A marine vibrator design method and system based on fluid-solid coupling analysis

Abstract

The application discloses a marine vibrator design method and system based on fluid-solid coupling analysis, and relates to the field of marine exploration equipment.The method comprises the following steps: obtaining a marine vibrator model placed in a given water area, setting an outflow field calculation domain, and generating a marine vibrator grid and a water area grid according to the calculation domain; coupling the marine vibrator grid and the water area grid to obtain the near-field pressure distribution of the model; setting a model control mode, setting a water pressure collection point, and setting an external shape change scheme; obtaining collection data of the model under different external shape change schemes at a fixed distance of the collection point, analyzing the collection data to obtain a vibrator movement rule; determining factors affecting the output water pressure of the model, analyzing the change of the output water pressure of the model by changing the factors, and obtaining a vibrator meeting the requirements by using the factors.The application realizes numerical analysis of fluid-solid coupling of a marine vibrator-seawater simulation, obtains factors affecting the output pressure of the vibrator, and provides a design method for the marine vibrator.

Description

Technical Field

[0001] This invention relates to the field of marine controllable seismic source technology, and more specifically to a marine controllable seismic source design method and system based on fluid-structure interaction analysis. Background Technology

[0002] In the field of marine seismic exploration and engineering, marine controlled-source technology is widely used to obtain information on underground structures, study seismic activity, and carry out marine engineering construction. A marine controlled-source refers to the generation of controlled seismic waves through coupling mechanical vibration with seawater, which propagate to the seabed and underground, thereby enabling the measurement and analysis of geological structures and properties.

[0003] Currently, increasing the output sound pressure of marine controlled seismic sources has attracted much attention, and empirical and experimental methods have gradually become the main means of researching this topic. However, problems such as low design efficiency, high computational costs, and inaccurate design results exist, making it difficult to meet the design and analysis needs of marine controlled seismic sources.

[0004] However, numerical simulation methods primarily focus on simplified structures and struggle to account for the complexities of the marine environment, such as the impact of water depth and currents on the seismic source. Furthermore, research on controllable marine seismic sources and seawater is relatively limited. These factors further complicate the design of controllable marine seismic sources. Therefore, there is an urgent need to find a more effective method to address the high sound pressure levels in small volumes, thereby increasing the output sound pressure level of controllable marine seismic sources to meet practical requirements.

[0005] Therefore, how to design a controllable marine seismic source to increase the output sound pressure is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a design method and system for a marine controllable seismic source based on fluid-structure interaction analysis. It studies the coupling between the marine controllable seismic source and seawater, realizes numerical analysis of the fluid-structure interaction between the marine controllable seismic source and seawater, and further analyzes the main factors affecting the output pressure of the marine controllable seismic source, providing a design method for a small-volume, high-sound-pressure output marine controllable seismic source.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for designing a controllable marine seismic source based on fluid-structure interaction analysis includes:

[0009] S1: Obtain the ocean controllable seismic source model, place it in a given water area, and set the external flow field calculation domain. Further generate the ocean controllable seismic source grid and the water area grid based on the calculation domain.

[0010] S2: Couple the ocean-controlled seismic source grid with the water area grid to further obtain the near-field pressure distribution of the ocean-controlled seismic source model;

[0011] S3: Set the control mode of the marine controllable seismic source model, and set water pressure acquisition points at a fixed distance from the marine controllable seismic source model, and determine the shape change scheme of the controllable seismic source in the marine controllable seismic source model;

[0012] S4: Based on the near-field pressure distribution, obtain the water pressure acquisition data of the ocean controllable seismic source model at a fixed distance and under different shape modification schemes of the water pressure acquisition point, and analyze the water pressure acquisition data to obtain the motion law of the controllable seismic source.

[0013] S5: Determine the factors affecting the output water pressure of the marine controlled seismic source model, analyze the changes in the output water pressure of the marine controlled seismic source model by changing the factors, and use the factors to obtain a marine controlled seismic source that meets the requirements.

[0014] Preferably, S1 specifically includes:

[0015] S1.1: Perform marine controllable source mesh generation on the marine controllable source model;

[0016] S1.2: Select a water area model and generate a water area grid based on the given water area.

[0017] Preferably, S1.1 specifically includes: setting the marine controllable seismic source material and material properties for the marine controllable seismic source model, performing mesh calculation on the marine controllable seismic source model, and obtaining the marine controllable seismic source mesh.

