Water-phase tracer agent and preparation method thereof

Abstract

The invention provides a water-phase tracer and a preparation method thereof, the water-phase tracer comprises sand grains and a slow-release layer coating the sand grains, the slow-release layer comprises fluorescent microspheres, a slow-release material, and a condensate formed by curing a diluent and support resin; the fluorescent microspheres, the sustained-release material and the diluent are hydrophilic, and the support resin comprises at least one of phenolic resin, modified phenolic resin or epoxy resin.

Description

Technical Field

[0001] The present application belongs to the technical field of tracers, and specifically relates to an aqueous phase tracer and a preparation method thereof. Background Art

[0002] Fluorescent microspheres are one or more fluorescent materials coated with a shell layer, and the shell layer mainly plays a protective role for the fluorescent material. Fluorescent materials mainly include: organic fluorescent dyes, quantum dots and metal oxides. These fluorescent materials are easily affected by the environment, such as easy degradation, easy photobleaching, not resistant to high temperature / strong light irradiation, not resistant to water and oxygen, etc. Therefore, most existing technologies use inorganic shells or organic polymer shells to coat fluorescent materials. Fluorescent materials emit fluorescence when excited by light or electricity. With the help of different types of fluorescent components and different fluorescence contents, multiple different luminous bands (colors) can be formed, which has a coding effect. Therefore, they are widely used in biomarkers, disease diagnosis, tracers, solid-phase chips, liquid-phase chips, immunochromatography, Raman scattering and other fields.

[0003] Fluorescent microspheres are used as oil tracers. They typically consist of a core of sand particles, such as quartz sand or ceramsite sand, coated with a sustained-release layer containing the fluorescent microspheres and a sustained-release material. The sustained-release material slowly dissolves in the desired application environment, slowly releasing the encapsulated fluorescent microspheres. Sampling and testing the fluorescent microspheres can reveal the tracer's location and distribution, the transport and flow status of the oil, and the connectivity between wells. Because underground oil is typically a mixture of oil and water, both oil-phase and water-phase tracers are often used. However, the production of existing aqueous tracers requires the use of flammable solvents such as ethanol, posing safety risks. They also release volatile compounds, such as formaldehyde, which are harmful to human health. The synthesis process is also time-consuming. Furthermore, the high temperatures used during synthesis can easily damage the fluorescent microspheres, making them prone to decomposition and instability.

[0004] In view of this, the present application provides an aqueous phase tracer and a preparation method thereof, which does not use solvents and adopts a dry process at room temperature, is safe to produce, and contains no volatiles; the synthesis steps are simple and the production time is short; and room temperature synthesis makes the fluorescent microspheres not easy to decompose and stable. Summary of the Invention

[0005] The purpose of the present application is to provide an aqueous phase tracer and a preparation method thereof, which does not use solvents and adopts a dry process at room temperature, is safe to produce, and contains no volatiles; the synthesis steps are simple and the production time is short; and the room temperature synthesis makes the fluorescent microspheres not easy to decompose and stable.

[0006] In a first aspect of the present application, a water-phase tracer is provided. The water-phase tracer includes: sand grains and a slow-release layer coating the sand grains. The slow-release layer includes: fluorescent microspheres, a slow-release material, and a cured product formed by curing a diluent and a support resin; the fluorescent microspheres, the slow-release material, and the diluent are hydrophilic, and the support resin includes at least one of phenolic resin, modified phenolic resin, or epoxy resin.

[0007] In some embodiments, the sand grains include at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles.

[0008] In some embodiments, 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 resins, and the glycidyl ether epoxy resins include at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, tetrabromobisphenol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol AD diglycidyl ether, aliphatic alcohol polyglycidyl ether, or linear phenolic polyglycidyl ether.

[0009] In some embodiments, when the diluent and the support resin are cured, a cross-linking reaction occurs to form a cured product coating the surface of the sand grains, and the fluorescent microspheres and the slow-release material are distributed between the cured products.

