dot tracer, a preparation method thereof, and an application thereof. Background Art
[0002] Quantum dots are semiconductor nanocrystals with size-dependent optical and electronic properties. When the size of a quantum dot (semiconductor nanocrystal) is reduced to below the exciton Bohr radius, a quantum confinement effect occurs, confining the exciton within a specific three-dimensional space. This results in their optical properties being highly dependent on their size. Consequently, quantum dots are characterized by their small size (<10nm) and excitation-light-dependent photoluminescence. Consequently, quantum dots are often used in fields such as photoelectric conversion and biomarkers.
[0003] In oilfield development and production, tracers can be deployed in oil well production tubing strings, either as pup joints or integrated tracer strings, to monitor fluid production profiles. However, currently used chemical tracers generally lack the required slow-release performance and detection accuracy, making it difficult to effectively distinguish differences in fluid production between horizontal well sections.
[0004] By placing quantum dot tracers at corresponding locations in underground horizontal wells and utilizing different excitation wavelengths of various water-soluble and oil-soluble quantum dots, dynamic monitoring of fluid production in different horizontal sections is achieved. The slow-release properties also enable long-term monitoring. This technology offers high monitoring accuracy, a simple analysis process, and stable, real-time monitoring without shutting down the well.
[0005] Therefore, it is very necessary and of great significance to develop a method for preparing quantum dot tracers with narrow tracing half-width, low detection limit and a distinguishable tracing wavelength range. Summary of the Invention
[0006] The purpose of the present invention is to address the defects of the prior art and provide a slow-release oil-soluble quantum dot tracer and its preparation method and application.
[0007] Specifically, the present invention is achieved through the following technical solutions:
[0008] A method for preparing a sustained-release oil-soluble quantum dot tracer comprises:
[0009] (1) adding a morphology modifier to a molten eutectic salt system, mixing uniformly, and then adding cadmium oxide and selenium powder to obtain a Cd-Se pre-bonded cluster;
[0010] (2) Under inert gas protection, heat to 350-450°C at 6-10°C / min and keep warm for 20-30 minutes, then quickly cool to 250-300°C;
[0011] (3) heating the material in a step-by-step manner and then cooling it down, adding a functional ligand during the cooling process, stirring for a period of time, and then using hot ethanol to dissolve the molten salt matrix for liquid-liquid extraction to obtain a fluorescent quantum dot material;
[0012] (4) The fluorescent quantum dot material is dissolved in an oil-soluble solvent, and then epoxy resin, polymer precursor solution and resin curing agent are added, mixed and stirred, and then heated and dried in a mold to obtain a slow-release tracer product.
[0013] In the above-mentioned method for preparing the sustained-release oil-soluble quantum dot tracer, the eutectic salt system includes one or more of cesium iodide, sodium iodide, cadmium iodide, and aluminum iodide.
[0014] In the above-mentioned method for preparing the sustained-release oil-soluble quantum dot tracer, the morphology control agent includes one or more of tellurium chloride, aluminum chloride, and potassium chloride.
[0015] In the preparation method of the above-mentioned sustained-release oil-soluble quantum dot tracer, the molar ratio of the eutectic salt system, the morphology control agent, the cadmium oxide and the selenium powder is (1-5): (0.05-0.8): (1-4): (1-2.5).
[0016] In the above-mentioned method for preparing the sustained-release oil-soluble quantum dot tracer, the inert gas is argon or nitrogen.
[0017] In the above-mentioned preparation method of the sustained-release oil-soluble quantum dot tracer, in step (3), the step-by-step heating and then cooling comprises: raising the temperature of the system from 240-260°C to 340-360°C at a rate of 6-10°C / min; then raising the temperature to 390-410°C at a rate of 4-6°C / min, and then raising the temperature to 440-460°C at a rate of 1-3°C / min, and then naturally cooling to room temperature.
[0018] In the above-mentioned method for preparing the sustained-release oil-soluble quantum dot tracer, the functional ligand comprises one or more of oleylamine-mercaptopropionic acid, oleic acid, and oleylamine.
[0019] In the preparation method of the above-mentioned sustained-release oil-soluble quantum dot tracer, the ratio of the functional ligand to the eutectic salt system is (0.5 mL-2 mL): (1 mmol-3 mmol).
