Film-coated fluorescent microsphere tracer agent and preparation method thereof

Abstract

The invention provides a film-coated fluorescent microsphere tracer and a preparation method thereof. The preparation method comprises the following steps: S1, modifying fluorescent microspheres into oily fluorescent microspheres; modifying the surfaces of the sand grains to be lipophilic: mixing a modifier, a catalyst and a first solvent to form a first mixture, and then adding the first mixture into the sand grains to react, so that the modifier is connected with the surfaces of the sand grains to obtain lipophilic sand grains; and S2, mixing the oily fluorescent microspheres, an oily sustained-release material, a second solvent and support resin to form a second mixture, then adding the second mixture into the lipophilic sand grains, uniformly mixing, and adding a curing agent for reaction to form a sustained-release layer coating the lipophilic sand grains, thereby obtaining the film-coated fluorescent microsphere tracer agent.

Description

Technical Field

[0001] This application belongs to the technical field of tracers. Specifically, it relates to a coated fluorescent microsphere tracer and a preparation method thereof. Background Art

[0002] Fluorescent microspheres are formed by coating one or more fluorescent materials with a shell layer, and the shell layer mainly plays a role in protecting the fluorescent materials. The fluorescent materials mainly include: organic fluorescent dyes, quantum dots, metal oxides, etc. These fluorescent materials are easily affected by the environment. For example, they are easily degraded, easily photobleached, not resistant to high temperature / strong light irradiation, not resistant to water and oxygen, etc. Therefore, in the prior art, most fluorescent materials are coated with inorganic shell layers or organic polymer shell layers. The fluorescent materials are excited by light or electricity and emit fluorescence. By means of different types of fluorescent components and different fluorescence contents, multiple different emission bands (colors) can be formed, which has the function of encoding. Therefore, they are widely used in the fields of biological labeling, disease diagnosis, tracers, solid-phase chips, liquid-phase chips, immunochromatography, Raman scattering, etc.

[0003] Fluorescent microspheres can be applied to petroleum tracers. By detecting data such as the types and quantities of fluorescent microspheres through sampling ports, parameters such as the production rate and flow rate of petroleum can be analyzed. Fluorescent microspheres usually cannot be directly applied to this environment. Usually, sand grains such as quartz sand and ceramsite sand are used as the core, and a slow-release layer is coated on the surface of the sand grains. The slow-release layer has oily fluorescent microspheres and a slow-release material that coats and fixes the oily fluorescent microspheres (slowly dissolves in petroleum to release the fluorescent microspheres into the petroleum); the slow-release layer also has a cured product formed by cross-linking and curing phenolic resin or epoxy resin, which plays a supporting role in the slow-release layer and also plays a role in protecting the oily fluorescent microspheres and the slow-release material, preventing the oily fluorescent microspheres from quickly dissolving and dispersing into the petroleum and failing to play a slow-release role. However, in the prior art, for the synthesized tracer products, when observed under a fluorescence microscope, the luminescence on the surface of the sand grains is uneven, that is, the distribution of the oily fluorescent microspheres is uneven, and there is a phenomenon that some oily fluorescent microspheres are coated but not fixed on the surface of the sand grains.

[0004] In view of this, this application provides a coated fluorescent microsphere tracer and a preparation method thereof. The fluorescent microspheres on the surface of the sand grains of the tracer are evenly distributed (uniform luminescence), reducing the phenomenon that oily fluorescent microspheres are not fixed on the surface of the sand grains. Summary of the Invention

[0005] The purpose of this application is to provide a coated fluorescent microsphere tracer and a preparation method thereof. The fluorescent microspheres on the surface of the sand grains of the tracer are evenly distributed (uniform luminescence), reducing the phenomenon that oily fluorescent microspheres are not fixed on the surface of the sand grains.

[0006] In the first aspect of this application, a preparation method of a coated fluorescent microsphere tracer is provided. The method includes:

[0007] S1. Modify the fluorescent microspheres into oil-based fluorescent microspheres; modify the surface of the sand grains to be lipophilic: mix a modifier, a catalyst, and a first solvent to form a first mixture, and then add it to the sand grains for reaction, so that the modifier is connected to the surface of the sand grains to obtain lipophilic sand grains;

[0008] S2. Mix the oil-based fluorescent microspheres, an oil-based sustained-release material, a second solvent, and a support resin to form a second mixture, then add it to the lipophilic sand grains and mix evenly, add a curing agent for reaction to form a sustained-release layer covering the lipophilic sand grains, and obtain a coated fluorescent microsphere tracer.

[0009] In some embodiments, in step S1, the sand grains include at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles. The natural minerals include at least one of vermiculite, perlite, hydromica, natural zeolite, agglomerated stone, or expanded clay.

[0010] In some embodiments, the modifier contains a siloxane group and a lipophilic group, and the siloxane group reacts with the surface of the sand grains under the action of a catalyst and binds.

[0011] Furthermore, the modifier includes at least one of γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, 3-(2-aminoethyl)-aminopropyltrimethoxysilane, 3-(2-aminoethyl)-aminopropylmethyldimethoxysilane, vinyltriethoxysilane, or vinyltrimethoxysilane.

[0012] In some embodiments, the catalyst includes at least one of organotin and its derivatives, inorganic acids, or fatty acids.

[0013] In some embodiments, the first solvent is a non-polar solvent, and the dielectric constant of the first solvent is 1-5.

[0014] In some embodiments, the first mixture further includes an accelerator, and the accelerator can promote the hydrolysis of the modifier, thereby increasing the reaction rate.

[0015] Furthermore, the accelerator includes at least one of water and alcohols. The alcohols include at least one of ethanol, ethylene glycol, methanol, benzyl alcohol, or glycerol.

[0016] In some embodiments, in the first mixture, the mass percentage of the modifier is 12 - 28 wt%, the mass percentage of the catalyst is 0.6 - 3 wt%, the mass percentage of the first solvent is 65 - 85 wt%, and the mass percentage of the promoter is 0.3 - 2 wt%; in step S1, the mass ratio of the added first mixture to the sand grains is 1:(20 - 30).

[0017] Preferably, in the first mixture, the mass percentage of the modifier is 15 - 25 wt%, the mass percentage of the catalyst is 1 - 2 wt%, the mass percentage of the first solvent is 70 - 85 wt%, and the mass percentage of the promoter is 0.5 - 1.5 wt%; in step S1, the mass ratio of the added first mixture to the sand grains is 1:(23 - 27).

[0018] In some embodiments, in step S1, the fluorescent microspheres include: a fluorescent material, a shell layer coating the fluorescent material, and the surface of the shell layer contains polar groups; an oily ligand or a linker and an oily ligand are used to modify the surface of the fluorescent material to be lipophilic, obtaining oily fluorescent microspheres.