[0010] In some embodiments, the diluent can dissolve the hydrophilic slow-release material and fluorescent microspheres, has epoxy groups, and its viscosity ≤ 120 mPa·s (at 25 °C). Preferably, the viscosity of the diluent ≤ 80 mPa·s (at 25 °C).

[0011] Furthermore, the diluent includes at least one of 1,4-butanediol diglycidyl ether, 2-ethylhexyleneglycol diglycidyl ether, polypropylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, ethylene glycol diglycidyl ether, dimer acid diglycidyl ether, polyglycerol polyglycidyl ether, polyethylene glycol diglycidyl ether, or glycerol triglycidyl ether.

[0012] In some embodiments, the slow-release material can slowly dissolve in a polar solvent (such as water).

[0013] Furthermore, the slow-release material includes at least one of polyvinylpyrrolidone (K13, K30, K60, K90), polyvinyl alcohol, polysorbic acid, or polyoxyethylene polyoxypropylene copolymer.

[0014] In some embodiments, the fluorescent microspheres include a fluorescent material and a shell layer coating the fluorescent material, and the surface of the shell layer contains polar groups.

[0015] 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.

[0016] Further, the polar group is a polar group inherent in the shell or a polar group modified on the surface of the shell. Preferably, the polar group is a polar group inherent in the shell.

[0017] In a second aspect of the present application, a method for preparing an aqueous tracer is provided, and the method includes:

[0018] S1, mixing fluorescent microspheres, a sustained-release material, a diluent, and a support resin uniformly to form a first mixed solution, and then adding the first mixed solution to sand grains and mixing uniformly; the fluorescent microspheres, the sustained-release material, and the diluent are hydrophilic, and the support resin includes at least one of phenolic resin, modified phenolic resin, or epoxy resin;

[0019] S2, mixing the first mixed solution with the sand grains uniformly, adding a curing agent, and reacting to form a sustained-release layer coating the sand grains to obtain an aqueous tracer.

[0020] In some embodiments, in step S1, the sand grains are added to a reaction device, the stirring speed is maintained at 100 - 1000 rpm, the temperature is maintained at 10 - 150 °C, and then the first mixed solution is added.

[0021] In some embodiments, in the first mixed solution, the mass ratio of the support resin is 50 - 70 wt%, the mass ratio of the diluent is 10 - 40 wt%, the mass ratio of the sustained-release material is 2 - 20 wt%, and the mass ratio of the fluorescent microspheres is 1 - 6 wt%; in step S1, the mass ratio of the added first mixed solution to the sand grains is 1:(15 - 32).

[0022] In some embodiments, the fluorescent microspheres, the sustained-release material, and the diluent are first mixed uniformly, and then the support resin is added and mixed uniformly to form a first mixed solution.

[0023] In some embodiments, in step S2, the first mixed solution and the curing agent are all added to the sand grains at one time to form a single-layer sustained-release layer; or the first mixed solution and the curing agent are added to the sand grains in multiple times (two or more times) to form a multi-layer sustained-release layer.

[0024] Further, when the first mixed solution and the curing agent are added to the sand grains in multiple times, the amounts of the first mixed solution and the curing agent added each time and the mass ratios of the components may be the same or different.

[0025] In some embodiments, the curing agent includes at least one of aliphatic amines and their modified products, cycloaliphatic amines and their modified products, low molecular weight polyamides, modified aromatic amines, polythiol type, or polyisocyanate type.

[0026] In some embodiments, the mass ratio of the first mixture to the curing agent added is (1 - 8):1.

[0027] In some embodiments, the sustained-release layer includes: fluorescent microspheres, a sustained-release material, and a cured product formed by curing a diluent and a support resin, and the fluorescent microspheres and the sustained-release material are distributed between the cured products.