[0018] Preferably, S1.2 specifically includes: setting seawater parameters and attributes for the water area model, performing grid calculation on the water area based on the seawater parameters and attributes, obtaining the water area grid, and densifying the interface with the marine controllable seismic source.

[0019] Preferably, the coupling specifically includes selecting a standard k-ε two-equation model to establish the coupling between the ocean-controlled seismic source grid and the water area grid, with the following equations:

[0020]

[0021]

[0022] In the formula, G K Y represents the generation of turbulent kinetic energy caused by the average velocity gradient. m The value represents the contribution of compressible flow to the dissipation rate, where μ is the viscosity. t For dynamic viscosity, x iLet x be the displacement in the i direction. j G is the displacement in the j-direction. b The turbulent kinetic energy generated by buoyancy, Y N C represents the contribution of wave expansion to the total dissipation rate in compressible turbulence. 1ε C 2ε and C 3ε It is a constant, σ K and σ ε Turbulent Prandtl number for turbulent kinetic energy K and divergence ε, respectively, S K and S ε It is a user-defined source term, with seawater density ρ and velocity u. i .

[0023] Preferably, the control method specifically includes determining the vibration curve of the marine controllable seismic source model, selecting a sine curve to control the vibration of the marine controllable seismic source, and the vibration control curve s(t) is obtained using the following equation:

[0024] s(t)=Q sin(2πf1t)sin(2πf2t);

[0025] In the formula, Q is the amplitude of the exciter output signal, f1 is the frequency of the signal, and f2 is the frequency of the window function.

[0026] Preferably, it further includes: setting the boundary of the given water area based on the dimensions of the ocean controllable seismic source model.

[0027] A marine controllable seismic source design system based on fluid-structure interaction analysis includes:

[0028] The grid structure module obtains a marine controllable seismic source model, places it in a given water area, sets the external flow field calculation domain, and further generates a marine controllable seismic source grid and a water area grid based on the calculation domain.

[0029] The coupling module couples the ocean-controlled seismic source grid with the water area grid to further obtain the near-field pressure distribution of the ocean-controlled seismic source model;

[0030] The module sets the control mode of the marine controllable seismic source model, sets water pressure acquisition points at fixed distances from the marine controllable seismic source model, and determines the shape change scheme of the controllable seismic source in the marine controllable seismic source model.

[0031] The analysis module obtains water pressure data of the ocean controllable seismic source model at a fixed distance and under different shape modification schemes based on the near-field pressure distribution, and analyzes the output water pressure to analyze the motion law of the controllable seismic source.

[0032] The seismic source acquisition module identifies the factors affecting the output water pressure of the marine controllable seismic source model, analyzes the changes in the output water pressure of the marine controllable seismic source model by changing the factors, and uses the factors to acquire a marine controllable seismic source that meets the requirements.

[0033] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a design method and system for a marine controllable seismic source based on fluid-structure interaction analysis. It uses simulation technology to generate aquatic environments that are more consistent with actual sea conditions; it simulates the movement of a marine controllable seismic source in the water, and by changing the shape of the marine seismic source, it conducts fluid-structure interaction analysis on marine controllable seismic sources of different shapes, studies the motion law and output pressure data of marine controllable seismic sources of different shapes, and then determines the main factors affecting the output pressure of marine controllable seismic sources. Based on these factors, a marine controllable seismic source with stronger output sound pressure is designed. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0035] Figure 1 The attached figure is a schematic diagram of the steps provided by the present invention.

[0036] Figure 2 The attached figure is a schematic diagram of the marine controllable seismic source water area grid provided by the present invention.

[0037] Figure 3 The attached figure is a schematic diagram of the pressure cloud after fluid-structure interaction of the marine controllable seismic source provided by the present invention.

[0038] Figure 4 The attached figure shows the radii of different marine controllable seismic source substrates provided by this invention.

[0039] Figure 5 The attached figure shows the pressure variation obtained from different substrate radii of the marine controllable seismic source provided by this invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] In one specific embodiment, a marine controllable seismic source structure is provided, and the output sound pressure is improved and optimized based on this structure. The modified model provides suggestions for the improvement of actual equipment.

[0042] The structure consists of three parts: a dual-sided output base plate, a housing, a sealing ring, and an observation window. The important function of the base plate is to output vibration signals under the drive force.

[0043] The shell serves to maintain structural stability and prevent seawater from entering and corroding the equipment.

[0044] The observation window is used to observe the internal operating status. It has two connectors, A and B, for supplying oil to the inside. The internal system uses hydraulic power to drive the double-sided base plate.