[0019] Further, the fluorescent material includes at least one of fluorescent nanoparticles, fluorescent polymers, and organic fluorescent dyes, and the fluorescent nanoparticles include at least one of quantum dots, metal oxide nanoparticles, nanorods, or nanosheets.

[0020] In some embodiments, in step S2, the support resin includes at least one of phenolic resin, modified phenolic resin, or epoxy resin.

[0021] In some embodiments, the oily sustained-release material can be slowly dissolved and released in an oily solvent (such as petroleum).

[0022] Further, the oily sustained-release material includes at least one of petroleum resin and calcium stearate; the petroleum resin includes at least one of C5 petroleum resin and its derivatives, C9 petroleum resin and its derivatives, and calcium stearate.

[0023] In some embodiments, the second solvent is a non-polar solvent, and its boiling point is between 40 and 100.

[0024] In some embodiments, to prepare the second mixture, first, the oily fluorescent microspheres, the oily sustained-release material, and the second solvent are mixed evenly, and then the support resin is added and mixed evenly.

[0025] In some embodiments, the lipophilic sand grains are mixed evenly with a third solvent, then the second mixture is added and mixed, and then the solvent is removed; the third solvent is used to prevent the lipophilic sand grains from caking.

[0026] Further, the second solvent includes at least one of ethanol and ethylene glycol.

[0027] In some embodiments, the second mixture and the curing agent are all added to the reaction equipment at one time, and a slow-release layer is formed immediately; or the second mixture and the curing agent are added to the reaction equipment in multiple times (two or more times), and multiple slow-release layers are formed.

[0028] Further, if the second mixture and the curing agent are added to the reaction equipment in multiple times, the amounts of the second mixture and the curing agent added each time and the mass ratios of the components are the same or different.

[0029] In some embodiments, the curing agent includes at least one of paraformaldehyde, hexamethylenetetramine, aliphatic amines and their modified products, alicyclic amines and their modified products, low molecular weight polyamides, polyetheramines, modified aromatic amines, polythiol type, or polyisocyanate type.

[0030] In some embodiments, in the second mixture, the mass ratio of the oil-based fluorescent microspheres is 4-9 wt%, the mass ratio of the oil-based slow-release material is 4-10 wt%, the mass ratio of the second solvent is 20-40 wt%, and the mass ratio of the support resin is 55-80 wt%; in step S2, the mass ratio of the added second mixture to the oil-wettable sand grains is 1:(25-35).

[0031] Preferably, in the second mixture, the mass ratio of the oil-based fluorescent microspheres is 5.5-7 wt%, the mass ratio of the oil-based slow-release material is 5.5-7 wt%, the mass ratio of the second solvent is 25-30 wt%, and the mass ratio of the support resin is 60-75 wt%; in step S2, the mass ratio of the added second mixture to the oil-wettable sand grains is 1:(27-33).

[0032] In the second aspect of the present application, a coated fluorescent microsphere tracer is provided. The coated fluorescent microsphere tracer includes: sand grains and a slow-release layer coating the sand grains; the surface of the sand grains is modified with a modifier to form oil-wettable sand grains; the slow-release layer includes a crosslinked reaction cured product of oil-based fluorescent microspheres, an oil-based slow-release material, and a support resin.

[0033] In some embodiments, the sand grains include at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles. The natural minerals include at least one of vermiculite, perlite, hydromica, natural zeolite, agglomerated stone, or expanded clay.

[0034] In some embodiments, the modifier contains a siloxane group and a lipophilic group, and the siloxane group reacts with the surface of the sand grains under the action of a catalyst to be bonded and connected.

[0035] Furthermore, the modifier includes at least one of γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, 3-(2-aminoethyl)-aminopropyltrimethoxysilane, 3-(2-aminoethyl)-aminopropylmethyldimethoxysilane, vinyltriethoxysilane, or vinyltrimethoxysilane.

[0036] In some embodiments, the oily fluorescent microspheres include a fluorescent material, a shell layer coating the fluorescent material, and an oily ligand modified on the surface of the shell layer, and the surface of the shell layer contains polar groups.

[0037] In some embodiments, the oily sustained-release material can be slowly dissolved and released in an oily solvent.

[0038] Furthermore, the oily sustained-release material includes at least one of a petroleum resin and calcium stearate; the petroleum resin includes at least one of a C5 petroleum resin and its derivatives, a C9 petroleum resin and its derivatives, and calcium stearate.

[0039] In some embodiments, the support resin includes at least one of a phenolic resin, a modified phenolic resin, or an epoxy resin.

[0040] The coated fluorescent microsphere tracer of the present application and its preparation method have at least the following advantages compared with the prior art:

[0041] (1) Under the action of a catalyst, the modifier described in the application reacts with the active groups on the surface of the sand grains to be bonded and connected. Moreover, since the modifier also has a lipophilic group, the sand grains have lipophilicity; and since the modifier is a long-chain or high-molecular-weight component, they can also entangle with each other on the surface of the sand grains to form a coating-like effect, further enhancing their lipophilicity. Since the sand grains have lipophilicity, and the oily fluorescent microspheres and the oily sustained-release material also have lipophilicity, when synthesizing the sustained-release layer, due to their similar properties, the oily fluorescent microspheres and the oily sustained-release material are easily coated on the surface of the lipophilic sand grains. Under a fluorescence microscope, the fluorescent microspheres coated on the surface of the sand grains are evenly distributed, and there is no phenomenon that some fluorescent microspheres are coated but not cured on the surface of the sand grains.

[0042] (2) By adding a promoter to the first mixture in the present application, the hydrolysis of the modifier can be promoted, thereby increasing the reaction rate and reducing the synthesis time; if the promoter is not added, the reaction time will be slower.

[0043] (3) In this application, the lipophilic sand grains are first mixed evenly with a third solvent, then the second mixture is added and mixed, and then the solvent is removed; the third solvent is used to prevent the lipophilic sand grains from caking. If the third solvent is not mixed with the lipophilic sand grains first and the second mixture is directly added, either caking is likely to occur or a large amount of the second solvent needs to be used. Description of the Drawings

[0044] When reading in conjunction with the following attached Figure 1 drawings, the above and other features of the content of this application will be more fully described. It can be understood that these drawings only depict several embodiments of the content of this application, and thus should not be considered as limiting the scope of the content of this application. By using the drawings, the content of this application will be described more clearly and in detail.

[0045] Figure 1 It is a microscope image of the film-coated fluorescent microsphere tracer of Example 1 of this application.

[0046] Figure 2 It is a microscope image of the film-coated fluorescent microsphere tracer of Example 2 of this application.

[0047] Figure 3 It is a microscope image of the film-coated fluorescent microsphere tracer of Example 3 of this application.

[0048] Figure 4 It is a microscope image of the film-coated fluorescent microsphere tracer of Example 4 of this application.

[0049] Figure 5 It is a microscope image of the film-coated fluorescent microsphere tracer of Comparative Example 1 of this application.