[0020] In the above-mentioned method for preparing the sustained-release oil-soluble quantum dot tracer, the temperature of the hot ethanol is 50-60°C.
[0021] In the above-mentioned method for preparing the sustained-release oil-soluble quantum dot tracer, the oil-soluble solvent includes one or more of n-hexane, octane, and butyl glycidyl ether.
[0022] In the above-mentioned method for preparing the sustained-release oil-soluble quantum dot tracer, the polymer precursor includes but is not limited to polyacrylic acid or polyacrylonitrile.
[0023] In the above-mentioned method for preparing the sustained-release oil-soluble quantum dot tracer, the resin curing agent includes polyether diamine, m-phenylenediamine or maleic anhydride.
[0024] In the preparation method of the above-mentioned sustained-release oil-soluble quantum dot tracer, the mass ratio of the fluorescent quantum dot material, the oil-soluble solvent, the epoxy resin, the polymer precursor and the resin curing agent is (1-5): (20-50): (60-100): (6-10): (15-25).
[0025] A sustained-release oil-soluble quantum dot tracer is prepared by adopting the above-mentioned method for preparing the sustained-release oil-soluble quantum dot tracer.
[0026] Application of the above-mentioned slow-release oil-soluble quantum dot tracer in oil field development.
[0027] The technical solution of the present invention has the following beneficial effects:
[0028] (1) The slow-release oil-soluble quantum dot tracer provided by the present invention realizes efficient dissociation and lattice reconstruction modification of the metal precursor by constructing a molten salt precursor, and at the same time enables the tracer to have a narrow excitation wavelength half-peak width, which can be used for downhole tracing in oil fields;
[0029] (2) The slow-release oil-soluble quantum dot tracer provided by the present invention has good tracer molecule slow-release performance and can provide long-term tracer performance for the produced fluid of the oil well;
[0030] (3) The preparation method of the slow-release oil-soluble quantum dot tracer provided by the present invention reduces production costs by using recyclable molten salt, and has the advantages of short reaction time and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Various other advantages and benefits will become apparent to those skilled in the art by reading the following detailed description of the preferred embodiment.The accompanying drawings are only for the purpose of illustrating the preferred embodiment and are not to be considered as limiting the present invention.
[0032] Figure 1 This is the ultraviolet excitation spectrum of the tracer prepared in Example 1.
[0033] Figure 2 This is the fluorescence spectrum of the tracer prepared in Example 1 at room temperature.
[0034] Figure 3 This is a fluorescence photograph of the tracer prepared in Example 1 after dispersion in mineralized water.
[0035] Figure 4 Transmission electron microscope image and particle size distribution diagram of the tracer prepared in Example 1.
[0036] Figure 5 This is the sustained-release performance of the sustained-release quantum dot tracer in Example 1. DETAILED DESCRIPTION
[0037] In order to fully understand the purpose, features and effects of the present invention, the present invention is described in detail through the following specific embodiments. Except for the following contents, the process of the present invention adopts conventional methods or devices in the art. Unless otherwise specified, the following terms have the meanings commonly understood by those skilled in the art.
[0038] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are understood to include any and all subranges subsumed therein.
[0039] Specifically, the method for preparing a sustained-release oil-soluble quantum dot tracer provided by the present invention includes: S1 preparation of oil-soluble quantum dots; S2 preparation of a sustained-release oil-soluble quantum dot tracer.
[0040] The preparation of the sustained-release oil-soluble quantum dot tracer comprises the following steps:
[0041] Preparation of S1 oil-soluble quantum dots
[0042] A morphology modifier is added to the molten eutectic salt system, mixed evenly, and then cadmium oxide and selenium powder are added to obtain a Cd-Se pre-bonded cluster; under the protection of an inert gas, the temperature is increased to 350-450°C at a rate of 6-10°C / min and kept warm for 20-30 minutes, and then the temperature is rapidly cooled to 350-400°C; the temperature is increased and then cooled in a step-by-step manner, and a functional ligand is added during the cooling process. After stirring for a period of time, hot ethanol is used to dissolve the molten salt matrix for liquid-liquid extraction to obtain a fluorescent quantum dot material.
