Method and apparatus for improving velocity model accuracy in full waveform inversion

Abstract

The application relates to a method and device for improving the precision of a velocity model in full waveform inversion, wherein the method comprises the following steps: selecting a target layer for inversion; according to the spatial coordinates of the target layer, using Fourier transform to calculate the actual acquisition direction of the inversion process and the azimuth range of the inversion process; according to the azimuth range and the parameters of a main ship, obtaining the starting point coordinate range of an auxiliary ship in the inversion process, so that any position of the target layer is taken as the starting point position of the main ship, inversion is carried out in the target layer according to the starting point coordinate range of the auxiliary ship and the actual acquisition direction, the refracted wave of the source on the auxiliary ship is received by the detector on the main ship, and a velocity model is established according to the refracted wave. The actual acquisition direction of the inversion process is obtained by Fourier transform according to the spatial coordinates of the target layer, and is more suitable for the occurrence of the structure; the detector on the main ship receives the refracted wave of the source on the auxiliary ship to establish the velocity model, and the modeling precision of the velocity model is improved.

Description

Technical Field

[0001] This invention belongs to the field of seismic exploration technology, specifically relating to a method and apparatus for improving the accuracy of velocity models in full waveform inversion. Background Technology

[0002] Currently, full-waveform inversion technology is gradually becoming the main method for conventional seismic exploration, improving the accuracy of velocity modeling in the seismic processing stage and thus significantly improving imaging accuracy, leading to its widespread adoption in the industry. Ultra-long offset acquisition is a core technology of current full-waveform inversion. In marine exploration, towed cable acquisition is limited by the towing capacity of ships, making it difficult to obtain information at ultra-long offsets. Towed cable operations typically use cables 5-8 km long. Based on full-waveform inversion experience, following the one-third rule, a velocity field at a depth of 1.7-2.7 km can be accurately constructed. However, the main target layers in domestic sea areas are concentrated at depths of 3-5 km, making it difficult to accurately construct deep velocity fields using conventional towed cable operations. Using seabed seismic acquisition methods instead of traditional towed cables can obtain seismic data greater than 8 km, but this significantly increases exploration costs. Summary of the Invention

[0003] In view of the above problems, the present invention is proposed to provide a method, apparatus, computing device and computer storage medium for improving the accuracy of velocity models in full waveform inversion to overcome or at least partially solve the above problems.

[0004] According to one aspect of the present invention, a method for improving the accuracy of velocity models in full waveform inversion is provided, comprising:

[0005] Select the target layer for inversion, and calculate the actual acquisition direction and azimuth range of the inversion process using Fourier transform based on the spatial coordinates of the target layer.

[0006] Based on the azimuth range and the parameters of the main ship, the starting coordinate range of the auxiliary ship during the inversion process is obtained, so that any position of the target layer can be used as the starting position of the main ship. The inversion is carried out within the target layer according to the starting coordinate range of the auxiliary ship and the actual acquisition direction, so that the detector on the main ship can receive the refracted wave of the seismic source on the auxiliary ship, and a velocity model can be established based on the refracted wave.

[0007] Furthermore, the step of selecting the target stratum for inversion, and calculating the actual acquisition direction and azimuth range of the inversion process using Fourier transform based on the spatial coordinates of the target stratum, further includes:

[0008] Select the target stratigraphic level for the inversion;

[0009] Using any point as the origin of the coordinate system, and taking due north as the positive y-axis and due east as the positive x-axis, a three-dimensional coordinate system is established according to the right-hand rule to obtain the set of spatial coordinates of the target layer.

[0010] A two-dimensional Fourier transform is performed on the set of spatial coordinates to obtain the wavenumber domain Fourier spectrum;

[0011] The orientation of the structure is determined based on the distribution characteristics of the energy field in the wavenumber domain Fourier spectrum.

[0012] The actual acquisition direction and azimuth range of the inversion process are determined based on the structural orientation.

