In-situ growth coated catalytic proppant, and preparation method and application thereof

Abstract

The application discloses in-situ growth coated catalytic proppant and a preparation method and application thereof, and the preparation method of the proppant comprises the following steps: dispersing a proppant matrix in a salt solution containing one or more transition metal precursors to form a solid-liquid suspension system; adding a precipitator to the suspension system to induce in-situ heterogeneous nucleation and growth of the metal precursors on the surface of the proppant matrix, thereby forming a precursor-coated proppant with a core-shell structure; and performing high-temperature calcination on the precursor-coated proppant to obtain the in-situ growth coated catalytic proppant. The application utilizes in-situ growth and high-temperature reactivity sintering technology to construct a firm high-entropy ceramic catalytic film on the surface of the proppant, thereby solving the problems that a traditional impregnated proppant coating is easy to fall off and has poor temperature resistance; meanwhile, the high-entropy effect and lattice oxygen vacancies are utilized to achieve a technical breakthrough that the proppant can efficiently catalyze thick oil viscosity reduction without an organic modifier.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development and catalytic materials technology, specifically to an in-situ grown coated catalytic proppant, its preparation method, and its application. Background Technology

[0002] my country possesses abundant heavy oil reserves, but these crude oils generally exhibit high viscosity, high density, low hydrogen-to-carbon ratio, and poor fluidity, leading to significant extraction difficulties and low recovery rates. Currently used conventional thermal recovery technologies, such as steam injection and steam drive, while technologically mature, suffer from low thermal efficiency, high CO2 emissions, and limited recovery rates. Furthermore, novel methods such as microbial viscosity reduction, chemical viscosity reduction, and electric heating also face challenges including high-temperature deactivation, short shelf life, severe equipment corrosion, and high production costs.

[0003] To overcome the limitations of single technologies, in-situ catalytic reforming of heavy oil has emerged. This technology involves injecting a catalyst into the formation, which, under the high temperature and pressure of steam injection, induces a hydrothermal cracking reaction in the heavy oil, converting large-molecule asphaltenes and gums into smaller-molecule saturated hydrocarbons and aromatic hydrocarbons with better flowability, thereby achieving irreversible viscosity reduction and reforming of the heavy oil. However, existing catalysts, such as water-soluble metal salts and oil-soluble organometallic compounds, are easily lost underground and have poor dispersibility, making it difficult to exert a long-term effect in deep oil reservoirs.

[0004] Fracturing technology is a key means to improve the permeability of low-permeability heavy oil reservoirs. Proppants, as the core material in fracturing operations, are used to support fractures and maintain high conductivity. In recent years, the preparation of "functionalized proppants" by loading catalysts onto the surface of proppants has become a research hotspot, aiming to achieve integrated synergistic effects of "fracturing and in-situ catalysis".

[0005] However, existing catalytic proppant technologies are mainly prepared by physical impregnation or low-temperature drying (<350℃). This preparation method results in only physical adsorption or weak chemical bonding between the catalyst layer and the proppant matrix, with low bonding strength. Under pumping and high formation closure pressure, it is very easy to peel off, which not only leads to rapid failure of catalytic function, but may also block pore throat channels. At the same time, simple metal salts or organically modified catalysts have poor thermal stability and are prone to decomposition, sintering or poisoning under high-temperature steam injection environment (>350℃), resulting in decreased activity. In addition, the catalytic active sites of single or bimetallic components are limited and cannot cope with the complex composition structure of heavy oil, ultimately resulting in limited viscosity reduction.