[0050] Figure 6 It is a microscope image of the film-coated fluorescent microsphere tracer of Comparative Example 2 of this application.

[0051] Figure 7 It is a microscope image of the film-coated fluorescent microsphere tracer of Comparative Example 3 of this application.

[0052] Figure 8 It is a microscope image of the film-coated fluorescent microsphere tracer of Comparative Example 4 of this application. Detailed Description of the Embodiments

[0053] The following embodiments are described to assist in understanding this application, and the embodiments are not and should not in any way be construed as limiting the scope of protection of this application.

[0054] Unless otherwise defined, all terms (including technical and scientific terms) used in this specification can be defined as commonly understood by those skilled in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in common dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of this disclosure and the relevant art, and will not be interpreted in an idealized or overly formal sense unless clearly so defined herein.

[0055] As used herein, the term "at least one", when preceding or following a list of elements, modifies the entire list of elements and not individual elements of the list, and will not be construed to limit to "one". "Or" means "and / or". The terms "comprising" and "including", when used in this specification, indicate the presence of the stated features, regions, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, regions, wholes, steps, operations, elements, components, and / or their combinations. Thus, the above wording will be understood to mean including the stated elements but not precluding any other elements. The term "and / or" includes any and all combinations of one or more of the associated listed items. The term "plurality" refers to two or more. The term "connected" refers to direct connection or indirect connection. It will be understood that when an element such as a layer, film, region, or substrate is referred to as "on" another element, it can be directly on the other element or there can also be an intermediate element. In contrast, when an element is referred to as "directly on" another element, there is no intermediate element. To clearly illustrate the embodiments in the figures, some parts that are not actually relevant to the description may be omitted. The terms "first", "second", "third", etc. may be used herein to describe and distinguish different various elements, components, regions, layers, and / or parts, but these elements, components, regions, layers, and / or parts should not be limited by these terms.

[0056] In a first aspect of the present application, a method for preparing a coated fluorescent microsphere tracer is provided, the method comprising:

[0057] S1, modifying the fluorescent microspheres into oil-based fluorescent microspheres; modifying the surface of the sand grains to be lipophilic: mixing a modifier, a catalyst, and a first solvent to form a first mixture, and then adding it to the sand grains for reaction so that the modifier is connected to the surface of the sand grains to obtain lipophilic sand grains;

[0058] S2, mixing the oil-based fluorescent microspheres, an oil-based sustained-release material, a second solvent, and a support resin to form a second mixture, then adding it to the lipophilic sand grains and mixing evenly, removing the solvent, adding a curing agent for reaction to form a sustained-release layer coating the lipophilic sand grains, and obtaining the coated fluorescent microsphere tracer.

[0059] In some embodiments, in step S1, the sand grains include at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles. The natural minerals include at least one of vermiculite, perlite, hydromica, natural zeolite, agglomerated stone, or expanded clay.

[0060] In some embodiments, the modifier contains a siloxane group and a lipophilic group, and the siloxane group reacts with the surface of the sand grains under the action of a catalyst to form a bond.

[0061] Furthermore, the modifier includes at least one of γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, 3-(2-aminoethyl)-aminopropyltrimethoxysilane, 3-(2-aminoethyl)-aminopropylmethyldimethoxysilane, vinyltriethoxysilane, or vinyltrimethoxysilane. In addition to the listed modifiers, any modifier containing a siloxane group and a lipophilic group is applicable to this application and is within the scope of protection of this application.

[0062] In the prior art, since the surfaces of sand grains such as quartz sand and ceramsite sand are hydrophilic, while oil-based fluorescent microspheres and oil-based sustained-release materials are lipophilic, the compatibility between them is poor. Therefore, in the formed sustained-release layer, the oil-based fluorescent microspheres and the oil-based sustained-release materials are unevenly distributed, and there is a phenomenon that the oil-based fluorescent microspheres coated with the oil-based sustained-release material are not fixed on the surface of the sand grains. In addition, after mixing the sand grains with the oil-based fluorescent microspheres, the oil-based sustained-release materials, the supporting resin, and the solvent, it is necessary to evaporate the solvent at a high temperature, which increases the phenomenon of uneven distribution and shedding of the oil-based fluorescent microspheres on the surface of the sand grains.

[0063] However, under the action of the catalyst, the modifier of the present application reacts with the active groups on the surface of the sand grains to form a bond. And because the modifier also has a lipophilic group, the sand grains have lipophilicity; and because the modifier is a long-chain or high-molecular-weight component, they can also entangle with each other on the surface of the sand grains to form a coating-like effect, further enhancing their lipophilicity. Since the sand grains have lipophilicity, and the oil-based fluorescent microspheres and the oil-based sustained-release materials also have lipophilicity, when synthesizing the sustained-release layer, due to their similar properties, the oil-based fluorescent microspheres and the oil-based sustained-release materials are easily coated on the surface of the lipophilic sand grains. Under a fluorescence microscope, the fluorescent microspheres coated on the surface of the sand grains are evenly distributed, and there is no phenomenon that some fluorescent microspheres are coated but not cured on the surface of the sand grains.

[0064] In some embodiments, the catalyst includes at least one of organotin and its derivatives, inorganic acids, or fatty acids.

[0065] The organotin and its derivatives include at least one of dibutyltin dilaurate, dibutyltin bis(laurate), dibutyltin bis(dodecyl sulfide), dibutyltin diacetate, stannous octoate, dibutyltin oxide, dibutyltin dibutyrate, dimethyltin dibutyrate, dioctyltin dibutyrate, dioctyltin diacetate, dibutyltin diacetate, dimethyltin diacetate, or dibutyltin dioleate.

[0066] In some embodiments, the first solvent is a non-polar solvent, and the dielectric constant of the first solvent is 1-5.

[0067] The first solvent includes at least one of liquid paraffin, hexadecane, dodecane, tetradecane, cyclohexane, toluene, bromobenzene, chlorobenzene, benzene, carbon disulfide, carbon tetrachloride, triethylamine, n-hexane, or isooctane.

[0068] In some embodiments, the first mixture further includes a promoter, which can promote the hydrolysis of the modifier, thereby increasing the reaction rate.

[0069] Furthermore, the promoter includes at least one of water and alcohols. The alcohols include at least one of ethanol, ethylene glycol, methanol, benzyl alcohol, or glycerol.

[0070] Adding a promoter to the first mixture can promote the hydrolysis of the modifier, thereby increasing the reaction rate and reducing the synthesis time; if no promoter is added, the reaction time will be slower.