[0028] The aqueous phase tracer and its preparation method of the present application have at least the following advantages compared with the prior art:

[0029] (1) The present application uses a diluent to replace the traditional solvent. This diluent can dissolve hydrophilic fluorescent microspheres and sustained-release materials, and has fluid-like fluidity and low viscosity. Since it also has epoxy groups, it cures (crosslinking reaction) with the support resin under the action of the curing agent, and its cured product firmly coats the surface of the sand grains. Therefore, since solvents such as ethanol are not used, the production safety cost is low; there is no need for a step of removing the solvent at high temperature, so there are no volatiles generated by high temperature, the synthesis steps are simple, the synthesis time is short, and the stability of the fluorescent microspheres is not affected by high temperature, and the sustained-release effect is better.

[0030] (2) Both the fluorescent microspheres and the sustained-release material in the present application are granular. The diluent can dissolve the fluorescent microspheres and the sustained-release material. First, the two are dissolved separately and then mixed, which is convenient for uniform stirring. Finally, the liquid support resin is added. The liquid support resin is insoluble in the diluent. This addition sequence is conducive to the uniform dispersion of the fluorescent microspheres in the sustained-release material.

[0031] (3) If the first mixture and the curing agent are added to the sand grains in multiple times in the present application, a multi-layer sustained-release layer can be formed. In the sustained-release layer, the cured product formed by the diluent and the support resin is high-temperature resistant and insoluble in polar and non-polar solvents, playing a role of a support framework. The sustained-release material and the fluorescent microspheres are dispersed between the cured products and will gradually be released into the polar solvent to form a multi-layer sustained-release layer, which can strengthen the protection of the cured product on the sustained-release material and the fluorescent microspheres, thereby increasing the sustained-release effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Combined with the following attached Figure 1 When reading together, the above and other features of the content of the present application will be more fully described. It can be understood that these drawings only depict several embodiments of the content of the present application, and therefore should not be considered as limiting the scope of the content of the present application. By using the drawings, the content of the present application will be more clearly and detailedly described.

[0033] Figure 1 Microscopic image of the aqueous phase tracer in Example 1 of this application.

[0034] Figure 2 Microscopic image of the aqueous phase tracer in Example 2 of this application.

[0035] Figure 3 Microscopic image of the aqueous phase tracer in Example 3 of this application.

[0036] Figure 4 Microscopic image of the aqueous phase tracer in Example 4 of this application.

[0037] Figure 5 Microscopic image of the aqueous phase tracer in Comparative Example 1 of this application.

[0038] Figure 6 Microscopic image of the aqueous phase tracer in Comparative Example 2 of this application. Detailed implementation manners

[0039] The following examples are described to assist in understanding this application, and the examples are not and should not be construed in any way as limiting the scope of protection of this application.

[0040] If not otherwise defined, all terms (including technical and scientific terms) in this specification can be defined as commonly understood by those skilled in the art to which this disclosure pertains. 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.

[0041] As used herein, the term "at least one", when preceding or following a list of elements, modifies the entire list of elements rather than individual elements of the list and will not be construed as limiting "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 language 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 intervening elements. In contrast, when an element is referred to as "directly on" another element, there are no intervening elements. 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 elements, components, regions, layers, and / or parts, but these elements, components, regions, layers, and / or parts should not be limited by these terms.

[0042] In a first aspect of the present application, there is provided an aqueous tracer, the aqueous tracer comprising: sand grains and a slow-release layer coating the sand grains, the slow-release layer comprising: fluorescent microspheres, a slow-release material, and a solidified product formed by curing a diluent and a support resin; the fluorescent microspheres, the slow-release material, and the diluent are hydrophilic, and the support resin comprises at least one of phenolic resin, modified phenolic resin, or epoxy resin.

[0043] In some embodiments, the sand grains comprise at least one of quartz sand, ceramsite sand, silica sand, zircon sand, or natural mineral particles. The natural minerals comprise at least one of vermiculite, perlite, hydromica, natural zeolite, agglomerated stone, or expanded clay.

[0044] In some embodiments, the modified phenolic resin comprises 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 comprises glycidyl ether epoxy resins, and the glycidyl ether epoxy resins comprise at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, tetrabromobisphenol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol AD diglycidyl ether, aliphatic alcohol polyglycidyl ether, or linear phenolic polyglycidyl ether.

