Nanosized acoustic contrast material and its preparation method and application

Abstract

This invention provides a nanoscale acoustic imaging material, its preparation method, and its application. The nanoscale acoustic imaging material is a composite mesh material comprising a metal MOF material, an elastic polymer, and metal particles. This invention addresses the problems of uncertain oil displacement area and efficiency in current secondary and tertiary oil recovery processes. The prepared nanoscale imaging material mixture system is stable, and the acoustic imaging frequency band and effect can be adjusted by adjusting the material ratio, thereby enabling imaging of underground interconnected spaces.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development, and more specifically, to a novel nanoscale acoustic imaging material, its preparation method, and its application. Background Technology

[0002] Currently, most oil and gas fields in China are in the secondary oil recovery stage (water injection) or the tertiary oil recovery stage (polymer injection). Due to the complex and highly heterogeneous and anisotropic reservoir space, it is difficult to determine the reservoir displacement zone, displacement efficiency, and remaining oil location between the injection well and the production well. Commonly used methods for monitoring the injection-production relationship between wells include inter-well tracer monitoring and inter-well testing. However, these methods can only determine the relationship between two wells and cannot obtain the flow path of the fluid in the injection well, thus failing to accurately assess the oil displacement effect of the water injection well and making it difficult to formulate further production enhancement measures.

[0003] For fracture-vuggy reservoirs, the distribution characteristics of fractures and vulnerabilities are characterized by strong heterogeneity, large differences in connectivity, and wide distribution. Electroimaging, dipole acoustic wave analysis, and azimuth lateral resistivity combined are currently the main evaluation methods. However, the detection range around the well is small, generally within a few meters, making it difficult to detect, identify, and evaluate fractures and vulnerabilities far from the wellbore. Therefore, determining the location and connectivity of fractures and vulnerabilities in fracture-vuggy reservoirs is currently quite difficult.

[0004] The previously proposed acoustic imaging composite materials are in the millimeter and micrometer scale. The composite material particles are large and solid, which cannot be used to monitor fluid transport in the micrometer and nanometer pores of underground reservoirs.

[0005] CN107740690A discloses an inter-well monitoring method using solid tracers, which relates to an inter-well monitoring method using solid tracers. This inter-well monitoring method includes: 1) selecting water-insoluble fluorescent solid particles as solid tracers; 2) mixing the solid tracer with water to prepare a tracer mixture; 3) injecting the tracer mixture into an injection well, and then taking samples from a monitoring well to detect the tracer production. The inter-well monitoring method using solid tracers provided by this invention uses water-insoluble solid particles as tracers, enabling microscopic visual differentiation, making analysis and testing more precise. It transforms tracer monitoring from data-driven to visual, enhancing the reliability of tracer technology and overcoming the bottleneck of tracer monitoring's inability to definitively determine the presence of fractures in oil reservoirs.

[0006] CN112324422A discloses a method, system, and pore structure characterization method for identifying fractures and cavities in electro-imaging logging, belonging to the field of petroleum logging technology. For the measurement signal from a one-dimensional button electrode plate, a one-dimensional adaptive morphological algorithm is employed to suppress noise and remove interference information from low-frequency components of the formation matrix, such as clay streaks and stratigraphy, thereby enhancing the information on fractures and cavities in the electro-imaging image. Singular spectrum analysis interpolation is applied to fill blank bands in the electro-imaging image. Furthermore, for two-dimensional electro-imaging images, an automatic identification and extraction method for fractures and dissolution cavities is established. This invention solves the problems of difficulty in removing stratigraphy and clay streaks and ineffective noise reduction in existing technologies. Moreover, the singular spectrum analysis interpolation method used in this invention also considers the inherent correlation between conductivity data related to formation lithology and structural changes, thus significantly improving the accuracy of automatic fracture and cavity identification.