[0006] Therefore, there is an urgent need to develop a new type of functionalized proppant with high bonding strength, resistance to high temperature erosion, and excellent catalytic activity to meet the stringent requirements of heavy oil thermal recovery fracturing operations. Summary of the Invention

[0007] This invention addresses the aforementioned problems by researching and designing an in-situ grown, coated catalytic proppant, its preparation method, and its applications. Utilizing in-situ growth and high-temperature reactive sintering techniques, this invention constructs a robust high-entropy ceramic catalytic film on the proppant surface, solving the problems of easy coating peeling and poor temperature resistance in traditional impregnated proppants. Simultaneously, by leveraging the high-entropy effect and lattice oxygen vacancies, a technological breakthrough is achieved in efficiently catalyzing the reduction of viscosity in heavy oil without the need for organic modifiers. The technical means employed in this invention are as follows:

[0008] A method for preparing an in-situ grown film-coated catalytic proppant includes the following steps: S1: The proppant matrix is ​​dispersed in a salt solution containing one or more transition metal precursors to form a solid-liquid suspension system; S2: Add a precipitant to the solid-liquid suspension system to induce the metal precursor to nucleate and grow in situ on the surface of the proppant matrix, forming a precursor with a core-shell structure that coats the proppant; the precipitant is a direct precipitant or a homogeneous precipitant. When the precipitant is a homogeneous precipitant, it is necessary to decompose the homogeneous precipitant by heating.

[0009] S3: The precursor-coated proppant is calcined at 200℃~1200℃ to decompose the transition metal precursor into oxides, which then react with the proppant matrix surface to form a ceramic bonding layer, thus obtaining an in-situ grown coated catalytic proppant.

[0010] Furthermore, prior to step S1, a surface pretreatment step is included for the proppant matrix, wherein the surface pretreatment includes at least one of acid etching, alkaline etching, or coupling agent modification to increase the surface roughness or the number of active sites of the proppant.

[0011] Further, the transition metal precursor mentioned in step S1 is selected from one or more of the nitrates, chlorides or sulfates of iron, manganese, nickel, cobalt, copper, zinc, zirconium and cerium; the preparation parameters of the salt solution are as follows: based on the mass of the support matrix, the total amount of transition metal precursor added is 0.1~10 mol / kg; based on the total mass of the transition metal precursor, the amount of deionized water added is 1~100 times.

[0012] Further, in step S2, the precipitant is selected from hydroxides, carbonates, bicarbonates, oxalates, sulfides, or urea; the amount of precipitant added is 0.1~10 mol / kg based on the mass of the support matrix; the precipitation reaction temperature is 60~95℃, and the aging time is 2~24 hours.

[0013] Furthermore, the proppant matrix is ​​selected from one or more of natural quartz sand, ceramsite, sintered bauxite, or artificial ceramic particles, and the particle size range of the proppant matrix is ​​75~8000μm.

[0014] Furthermore, a drying step is included before step S3; the drying step adopts high-temperature drying or microwave drying; when high-temperature drying is adopted, the temperature is 90~150℃ and the time is 3~12 hours; when microwave drying is adopted, the power is 500~1500W and the time is 10~20min; in step S3, the atmosphere of high-temperature calcination is air atmosphere, inert atmosphere or reducing atmosphere.

[0015] Furthermore, the reducing atmosphere is one or a mixture of hydrogen, carbon monoxide, and ammonia. When hydrogen, carbon monoxide, or ammonia is introduced as a reducing atmosphere, lattice oxygen vacancy defects are induced on the surface of the ceramic bonding layer.

[0016] Furthermore, in step S3, the high-temperature calcination temperature is preferably 500℃~1000℃, more preferably 800℃~1000℃.

[0017] An in-situ growth coating catalytic proppant is prepared by the method described in this invention.

[0018] The application of the in-situ grown film-coated catalytic proppant of the present invention in heavy oil thermal recovery is characterized in that the proppant is injected into the formation as a fracturing proppant along with fracturing fluid at a water-to-proppant mass ratio of 30:1 to 100:1; during the steam injection thermal recovery stage, a heat source of 180℃ to 350℃ provided by steam injection is used to perform well shut-in treatment, and the well shut-in reaction time is controlled to be 2 to 15 days, preferably 5 to 7 days. During this period, the proppant catalyzes the hydrothermal cracking reaction of underground heavy oil in situ, thereby achieving viscosity reduction and quality improvement of heavy oil.