[0071] In some embodiments, in the first mixture, the mass percentage of the modifier is 12 - 28 wt%, such as 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, or 28 wt%, but not limited to the listed values, and other unlisted values within the above range are equally applicable; the mass percentage of the catalyst is 0.6 - 3 wt%, such as 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2.0 wt%, 2.1 wt%, 2.2 wt%, 2.3 wt%, 2.4 wt%, 2.5 wt%, 2.6 wt%, 2.7 wt%, 2.8 wt%, 2.9 wt%, or 3.0 wt%, but not limited to the listed values, and other unlisted values within the above range are equally applicable; the mass percentage of the first solvent is 65 - 85 wt%, such as 65 wt%, 66 wt%, 67 wt%, 68 wt%, 69 wt%, 70 wt%, 71 wt%, 72 wt%, 73 wt%, 74 wt%, 75 wt%, 76 wt%, 77 wt%, 78 wt%, 79 wt%, 80 wt%, 81 wt%, 82 wt%, 83 wt%, 84 wt%, or 85 wt%, but not limited to the listed values, and other unlisted values within the above range are equally applicable; the mass percentage of the promoter is 0.3 - 2 wt%, such as 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, or 2.0 wt%, but not limited to the listed values, and other unlisted values within the above range are equally applicable; in step S1, the mass ratio of the added first mixture to the sand grains is 1:(20 - 30), such as 1:20, 1:21, 1:22, 1:23, 1:24, 1:25, 1:26, 1:27, 1:28, 1:29, or 1:30, but not limited to the listed values, and other unlisted values within the above range are equally applicable.

[0072] Preferably, in the first mixture, the mass ratio of the modifier is 15-25 wt%, the mass ratio of the catalyst is 1-2 wt%, the mass ratio of the first solvent is 70-85 wt%, and the mass ratio of the promoter is 0.5-1.5 wt%; in step S1, the mass ratio of the added first mixture to the sand grains is 1:(23-27).

[0073] In some embodiments, in step S1, the fluorescent microspheres include: a fluorescent material, a shell layer coating the fluorescent material, and the surface of the shell layer contains polar groups; an oily ligand or a linker and an oily ligand are used to modify the surface of the fluorescent material to be lipophilic to obtain oily fluorescent microspheres.

[0074] Further, the fluorescent material includes at least one of fluorescent nanoparticles, fluorescent polymers, and organic fluorescent dyes, and the fluorescent nanoparticles include at least one of quantum dots, metal oxide nanoparticles, nanorods, or nanosheets.

[0075] The quantum dots include at least one of IIB-VIA group quantum dots, IIIA-VA group quantum dots, IVA-VIA group quantum dots, IVA group quantum dots, IB-IIIA-VIA group quantum dots, IB-IIB-IVA-VIA group quantum dots, VIII-VIA group quantum dots, perovskite quantum dots, and carbon quantum dots (carbon dots). For example, the IIB-VIA group quantum dots include: CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, or a combination thereof. For example, the IIIA-VA group quantum dots include: GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, InZnP, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or a combination thereof. For example, the IVA-VIA group quantum dots include: SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe, or a combination thereof. For example, the IVA group quantum dots include: Si, Ge, SiC, SiGe, or a combination thereof. For example, the IB-IIIA-VIA group quantum dots include: CuInSe2, CuInS2, CuInGaSe, CuInGaS, or a combination thereof. For example, the IB-IIB-IVA-VIA group quantum dots include: CuZnSnSe, CuZnSnS, or a combination thereof.For example, the general structural formula of perovskite quantum dots is one of ABX3, A2B2X6, A3B3X9, where A is a monovalent amine organic cation, a monovalent inorganic metal cation (such as CH3NH3. + , NH2CHNH2+, C(NH2)3 + , Cs + , Li + , Na + , K + , Rb + , an aryl group, etc.), B is a divalent inorganic metal cation (such as a divalent cation of a rare earth metal, a divalent cation of an alkaline earth metal, a divalent cation of a transition metal, a divalent cation of a post-transition metal, etc.), and X is a monovalent anion (such as a halogen, etc.). For example, carbon quantum dots are carbon sources such as organic acids, and under high-temperature conditions such as microwave ovens or heating, carbon quantum dots with a particle size of about 10 nm are synthesized by carbonization. Most carbon quantum dots are mainly composed of amorphous carbon to crystalline carbon nuclei and are carbon mainly hybridized with sp 2 . These components are usually the nuclear components of quantum dots. Quantum dots usually also include one or more shells that wrap the nuclear body (the outer shell is usually ZnS). In addition to these listed quantum dots, other common quantum dots are also applicable to this application and are within the protection scope of this application. The metal oxides of metal oxide nanoparticles include: Zn, Cr, Co, Dy, Er, Eu, Fe, Gd, Gd, Pr, Nd, Ni, In, Pr, Sm, Tb, Tm, and combinations thereof. The structure of the fluorescent polymer has a functional group that can emit fluorescence (such as fluorescein, etc.) and monomers that can undergo polymerization reactions. The monomers polymerize with each other or with other monomers that do not contain fluorescence to prepare the fluorescent polymer. Organic fluorescent dyes include: fluorescein (stilbenes, coumarins, fluorans, benzoxazoles, naphthalene dicarboximides, thiophene dicarboxylic acid amides, polycyclic aromatic hydrocarbons, perylene tetracarboxylic diimides, etc.), aromatic polycyclic compounds, intramolecular charge transfer compounds, metal complex fluorescent materials, enzymes, rare earth metal chelates.

[0076] The shell containing polar groups includes: a silica shell, a titanium dioxide shell, a zirconium dioxide shell, a urea-formaldehyde / polyformaldehyde shell, a melamine-formaldehyde / polyformaldehyde shell, a urea-melamine-formaldehyde / polyformaldehyde, an acrylic polymer shell.

[0077] The linker includes at least one of poly (maleic anhydride octadecene), poly (maleic anhydride hexadecene), poly (maleic anhydride tetradecene), methyl methacrylate-styrene copolymer, glycidyl methacrylate-styrene copolymer, polyethylene-alt-maleic anhydride copolymer, polypropylene-alt-maleic anhydride copolymer, or polystyrene-alt-maleic anhydride copolymer.

[0078] The oily ligand includes at least one of: polyoxyethylene-polyoxypropylene copolymer, long-chain fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, sorbitan trioleate, sorbitan monostearate, sorbitan monooleate, sorbitan laurate, hydroxyl-terminated polydimethylsiloxane, triethylvinylsilane, epoxyhexadecane, epoxy tetradecane, hexadecylamine, octadecylamine, or chlorinated polystyrene-terminated.

[0079] The hydrogen bond connection between the polar group on the surface of the fluorescent microsphere and a part of the active chain segment of the linker is converted into an esterification reaction connection, and the other part of the active chain segment of the linker undergoes an esterification reaction connection with the active end group of the oily ligand to form a strong and irreversible chemical bond connection.

[0080] Furthermore, the fluorescent microsphere further includes a magnetic material, and the shell layer coats the fluorescent material and the magnetic material. The magnetic substance includes one or more of: iron tetroxide, iron oxide, nickel oxide, cobalt oxide, magnetite, iron oleate, iron chloride, iron sulfate, iron nitrate, ferrous chloride tetrahydrate, ferric chloride hexahydrate, nickel ferrite, aluminum ferrite, manganese ferrite, zinc ferrite, cobalt ferrite, CoFe2O4, NiFe2O4, or MnFe2O4.