[0007] CN113378877A discloses a method, apparatus, medium, and electronic device for multi-information fusion characterization of seismic data. The method includes: extracting at least two types of seismic attribute data from seismic profile data to obtain fault information at at least two scales; performing fracture network standardization on the at least two scales of fault information to obtain spatial fracture network information; performing impedance inversion on the seismic profile data to obtain karst reservoir information; performing fracture-cavity standardization on the spatial fracture network information and the karst reservoir information, and fusing the standardized spatial fracture network information and the standardized karst reservoir information to obtain a spatial multi-information fusion result. Implementing this method allows for the fusion of multi-information from faults, fractures, and reservoir fractures of different grades, thereby forming an integrated model to effectively characterize the spatial distribution characteristics of fracture-cavity reservoirs. Summary of the Invention

[0008] To address the problems of uncertain oil displacement area and efficiency in current secondary and tertiary oil recovery processes, this invention proposes a novel nanoscale acoustic imaging material, its preparation method, and its application, which can achieve imaging of underground interconnected spaces.

[0009] One objective of this invention is to provide a nanoscale acoustic imaging material, which is a composite mesh material comprising metal MOF material, elastic polymer, and metal particles.

[0010] The nanoscale acoustic imaging material has a composite network structure, with Figure 1 Taking a nanoscale acoustic imaging material as an example, metal particles such as nano-iron powder act as a hard, high-density core; an elastic polymer encapsulates the nano-iron powder, which enhances the suspension of the nano-iron powder particles, while its cross-linked structure provides elasticity; MOF-Fe acts as a network elastic framework. The overall structure of the imaging material conforms to the basic structure of acoustic metamaterials, but its smaller size allows it to penetrate smaller geological spaces.

[0011] The size of the nanoscale acoustic imaging material is 100–500 nm, preferably 200–400 nm.

[0012] The elastic polymer is an acrylamide-p-isopropylstyrene-tetravinylsulfonate copolymer.

[0013] Preferably, in the elastic polymer, the mass ratio of acrylamide structural unit, p-isopropylstyrene structural unit and sodium tetravinylsulfonate structural unit is 1:(2-4):(4-8).

[0014] The elastic polymer can be commercially available or prepared using methods commonly used in the art.

[0015] The particle size of the metal particles is 5–20 nm, preferably 8–15 nm.

[0016] The metal particles are at least one of iron particles and lead particles, preferably iron particles.

[0017] The metal MOF material is preferably at least one of MOF-Fe and MOF-Cr, more preferably MOF-Fe.

[0018] According to a preferred embodiment of the present invention, the metal MOF material may be MIL-100(Fe), which can be obtained commercially or prepared using methods commonly used in the art.

[0019] The nanoscale acoustic imaging material may also be a suspension of a composite network material including metal MOF materials, elastic polymers, and metal particles.

[0020] The second objective of this invention is to provide a method for preparing the nanoscale acoustic imaging material, comprising mixing an elastic polymer, a stabilizer and water to obtain a mixture D, then mixing it with a metal MOF material suspension to obtain a mixture F, and finally adding metal powder particles and a dispersant.

[0021] The stabilizer is selected from at least one of carboxymethyl cellulose, sodium dodecyl sulfate, and xanthan gum.

[0022] Based on 100 wt% of the mixture D, the elastic polymer comprises 10–35 wt%, the stabilizer comprises 0.5–1 wt%, and the water comprises 64–89.5 wt%. Preferably, the elastic polymer comprises 15–25 wt%, the stabilizer comprises 0.7–0.9 wt%, and the water comprises 74.1–84.3 wt%.

[0023] The concentration of MOF material in the metal MOF material suspension is 10-30 wt%, preferably 15-25 wt%.

[0024] The mass ratio of the mixture D to the metal MOF material suspension is 5:(1-2), preferably 5:(1.4-1.8), for example, it can be 5:1, 5:1.1, 5:1.2, 5:1.3, 5:1.4, 5:1.5, 5:1.6, 5:1.7, 5:1.8, 5:1.9, 5:2, etc.

[0025] The mass ratio of the metal particles to the mixture F is 1:(20-50), preferably 1:(20-40), and for example, it can be 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, etc.

[0026] The dispersant is selected from at least one of carboxymethyl cellulose, sodium dodecyl sulfate, and xanthan gum.

[0027] The mass ratio of the dispersant to the iron powder particles is 5:(1-4), preferably 5:(2-4); for example, it can be 5:1, 5:1.5, 5:2, 5:2.5, 5:3, 5:3.5, 5:4, etc.

[0028] Preferably, the iron powder particles are mixed with the mixture F using a high-speed disperser with a stirring speed of 600-3500 rpm and a stirring time of 15-60 min. At the same time, a dispersant is added to ensure that the nano iron powder is uniformly and stably dispersed in the system.