[0013] Furthermore, the specific details of obtaining the starting coordinate range of the auxiliary ship during the inversion process based on the azimuth range and the parameters of the main ship are as follows:

[0014] If two azimuth ranges are determined based on the aforementioned structural orientation, an inversion mode combining longitudinal full waveform inversion and transverse full waveform inversion is adopted. Based on one of the azimuth ranges and the parameters of the main ship, the starting coordinate range of one auxiliary ship is obtained, and based on the other azimuth range and the parameters of the main ship, the starting coordinate range of the other auxiliary ship is obtained.

[0015] If only one azimuth range can be determined based on the aforementioned structural orientation, then the starting coordinate range of the auxiliary ship during the inversion process can be obtained based on the azimuth range and the parameters of the main ship.

[0016] Furthermore, if only one azimuth range can be determined based on the structural orientation, then obtaining the starting coordinate range of the auxiliary ship during the inversion process based on the azimuth range and the parameters of the main ship further includes:

[0017] The inversion mode of the inversion process is determined based on the relationship between the actual acquisition direction and the preset acquisition direction, as well as the accuracy requirements in the inversion process. The inversion mode includes a longitudinal full waveform inversion mode and a transverse full waveform inversion mode.

[0018] Based on the azimuth range and the parameters of the main ship, combined with the inversion mode, the starting coordinate range of the auxiliary ship during the inversion process is obtained.

[0019] Furthermore, the determination of the inversion mode of the inversion process based on the relationship between the actual acquisition direction and the preset acquisition direction, as well as the accuracy requirements in the inversion process, specifically involves:

[0020] If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the first direction, and the actual acquisition direction is parallel to the preset acquisition direction or parallel to the opposite direction of the preset acquisition direction, then the transverse full waveform inversion mode is adopted; the first direction refers to the direction perpendicular to the construction direction.

[0021] If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the first direction, and the actual acquisition direction is orthogonal to the preset acquisition direction, then the longitudinal full waveform inversion mode is adopted.

[0022] If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the second direction, and the actual acquisition direction is parallel to the preset acquisition direction or parallel to the opposite direction of the preset acquisition direction, then the longitudinal full waveform inversion mode is adopted; the second direction refers to the direction parallel to the construction direction.

[0023] If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the second direction, and the actual acquisition direction is orthogonal to the preset acquisition direction, then the transverse full waveform inversion mode is adopted.

[0024] Furthermore, based on the azimuth range and the parameters of the main ship, combined with the inversion mode, the starting coordinate range of the auxiliary ship during the inversion process is specifically obtained as follows:

[0025] With the direction opposite to the main ship's direction of travel as the X-axis and the center of symmetry of the first row of detectors at the rear of the main ship as the origin, a coordinate system is established to obtain the coordinate set of all detectors at the rear of the main ship.

[0026] The starting coordinate range of the auxiliary ship is obtained based on the coordinate set of all the detectors behind the main ship, the azimuth range, and the inversion mode.

[0027] Furthermore, the main ship also carries a seismic source so that a detector on the main ship can receive the reflected waves from the seismic source on the main ship, so as to perform offset imaging based on the reflected waves.

[0028] According to another aspect of the present invention, an apparatus for improving the accuracy of velocity models in full waveform inversion is provided, comprising:

[0029] The Fourier transform module is used to calculate the actual acquisition direction and azimuth range of the inversion process based on the spatial coordinates of the target layer after selecting the target layer for inversion.

[0030] The auxiliary vessel's starting coordinate range determination module is used to obtain the starting coordinate range of the auxiliary vessel during the inversion process based on the azimuth range and the parameters of the main vessel, so that any position of the target layer can be used as the starting position of the main vessel, and inversion can be performed within the target layer according to the starting coordinate range of the auxiliary vessel and the actual acquisition direction, so that the detector on the main vessel can receive the refracted wave from the seismic source on the auxiliary vessel, and a velocity model can be established based on the refracted wave.

[0031] According to another aspect of the present invention, a computing device is provided, comprising: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other via the communication bus;

[0032] The memory is used to store at least one executable instruction, which causes the processor to perform the operation corresponding to the method described above for improving the accuracy of the velocity model in full waveform inversion.