[0019] Compared with the prior art, the present invention has the following beneficial effects: By employing an "in-situ growth + high-temperature reactive sintering" process, atomic-level diffusion ceramic chemical bonds are formed between the catalytic active layer and the proppant matrix, completely solving the problem of easy coating detachment in traditional physical impregnation methods. This achieves long-term catalysis while maintaining high conductivity. The high-entropy composite oxide system utilizes abundant oxygen vacancies generated by lattice distortion as active centers, achieving efficient viscosity reduction of heavy oil without the need for external organic additives. At the same time, the high-entropy structure endows the material with excellent high-temperature resistance and corrosion resistance, enabling it to adapt to harsh underground environments. Furthermore, the proppant of this invention has dual functions of "fracturing support" and "in-situ modification," and the high-temperature sintering process helps repair microcracks on the proppant surface, further improving the proppant's resistance to breakage and demonstrating significant engineering application value. Detailed Implementation

[0020] This invention provides an in-situ grown high-entropy composite oxide ceramic coating support, its preparation method, and its application. The general preparation steps are as follows: This method abandons traditional physical impregnation or low-temperature drying processes, and innovatively employs "in-situ heterogeneous nucleation" combined with "high-temperature reactive sintering" technology to construct a high-strength ceramic catalytic layer on the support surface. The general preparation steps are as follows: S1: Constructing a multi-component reaction system: One or more transition metal precursors are dissolved in deionized water at a predetermined molar ratio to prepare a mixed metal salt solution. The proppant matrix is ​​then added to this solution and stirred to form a homogeneous solid-liquid suspension. During this stage, metal ions are uniformly adsorbed on the proppant surface, providing sites for subsequent nucleation.

[0021] S2: Heterogeneous nucleation and in-situ growth: A precipitant is added to the suspension system, and the pH and supersaturation of the solution are precisely controlled. Under the induction of the high surface energy of the proppant surface, metal ions preferentially undergo heterogeneous nucleation on the proppant surface and grow in situ a dense and uniform layered bimetallic / multimetallic hydroxide or carbonate precursor layer, forming an intermediate with a core-shell structure.

[0022] S3: High-Temperature Reactive Sintering and Defect Control: The precursor, after solid-liquid separation, washing, and drying, is coated with a support and placed in a high-temperature furnace for reactive sintering at 200℃~1000℃. During this process, the precursor layer decomposes and transforms into a high-entropy spinel-type composite oxide; simultaneously, elemental interdiffusion and solid-phase reactions occur at the interface between the oxide layer and the support matrix, forming a strong ceramic bond. Depending on the needs, the sintering atmosphere can be adjusted, such as introducing a weakly reducing atmosphere to induce oxygen vacancy defects in the crystal lattice.

[0023] In a preferred embodiment of the present invention, the specific parameter adjustments for each step are as follows: Regarding step S1: In one embodiment, the transition metal precursor is preferably one or more of a transition metal nitrate, chloride, or sulfate. To construct a high-entropy structure, it is preferable to use three of ferric nitrate, nickel nitrate, and copper nitrate simultaneously.

[0024] In one embodiment, when preparing the mixed salt solution, the total amount of transition metal precursor added is 0.1~10 mol / kg, preferably 6 mol / kg, based on the mass of the support matrix, to ensure that the coating has sufficient thickness and catalytic capacity.

[0025] In one embodiment, the mass ratio of deionized water added to the total mass of the transition metal precursor in the mixed salt solution is 1:1 to 100:1, preferably 4:1 to 10:1, to ensure that the system viscosity is moderate and conducive to mass transfer.

[0026] In one embodiment, the precipitant precursor may be selected from hydroxides, carbonates, bicarbonates, or homogeneous precipitants such as urea. Urea or sodium carbonate is preferred because it can control the nucleation rate by slowly releasing precipitated ions, resulting in a denser and more uniform coating.