[0029] The metal MOF material suspension is preferably a MOF-Fe suspension.

[0030] The MOF-Fe suspension can be prepared directly using MIL-100(Fe), or it can be prepared using methods commonly used in the art.

[0031] According to a preferred embodiment of the present invention, it can be prepared by the following steps:

[0032] S1: Add pyromellitic acid to sodium hydroxide solution and stir to obtain clear solution A;

[0033] S2: Dissolve ferrous sulfate heptahydrate in water to obtain a clear, light green solution B;

[0034] S3: Slowly add solution A to solution B and stir to obtain mixed liquid C;

[0035] S4: Add hydrogen peroxide solution to the mixed liquid C and stir at room temperature to obtain MOF-Fe suspension.

[0036] Further, in S1, the molar ratio of pyromellitic acid to sodium hydroxide is 1:(2-3); in solution A, the concentration of pyromellitic acid is 475-640 mmol / L, and the concentration of sodium hydroxide is 1425-1920 mmol / L.

[0037] In S2, the molar concentration of ferrous sulfate heptahydrate in solution B is 160–570 mmol / L.

[0038] Furthermore, the molar ratio of ferrous sulfate heptahydrate, sodium hydroxide, and hydrogen peroxide is 1.5:(2-3):(0.3-3).

[0039] Furthermore, in S1 to S4, the stirring speed is 200 to 800 rpm.

[0040] Furthermore, after S3, hydrogen peroxide solution is added again after an interval of 0.5 to 120 minutes, and the stirring time at room temperature is 1 to 4 hours.

[0041] Furthermore, the mass concentration of hydrogen peroxide is 0.1%–30%.

[0042] The third objective of this invention is to provide the application of the nanoscale acoustic imaging material or the nanoscale acoustic imaging material obtained by the preparation method in oilfield imaging.

[0043] Preferably, nano-sized acoustic imaging material is mixed with an oil displacement agent and injected into the wellbore to form an imaging plug, and an imaging method is used to visualize underground interconnected spaces.

[0044] One method, VSP, utilizes the properties of seismic waves propagating underground to locate formation materials. This involves generating seismic waves at the surface and receiving them at different depths underground. It can distinguish between ascending and descending waves, as well as P-waves and S-waves, thus providing detailed information about the formation's interior. VSP can be used to accurately measure formation velocities, identify formation interfaces, and assess geological structures.

[0045] More preferably, the nano-sized acoustic imaging material is 5-10 wt% of the oil displacement agent.

[0046] The nano-contrast material mixture system prepared by this invention is stable, and the acoustic contrast frequency band and effect can be adjusted by adjusting the material ratio, thereby realizing the contrast imaging of underground interconnected spaces.

[0047] This invention provides a nanoscale acoustic imaging composite material and its preparation process. First, a suspension of metal MOF material is prepared, then an elastic polymer solution is added, and finally, nano-iron powder particles are added and mixed to form an elastic imaging particle dispersion system composed of nanoparticles. In practical use, it is mixed with an oil displacement agent (water or surfactant, etc.) at a ratio of 5wt% to 10wt% to form a 50m... 3 The above are the sections.

[0048] The nanoscale acoustic imaging material of this invention has the function of acoustic imaging, and the particle size of the dispersion is at the nanoscale. Furthermore, the acoustic imaging frequency band and effect can be adjusted by the material ratio. It can be used for reservoir fluid imaging monitoring with nanoscale pores during injection and production. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the structure of a nanoscale acoustic imaging material according to the present invention.

[0050] Figure 2 Example 1 uses sandstone cores with a porosity of 15%. The dynamic Young's modulus of injected nano-imprinted sandstone samples, injected pure water sandstone samples, and dry sandstone samples was measured using the Xiangke DTM-II dynamic method elastic modulus meter. The curves show that the dynamic Young's modulus of the sandstone samples after imaging is lower than that of the dry and water-wet sandstone samples. By monitoring seismic wave information at the same location before and after displacement, the Young's modulus at the same location was obtained through inversion. The Young's modulus at the displaced location is lower. This result can be used to monitor the displacement area and location of water injected with nano-imprinted material.