[0045] The sealing ring connects the base plate and the housing, and its main function is to provide an effective stroke while achieving a sealing effect.

[0046] This invention discloses a method for designing a controllable marine seismic source based on fluid-structure interaction analysis, such as... Figure 1 As shown, it includes:

[0047] S1: Obtain the ocean controllable seismic source model, place it in a given water area, and set the external flow field calculation domain. Further generate the ocean controllable seismic source grid and the water area grid based on the calculation domain.

[0048] S2: Couple the ocean-controlled seismic source grid with the water area grid to further obtain the near-field pressure distribution of the ocean-controlled seismic source model;

[0049] S3: Set the control mode of the marine controllable seismic source model, and set water pressure acquisition points at a fixed distance from the marine controllable seismic source model, and determine the shape change scheme of the controllable seismic source in the marine controllable seismic source model;

[0050] S4: Based on the near-field pressure distribution, obtain the water pressure acquisition data of the ocean controllable seismic source model at a fixed distance and under different shape modification schemes of the water pressure acquisition point, and analyze the water pressure acquisition data to obtain the motion law of the controllable seismic source.

[0051] S5: Determine the factors affecting the output water pressure of the marine controlled seismic source model, analyze the changes in the output water pressure of the marine controlled seismic source model by changing the factors, and use the factors to obtain a marine controlled seismic source that meets the requirements.

[0052] In one specific embodiment, S1 specifically includes:

[0053] S1.1: Perform marine controllable source mesh generation on the marine controllable source model;

[0054] S1.2: Select a water area model and generate a water area grid based on the given water area.

[0055] In one specific embodiment, S1.1 specifically includes: setting the marine controllable seismic source material and material properties for the marine controllable seismic source model, performing mesh calculation on the marine controllable seismic source model, and obtaining the marine controllable seismic source mesh.

[0056] In one specific embodiment, seawater parameters and properties are set for a given water area;

[0057] The water area is subjected to grid calculation based on seawater parameters and properties, and the grid of the marine controllable seismic source and the water area are densified.

[0058] In one specific embodiment, S1.2 specifically includes: setting seawater parameters and attributes for the water area model, performing grid calculation on the water area based on the seawater parameters and attributes, obtaining the water area grid, and densifying the interface with the marine controllable seismic source.

[0059] By refining the mesh, or making the mesh more detailed, these cells can be made smaller and smaller, thus making the solution closer and closer to the true solution.

[0060] In one specific embodiment, the coupling specifically includes selecting a standard k-ε two-equation model to establish the coupling between the ocean-controlled seismic source grid and the water area grid, with the following equations:

[0061]

[0062]

[0063] In the formula, G K Y represents the generation of turbulent kinetic energy caused by the average velocity gradient. m The value represents the contribution of compressible flow to the dissipation rate, where μ is the viscosity. t For dynamic viscosity, x i Let x be the displacement in the i direction. j G is the displacement in the j-direction. b The turbulent kinetic energy generated by buoyancy, Y N C represents the contribution of wave expansion to the total dissipation rate in compressible turbulence. 1ε C 2ε and C 3ε It is a constant, σ K and σ ε Turbulent Prandtl number for turbulent kinetic energy K and divergence ε, respectively, S K and S ε It is a user-defined source term, with seawater density ρ and velocity u. i .

[0064] In one specific embodiment, the control method specifically includes determining the vibration curve of the ocean-controlled seismic source model, selecting a sine curve to control the vibration of the ocean-controlled seismic source, and the vibration control curve s(t) is obtained using the following equation:

[0065] s(t)=Q sin(2πf1t)sin(2πf2t);

[0066] In the formula, Q is the amplitude of the exciter output signal, f1 is the frequency of the signal, and f2 is the frequency of the window function.

[0067] In one specific embodiment, the method further includes setting the boundary of the given water area based on the dimensions of the ocean controllable seismic source model.

[0068] In one specific embodiment, the upper boundary, lower boundary, left boundary, right boundary, front boundary, and rear boundary of the water area are set based on the size of the marine controllable seismic source;

[0069] The distance from the upper boundary to the center of the marine controlled seismic source is set to 6 times the diameter of the marine controlled seismic source enclosure; the distance from the lower boundary to the center of the marine controlled seismic source is set to 6 times the diameter of the marine controlled seismic source enclosure; the distance from the left boundary to the center of the marine controlled seismic source is set to 3 times the diameter of the marine controlled seismic source enclosure; the distance from the right boundary to the center of the marine controlled seismic source is set to 3 times the diameter of the marine controlled seismic source enclosure; the distance from the rear boundary to the center of the marine controlled seismic source is set to 6 times the diameter of the marine controlled seismic source enclosure; and the distance from the front boundary to the center of the marine controlled seismic source is set to 6 times the diameter of the marine controlled seismic source enclosure.