[0027] In one embodiment, the amount of precipitant added is 0.1~10 mol / kg, preferably 2.5~8 mol / kg, based on the mass of the proppant matrix, to ensure complete precipitation of metal ions.

[0028] In one embodiment, the reacted mixture needs to be aged for 2 to 24 hours, preferably 12 to 24 hours. The aging process helps the precursor crystals grow and rearrange their structure, improving the adhesion of the film.

[0029] In one embodiment, the proppant matrix is ​​selected from high-temperature resistant inorganic materials, such as natural quartz sand, river sand, sea sand, ceramsite, or sintered bauxite.

[0030] In one embodiment, the particle size of the proppant ranges from 75 to 8000 μm, preferably from 380 to 830 μm, corresponding to 20 to 40 mesh commonly used in the petroleum industry.

[0031] In one embodiment, the calcination temperature range is 200~1000℃, preferably 800~1000℃. This temperature range is much higher than the drying temperature of the prior art, aiming to achieve ceramic sintering and significantly improve the sealing strength and wear resistance of the coating.

[0032] In one embodiment, an air atmosphere can be used during calcination to obtain a stoichiometric composite oxide; preferably, a weakly reducing atmosphere is used to remove some of the lattice oxygen, creating a high concentration of oxygen vacancy defects in situ on the surface. These oxygen vacancies not only significantly improve the oleophilicity of the material, but also serve as active centers for the hydrothermal pyrolysis of heavy oil, greatly enhancing the viscosity reduction effect.

[0033] This invention also provides a method for applying the in-situ grown coated catalytic proppant in heavy oil thermal recovery, the specific process flow of which is as follows: In one embodiment, the in-situ grown film-coated catalytic proppant prepared above is used as solid proppant particles and mixed with fracturing fluid. During the mixing process, the mass ratio of water to proppant is controlled at 30:1 to 100:1 (preferably 40:1 to 60:1) to form a homogeneous proppant-carrying fluid. The proppant-carrying fluid is pumped into the heavy oil formation using a high-pressure pump set to break up the formation rock and form fractures. After the fracturing fluid breaks down and flows back, the proppant remains in the formation fractures, constructing an "artificial fracture catalytic bed" with high conductivity and rich catalytically active sites. In the subsequent steam injection thermal recovery stage, high-temperature steam is injected into the formation. Using the 180℃ to 350℃ heat source provided by the steam injection, a high-temperature and high-pressure hydrothermal system is formed in the formation environment. At this time, the high-entropy composite oxide ceramic film on the surface of the proppant retained in the fractures begins to exert its catalytic effect. When heavy oil flows over the proppant surface, the lattice oxygen vacancies on the coating surface act as active centers, adsorbing and activating high-temperature water molecules to generate highly active hydrogen species. Simultaneously, high-entropy metal active sites adsorb gum and asphaltenes macromolecules from the heavy oil. Under the synergistic effect of the catalyst, an in-situ hydrothermal pyrolysis reaction occurs, significantly reducing the viscosity of the heavy oil and improving its flowability, ultimately achieving efficient heavy oil extraction and in-situ quality enhancement.

[0034] Example 1 This embodiment provides a pentagonal high-entropy spinel-coated proppant (FeNiCoCuMn) and its application in reducing viscosity of heavy oil.

[0035] Step S1: Weigh out equal molar ratios of ferric nitrate nonahydrate, nickel nitrate hexahydrate, cobalt nitrate hexahydrate, copper nitrate trihydrate, and 50% manganese nitrate solution, mix them, and dissolve them in deionized water to prepare a mixed salt solution with a total metal ion concentration of 1.0 mol / L.

[0036] Step S2: Weigh 20-40 mesh quartz sand proppant and add it to the above mixed salt solution, stirring to form a suspension. Add urea to the suspension as a homogeneous precipitant (the total molar ratio of urea to metal ions is 4:1), heat to 90°C and stir at a constant temperature for 12 hours to allow the metal ions to precipitate uniformly in situ on the surface of the quartz sand, forming a precursor coating.