[0033] According to another aspect of the present invention, a computer storage medium is provided, the storage medium storing at least one executable instruction, the executable instruction causing a processor to perform the corresponding operation described in any of the preceding claims to improve the accuracy of the velocity model in full waveform inversion.

[0034] As can be seen from the above technical solution, the method and apparatus for improving the accuracy of velocity models in full waveform inversion provided by the present invention have the following beneficial effects:

[0035] The actual acquisition direction in the inversion process of this invention is obtained by Fourier transform of the spatial coordinates of the target layer, and the obtained actual acquisition direction is more consistent with the attitude of the structure; the detector on the main ship receives the refracted waves from the seismic source on the auxiliary ship to establish the velocity model, which improves the modeling accuracy of the velocity model.

[0036] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0037] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0038] Figure 1 This is a flowchart illustrating a method for improving the accuracy of velocity models in full waveform inversion according to an embodiment of the present invention;

[0039] Figure 2 Spatial domain distribution map of the target stratum;

[0040] Figure 3 Wavenumber domain distribution map of the target stratum;

[0041] Figure 4 A schematic diagram for determining the deflection angle;

[0042] Figure 5 A schematic diagram of an inversion mode that combines longitudinal full waveform inversion and transverse full waveform inversion;

[0043] Figure 6 This is a schematic diagram of another inversion mode that combines longitudinal full waveform inversion and transverse full waveform inversion;

[0044] Figures 7-11 This is a schematic diagram of the longitudinal full waveform inversion mode;

[0045] Figures 12-14 This is a schematic diagram of the transverse full waveform inversion mode;

[0046] Figure 15 This is a schematic diagram of the positional relationship between the main ship and the auxiliary ship in the longitudinal full waveform inversion mode;

[0047] Figure 16 The statistical curve of the azimuth angle is given when the distance between the auxiliary vessel and the origin is 3525m in the longitudinal full waveform inversion mode.

[0048] Figure 17 The statistical curves of the azimuth angle are shown when the distance between the auxiliary vessel and the coordinate origin is set to different values ​​in the longitudinal full waveform inversion mode.

[0049] Figure 18 and Figure 19 This is a schematic diagram of the positional relationship between the main ship and the auxiliary ship in the transverse full waveform inversion mode;

[0050] Figure 20 and Figure 21 The statistical curves of the azimuth angle when the auxiliary vessel is at different coordinates in the transverse full waveform inversion mode are shown.

[0051] Figure 22 This is a block diagram of a device for improving the accuracy of velocity models in full-waveform inversion according to an embodiment of the present invention;

[0052] Figure 23 This is a schematic diagram of the structure of a computing device according to an embodiment of the present invention. Detailed Implementation

[0053] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0054] Figure 1 A flowchart illustrating an embodiment of the present invention provides a method for improving the accuracy of a velocity model in full waveform inversion, applied in a computing device. The computing device includes a processor, a memory, a communication interface, and a communication bus. The processor, the memory, and the communication interface communicate with each other via the communication bus. The memory stores at least one executable instruction that causes the processor to perform an operation corresponding to an auxiliary acceleration method for network flows. Figure 1 As shown, the method includes the following steps:

[0055] S110: Select the target layer for inversion, and calculate the actual acquisition direction and azimuth range of the inversion process using Fourier transform based on the spatial coordinates of the target layer.

[0056] S120: Based on the azimuth range and the parameters of the main ship, the starting coordinate range of the auxiliary ship is obtained during the inversion process. This allows any position of the target layer to be used as the starting position of the main ship. The inversion is performed according to the starting coordinate range of the auxiliary ship and the actual acquisition direction, so that the geophone on the main ship can receive the refracted waves from the seismic source on the auxiliary ship, and a velocity model can be established based on the refracted waves.

[0057] In this embodiment, both the actual acquisition direction and the azimuth range during the inversion process are calculated using Fourier transform based on the spatial coordinates of the target stratum. In existing technologies, the actual acquisition direction is obtained statistically based on the attitude of the underground structures at the starting point; therefore, the actual acquisition direction obtained in this embodiment is more accurate.