[0051] Figure 3 Example 2 uses sandstone cores with a porosity of 15%. The dynamic Young's modulus of injected nano-contrast sandstone samples, injected pure water sandstone samples, and dry sandstone samples was measured using the Xiangke DTM-II dynamic method elastic modulus meter. The curves show that reducing the amount of elastic polymer mixture D increases the Young's modulus of the contrast-enhanced rock samples.

[0052] Figure 4 Example 3 uses sandstone cores with a porosity of 15%. The dynamic Young's modulus of injected nano-imprinted sandstone, injected pure water sandstone, and dry sandstone samples was measured using the Xiangke DTM-II dynamic method elastic modulus meter. The curves show that increasing the amount of nano-iron powder causes a decrease in the Young's modulus of the imprinted rock sample at low frequencies and an increase at high frequencies. Detailed Implementation

[0053] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0054] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0055] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0056] According to a preferred embodiment of the present invention, the nanoscale acoustic imaging material can be prepared by the following steps:

[0057] S1: Add pyromellitic acid to sodium hydroxide solution and stir to obtain clear solution A;

[0058] S2: Dissolve ferrous sulfate heptahydrate in water to obtain a clear, light green solution B;

[0059] S3: Slowly add solution A to solution B and stir to obtain mixed liquid C;

[0060] S4: Add hydrogen peroxide solution to the mixed liquid C, stir at room temperature, and finally obtain crude MOF-Fe suspension;

[0061] S5: Mix 10-35 wt% of elastic polymer, 0.5-1 wt% of stabilizer and 64-89.5 wt% of injected water to obtain mixture D;

[0062] The elastic polymer is a copolymer of acrylamide, p-isopropylstyrene, and sodium tetravinyl sulfonate.

[0063] S6: Slowly add mixture D to the MOF-Fe suspension while stirring to obtain mixture F;

[0064] In S6, the stirring speed of the mixture D and the MOF-Fe suspension is 500-1000 rpm;

[0065] S7: Slowly add iron powder particles with a particle size of 5-20nm to the mixture F, while adding a dispersant. Stir while adding to keep the nano-iron powder uniformly dispersed in the system, and finally obtain a nano-sized acoustic imaging material suspension.

[0066] In S7, nano-iron powder particles and mixed liquid F are added at a mass ratio of 1:(20-50), and a high-speed disperser is used to stir at a speed of 600-3500 rpm for 15-60 min. At the same time, a dispersant is added to ensure that the nano-iron powder is evenly and stably dispersed in the system.

[0067] In S7, the ratio of the amount of dispersant used to the mass of iron powder particles is 5:(1-4).

[0068] In Examples 1-3, the dispersant used was KMT-310 metal powder dispersant.

[0069] The acrylamide-p-isopropylstyrene-tetravinylsulfonate copolymers in Examples 1-3 were obtained by copolymerization using 60g of acrylamide from Suzhou Ruri Chemical Technology Co., Ltd., 180g of p-isopropylstyrene from Futian Chemical, and 300g of tetravinylsulfonate from Huaxu Chemical.

[0070] Example 1

[0071] (1) Dissolve 300 mg of sodium hydroxide in 4.4 g of water, then add 525 mg of pyromellitic acid and stir until completely dissolved to obtain solution A.

[0072] (2) First, measure 12.5g of water into a reagent bottle, add 1042mg of ferrous sulfate heptahydrate, and stir until completely dissolved to obtain solution B.

[0073] (3) Add solution A dropwise to solution B while stirring (add within 30 seconds). When all solutions A and B have been added, record the reaction time as zero.

[0074] (4) After half a minute of reaction, add 10 mL of 1% hydrogen peroxide to the solution. React for 2 hours. A 20 wt% MOF-Fe suspension is formed.

[0075] (5) Add 140g of acrylamide-p-isopropylstyrene-tetravinylsulfonate copolymer and 5.6g of carboxymethyl cellulose stabilizer to 554.4g of water in sequence, while stirring slowly for 20min to form mixture D.

[0076] (6) Take 90 ml of mixture D and slowly add 28.8 ml of MOF-Fe suspension while stirring to obtain mixture F;

[0077] (7) Slowly add 5g of 5-20nm nano iron powder particles to the mixture F, stir at 2000rpm using a high-speed disperser for 30min, and add 10g of KMT-310 metal powder dispersant at the same time. The nano iron powder is evenly and stably dispersed in the system.