[0037] Step S3: The precursor coating support after filtration, washing and drying at 120°C is placed in a tube furnace and calcined at 900°C in air atmosphere for 4 hours to obtain a ceramic coating support with a strong surface bond and a high-entropy spinel structure.

[0038] Step S4: Inject the proppant into a high-temperature, high-pressure reactor at a water-to-proppant mass ratio of 50:1. Then, add heavy oil at a proppant mass ratio of 100:1 to conduct a heavy oil viscosity reduction experiment.

[0039] In this embodiment, the viscosity reduction rate of heavy oil reached as high as 96.5%. SARA analysis of the oil sample after the reaction showed that the total content of resinous asphaltenes decreased by 8.5%, while the content of saturated hydrocarbons and aromatic hydrocarbons increased by 5.2%.

[0040] Example 2 Step S1: Weigh out equimolar amounts of ferric nitrate nonahydrate, nickel nitrate hexahydrate, cobalt nitrate hexahydrate, and copper nitrate trihydrate, mix them, and dissolve them in deionized water to prepare a mixed salt solution with a total metal ion concentration of 1.0 mol / L.

[0041] Step S2: Weigh 20-40 mesh quartz sand proppant and add it to the above mixed salt solution, stirring to form a suspension. Add sodium carbonate solution as a precipitant to the suspension (the molar ratio of sodium carbonate solution to metal ions is 4:1), using a parallel-flow dropping method, controlling the pH value at 8.5-9.0, so that the metal ions are uniformly precipitated in situ on the surface of the quartz sand, forming a precursor coating.

[0042] Step S3: The filtered, washed, and dried precursor-coated support agent is placed in a tube furnace and calcined at 700°C in air for 4 hours to obtain a ceramic-coated support agent with a strong surface bond and a high-entropy spinel structure. In this embodiment, the viscosity reduction rate of the heavy oil was 91.2%. Compared with Example 1, the degree of crystallization was slightly lower due to the slightly lower temperature, but it was still significantly better than the catalyst prepared by traditional low temperature methods. The coating's acid corrosion resistance was 98.5%.

[0043] Example 3 Step S1: Weigh out equal molar ratios of ferric nitrate nonahydrate, nickel nitrate hexahydrate, cobalt nitrate hexahydrate, copper nitrate trihydrate, and 50% manganese nitrate solution, mix them, and dissolve them in deionized water to prepare a mixed salt solution with a total metal ion concentration of 1.0 mol / L.

[0044] Step S2: Weigh 20-40 mesh quartz sand proppant and add it to the above mixed salt solution, stirring to form a suspension. Add urea to the suspension as a homogeneous precipitant (the total molar ratio of urea to metal ions is 4:1), heat to 90°C and stir at a constant temperature for 12 hours to allow the metal ions to precipitate uniformly in situ on the surface of the quartz sand, forming a precursor coating.

[0045] Step S3: Calcination is divided into two stages. First, it is calcined in air at 900℃ for 2 hours. Then, it is switched to a weak reducing atmosphere of 95% N2 + 5% H2 and calcined for another hour. Finally, it is cooled with the furnace.

[0046] In this embodiment, the viscosity reduction rate of heavy oil was increased to 98.2%, and the induction period was shortened. Oxygen vacancies significantly enhanced the activation ability of water molecules, generating more active hydrogen species.

[0047] Example 4 Step S1: Weigh out equal molar ratios of ferric nitrate nonahydrate, nickel nitrate hexahydrate, cobalt nitrate hexahydrate, copper nitrate trihydrate, and 50% manganese nitrate solution, mix them, and dissolve them in deionized water to prepare a mixed salt solution with a total metal ion concentration of 1.0 mol / L.

[0048] Step S2: Weigh 20-40 mesh ceramsite support agent and add it to the above mixed salt solution, stirring to form a suspension. Add urea to the suspension as a homogeneous precipitant (the total molar ratio of urea to metal ions is 4:1), heat to 90°C and stir at a constant temperature for 12 hours to allow the metal ions to precipitate uniformly in situ on the surface of the ceramsite, forming a precursor coating.