[0045] In some embodiments, when the diluent and the support resin are cured, a cross-linking reaction occurs to form a cured product coating the surface of the sand grains, and the fluorescent microspheres and the sustained-release material are distributed between the cured products.

[0046] In some embodiments, the diluent can dissolve the hydrophilic sustained-release material and the fluorescent microspheres, has an epoxy group, and its viscosity ≤ 120 mPa·s (at 25 °C). Preferably, the viscosity of the diluent ≤ 80 mPa·s (at 25 °C).

[0047] Further, the diluent includes at least one of: 1,4-butanediol diglycidyl ether, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol diglycidyl ether, polypropylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, ethylene glycol diglycidyl ether, dimer acid diglycidyl ether, polyglycerol glycidyl ether, polyethylene glycol diglycidyl ether, or glycerol triglycidyl ether.

[0048] In some embodiments, the sustained-release material can slowly dissolve in a polar solvent (such as water).

[0049] Further, the sustained-release material includes at least one of: polyvinylpyrrolidone (K13, K30, K60, K90), polyvinyl alcohol, polysorbic acid, or a polyoxyethylene-polyoxypropylene copolymer.

[0050] In some embodiments, the fluorescent microspheres include: a fluorescent material, a shell layer coating the fluorescent material, and the surface of the shell layer contains polar groups.

[0051] 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.

[0052] 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, and A3B3X9, wherein A is a monovalent amine organic cation or a monovalent inorganic metal cation (such as CH3NH3. + 、NH2CHNH2+、C(NH2)3 + 、Cs + 、Li + 、Na + , K + , Rb + , aromatic groups, 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 are carbonized under high temperature conditions such as microwave ovens or heating to form carbon quantum dots with a particle size of about 10 nm. Most carbon quantum dots are mainly composed of amorphous carbon to crystallized carbon cores with a sp 2 Hybridized carbon. These components are usually the core components of quantum dots, and quantum dots usually also include one or more shells that wrap around the core (the outer shell is usually ZnS). In addition to the quantum dots listed above, other common quantum dots are also applicable to this application and are within the scope of protection of this application. The metal oxides of the 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 a monomer that can undergo polymerization reaction. The monomers are polymerized with each other or with other monomers that do not contain fluorescence, thereby preparing a fluorescent polymer. Organic fluorescent dyes include: fluoresceins (stilbenes, coumarins, fluorans, benzoxazoles, naphthalene dicarboximides, thiophene dicarboxamides, condensed aromatic hydrocarbons, perylene tetracarboximide, etc.), aromatic condensed ring compounds, intramolecular charge transfer compounds, metal complex fluorescent materials, enzymes, and rare earth metal chelates.

[0053] Furthermore, the polar groups are polar groups inherent in the shell layer, or polar groups modified on the surface of the shell layer. Preferably, the polar groups are polar groups inherent in the shell layer.

[0054] When the polar group is a polar group inherent in the shell, the shell includes: a silica shell, a titanium dioxide shell, a zirconium dioxide shell, a urea-formaldehyde / paraformaldehyde shell, a melamine-formaldehyde / paraformaldehyde shell, a urea-melamine-formaldehyde / paraformaldehyde, and an acrylic polymer shell.

[0055] Further, the fluorescent microspheres further comprise a magnetic material, and the shell layer coats the fluorescent material and the magnetic material. The magnetic substances include one or more of: magnetite, iron oxide, nickel oxide, cobalt oxide, magnetite, iron oleate, ferric chloride, ferric sulfate, ferric nitrate, ferrous chloride tetrahydrate, ferric chloride hexahydrate, nickel ferrite, aluminum ferrite, manganese ferrite, zinc ferrite, cobalt ferrite, CoFe2O4, NiFe2O4, or MnFe2O4.