[0078] (8) Sandstone cores with a porosity of 15% (pore size range of 100nm~20μm) were selected. The dynamic Young's modulus of injected nano-imaging sandstone samples, injected pure water sandstone samples, and dry sandstone samples were measured using the Xiangke DTM-II dynamic method elastic modulus measuring instrument. Figure 2 As shown, the dynamic Young's modulus of the sandstone sample after imaging is lower than that of the dry sandstone sample and the wet sandstone sample.

[0079] Example 2

[0080] (1) Dissolve 300 mg of sodium hydroxide in 4.4 g of water, then add 525 mg of pyromellitic acid and stir until completely dissolved to obtain solution A.

[0081] (2) First, measure 12.5g of water into a reagent bottle, add 1042mg of ferrous sulfate heptahydrate, and stir until completely dissolved to obtain solution B.

[0082] (3) Add solution A dropwise to solution B while stirring (add within 30 seconds). When all solutions A and B have been added, record the reaction time as zero.

[0083] (4) After half a minute of reaction, add 10 mL of 1% hydrogen peroxide to the solution. React for 2 hours. A 20 wt% MOF-Fe suspension is formed.

[0084] (5) Add 35g of acrylamide-p-isopropylstyrene-tetravinylsulfonate copolymer and 1.4g of stabilizer to 140g of water in sequence, while stirring slowly for 20min to form mixture D.

[0085] (6) Take 75 ml of mixture D and slowly add it to 28.8 ml of MOF-Fe suspension while stirring to obtain mixture F;

[0086] (7) Slowly add 5g of 5-20nm nano iron powder particles to the mixture F, stir at 2000rpm using a high-speed disperser for 30min, and add 10g of KMT-310 metal powder dispersant at the same time. The nano iron powder is evenly and stably dispersed in the system.

[0087] (8) Same as in Example 1, sandstone cores with a porosity of 15% (pore size range of sandstone cores: 100 nm to 20 μm) were selected. The dynamic Young's modulus of injected nano-imaging sandstone samples, injected pure water sandstone samples, and dry sandstone samples were measured using the Xiangke DTM-II dynamic method elastic modulus measuring instrument. Figure 3 As shown, reducing the amount of elastic polymer mixture D will increase the Young's modulus of the chromatographic rock sample.

[0088] Example 3

[0089] (1) Dissolve 300 mg of sodium hydroxide in 4.4 g of water, then add 525 mg of pyromellitic acid and stir until completely dissolved to obtain solution A.

[0090] (2) First, measure 12.5g of water into a reagent bottle, add 1042mg of ferrous sulfate heptahydrate, and stir until completely dissolved to obtain solution B.

[0091] (3) Add solution A dropwise to solution B while stirring (add within 30 seconds). When all solutions A and B have been added, record the reaction time as zero.

[0092] (4) After half a minute of reaction, add 10 mL of 1% hydrogen peroxide to the solution. After 2 hours of reaction, a 20 wt% MOF-Fe suspension is formed.

[0093] (5) Add 140g of acrylamide-p-isopropylstyrene-tetravinylsulfonate copolymer and 5.6g of carboxymethyl cellulose stabilizer to 554.4g of water in sequence, while stirring slowly for 20min to form mixture D.

[0094] (6) Take 90 ml of mixture D and slowly add 28.8 ml of MOF-Fe suspension while stirring to obtain mixture F.

[0095] (7) Slowly add 8g of 5-20nm nano iron powder particles to the mixture F, stir at 2000rpm using a high-speed disperser for 30min, and add 10g of KMT-310 metal powder dispersant at the same time. The nano iron powder is evenly and stably dispersed in the system.

[0096] (8) Same as in Example 1, sandstone cores with a porosity of 15% (pore size range of sandstone cores: 100 nm to 20 μm) were selected. The dynamic Young's modulus of injected nano-imaging sandstone samples, injected pure water sandstone samples, and dry sandstone samples were measured using the Xiangke DTM-II dynamic method elastic modulus measuring instrument. Figure 4 As shown, increasing the amount of nano-iron powder will cause the Young's modulus of the contrast rock sample to decrease at low frequencies and increase at high frequencies.

[0097] As can be seen from Examples 1-3, the dispersion particles of the nanoscale acoustic imaging material of the present invention are in the nanoscale, and can be used to monitor fluid transport in micron and nanoscale pores of underground reservoirs.