[0049] Step S3: The precursor coating support after filtration, washing and drying at 120°C is placed in a tube furnace and calcined at 900°C in air atmosphere for 4 hours to obtain a ceramic coating support with a strong surface bond and a high-entropy spinel structure.

[0050] In this embodiment, the viscosity reduction rate is 95.8%. Because the surface roughness of ceramsite is greater than that of quartz sand, and the ceramsite components and coating components undergo a deeper solid-phase reaction at 900℃, the coating adhesion is extremely strong.

[0051] Example 5 Step S1: Weigh out equal molar ratios of ferric nitrate nonahydrate, zinc nitrate hexahydrate, zirconium oxychloride, cerium nitrate hexahydrate, and 50% manganese nitrate solution, mix them, and dissolve them in deionized water to prepare a mixed salt solution with a total metal ion concentration of 0.8 mol / L.

[0052] Step S2: Weigh 20-40 mesh quartz sand proppant and disperse it in the above solution. Use sodium hydroxide solution as a precipitant and slowly add it dropwise to the suspension at 60°C, strictly controlling the dropping rate and stirring, maintaining the pH of the system between 10 and 11, inducing heterogeneous nucleation and growth of metal hydroxides on the quartz sand surface for 4 hours.

[0053] Step S3: Place the filtered, washed and dried material in an air atmosphere at 950℃ for 3 hours.

[0054] Application results: Tests showed that the zirconium / cerium-containing high-entropy coating proppant has excellent high-temperature hydrothermal stability, with a viscosity reduction rate of 94.5% for heavy oil, and no significant attenuation of catalytic activity after continuous aging at 350℃ for 7 days.

[0055] Example 6 Step S1: Weigh out a single nickel nitrate hexahydrate and dissolve it in deionized water to prepare a nickel salt solution with a concentration of 1.5 mol / L.

[0056] Step S2: Add ceramic proppant to form a suspension. Add ammonium bicarbonate as a precipitant (molar ratio of 3:1 to nickel ions) to the system and react at 80°C for 6 hours to form a nickel carbonate precursor coating.

[0057] Step S3: Calcine at 500°C in air for 4 hours to form a nickel oxide coated support.

[0058] Application results: The viscosity reduction rate of heavy oil was 68.2%.

[0059] Example 7 Step S1: Weigh copper sulfate, zinc sulfate and cobalt sulfate in a molar ratio of 1:1:1 and prepare a mixed solution with a total concentration of 1.0 mol / L.

[0060] Step S2: Add quartz sand proppant. Add sodium oxalate solution to the system and stir at 75°C for 5 hours. Oxalate ions have a strong coordination ability with metal ions, forming a dense metal oxalate coprecipitate layer on the proppant surface.

[0061] Step S3: Calcination and decomposition are carried out in an air atmosphere at 400℃. The oxalate ions decompose to produce reducing gases, which helps to form fine metal oxide grains.

[0062] Application results: The viscosity reduction rate of heavy oil is 85.6%. This formula has a low cost, and the introduction of zinc significantly improves the antibacterial and anti-corrosion properties of the coating.

[0063] Example 8 Step S1: Weigh out ferric chloride and nickel chloride in equal molar ratio.

[0064] Step S2: Add a supporting agent. Use sodium sulfide or thioacetamide as a precipitant. If thioacetamide is used, utilize its hydrolysis at 85°C to produce S 2- Homogeneous precipitation is achieved to form a metal sulfide precursor coating.

[0065] Step S3: Here, a special two-step calcination is performed: first, the sulfide morphology is fixed by heat treatment under nitrogen protection at 300℃, and then reactive sintering is carried out in a micro-oxygen environment (or in air) at 800℃, so that the sulfide is transformed in situ into a metal oxide / sulfide oxide composite layer with abundant lattice defects.