[0056] In a second aspect of the present application, a method for preparing an aqueous tracer is provided, the method comprising:

[0057] S1, uniformly mixing fluorescent microspheres, a sustained-release material, a diluent, and a support resin to form a first mixed solution, and then adding the first mixed solution to sand grains and mixing uniformly; the fluorescent microspheres, the sustained-release material, and the diluent are hydrophilic, and the support resin includes at least one of: phenolic resin, modified phenolic resin, or epoxy resin;

[0058] S2, uniformly mixing the first mixed solution with the sand grains, adding a curing agent, and reacting to form a sustained-release layer coating the sand grains to obtain an aqueous tracer.

[0059] In some embodiments, in step S1, the sand grains are added to a reaction device, the stirring speed is maintained at 100 - 1000 rpm, the temperature is maintained at 10 - 150 °C, and then the first mixed solution is added.

[0060] Preferably, the stirring speed of the sand grains in the reaction device is 200 - 700 rpm, and the first temperature is 10 - 80 °C. More preferably, the first temperature is 10 - 40 °C.

[0061] In some embodiments, in the first mixed solution, the mass ratio of the support resin is 50 - 70 wt%, the mass ratio of the diluent is 10 - 40 wt%, the mass ratio of the sustained-release material is 2 - 20 wt%, and the mass ratio of the fluorescent microspheres is 1 - 6 wt%; in step S1, the mass ratio of the added first mixed solution to the sand grains is 1:(15 - 32).

[0062] Preferably, in the first mixed solution, the mass ratio of the support resin is 55 - 65 wt%, the mass ratio of the diluent is 20 - 30 wt%, the mass ratio of the sustained-release material is 5 - 15 wt%, and the mass ratio of the fluorescent microspheres is 1.5 - 3.5 wt%; in step S1, the mass ratio of the added first mixed solution to the sand grains is 1:(20 - 28).

[0063] This application uses a diluent to replace traditional solvents. This diluent can dissolve hydrophilic fluorescent microspheres and sustained-release materials, and has fluid-like fluidity and low viscosity. Since it also has epoxy groups, it cures (crosslinks) with the support resin under the action of a curing agent, and its cured product firmly coats the surface of the sand grains. Therefore, since solvents such as ethanol are not used, the production safety cost is low; there is no need for a step of removing solvents at high temperature, so there are no volatiles generated by high temperature, the synthesis steps are simple, the synthesis time is short, and the stability of the fluorescent microspheres is not affected by high temperature, and the sustained-release effect is better.

[0064] In some embodiments, the fluorescent microspheres, the sustained-release materials and the diluent are first mixed evenly, and then the support resin is added and mixed evenly to form a first mixed solution.

[0065] Both the fluorescent microspheres and the sustained-release materials are granular. The diluent can dissolve the fluorescent microspheres and the sustained-release materials. First, the two are dissolved separately and then mixed, which is convenient for stirring evenly. Finally, the liquid support resin is added. The liquid support resin is insoluble in the diluent. This addition sequence is conducive to the uniform dispersion of the fluorescent microspheres in the sustained-release materials.

[0066] In some embodiments, in step S2, the first mixed solution and the curing agent are all added to the sand grains at one time, that is, a layer of sustained-release layer is formed; or the first mixed solution and the curing agent are added to the sand grains in multiple times (two or more times), that is, multiple layers of sustained-release layers are formed.

[0067] Preferably, the first mixed solution and the curing agent are added to the sand grains in multiple times.

[0068] If the first mixed solution and the curing agent are added to the sand grains in multiple times, multiple layers of sustained-release layers can be formed. In the sustained-release layer, the cured product formed by the diluent and the support resin is high-temperature resistant and insoluble in polar and non-polar solvents, playing a role of a support framework. The sustained-release materials and the fluorescent microspheres are dispersed between the cured products and will gradually release into the polar solvent, forming multiple layers of sustained-release layers, which can strengthen the protection of the cured products on the sustained-release materials and the fluorescent microspheres, thereby increasing the sustained-release effect.

[0069] Furthermore, when the first mixed solution and the curing agent are added to the sand grains in multiple times, the amounts of the first mixed solution and the curing agent added each time and the mass ratios of the components are the same or different.