[0058] After obtaining the azimuth range, the starting coordinate range of the auxiliary ship during the inversion process can be obtained based on the azimuth range and the main ship parameters during the inversion process, which can then be used for specific inversions.

[0059] In the specific inversion process, the main ship tows a geophone and the auxiliary ship tows a cable. The geophone on the main ship receives the refracted waves from the seismic source on the auxiliary ship, and a velocity model is established based on the received refracted waves.

[0060] Currently, in addition to high-quality seismic data, high-quality velocity modeling is also an important guarantee for high-precision seismic exploration. The refracted wave information of the auxiliary vessel collected in this embodiment of the invention is used to establish a high-quality velocity model.

[0061] In an optional approach, step S110, which involves selecting the target layer for inversion and calculating the actual acquisition direction and azimuth range of the inversion process using Fourier transform based on the spatial coordinates of the target layer, further includes:

[0062] Select the target stratigraphic level for the inversion;

[0063] Using any point as the origin of the coordinate system, and taking due north as the positive y-axis and due east as the positive x-axis, a three-dimensional coordinate system is established according to the right-hand rule to obtain the spatial coordinates of the target layer.

[0064] A two-dimensional Fourier transform is performed on the spatial coordinates to obtain the wavenumber domain Fourier spectrum;

[0065] The orientation of the structure is determined based on the distribution characteristics of the energy field in the wavenumber domain Fourier spectrum.

[0066] The actual acquisition direction and azimuth range of the inversion process are determined based on the structural orientation.

[0067] Specifically, after selecting the target stratum, the spatial coordinates of the target stratum can be obtained based on the established three-dimensional coordinate system, such as... Figure 2 As shown; by using the two-dimensional Fourier transform method to convert spatial coordinates into wavenumber domain data, a wavenumber domain distribution map can be obtained, as shown. Figure 3 As shown.

[0068] The direction of the structure, i.e., the main distribution direction of the structure, can be determined based on the energy distribution characteristics of the wavenumber domain amplitude spectrum in space. Figure 4 Using the intersection of the white, strong energy fields as the origin, and with the north and east axes as coordinate axes, the angle between the dashed line and the north direction is the deflection angle θ. According to... Figure 4 The deflection angle can yield three possible structural orientation directions: θ (unit degree), θ+90 degrees, or θ-90 degrees. Based on these three possible structural orientation directions, the structural orientation direction can be determined. The perpendicular direction of the structural orientation direction is the actual acquisition direction, which is also the main ship's direction of travel during the inversion process. The azimuth range of the inversion process is determined based on the deflection angle and error accuracy. For example, if the error accuracy is dθ, then the azimuth range is θ±dθ.

[0069] Secondly, there are two perpendicular directions to the actual structural orientation, which means there are two actual acquisition directions, which are 180 degrees apart. Therefore, in actual inversion, the inversion is generally completed by going back and forth between the two actual acquisition directions that are 180 degrees apart.

[0070] In one alternative approach, step S120, based on the azimuth range and the parameters of the main ship, obtains the starting coordinate range of the auxiliary ship during the inversion process as follows:

[0071] If two azimuth ranges are determined based on the aforementioned structural orientation, an inversion mode combining longitudinal full waveform inversion and transverse full waveform inversion is adopted. Based on one of the azimuth ranges and the parameters of the main ship, the starting coordinate range of one auxiliary ship is obtained, and based on the other azimuth range and the parameters of the main ship, the starting coordinate range of the other auxiliary ship is obtained.

[0072] If only one azimuth range can be determined based on the aforementioned structural orientation, then the starting coordinate range of the auxiliary ship during the inversion process can be obtained based on the azimuth range and the parameters of the main ship.

[0073] Specifically, Figure 4 There is only one intersection point of the strong energy field in the white center, from which a deflection angle can be obtained, and only one azimuth range can be determined. Based on the determined azimuth range and the parameters of the main ship, the starting coordinate range of the auxiliary ship in the inversion process can be obtained.