[0081] In some embodiments, in step S2, the support resin includes at least one of: phenolic resin, modified phenolic resin, or epoxy resin.

[0082] The modified phenolic resin includes at least one of: polyamide-modified phenolic resin, dicyandiamide-modified phenolic resin, epoxy-modified phenolic resin, or polyvinyl acetal-modified phenolic resin. The epoxy resin includes: glycidyl ether epoxy resin. The glycidyl ether epoxy resin includes at least one of: bisphenol A epoxy resin (bisphenol A monoglycidyl ether), bisphenol F epoxy resin (bisphenol F diglycidyl ether), tetrabromobisphenol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol AD diglycidyl ether, aliphatic alcohol polyglycidyl ether, or linear phenolic polyglycidyl ether. Except for these listed support resins, as long as the crosslinked cured product is heat-resistant and does not dissolve or melt in petroleum, the support resin components are within the protection scope of this application.

[0083] The supporting resin undergoes a cross-linking reaction under the action of a curing agent and cures to form a network-structured polymer (cured product), which coats and firmly adheres to the surface of the sand grains. The cured product of the supporting resin is heat-resistant and insoluble and infusible in oily solvents such as petroleum and gasoline. Moreover, it has strong adhesiveness to the sand grains and high consolidation strength, playing a role in protecting the oily sustained-release material and the oily fluorescent microspheres, preventing the oily sustained-release material and the oily fluorescent microspheres from being rapidly dissolved and failing to achieve the sustained-release effect.

[0084] In some embodiments, the oily sustained-release material can be slowly dissolved and released in an oily solvent (such as petroleum).

[0085] Furthermore, the oily sustained-release material includes at least one of petroleum resin and calcium stearate; the petroleum resin includes at least one of C5 petroleum resin and its derivatives, C9 petroleum resin and its derivatives, and calcium stearate.

[0086] In some embodiments, the second solvent is a non-polar solvent and its boiling point is between 40 and 100.

[0087] The second solvent includes at least one of ethyl acetate, chloroform, benzene, carbon disulfide, carbon tetrachloride, triethylamine, n-hexane, cyclohexane, or tetrahydrofuran.

[0088] In some embodiments, to prepare the second mixture, first, the oily fluorescent microspheres, the oily sustained-release material, and the second solvent are mixed evenly, and then the supporting resin is added and mixed evenly.

[0089] Both the oily fluorescent microspheres and the oily sustained-release material are granular. The second solvent can dissolve the oily fluorescent microspheres and the oily sustained-release material. First, dissolve them separately and then mix them, which is convenient for stirring evenly. Finally, the liquid supporting resin is added.

[0090] In some embodiments, the lipophilic sand grains are mixed evenly with a third solvent, then the second mixture is added and mixed, and then the solvent is removed; the third solvent is used to prevent the lipophilic sand grains from caking.

[0091] Furthermore, the second solvent includes at least one of ethanol and ethylene glycol.

[0092] If the third solvent is not mixed with the lipophilic sand grains first and the second mixture is directly added, either it is easy to cake or a large amount of the second solvent needs to be used.

[0093] In some embodiments, in step S2, the oily fluorescent microspheres, the oily sustained-release material, the second solvent, and the support resin are mixed to form a second mixture, which is then added to the lipophilic sand grains and mixed evenly. A curing agent is added for reaction, and the solvent is removed to form a sustained-release layer coating the lipophilic sand grains, thereby obtaining the coated fluorescent microsphere tracer.

[0094] Furthermore, the second mixture and the curing agent are all added to the reaction device at once, forming a single sustained-release layer; or the second mixture and the curing agent are added to the reaction device in multiple times (two or more times), forming multiple sustained-release layers.

[0095] Preferably, the second mixture and the curing agent are added to the reaction device in multiple times to form layer upon layer of sustained-release layers. With this process, the cured product formed by the support resin can better fix and protect the oily fluorescent microspheres and the oily sustained-release material, improving the sustained-release effect.

[0096] Furthermore, if the second mixture and the curing agent are added to the reaction device in multiple times, the amounts of the second mixture and the curing agent added each time and the mass ratios of the components may be the same or different.

[0097] In some embodiments, the curing agent includes at least one of paraformaldehyde, hexamethylenetetramine, aliphatic amines and their modified products, cycloaliphatic amines and their modified products, low molecular weight polyamides, polyetheramines, modified aromatic amines, polythiol type, or polyisocyanate type.

[0098] In some embodiments, in the second mixture, the mass percentage of the oily fluorescent microspheres is 4-9 wt%, such as 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, or 9 wt%, but not limited to the listed values, and other unlisted values within the above range are equally applicable; the mass percentage of the oily sustained-release material is 4-10 wt%, such as 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%, but not limited to the listed values, and other unlisted values within the above range are equally applicable; the mass percentage of the second solvent is 20-40 wt%, such as 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, 31 wt%, 32 wt%, 33 wt%, 34 wt%, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, or 40 wt%, but not limited to the listed values, and other unlisted values within the above range are equally applicable; the mass percentage of the support resin is 55-80 wt%, such as 55 wt%, 56 wt%, 57 wt%, 58 wt%, 59 wt%, 60 wt%, 61 wt%, 62 wt%, 63 wt%, 64 wt%, 65 wt%, 66 wt%, 67 wt%, 68 wt%, 69 wt%, 70 wt%, 71 wt%, 72 wt%, 73 wt%, 74 wt%, 75 wt%, 76 wt%, 77 wt%, 78 wt%, 79 wt%, or 80 wt%, but not limited to the listed values, and other unlisted values within the above range are equally applicable; in step S2, the mass ratio of the added second mixture to the lipophilic sand grains is 1:(25-35), such as 1:25, 1:26, 1:27, 1:28, 1:29, 1:30, 1:31, 1:32, 1:33, 1:34, 1:35, but not limited to the listed values, and other unlisted values within the above range are equally applicable.

[0099] Preferably, in the second mixture, the mass percentage of the oily fluorescent microspheres is 5.5-7 wt%, the mass percentage of the oily sustained-release material is 5.5-7 wt%, the mass percentage of the second solvent is 25-30 wt%, and the mass percentage of the support resin is 60-75 wt%; in step S2, the mass ratio of the added second mixture to the lipophilic sand grains is 1:(27-33).

[0100] In a second aspect of the present application, a coated fluorescent microsphere tracer is provided. The coated fluorescent microsphere tracer includes: sand grains and a slow-release layer coating the sand grains; the surface of the sand grains is modified with a modifier to form lipophilic sand grains; the slow-release layer includes: oil-based fluorescent microspheres, an oil-based slow-release material, and a cross-linked reaction cured product of a supporting resin.