[0098] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0099] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0100] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0101] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

Claims

1. A nanoscale acoustic imaging material, comprising a metal MOF material, an elastic polymer, and metal particles, wherein the size of the nanoscale acoustic imaging material is 100-500 nm; wherein the elastic polymer is an acrylamide-p-isopropylstyrene-tetravinylsulfonate copolymer, wherein the mass ratio of acrylamide structural units, p-isopropylstyrene structural units, and tetravinylsulfonate structural units in the elastic polymer is 1:(2-4):(4-8); the metal particles are at least one of iron particles and lead particles; and the metal MOF material is at least one of MOF-Fe and MOF-Cr.

2. The nanoscale acoustic imaging material according to claim 1, characterized in that: The size of the nanoscale acoustic imaging material is 200~400nm.

3. The nanoscale acoustic imaging material according to claim 1, characterized in that: The particle size of the metal particles is 5~20 nm; and / or, The metal MOF material is MOF-Fe.

4. The nanoscale acoustic imaging material according to claim 3, characterized in that: The particle size of the metal particles is 8~15nm; and / or, The metal MOF material is MIL-100(Fe).

5. A method for preparing nanoscale acoustic imaging materials according to any one of claims 1 to 4, comprising the steps of mixing an elastic polymer, a stabilizer and water to obtain a mixture D, then mixing it with a metal MOF material suspension to obtain a mixture F, and finally adding metal particles and a dispersant.

6. The preparation method according to claim 5, characterized in that: The stabilizer is selected from at least one of carboxymethyl cellulose, sodium dodecyl sulfate, and xanthan gum; and / or, Based on the mixture D being 100 wt%, the elastic polymer is 10-35 wt%, the stabilizer is 0.5-1 wt%, and the water is 64-89.5 wt%.

7. The preparation method according to claim 6, characterized in that: Based on the mixture D being 100 wt%, the elastic polymer is 15-25 wt%, the stabilizer is 0.7-0.9 wt%, and the water is 74.1-84.3 wt%.

8. The preparation method according to claim 5, characterized in that: The concentration of the metal MOF material in the metal MOF material suspension is 10~30 wt%; and / or, The mass ratio of the mixture D to the metal MOF material suspension is 5:(1~2); and / or, The mass ratio of the metal particles to the mixture F is 1:(20~50).

9. The preparation method according to claim 8, characterized in that: The concentration of the metal MOF material in the metal MOF material suspension is 15~25wt%; and / or, The mass ratio of the mixture D to the metal MOF material suspension is 5:(1.4~1.8); and / or, The mass ratio of the metal particles to the mixture F is 1:(20~40).

10. The preparation method according to claim 5, characterized in that: The dispersant is selected from at least one of carboxymethyl cellulose, sodium dodecyl sulfate, xanthan gum, and KMT-310 metal powder dispersant; The metal particles are iron particles, and the mass ratio of the dispersant to the iron particles is 5:(1~4).

11. The preparation method according to claim 10, characterized in that: The mass ratio of the dispersant to the iron particles is 5:(2~4).

12. The preparation method according to claim 5, characterized in that: The metal MOF material suspension is a MOF-Fe suspension.

13. The preparation method according to claim 12, characterized in that: The MOF-Fe suspension was prepared by the following steps: S1: Add pyromellitic acid to sodium hydroxide solution and stir to obtain clear solution A; S2: Dissolve ferrous sulfate heptahydrate in water to obtain a clear, light green solution B; S3: Slowly add solution A to solution B and stir to obtain mixed liquid C; S4: Add hydrogen peroxide solution to the mixed liquid C and stir at room temperature to obtain MOF-Fe suspension.

14. The application of the nanoscale acoustic imaging material according to any one of claims 1 to 4 or the nanoscale acoustic imaging material obtained by the preparation method according to any one of claims 5 to 13 in oilfield imaging.

15. The application according to claim 14, characterized in that: Nanoscale acoustic imaging materials are mixed with oil displacement agents and injected into the wellbore to form imaging plugs. Seismic methods are then used to image underground interconnected spaces.

16. The application according to claim 15, characterized in that: The nanoscale acoustic imaging material is 5-10 wt% of the oil displacement agent.

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