[0070] A marine controllable seismic source design system based on fluid-structure interaction analysis includes:

[0071] The grid structure module obtains a marine controllable seismic source model, places it in a given water area, sets the external flow field calculation domain, and further generates a marine controllable seismic source grid and a water area grid based on the calculation domain.

[0072] The coupling module couples the ocean-controlled seismic source grid with the water area grid to further obtain the near-field pressure distribution of the ocean-controlled seismic source model;

[0073] The module sets the control mode of the marine controllable seismic source model, sets water pressure acquisition points at fixed distances from the marine controllable seismic source model, and determines the shape change scheme of the controllable seismic source in the marine controllable seismic source model.

[0074] The analysis module obtains water pressure data of the ocean controllable seismic source model at a fixed distance and under different shape modification schemes based on the near-field pressure distribution, and analyzes the output water pressure to analyze the motion law of the controllable seismic source.

[0075] The seismic source acquisition module identifies the factors affecting the output water pressure of the marine controllable seismic source model, analyzes the changes in the output water pressure of the marine controllable seismic source model by changing the factors, and uses the factors to acquire a marine controllable seismic source that meets the requirements.

[0076] In one specific embodiment, the substrate radius is approximately 0.15m. Using this as an example, a marine controllable seismic source model is established through finite element modeling, and fluid-structure interaction simulation is performed to study its motion laws and explore the factors affecting its output pressure, thereby providing a theoretical basis for the design of marine controllable seismic sources.

[0077] Figure 2 This is a schematic diagram of the mesh generation of a marine controlled seismic source in one embodiment of the present invention. Specifically, the given water area is imported into a water area mesh with pre-set parameters, and the mesh is refined in the area in contact with the marine controlled seismic source to generate the water area mesh. By dividing the finite element model, the marine controlled seismic source finite element model can interact with the water area mesh to obtain the pressure data in the water area.

[0078] Figure 3 The following is a schematic diagram of the pressure cloud after fluid-structure interaction of a marine controllable seismic source in one embodiment of the present invention: It can be clearly seen from the finite element fluid-structure interaction reaction analysis that the effect of the marine controllable seismic source on water is mainly concentrated near the substrate. In other words, one of the main factors affecting the output pressure of the marine controllable seismic source may be the substrate.

[0079] Figure 4 This is a schematic diagram of different substrate radii of a marine controllable seismic source according to an embodiment of the present invention, as detailed below: Figure 3 In the fluid-structure interaction analysis, the moving part is mainly the substrate, and the seawater is subjected to pressure from the substrate, causing changes in its flow velocity. Therefore, the substrate can be pre-determined as one of the main factors affecting the output pressure of the marine controlled seismic source. By changing its shape, further fluid-structure interaction is performed, and simulations are conducted under the same control signal to obtain the output pressure of the marine controlled seismic source under various shapes. In this embodiment, the main variable of the substrate shape is set as the radius of the substrate, and the output pressure of the marine controlled seismic source is collected by changing the substrate radius.

[0080] Figure 5This is a schematic diagram illustrating the pressure variations obtained from different substrate radii of a marine controlled seismic source according to an embodiment of the present invention. Specifically, finite element models of marine controlled seismic sources with different radii were designed and fluid-structure interaction was performed. Pressure data was obtained at the same acquisition point. This pressure data shows that the substrate radius is a key factor affecting the output pressure of the marine controlled seismic source, and the substrate radius of the marine seismic source can be determined based on this data. For example, if the required pressure is 0.24 Pa, a substrate radius of 0.45 m meets the design requirements. Further designing a marine controlled seismic source with a substrate radius of 0.45 m yields a marine controlled seismic source that meets the requirements.

[0081] It should be noted that although several modules or units of the device for performing actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of the present invention, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0082] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solution of the embodiments of the present invention can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, portable hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, touch terminal, or network device, etc.) to execute the method according to the embodiments of the present invention.