[0101] In some embodiments, the sand grains include at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles. The natural minerals include at least one of vermiculite, perlite, hydromica, natural zeolite, agglomerated stone, or expanded clay.

[0102] In some embodiments, the modifier contains a siloxane group and a lipophilic group, and the siloxane group reacts with the surface of the sand grains under the action of a catalyst and binds to it.

[0103] Furthermore, the modifier includes at least one of γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, 3-(2-aminoethyl)-aminopropyltrimethoxysilane, 3-(2-aminoethyl)-aminopropylmethyldimethoxysilane, vinyltriethoxysilane, or vinyltrimethoxysilane.

[0104] In some embodiments, the oil-based fluorescent microspheres include: a fluorescent material, a shell layer coating the fluorescent material, and an oil-based ligand modified on the surface of the shell layer, and the surface of the shell layer contains polar groups.

[0105] In some embodiments, the oil-based slow-release material can slowly dissolve and release in an oil-based solvent.

[0106] Furthermore, the oil-based slow-release material includes at least one of petroleum resin and calcium stearate; the petroleum resin includes at least one of C5 petroleum resin and its derivatives, C9 petroleum resin and its derivatives, and calcium stearate.

[0107] In some embodiments, the supporting resin includes at least one of phenolic resin, modified phenolic resin, or epoxy resin.

[0108] The present invention will be further described in detail below with reference to specific examples and comparative examples, but the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to different requirements of specific use, and the conditions not specified are the conventional conditions in the industry.

[0109] Example 1:

[0110] Preparation of lipophilic sand grains: Take 250 g of γ-methacryloxypropyltrimethoxysilane (KH570), 15 ml of dibutyltin dilaurate, 10 g of ethanol and 1 kg of paraffin, and mix them evenly (stir at 500 rmp for 20 min at room temperature of 25°C) to form a first mixture; Add 30 kg of ceramsite sand to the reaction kettle, stir at a speed of 30 HZ and heat to 70°C. After the ceramsite sand reaches 70°C, add the first mixture, and after adding, raise the temperature to 100°C and react for 2 h. After cooling, centrifuge to obtain lipophilic sand grains.

[0111] Take 60 g of oil-based fluorescent microspheres (MF microspheres, the fluorescent material is sodium fluorescein, the shell layer is melamine-polyformaldehyde, and the oil-based ligand is polymaleic anhydride-1-octadecene and polyethylene oxide-polypropylene oxide copolymer), add 60 g of calcium stearate and 250 g of ethyl acetate, and mix them evenly (ultrasonic mix at a power of 400 W for 10 min at room temperature of 25°C), then add 600 g of bisphenol A epoxy resin and mix evenly (stir at 500 rmp for 20 min at room temperature of 25°C) to form a second mixture. Mix the obtained lipophilic sand grains with 15 kg of ethanol evenly in the reaction kettle (stir at 30 HZ for 20 min), and raise the temperature in the reaction kettle to 70°C. Immediately after reaching 70°C, add the second mixture to the reaction kettle and mix evenly (stir at 30 HZ for 20 min), then raise the temperature to 80°C to remove the solvent; After all the solvent is removed, cool down to 30°C, add 150 g of polyetheramine curing agent (T403), and then raise the temperature to 60°C to cure for 2 h. After cooling, discharge to obtain a coated fluorescent microsphere tracer.

[0112] Example 2:

[0113] Preparation of lipophilic sand grains: Take 250 g of γ-glycidyletheroxypropyltrimethoxysilane, 14 ml of dioctyltin diacetate, 12 g of ethanol and 1.1 kg of n-hexane, and mix them evenly (stir at 500 rmp for 20 min at room temperature of 25°C) to form a first mixture; Add 30 kg of ceramsite sand to the reaction kettle, stir at a speed of 30 HZ and heat to 70°C. After the ceramsite sand reaches 70°C, add the first mixture, and after adding, raise the temperature to 100°C and react for 2 h. After cooling, centrifuge to obtain lipophilic sand grains.

[0114] Take 60 g of oil-based fluorescent microspheres (silica microspheres, the fluorescent material is CdSe red quantum dots, the shell layer is silica, the oil-based ligand is poly(maleic anhydride octadecene) and hydroxyl-terminated polydimethylsiloxane), add 58 g of C5 petroleum resin and 300 g of ethyl acetate and mix evenly (ultrasonic mixing at 400 W power for 10 min at room temperature of 25 °C), then add 650 g of phenolic resin and mix evenly (stirring at 500 rmp for 20 min at room temperature of 25 °C) to form a second mixture. Mix the obtained lipophilic sand grains evenly with 15 kg of ethanol in a reaction kettle (stirring at 30 HZ for 20 min), and raise the temperature in the reaction kettle to 70 °C. Immediately after reaching 70 °C, put the second mixture into the reaction kettle and mix evenly (stirring at 30 HZ for 20 min), and raise the temperature to 80 °C to remove the solvent; after all the solvent is removed, cool down to 30 °C, add 150 g of modified aliphatic amine curing agent (curing agent 593), and then raise the temperature to 60 °C for curing for 2 h. After cooling, discharge the material to obtain a coated fluorescent microsphere tracer.

[0115] Example 3:

[0116] Prepare lipophilic sand grains: Take 250 g of γ-methacryloxypropyltrimethoxysilane (KH570), 15 ml of dibutyltin dilaurate, 12 g of ethanol and 1 kg of paraffin and mix evenly (stirring at 500 rmp for 20 min at room temperature of 25 °C) to form a first mixture; add 30 kg of quartz sand to a reaction kettle, stir at 30 HZ and heat to 70 °C. After the quartz sand reaches 70 °C, put in the first mixture, and raise the temperature to 100 °C after putting it in and react for 2 h. After cooling, centrifuge to obtain lipophilic sand grains.

[0117] Take 60 g of oil-based fluorescent microspheres (MF microspheres, the fluorescent material is sodium fluorescein, the shell layer is melamine-polyformaldehyde, the oil-based ligand is poly(maleic anhydride-1-octadecene) and polyoxyethylene-polyoxypropylene copolymer), add 62 g of C9 petroleum resin and 250 g of ethyl acetate and mix evenly (ultrasonic mixing at 400 W power for 10 min at room temperature of 25 °C), then add 600 g of bisphenol A epoxy resin and mix evenly (stirring at 500 rmp for 20 min at room temperature of 25 °C) to form a second mixture. Mix the obtained lipophilic sand grains evenly with 16 kg of ethanol in a reaction kettle (stirring at 30 HZ for 20 min), and raise the temperature in the reaction kettle to 70 °C. Immediately after reaching 70 °C, put the second mixture into the reaction kettle and mix evenly (stirring at 30 HZ for 20 min), and raise the temperature to 80 °C to remove the solvent; after all the solvent is removed, cool down to 30 °C, add 150 g of modified aliphatic amine curing agent (curing agent EH-451K), and then raise the temperature to 60 °C for curing for 2 h. After cooling, discharge the material to obtain a coated fluorescent microsphere tracer.