[0043] Preparation of S2 sustained-release oil-soluble quantum dot tracer
[0044] The fluorescent quantum dot material is dissolved in an oil-soluble solvent, and then epoxy resin, polymer precursor solution and resin curing agent are added. After mixing and stirring, the mixture is heated and dried in a mold to obtain a slow-release tracer product.
[0045] In the process of preparing oil-soluble quantum dots, the fluorescent quantum dot material is evenly dispersed in the precursor solution and shaped in the mold through the resin curing reaction to form a product with a fixed shape.
[0046] In the present invention, the eutectic salt synthesis method is a basic method for synthesizing fluorescent quantum dot materials, and oil-soluble fluorescent quantum dots are obtained by using molten salt as a reaction medium.
[0047] In some preferred embodiments, the eutectic salt system includes but is not limited to one or more of cesium iodide, sodium iodide, cadmium iodide, and aluminum iodide; further preferably, the eutectic salt system is cadmium iodide.
[0048] In the present invention, the role of the morphology regulator is mainly to control the local reaction environment and inhibit excessive grain growth.
[0049] In some preferred embodiments, the morphology control agent includes one or more of cadmium chloride, aluminum chloride, and potassium chloride; further preferably, the morphology control agent is cadmium chloride.
[0050] In the present invention, cadmium oxide and selenium powder are basic raw materials of fluorescent quantum dot tracers, which are cadmium source and selenium source respectively. The cadmium selenide semiconductor structure is formed by the reaction of the two, thereby forming quantum dots.
[0051] In some preferred embodiments, the molar ratio of the eutectic salt system, the morphology modifier, the cadmium oxide, and the selenium powder is (1-5): (0.05-0.8): (1-4): (1-2.5). When the raw material ratio is outside the above range, problems such as increased particle size and reduced yield may occur, thereby reducing the fluorescence yield and tracer detection effect.
[0052] Further preferably, the molar ratio of the eutectic salt system, the morphology modifier, the cadmium oxide and the selenium powder is (1.5-3): (0.1-0.15): (1.5-3): (1-2).
[0053] In some preferred embodiments, the inert gas is argon or nitrogen, thereby preventing the chemical components from being oxidized; further preferably, the inert gas is argon.
[0054] The present invention heats the Cd-Se pre-bonded cluster by raising the temperature to 350-450°C at 6-10°C / min and keeping the temperature for 20-30min, and then rapidly cooling the temperature to 250-300°C. By heating / cooling the temperature in stages, the nucleation and growth dynamics are optimized and the lattice defects are reduced.
[0055] More preferably, in the present invention, the Cd-Se pre-bonded cluster is heated at 10°C / min to 450°C and kept at this temperature for 30 minutes, and then rapidly cooled to 280°C.
[0056] The rapid cooling rate is 10-20°C / min, more preferably 20°C / min.
[0057] In some preferred embodiments, in step (3), the step cooling specifically includes: raising the temperature of the system from 240-260°C to 340-360°C at a rate of 6-10°C / min; then raising the temperature to 390-410°C at a rate of 4-6°C / min, and then raising the temperature to 440-460°C at a rate of 1-3°C / min, and cooling by natural cooling.
[0058] In some preferred embodiments, in step (3), the step cooling specifically includes: raising the temperature of the system from 250°C to 350°C at a rate of 8°C / min; then raising the temperature to 400°C at a rate of 5°C / min, and then raising the temperature to 450°C at a rate of 2°C / min, and cooling by natural cooling.
[0059] In the present invention, the function of the functional ligand is mainly to passivate surface defects and impart oil solubility to the quantum dots.
[0060] In some preferred embodiments, the functional ligand includes one or more of oleylamine-mercaptopropionic acid, oleic acid, and oleylamine, and is more preferably oleylamine.
[0061] In some preferred embodiments, the ratio of the functional ligand to the eutectic salt system is (0.5 mL-2 mL): (1 mmol-3 mmol); more preferably (0.5 mL-2 mL): (1.5 mmol-2.5 mmol).
[0062] The present invention can preliminarily synthesize cadmium selenide quantum dots by adopting a step-by-step temperature increase method; and can perform surface passivation on the cadmium selenide quantum dots by injecting functional ligands during the temperature reduction process and stirring for a period of time.
[0063] More preferably, the stirring time after adding the functional ligand is 10-60 min.