[0070] In some embodiments, the curing agent includes at least one of aliphatic amines and their modified products, cycloaliphatic amines and their modified products, low molecular weight polyamides, modified aromatic amines, polythiol type, or polyisocyanate type.

[0071] In some embodiments, the mass ratio of the added first mixed solution to the curing agent is (1-8):1.

[0072] Preferably, the mass ratio of the first mixture to the curing agent added is (2-6):1.

[0073] In some embodiments, the sustained-release layer includes: fluorescent microspheres, a sustained-release material, and a solidified product formed by curing a diluent and a support resin, and the fluorescent microspheres and the sustained-release material are distributed between the solidified products.

[0074] 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 conventional conditions in the industry.

[0075] Example 1:

[0076] Take 50 g of fluorescent microspheres (the fluorescent material is coumarin and the shell layer is melamine-polyformaldehyde), and sequentially add 550 g of ethylene glycol diglycidyl ether and 230 g of polyvinylpyrrolidone (PVP-K30). Stir at 25 °C and 500 rmp for 15 min; then add 1250 g of bisphenol A epoxy resin and continue to stir for 20 min under the same conditions to obtain a first mixture.

[0077] Add 50 kg of quartz sand to a 50 L reaction kettle, stir at 25 °C and maintain a rotation speed of 400 rmp; add the first mixture to the reaction kettle and stir for dispersion for 15 min; then add 500 g of modified aliphatic amine (curing agent 593), react and cure for 1 h; discharge to obtain an aqueous phase tracer.

[0078] Example 2:

[0079] Take 50 g of fluorescent microspheres (the fluorescent material is coumarin and the shell layer is silica), and sequentially add 500 g of 1,4-butanediol diglycidyl ether and 225 g of polyvinyl alcohol. Stir at 25 °C and 500 rmp for 15 min; then add 1300 g of phenolic resin and continue to stir for 20 min under the same conditions to obtain a first mixture.

[0080] Add 50 kg of quartz sand to a 50 L reaction kettle, stir at 25 °C and maintain a rotation speed of 400 rmp; add the first mixture to the reaction kettle and stir for dispersion for 15 min; then add 510 g of modified aliphatic amine (curing agent EH-451K), react and cure for 1 h; discharge to obtain an aqueous phase tracer.

[0081] Example 3:

[0082] Take 50 g of fluorescent microspheres (the fluorescent material is sodium fluorescein and the shell layer is urea - paraformaldehyde), and successively add 560 g of dipropylene glycol diglycidyl ether and 220 g of polyvinylpyrrolidone (PVP - K60). Stir at 25 °C at a rotation speed of 500 rmp for 15 min; then add 1200 g of epoxy - modified phenolic resin and continue to stir for 20 min under the same conditions to obtain the first mixed solution.

[0083] Add 50 kg of quartz sand to a 50 L reaction kettle, and stir at 25 °C at a rotation speed of 400 rmp; add the first mixed solution to the reaction kettle and stir for dispersion for 15 min; then add 510 g of modified aliphatic amine (curing agent EH - 485), react and cure for 1 h; discharge to obtain the aqueous phase tracer.

[0084] Example 4:

[0085] Take 50 g of fluorescent microspheres (the fluorescent material is sodium fluorescein and the shell layer is titanium dioxide), and successively add 550 g of glycerol triglycidyl ether and 215 g of polyoxyethylene polyoxypropylene copolymer. Stir at 25 °C at a rotation speed of 500 rmp for 15 min; then add 1250 g of bisphenol AD diglycidyl ether and continue to stir for 20 min under the same conditions to obtain the first mixed solution.

[0086] Add 50 kg of ceramsite sand to a 50 L reaction kettle, and stir at 25 °C at a rotation speed of 400 rmp; add the first mixed solution to the reaction kettle and stir for dispersion for 15 min; then add 510 g of modified aliphatic amine (curing agent EH - 3895L), react and cure for 1 h; discharge to obtain the aqueous phase tracer.