[0118] Example 4:

[0119] Preparation of lipophilic sand grains: Take 250 g of γ-glycidyl ether oxypropyltrimethoxysilane, 14 ml of dioctyltin diacetate, 12 g of ethanol and 1.1 kg of n-hexane and mix them evenly (stir at 500 rmp for 20 min at room temperature of 25 °C) to form a first mixture; Add 30 kg of quartz sand into the reaction kettle, stir at 30 HZ and heat to 70 °C. After the quartz sand reaches 70 °C, add the first mixture, and after adding, raise the temperature to 100 °C and react for 2 h. After cooling, centrifuge to obtain lipophilic sand grains.

[0120] Take 60 g of oil-soluble fluorescent microspheres (silica microspheres, the fluorescent material is rhodamine B, the shell layer is silica, and the oil-soluble ligand is poly(maleic anhydride octadecene) and hydroxyl-terminated polydimethylsiloxane), add 58 g of C5 petroleum resin and 300 g of ethyl acetate and mix them evenly (ultrasonic mixing at 400 W for 10 min at room temperature of 25 °C), then add 650 g of phenolic resin and mix them evenly (stir at 500 rmp for 20 min at room temperature of 25 °C) to form a second mixture. Mix the obtained lipophilic sand grains with 15 kg of ethanol evenly in the reaction kettle (stir at 30 HZ for 20 min), and raise the temperature in the reaction kettle to 70 °C. Immediately after reaching 70 °C, add the second mixture into the reaction kettle and mix evenly (stir at 30 HZ for 20 min), and then raise the temperature to 80 °C to remove the solvent; After all the solvent is removed, cool down to 30 °C, add 150 g of modified aliphatic amine curing agent (curing agent 593), and then raise the temperature to 60 °C and cure for 2 h. After cooling, discharge to obtain the coated fluorescent microsphere tracer.

[0121] Comparative Example 1:

[0122] Take 60 g of oil-soluble fluorescent microspheres (MF microspheres, the fluorescent material is sodium fluorescein, the shell layer is melamine-polyformaldehyde, and the oil-soluble ligand is poly(maleic anhydride-1-octadecene) and poly(ethylene oxide)-poly(propylene oxide) copolymer), add 60 g of calcium stearate and 250 g of ethyl acetate and mix them evenly (ultrasonic mixing at 400 W for 10 min at room temperature of 25 °C), then add 600 g of bisphenol A epoxy resin and mix them evenly (stir at 500 rmp for 20 min at room temperature of 25 °C) to form a premix.

[0123] Mix 30 kg of ceramsite sand with 15 kg of ethanol evenly in the reaction kettle (stir at 30 HZ for 20 min), and raise the temperature in the reaction kettle to 70 °C. Immediately after reaching 70 °C, add the premix into the reaction kettle and mix evenly (stir at 30 HZ for 20 min), and then raise the temperature to 80 °C to remove the solvent; After all the solvent is removed, cool down to 30 °C, add 150 g of polyetheramine curing agent (T403), and then raise the temperature to 60 °C and cure for 2 h. After cooling, discharge to obtain the coated fluorescent microsphere tracer.

[0124] Comparative Example 2:

[0125] Take 60 g of oil-based fluorescent microspheres (silica microspheres, with the fluorescent material being CdSe red quantum dots, the shell being silica, and the oil-based ligands being poly(maleic anhydride octadecene) and hydroxyl-terminated polydimethylsiloxane), add 58 g of C5 petroleum resin and 300 g of ethyl acetate and mix evenly (ultrasonic mixing at 400 W power for 10 min at room temperature of 25°C), then add 650 g of phenolic resin and mix evenly (stirring at 500 rmp for 20 min at room temperature of 25°C) to form a pre-mixture.

[0126] Mix 30 kg of ceramsite sand with 15 kg of ethanol evenly in a reaction kettle (stirring at 30 HZ for 20 min), raise the temperature in the reaction kettle to 70°C, and immediately put the pre-mixture into the reaction kettle and mix evenly (stirring at 30 HZ for 20 min) after reaching 70°C, introduce nitrogen for protection, and raise the temperature to 80°C to remove the solvent; after all the solvent is removed, cool down to 30°C, add 150 g of modified aliphatic amine curing agent (curing agent 593), and then raise the temperature to 60°C for curing for 2 h. After cooling, discharge the material to obtain a coated fluorescent microsphere tracer.

[0127] Comparative Example 3:

[0128] Take 60 g of oil-based fluorescent microspheres (MF microspheres, with the fluorescent material being sodium fluorescein, the shell being melamine-polyformaldehyde, and the oil-based ligands being poly(maleic anhydride-1-octadecene) and poly(oxyethylene)-poly(oxypropylene) copolymer), add 62 g of C9 petroleum resin and 250 g of ethyl acetate and mix evenly (ultrasonic mixing at 400 W power for 10 min at room temperature of 25°C), then add 600 g of bisphenol A epoxy resin and mix evenly (stirring at 500 rmp for 20 min at room temperature of 25°C) to form a pre-mixture.

[0129] Mix 30 kg of quartz sand with 16 kg of ethanol evenly in a reaction kettle (stirring at 30 HZ for 20 min), raise the temperature in the reaction kettle to 70°C, and immediately put the pre-mixture into the reaction kettle and mix evenly (stirring at 30 HZ for 20 min) after reaching 70°C, raise the temperature to 80°C to remove the solvent; after all the solvent is removed, cool down to 30°C, add 150 g of modified aliphatic amine curing agent (curing agent EH-451K), and then raise the temperature to 60°C for curing for 2 h. After cooling, discharge the material to obtain a coated fluorescent microsphere tracer.

[0130] Comparative Example 4:

[0131] Take 60 g of oily fluorescent microspheres (silica microspheres, with rhodamine B as the fluorescent material, silica as the shell layer, and poly (maleic anhydride octadecene) and hydroxyl-terminated polydimethylsiloxane as the oily ligands), add 58 g of C5 petroleum resin and 300 g of ethyl acetate, and mix them evenly (ultrasonic mixing at 400 W for 10 min at room temperature of 25 °C). Then add 650 g of phenolic resin and mix evenly (stirring at 500 rmp for 20 min at room temperature of 25 °C) to form a pre-mixture.

[0132] Mix 30 kg of quartz sand with 15 kg of ethanol evenly in a reaction kettle (stirring at 30 HZ for 20 min), and heat the temperature in the reaction kettle to 70 °C. Immediately after reaching 70 °C, put the pre-mixture into the reaction kettle and mix evenly (stirring at 30 HZ for 20 min), and then heat it to 80 °C to remove the solvent. After all the solvent is removed, cool it to 30 °C, add 150 g of modified aliphatic amine curing agent (curing agent 593), and then heat it to 60 °C for curing for 2 h. After cooling, discharge the material to obtain the coated fluorescent microsphere tracer.