[0066] Application results: The viscosity reduction rate of heavy oil was 92.1%. The introduction of the sulfur source created a large number of lattice distortions on the catalyst surface, which had a unique selectivity for the cracking of gums in heavy oil.

[0067] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing an in-situ grown film-coated catalytic proppant, characterized in that, Includes the following steps: S1: The proppant matrix is ​​dispersed in a salt solution containing one or more transition metal precursors to form a solid-liquid suspension system; S2: Add a precipitant to the solid-liquid suspension system to induce the metal precursor to nucleate and grow in situ on the surface of the proppant matrix, forming a precursor with a core-shell structure to coat the proppant. S3: The precursor-coated proppant is calcined at 200℃~1200℃ to decompose the transition metal precursor into oxides, which then react with the proppant matrix surface to form a ceramic bonding layer, thus obtaining an in-situ grown coated catalytic proppant.

2. The method for preparing the in-situ grown film-coated catalytic proppant according to claim 1, characterized in that, Before step S1, the method further includes a surface pretreatment step of the proppant matrix, wherein the surface pretreatment includes at least one of acid etching, alkaline etching, or coupling agent modification.

3. The method for preparing the in-situ grown film-coated catalytic proppant according to claim 1, characterized in that, The transition metal precursor mentioned in step S1 is selected from one or more of the nitrates, chlorides or sulfates of iron, manganese, nickel, cobalt, copper, zinc, zirconium and cerium; the preparation parameters of the salt solution are as follows: based on the mass of the support matrix, the total amount of transition metal precursor added is 0.1~10 mol / kg; based on the total mass of the transition metal precursor, the amount of deionized water added is 1~100 times.

4. The method for preparing the in-situ grown film-coated catalytic proppant according to claim 1, characterized in that, In step S2, the precipitant is selected from hydroxides, carbonates, bicarbonates, oxalates, sulfides, or urea; the amount of precipitant added is 0.1~10 mol / kg based on the mass of the support matrix; the precipitation reaction temperature is 60~95℃, and the aging time is 2~24 hours.

5. The method for preparing the in-situ grown film-coated catalytic proppant according to claim 1, characterized in that, The proppant matrix is ​​selected from one or more of natural quartz sand, ceramsite, sintered bauxite, or artificial ceramic particles, and the particle size range of the proppant matrix is ​​75~8000μm.

6. The method for preparing the in-situ grown film-coated catalytic proppant according to claim 1, characterized in that, The process includes a drying step before step S3; the drying step uses high-temperature drying or microwave drying; when using high-temperature drying, the temperature is 90~150℃ and the time is 3~12 hours; when using microwave drying, the power is 500~1500W and the time is 10~20min; in step S3, the atmosphere for high-temperature calcination is an air atmosphere, an inert atmosphere or a reducing atmosphere.

7. The method for preparing the in-situ grown film-coated catalytic proppant according to claim 1, characterized in that, The reducing atmosphere is one or more of the following: hydrogen, carbon monoxide, and ammonia.

8. The method for preparing the in-situ grown film-coated catalytic proppant according to claim 7, characterized in that, In step S3, the high-temperature calcination temperature is 500℃~1000℃.

9. An in-situ grown film-coated catalytic proppant, characterized in that, It is prepared by the method described in any one of claims 1 to 8.

10. The application of the in-situ grown film-coated catalytic proppant as described in claim 9 in heavy oil thermal recovery, characterized in that, The proppant is injected into the formation as a fracturing proppant along with the fracturing fluid at a water-to-proppant mass ratio of 30:1 to 100:

1. During the steam injection thermal recovery stage, the 180℃ to 350℃ heat source provided by the steam injection is used to perform well shut-in treatment, and the well shut-in reaction time is controlled to be 2 to 15 days. During this period, the proppant catalyzes the hydrothermal cracking reaction of the underground heavy oil in situ, thereby achieving viscosity reduction and quality improvement of the heavy oil.