[0087] Comparative Example 1:

[0088] Take 50 g of fluorescent microspheres (the fluorescent material is coumarin and the shell layer is melamine - paraformaldehyde), add 230 g of polyvinylpyrrolidone (PVP - K30) and 650 g of ethyl acetate and mix evenly (stir at 25 °C at a rotation speed of 500 rmp for 15 min); then add 1250 g of bisphenol A epoxy resin and continue to stir for 20 min under the same conditions to obtain the first mixed solution.

[0089] Mix 50 kg of quartz sand and 27 kg of ethanol evenly in a 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, put the first mixture into the reaction kettle and mix evenly (stir at 30 HZ for 20 min), and raise the temperature to 80 °C to remove the solvent; after all the solvent is removed, add 500 g of polyetheramine curing agent (curing agent T403) and react for 2 h. After cooling, discharge to obtain the aqueous phase tracer.

[0090] Comparative Example 2:

[0091] Take 50 g of fluorescent microspheres (the fluorescent material is sodium fluorescein and the shell layer is titanium dioxide), add 215 g of polyoxyethylene polyoxypropylene copolymer and 600 g of ethyl acetate and mix evenly (stir at 500 rmp for 15 min at room temperature of 25 °C); then add 1250 g of bisphenol AD diglycidyl ether and continue stirring for 20 min under the same conditions to obtain a first mixed solution.

[0092] Mix 50 kg of ceramsite sand and 26 kg of ethanol evenly in a 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, put the first 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, add 510 g of polyetheramine curing agent (curing agent T403) and react for 2 h. After cooling, discharge the material to obtain an aqueous phase tracer.

[0093] In Comparative Examples 1-2, ethanol and ethyl acetate were used as solvents. Ethanol was used to prevent quartz sand and ceramsite sand from caking, and ethyl acetate was used to dissolve fluorescent microspheres and sustained-release materials, and then the solvent was evaporated by heating. Among them, ethanol, as a flammable component, is unsafe in production, has high regulatory requirements for the production plant area, and has high production costs; while the technical solution of the present application does not require the use of solvents. During the high-temperature synthesis process, shell layers such as MF (melamine-polyformaldehyde) will also release formaldehyde volatiles, which is not environmentally friendly and harmful to the health of researchers / workers; while the technical solution of the present application can adopt room-temperature synthesis. High-temperature synthesis requires heating time and longer cooling time. Compared with the technical solution of the present application, the synthesis time will be much longer.

[0094] Take pictures of the aqueous phase tracers obtained in Examples 1-4 and Comparative Examples 1-2 respectively using a fluorescence microscope to obtain microscope Figures 1-6 . Take 25 g of the aqueous phase tracers of Examples 1-4 and Comparative Examples 1-2 respectively and put them into bags woven from dust-free cloth. Fix the bags in the middle of a straight condenser respectively, and then put them into a water bath and turn on a peristaltic pump (pump speed is 10 rmp). The temperature in the water bath is 85 °C. Start timing, and take 20 ml of samples from the outlet of the straight condenser at the 1st h, 2nd h, 3rd h, 5th h, and 7th h respectively. Concentrate 20 ml of each sample by centrifuging at 8000 rmp for 5 min, ultrasonicate for 20 min, take 2 μl and drop it onto a glass slide, and after natural drying (to prevent the diffusion of fluorescent microspheres), count the number of fluorescent microspheres under a fluorescence microscope observation. Count twice and take the average value. The counting results are shown in Table 1.

[0095] Table 1: Sustained-release data of the aqueous phase tracers of Examples 1-4 and Comparative Examples 1-2.

[0096]

[0097] As can be seen from Table 1, the slow-release effect of the aqueous phase tracers in Examples 1-4 is relatively gentle. The released fluorescent microspheres gradually decrease and tend to be stable, without being released into the water in large quantities in a short time, and can be used for oil monitoring for a long time. For Comparative Examples 1-2, a large number of fluorescent microspheres are released in the first 2 hours, and very few released fluorescent microspheres are detected at the subsequent 5th hour and 7th hour, and the service life is significantly shorter.