[0083] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0084] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for designing a controllable marine seismic source based on fluid-structure interaction analysis, characterized in that, include: S1: Obtain the marine controllable seismic source model, place it in a given water area, and set the external flow field calculation domain. Further generate the marine controllable seismic source grid and the water area grid based on the calculation domain. S2: Couple the ocean-controlled seismic source grid with the water area grid to further obtain the near-field pressure distribution of the ocean-controlled seismic source model; S3: Set the control mode of the marine controllable seismic source model, and set water pressure acquisition points at a fixed distance from the marine controllable seismic source model, and determine the shape change scheme of the controllable seismic source in the marine controllable seismic source model; S4: Based on the near-field pressure distribution, obtain the water pressure acquisition data of the ocean controllable seismic source model at a fixed distance and under different shape modification schemes of the water pressure acquisition point, and analyze the water pressure acquisition data to obtain the motion law of the controllable seismic source. S5: Determine the factors affecting the output water pressure of the marine controlled seismic source model, analyze the changes in the output water pressure of the marine controlled seismic source model by changing the factors, and use the factors to obtain a marine controlled seismic source that meets the requirements.

2. The marine controllable seismic source design method based on fluid-structure interaction analysis according to claim 1, characterized in that, S1 specifically includes: S1.1: Perform marine controllable source mesh generation on the marine controllable source model; S1.2: Select a water area model and generate a water area grid based on the given water area.

3. The marine controllable seismic source design method based on fluid-structure interaction analysis according to claim 2, characterized in that, S1.1 specifically includes: setting the marine controllable seismic source material and material properties for the marine controllable seismic source model, performing mesh calculation on the marine controllable seismic source model, and obtaining the marine controllable seismic source mesh.

4. The marine controllable seismic source design method based on fluid-structure interaction analysis according to claim 2, characterized in that, S1.2 specifically includes: setting seawater parameters and attributes for the water area model, performing grid calculation on the water area based on the seawater parameters and attributes, obtaining the water area grid, and densifying the interface with the marine controllable seismic source.

5. The marine controllable seismic source design method based on fluid-structure interaction analysis according to claim 1, characterized in that, The coupling specifically includes selecting a standard k-ε two-equation model to establish the coupling between the ocean-controlled seismic source grid and the water area grid, with the following equations: In the formula, G K Y represents the generation of turbulent kinetic energy caused by the average velocity gradient. m The value represents the contribution of compressible flow to the dissipation rate, where μ is the viscosity. t For dynamic viscosity, x i Let x be the displacement in the i direction. j G is the displacement in the j-direction. b The turbulent kinetic energy generated by buoyancy, Y N C represents the contribution of wave expansion to the total dissipation rate in compressible turbulence. 1ε C 2ε and C 3ε It is a constant, σ K and σ ε Turbulent Prandtl number for turbulent kinetic energy K and divergence ε, respectively, S K and S ε It is a user-defined source term, with seawater density ρ and velocity u. i .

6. The method for designing a controllable marine seismic source based on fluid-structure interaction analysis according to claim 1, characterized in that, The control method specifically includes determining the vibration curve of the ocean-controlled seismic source model, selecting a sine curve to control the vibration of the ocean-controlled seismic source, and obtaining the vibration control curve s(t) using the following equation: s(t)=Q sin(2πf1t)sin(2πf2t); In the formula, Q is the amplitude of the exciter output signal, f1 is the frequency of the signal, and f2 is the frequency of the window function.

7. The method for designing a controllable marine seismic source based on fluid-structure interaction analysis according to claim 1, characterized in that, Also includes: The boundaries of the given water area are set based on the dimensions of the ocean-controlled seismic source model.

8. A marine controllable seismic source design system based on fluid-structure interaction analysis, characterized in that, include: The grid structure module obtains a marine controllable seismic source model, places it in a given water area, sets the external flow field calculation domain, and further generates a marine controllable seismic source grid and a water area grid based on the calculation domain. The coupling module couples the ocean-controlled seismic source grid with the water area grid to further obtain the near-field pressure distribution of the ocean-controlled seismic source model; The module sets the control mode of the marine controllable seismic source model, sets water pressure acquisition points at fixed distances from the marine controllable seismic source model, and determines the shape change scheme of the controllable seismic source in the marine controllable seismic source model. The analysis module obtains water pressure data from the water pressure acquisition point at a fixed distance under different shape modification schemes based on the near-field pressure distribution. It then analyzes the output water pressure to analyze the motion law of the controllable seismic source. The seismic source acquisition module identifies the factors affecting the output water pressure of the marine controllable seismic source model, analyzes the changes in the output water pressure of the marine controllable seismic source model by changing the factors, and uses the factors to acquire a marine controllable seismic source that meets the requirements.

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