[0074] However, for cases with two orthogonal strong energy fields, i.e., two deflection angles, the actual acquisition direction is determined based on the two deflection angles. Under the actual acquisition direction, two azimuth ranges are determined. Then, an inversion mode combining longitudinal full waveform inversion and lateral full waveform inversion is adopted. Based on one of the azimuth ranges and the parameters of the main ship, the starting coordinate range of one auxiliary ship is obtained. Based on the other azimuth range and the parameters of the main ship, the starting coordinate range of the other auxiliary ship is obtained. Thus, an inversion mode of two auxiliary ships and one main ship is used for inversion.

[0075] For inversion modes that combine longitudinal and transverse full waveform inversion, such as... Figure 5 As shown, Figure 5 The system consists of four auxiliary vessels 1 and one main vessel 2. Each auxiliary vessel 1 is towed with a seismic source 11, and the main vessel 2 is towed with a cable 21, on which a detector for receiving reflected waves is installed. One auxiliary vessel 1 is located directly in front of the main vessel 2, and another auxiliary vessel 1 is located directly behind the main vessel 2. These two auxiliary vessels 1 form a longitudinal full-waveform inversion mode with the main vessel 2. The other two auxiliary vessels 1 are located to the right and left of the main vessel 2, respectively. These two auxiliary vessels 1 form a transverse full-waveform inversion mode with the main vessel 2. For the inversion mode combining longitudinal and transverse full-waveform inversion, the starting coordinate range of each auxiliary vessel is determined based on the specific azimuth range and the parameters of the main vessel.

[0076] Again, such as Figure 6 As shown, Figure 6A main ship 2 and an auxiliary ship 1 were adopted. The auxiliary ship 1 was also towed with a seismic source 11, and the main ship 2 was also towed with a cable 21. The cable was equipped with a detector for receiving reflected waves. By adjusting the longitudinal offset and the lateral offset between the auxiliary ship 1 and the main ship 2, an inversion mode combining longitudinal full waveform inversion and lateral full waveform inversion was achieved.

[0077] In one alternative approach, if only one azimuth range can be determined based on the construction orientation, then the starting coordinate range of the auxiliary vessel during the inversion process, obtained based on the azimuth range and the parameters of the main vessel, further includes:

[0078] The inversion mode of the inversion process is determined based on the relationship between the actual acquisition direction and the preset acquisition direction, as well as the accuracy requirements in the inversion process. The inversion mode includes a longitudinal full waveform inversion mode and a transverse full waveform inversion mode.

[0079] Based on the azimuth range and the parameters of the main ship, combined with the inversion mode, the starting coordinate range of the auxiliary ship during the inversion process is obtained.

[0080] Specifically, the preset acquisition direction will be suggested in the early stage of the observation system design; however, the starting coordinate range of the auxiliary ship will be different depending on the inversion mode. Therefore, in this embodiment, the inversion mode of the inversion process is first determined based on the relationship between the actual acquisition direction and the preset acquisition direction, as well as the accuracy requirements in the inversion process. Then, based on the azimuth range, the parameters of the main ship, and the determined inversion mode, the starting coordinate range of the auxiliary ship in the inversion process can be obtained.

[0081] In one alternative approach, the inversion mode of the inversion process is determined based on the relationship between the actual acquisition direction and the preset acquisition direction, as well as the accuracy requirements during the inversion process, as follows:

[0082] If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the first direction, and the actual acquisition direction is parallel to the preset acquisition direction or parallel to the opposite direction of the preset acquisition direction, then the transverse full waveform inversion mode is adopted; the first direction refers to the direction perpendicular to the construction direction.

[0083] If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the first direction, and the actual acquisition direction is orthogonal to the preset acquisition direction, then the longitudinal full waveform inversion mode is adopted.

[0084] If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the second direction, and the actual acquisition direction is parallel to the preset acquisition direction or parallel to the opposite direction of the preset acquisition direction, then the longitudinal full waveform inversion mode is adopted; the second direction refers to the direction parallel to the construction direction.