[0098] 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 modifications and improvements can still be made, and these all fall within the protection scope of the present application. The multiple aspects and embodiments disclosed in the present application are only used for illustrative purposes, 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. An aqueous tracer, characterized in that, The aqueous tracer includes: sand grains and a slow-release layer coating the sand grains, and the slow-release layer includes: fluorescent microspheres, a slow-release material, and a cured product formed by curing a diluent and a support resin; the fluorescent microspheres, the slow-release material, and the diluent are hydrophilic, and the support resin includes at least one of phenolic resin, modified phenolic resin, or epoxy resin.

2. The aqueous tracer according to claim 1, 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 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, and the glycidyl ether epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, tetrabromobisphenol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol AD diglycidyl ether, aliphatic alcohol polyglycidyl ether, or linear phenolic polyglycidyl ether; (3) When the diluent and the support resin are cured, a cross-linking reaction occurs to form a cured product coating the surface of the sand grains, and the fluorescent microspheres and the slow-release material are distributed between the cured products; (4) The slow-release material can be slowly dissolved in a polar solvent; (5) The fluorescent microspheres include: a fluorescent material and a shell layer coating the fluorescent material, and the surface of the shell layer contains polar groups.

3. The aqueous tracer according to claim 1, wherein The diluent can dissolve the hydrophilic slow-release material and fluorescent microspheres, has epoxy groups, and has a viscosity ≤ 120 mPa·s.

4. The aqueous tracer according to claim 3, wherein The diluent includes at least one of 1,4-butanediol diglycidyl ether, 2-ethylhexyl diglycidyl ether, polypropylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, ethylene glycol diglycidyl ether, dimer acid diglycidyl ether, polyglycerol diglycidyl ether, polyethylene glycol diglycidyl ether, or glycerol triglycidyl ether.

5. A preparation method of an aqueous tracer, characterized in that, The method includes: S1, mixing the fluorescent microspheres, the slow-release material, the diluent, and the support resin evenly to form a first mixed solution, and then adding it to the sand grains and mixing evenly; the fluorescent microspheres, the slow-release material, and the diluent are hydrophilic, and the support resin includes at least one of phenolic resin, modified phenolic resin, or epoxy resin; S2, mixing the first mixed solution and the sand grains evenly, adding a curing agent, and reacting to form a slow-release layer coating the sand grains to obtain an aqueous tracer.

6. The preparation method of the aqueous tracer according to claim 5, characterized in that, In the first mixed solution, the mass ratio of the support resin is 50-70 wt%, the mass ratio of the diluent is 10-40 wt%, the mass ratio of the slow-release material is 2-20 wt%, and the mass ratio of the fluorescent microspheres is 1-6 wt%; in step S1, the mass ratio of the added first mixed solution to the sand grains is 1:(15-32).

7. The preparation method of the aqueous tracer according to claim 5, characterized in that, First, mix the fluorescent microspheres, the slow-release material, and the diluent evenly, and then add the support resin and mix evenly to form a first mixed solution.

8. The preparation method of the aqueous tracer according to claim 5, characterized in that, In step S2, the first mixture and the curing agent are all added to the sand grains at one time to form a slow-release layer; or the first mixture and the curing agent are added to the sand grains in multiple times to form multiple slow-release layers.

9. The preparation method of the aqueous tracer according to claim 5, characterized in that, The mass ratio of the added first mixture to the curing agent is (1-8):1; the curing agent includes at least one of aliphatic amines and their modified products, alicyclic amines and their modified products, low molecular weight polyamides, modified aromatic amines, polythiol type, or polyisocyanate type.

10. The preparation method of the aqueous phase tracer according to claim 5, characterized in that, The slow-release layer includes: fluorescent microspheres, a slow-release material, and a cured product formed by curing a diluent and a support resin, and the fluorescent microspheres and the slow-release material are distributed between the cured products.

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