[0064] In some preferred embodiments, the temperature of the hot ethanol is 50-60°C, more preferably 60°C.
[0065] Among them, the main function of the oil-soluble solvent is to dissolve and disperse the oil-soluble quantum dots; the main function of the polymer precursor is to use the polymer to increase the pore structure of the tracer after curing and provide a certain toughness; the main function of the resin curing agent is to react with the resin to form a cured cross-linked structure, forming a slow-release carrier for the tracer.
[0066] In some preferred embodiments, the oil-soluble solvent includes one or more of n-hexane, octane, and butyl glycidyl ether; n-hexane is further preferred.
[0067] In some preferred embodiments, the polymer precursor includes but is not limited to polyacrylic acid or polyacrylonitrile.
[0068] More preferably, the molecular weight of the polyacrylic acid is in the range of 10,000-200,000; and the molecular weight of the polyacrylonitrile is in the range of 100,000-500,000.
[0069] In some preferred embodiments, the resin curing agent includes polyetherdiamine, m-phenylenediamine or maleic anhydride.
[0070] In some preferred embodiments, the mass ratio of the fluorescent quantum dot material, the oil-soluble solvent, the epoxy resin, the polymer precursor, and the resin curing agent is (1-5): (20-50): (60-100): (6-10): (15-25). If the above raw materials are not within the scope of the present invention, defects such as the tracer carrier material being too soft, insufficient tracer active ingredient, and the tracer having no sustained-release performance may occur.
[0071] Further preferably, the mass ratio of the fluorescent quantum dot material, the oil-soluble solvent, the epoxy resin, the polymer precursor and the resin curing agent is (1-3): (25-50): (80-100): (8-10): (20-25).
[0072] In practice, the slow-release oil-soluble quantum dot tracer prepared according to the method of this invention exhibits slow-release properties, a narrow half-width (FWHM) of the tracer, a low detection limit, and a tracer wavelength range suitable for long-term monitoring. This meets the slow-release performance and detection accuracy requirements of tracers during oilfield development, effectively distinguishing differences in fluid production between different horizontal well sections.
[0073] Example
[0074] The present invention is further illustrated by way of examples below, but the invention is not limited to the scope of the examples. The experimental methods in the following examples where specific conditions are not specified were based on conventional methods and conditions. The raw materials used in the following examples were all commercially available.
[0075] Epoxy resin: purchased from Baling Petrochemical Co., Ltd., product model E51;
[0076] Polyacrylic acid: purchased from Shandong Wanhua Tianhe New Materials Co., Ltd., product model CA-06;
[0077] Polyacrylonitrile: purchased from Shanghai MacLean Biochemical Technology Co., Ltd., product model P750088.
[0078] Example 1
[0079] Preparation of S1 oil-soluble quantum dots
[0080] A molten eutectic salt system (3 mmol of cesium iodide and 1 mmol of sodium iodide) was used as the reaction medium, and 0.2 mmol of tellurium chloride was added and mixed evenly; then 2 mmol of cadmium oxide and 2.0 mmol of selenium powder were mixed and added to the eutectic salt system to form a Cd-Se pre-bonded cluster; under argon protection, the temperature was raised to 450°C at 10°C / min and kept warm for 30 minutes, and then rapidly cooled to 280°C at a rate of 20°C / min; a step-by-step heating method was used (the temperature of the system was raised from 250°C to 350°C at a rate of 8°C / min; then raised to 400°C at a rate of 5°C / min, and then raised to 450°C at a rate of 2°C / min. The cooling was natural cooling to room temperature) to preliminarily synthesize cadmium selenide quantum dots in an oven; during the cooling process, 0.6 mL of oleic acid was injected and stirred for 30 minutes for surface passivation; finally, 60°C hot ethanol was used to dissolve the molten salt matrix for liquid-liquid extraction to obtain fluorescent quantum dot materials.
[0081] Preparation of S2 Oil-Soluble Quantum Dot Tracer
[0082] 6 mg of fluorescent quantum dot material was dissolved in 0.3 g of n-hexane, and then 0.6 g of epoxy resin and 60 mg of polyacrylic acid solution were added, and then 0.18 g of resin curing agent maleic anhydride was added and mixed, and heated and dried for 24 hours to obtain a sustained-release tracer product.