[0133] Take pictures of the coated fluorescent microsphere tracers obtained in Examples 1-4 and Comparative Examples 1-4 respectively using a fluorescence microscope, and obtain microscope Figures 1 - 8 . From Figures 1 - 4 It can be seen that the surface of the coated fluorescent microsphere tracers in Examples 1-4 emits light evenly, indicating that the oily fluorescent microspheres on the surface of the sand grains are distributed evenly, that is, the components of the slow-release layer are distributed evenly; and there is almost no phenomenon that although the oily fluorescent microspheres are coated, they are not fixed on the surface of the sand grains. From Figures 5 - 8 It can be seen that for the coated fluorescent microsphere tracers in Comparative Examples 1-4, the oily fluorescent microspheres on the surface of the sand grains are not distributed evenly, and there is a phenomenon that some oily fluorescent microspheres are coated but not fixed on the surface of the sand grains.

[0134] Although the present application has disclosed multiple aspects and embodiments, other aspects and embodiments will be obvious to those skilled in the art. Without departing from the concept of the present application, several deformations and improvements can be made, and these all belong to the protection scope of the present application. The multiple aspects and embodiments disclosed in the present application are only used for illustration, and they are not intended to limit the present application. The actual protection scope of the present application is subject to the claims.

Claims

1. A preparation method of a coated fluorescent microsphere tracer, characterized in that, The method includes: S1. Modify the fluorescent microspheres into oil-based fluorescent microspheres; modify the surface of the sand grains to be lipophilic: mix a modifier, a catalyst, and a first solvent to form a first mixture, and then add it to the sand grains for reaction, so that the modifier is connected to the surface of the sand grains to obtain lipophilic sand grains; S2. Mix the oil-based fluorescent microspheres, an oil-based sustained-release material, a second solvent, and a support resin to form a second mixture, then add it to the lipophilic sand grains and mix evenly, and add a curing agent for reaction to form a sustained-release layer covering the lipophilic sand grains to obtain a coated fluorescent microsphere tracer.

2. The preparation method of the coated fluorescent microsphere tracer according to claim 1, characterized in that, In step S1, it includes one or more of the following features: ( 1) The sand grains include at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles; (2) The catalyst includes at least one of organotin and its derivatives, inorganic acids, or fatty acids; (3) The first solvent is a non-polar solvent, and the dielectric constant of the first solvent is 1-5; (4) The fluorescent microspheres include a fluorescent material and a shell layer covering the fluorescent material, and the surface of the shell layer contains polar groups; use an oil-based ligand or a linker and an oil-based ligand to modify the surface of the fluorescent material to be lipophilic to obtain oil-based fluorescent microspheres; (5) In the first mixture, the mass ratio of the modifier is 12-28 wt%, the mass ratio of the catalyst is 0.6-3 wt%, the mass ratio of the first solvent is 65-85 wt%, and the mass ratio of the accelerator is 0.3-2 wt%; in step S1, the mass ratio of the added first mixture to the sand grains is 1:(20-30).

3. The preparation method of the coated fluorescent microsphere tracer according to claim 1, wherein, The modifier contains a siloxane group and a lipophilic group, and the siloxane group reacts with the surface of the sand grains under the action of the catalyst and is combined and connected.

4. The preparation method of the coated fluorescent microsphere tracer according to claim 2, characterized in that, The modifier includes at least one of γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-glycidylethoxypropyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, 3-(2-aminoethyl)-aminopropyltrimethoxysilane, 3-(2-aminoethyl)-aminopropylmethyldimethoxysilane, vinyltriethoxysilane, or vinyltrimethoxysilane.

5. The preparation method of the coated fluorescent microsphere tracer according to claim 1, wherein, The first mixture further includes an accelerator, and the accelerator can promote the hydrolysis of the modifier, thereby increasing the reaction rate.

6. The preparation method of the coated fluorescent microsphere tracer according to claim 1, wherein In step S2, it includes one or more of the following features: (1) The support resin includes at least one of phenolic resin, modified phenolic resin, or epoxy resin; (2) The oil-based sustained-release material can slowly dissolve and release in an oil-based solvent; the oil-based sustained-release material includes at least one of petroleum resin and calcium stearate; (3) The second solvent is a non-polar solvent, and its boiling point is between 40 and 100; (4) The curing agent includes at least one of paraformaldehyde, hexamethylenetetramine, aliphatic amines and their modified products, cycloaliphatic amines and their modified products, low molecular weight polyamides, polyetheramines, modified aromatic amines, polythiol type, or polyisocyanate type; (5) In the second mixture, the mass ratio of the oily fluorescent microspheres is 4-9 wt%, the mass ratio of the oily sustained-release material is 4-10 wt%, the mass ratio of the second solvent is 20-40 wt%, and the mass ratio of the support resin is 55-80 wt%; in step S2, the mass ratio of the added second mixture to the lipophilic sand grains is 1:(25-35).

7. The preparation method of the coated fluorescent microsphere tracer according to claim 1, characterized in that, The lipophilic sand grains are mixed evenly with a third solvent, then the second mixture is added and mixed, and then the solvent is removed; the third solvent is used to prevent the lipophilic sand grains from caking.

8. The preparation method of the coated fluorescent microsphere tracer according to claim 1, wherein In step S2, the second mixture and the curing agent are all added to the reaction equipment at one time, namely, a single sustained-release layer is formed; or the second mixture and the curing agent are added to the reaction equipment in multiple times, namely, multiple sustained-release layers are formed.

9. A coated fluorescent microsphere tracer, characterized in that, The coated fluorescent microsphere tracer includes: sand grains and a sustained-release layer coating the sand grains; the surface of the sand grains is modified with a modifier to form lipophilic sand grains; the sustained-release layer includes: a cross-linked reaction cured product of oily fluorescent microspheres, an oily sustained-release material, and a support resin.

10. The coated fluorescent microsphere tracer according to claim 9, wherein Comprising one or more features selected from the group consisting of: (1) The sand grains include at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles; (2) The modifier contains a siloxane group and a lipophilic group, and the siloxane group reacts with the surface of the sand grains under the action of a catalyst to be bonded and connected; (3) The modifier includes at least one of γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-glycidylethoxypropyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, 3-(2-aminoethyl)-aminopropyltrimethoxysilane, 3-(2-aminoethyl)-aminopropylmethyldimethoxysilane, vinyltriethoxysilane, or vinyltrimethoxysilane; [[ID=,8]](4) The oily fluorescent microspheres include: a fluorescent material, a shell layer coating the fluorescent material, and an oily ligand modified on the surface of the shell layer, and the surface of the shell layer contains polar groups. (5) The oily sustained-release material can be slowly dissolved and released in an oily solvent; the oily sustained-release material includes at least one of petroleum resin and calcium stearate.

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