[0083] The sustained-release tracer product prepared in Example 1 was tested according to the existing method. Figure 1 , the fluorescence spectrum at room temperature is shown in Figure 2 , the fluorescence spectrum after dispersion in mineralized water is shown in Figure 3 , as shown in the transmission electron microscopy and particle size distribution Figure 4 , sustained release performance test results are shown in Figure 5 .
[0084] Figure 1 This indicates that the tracer has the characteristic of luminescence under ultraviolet light excitation and can be detected by ultraviolet light excitation; Figure 2 This indicates that the tracer has fluorescent properties and can be detected by fluorescence spectroscopy at room temperature; Figure 3 This indicates that the tracer has fluorescence detectability. Under 365 nm ultraviolet light, fluorescence was observed after the tracer was dispersed in n-hexane. Figure 4This indicates that the tracer is nanoscale, with a particle size ranging from 2 to 6 nm and an average particle size of 4 nm; Figure 5 This indicates that the sustained-release performance of the tracer is stable, and the fluorescence concentration of the quantum dot tracer detected gradually increases with time, showing a linear growth.
[0085] Example 2
[0086] Preparation of S1 oil-soluble quantum dots
[0087] A molten eutectic salt system (3 mmol of cesium iodide and 1 mmol of potassium iodide) was used as the reaction medium, and 0.8 mmol of tellurium chloride was added and mixed evenly; then 2 mmol of cadmium oxide and 2 mmol of selenium powder were mixed and added to the eutectic salt system to form Cd-Se pre-bonded clusters; under argon protection, the temperature was raised to 450°C at 10°C / min and kept warm for 30 minutes, and then rapidly cooled to 280°C (cooling rate 20°C / min); a step-by-step heating method was used (the temperature of the system was raised from 250°C to 350°C at a rate of 5°C / min; then raised to 400°C at a rate of 5°C / min, and then raised to 450°C at a rate of 2°C / min, and then naturally cooled to room temperature) to preliminarily synthesize cadmium selenide quantum dots in an oven; during the cooling process, 2.4 mL of oleic acid-mercaptopropionic acid was injected and stirred for 10 minutes for surface passivation; finally, 60°C hot ethanol was used to dissolve the molten salt matrix for liquid-liquid extraction to obtain fluorescent quantum dot materials.
[0088] Preparation of S2 Oil-Soluble Quantum Dot Tracer
[0089] 10 mg of fluorescent quantum dot material was dissolved in 0.25 g of n-hexane, and then 0.8 g of 20% epoxy resin and 80 mg of polyacrylonitrile solution were added, and then 0.2 g of resin curing agent maleic anhydride was added and mixed, and heated and dried for 36 hours to obtain a sustained-release tracer product.
[0090] Example 3
[0091] Preparation of S1 oil-soluble quantum dots
[0092] A molten eutectic salt system (3 mmol of cesium iodide and 1.5 mmol of sodium iodide) was used as the reaction medium, and 0.32 mmol of tellurium chloride was added and mixed evenly. Then, 4 mmol of cadmium oxide and 2.5 mmol of selenium powder were mixed and added to the eutectic salt system to form Cd-Se pre-bonded clusters. Under argon protection, the temperature was raised to 450°C at a rate of 10°C / min and kept at this temperature for 30 minutes, and then rapidly cooled to 380°C (cooling rate of 20°C / min). Cdse quantum dots were preliminarily synthesized in an oven by a step-by-step heating method (the temperature of the system was raised from 250°C to 350°C at a rate of 5°C / min; then to 400°C at a rate of 5°C / min, and then to 450°C at a rate of 2°C / min, and then naturally cooled to room temperature). During the cooling process, 2.4 mL of oleylamine was injected and stirred for 10 minutes for surface passivation. Finally, the molten salt matrix was dissolved in 60°C hot ethanol for liquid-liquid extraction to obtain fluorescent quantum dot materials.
[0093] Preparation of S2 Oil-Soluble Quantum Dot Tracer
[0094] 5 mg of fluorescent quantum dot material was dissolved in 0.25 g of n-hexane, and then 0.5 g of 20% epoxy resin and 50 mg of polyacrylonitrile solution were added, and then 0.1 g of resin curing agent maleic anhydride was added and mixed, and heated and dried for 36 hours to obtain a sustained-release tracer product.
[0095] The present invention has been disclosed above with reference to preferred embodiments. However, those skilled in the art will appreciate that these embodiments are intended only to illustrate the present invention and are not to be construed as limiting the scope of the present invention. It should be noted that any equivalent variations and substitutions to these embodiments are to be considered encompassed within the scope of the claims of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope defined in the claims.
Claims
1. A method for preparing a sustained-release oil-soluble quantum dot tracer, characterized in that: include: (1) adding a morphology modifier to a molten eutectic salt system, mixing uniformly, and then adding cadmium oxide and selenium powder to obtain a Cd-Se pre-bonded cluster; (2) Under inert gas protection, heat to 350-450°C at 6-10°C / min and keep warm for 20-30 minutes, then quickly cool to 250-300°C; (3) heating the material in a step-by-step manner and then cooling it down, adding a functional ligand during the cooling process, stirring for a period of time, and then using hot ethanol to dissolve the molten salt matrix for liquid-liquid extraction to obtain a fluorescent quantum dot material; (4) The fluorescent quantum dot material is dissolved in an oil-soluble solvent, and then epoxy resin, polymer precursor solution and resin curing agent are added, mixed and stirred, and then heated and dried in a mold to obtain a slow-release tracer product.
2. The method for preparing the sustained-release oil-soluble quantum dot tracer according to claim 1, characterized in that: The eutectic salt system includes one or more of cesium iodide, sodium iodide, cadmium iodide, and aluminum iodide.
3. The method for preparing the sustained-release oil-soluble quantum dot tracer according to claim 1, characterized in that: The morphology control agent includes one or more of tellurium chloride, aluminum chloride, and potassium chloride.
4. The method for preparing a sustained-release oil-soluble quantum dot tracer according to claim 1, wherein: The molar ratio of the eutectic salt system, the morphology control agent, the cadmium oxide and the selenium powder is (1-5): (0.05-0.8): (1-4): (1-2.5).
5. The method for preparing the sustained-release oil-soluble quantum dot tracer according to claim 1, characterized in that: The inert gas is argon or nitrogen.
6. The method for preparing the sustained-release oil-soluble quantum dot tracer according to claim 1, characterized in that: In step (3), the step-by-step heating method of heating and then cooling specifically includes: heating the system temperature from 240-260°C to 340-360°C at a rate of 6-10°C / min; then heating it to 390-410°C at a rate of 4-6°C / min, and then heating it to 440-460°C at a rate of 1-3°C / min, and then naturally cooling it to room temperature.
7. The method for preparing a sustained-release oil-soluble quantum dot tracer according to claim 1, characterized in that: The functional ligand includes one or more of oleylamine-mercaptopropionic acid, oleic acid, and oleylamine.
8. The method for preparing a sustained-release oil-soluble quantum dot tracer according to claim 1, characterized in that: The ratio of the functional ligand to the eutectic salt system is (0.5 mL-2 mL): (1 mmol-3 mmol).
9. The method for preparing a sustained-release oil-soluble quantum dot tracer according to claim 1, characterized in that: The temperature of the hot ethanol is 50-60°C.
10. The method for preparing a sustained-release oil-soluble quantum dot tracer according to claim 1, characterized in that: The oil-soluble solvent includes one or more of n-hexane, octane, and butyl glycidyl ether.
11. The method for preparing a sustained-release oil-soluble quantum dot tracer according to claim 1, characterized in that: The polymer precursor includes but is not limited to polyacrylic acid or polyacrylonitrile.
12. The method for preparing a sustained-release oil-soluble quantum dot tracer according to claim 1, characterized in that: The resin curing agent includes polyether diamine, m-phenylenediamine or maleic anhydride.
13. The method for preparing a sustained-release oil-soluble quantum dot tracer according to claim 1, characterized in that: The mass ratio of the fluorescent quantum dot material, the oil-soluble solvent, the epoxy resin, the polymer precursor and the resin curing agent is (1-5): (20-50): (60-100): (6-10): (15-25).
14. A sustained-release oil-soluble quantum dot tracer, characterized in that: The sustained-release oil-soluble quantum dot tracer is prepared by the preparation method of any one of claims 1 to 13.
15. Use of the slow-release oil-soluble quantum dot tracer according to claim 14 in oil field development.