[0085] If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the second direction, and the actual acquisition direction is orthogonal to the preset acquisition direction, then the transverse full waveform inversion mode is adopted.

[0086] Specifically, this embodiment considers two cases: improving the accuracy of the velocity model in the first direction and improving the accuracy of the velocity model in the second direction. In each case, the relationship between the actual acquisition direction and the preset acquisition direction is considered, thus obtaining a more suitable inversion mode.

[0087] Longitudinal full waveform inversion mode such as Figures 7-11 As shown, where, Figure 7 For the longitudinal full waveform inversion mode of auxiliary ship 1 directly in front of main ship 2, Figure 8 The first is the longitudinal full-waveform inversion mode with the main ship 2 directly in front of the auxiliary ship 1; secondly, in the specific inversion, two auxiliary ships can also be used. Figure 9 Both auxiliary vessels 1 are located ahead of the main vessel 2. Figure 10 Both auxiliary vessels 1 are located behind the main vessel 2. Figure 9 and Figure 10 The arrangement of the two auxiliary ships allows for the acquisition of refracted wave information from a greater distance; Figure 11 Similarly, two auxiliary vessels 1 are set up, one in front of the main vessel 2 and the other behind the main vessel 2. In the specific inversion, the relative positions of the auxiliary vessels and the main vessel, as well as the number of auxiliary vessels, can be set as needed.

[0088] The longitudinal full-waveform inversion mode can acquire abundant refracted wave information in the direction parallel to the towed cable of the main ship. This allows for high-precision velocity field modeling in this direction using the obtained refracted wave information. However, in actual acquisition, the direction perpendicular to the cable is a weak area for high-precision imaging, where data quality is not guaranteed, and coverage and azimuth information are insufficient. To ensure high-precision imaging in the direction perpendicular to the cable, a transverse full-waveform inversion mode is proposed from the perspective of high-precision velocity modeling. This mode guarantees the accuracy of transverse velocity modeling, thereby ensuring high-precision imaging.

[0089] Lateral full waveform inversion mode such as Figures 12-14 As shown, where, Figure 12 Auxiliary vessel 1 is located to the left of main vessel 2. Figure 13 Auxiliary vessel 1 is located on the starboard side of main vessel 2. Figure 14 A secondary vessel 1 is located on both the left and right sides of the main ship 2.

[0090] In one alternative approach, based on the azimuth range and the parameters of the main ship, combined with the inversion mode, the starting coordinate range of the auxiliary ship during the inversion process is specifically obtained as follows:

[0091] Taking the opposite direction of the traveling direction of the main ship as the X-axis direction and the symmetric center of the first row of geophones behind the main ship as the coordinate origin, a coordinate system is established to obtain the coordinate set of all the geophones behind the main ship;

[0092] According to the coordinate set of all the geophones behind the main ship, the azimuth range, and the inversion mode, the starting coordinate range of the auxiliary ship during the inversion process is obtained.

[0093] Specifically, the parameters of the main ship refer to the coordinate set of all the geophones behind the main ship. For example, if the length of the cable towed by the main ship is 7050 m and the distance between adjacent two geophones on each cable is 12.5 m, then each cable behind the main ship towes 565 geophones; it is set that a total of 10 cables are towed behind the main ship, and the distance between adjacent two cables is 100 m. Taking the symmetric center of the first row of geophones behind the main ship as the coordinate origin O, the X-axis is set to have an angle of 180 degrees with the traveling direction of the main ship. According to the right-hand rule, the Y-axis can be obtained, so that in the XOY coordinate system, the coordinate set [X R , Y R composed of the coordinates of all the geophones behind the main ship can be obtained.

[0094] Again, according to the coordinate set [X R , Y R of the coordinates of all the geophones behind the main ship, the determined inversion mode, and the range of the azimuth angle, the starting coordinate range of the auxiliary ship can be obtained.

[0095] First, set the determined inversion mode as the longitudinal full-waveform inversion mode. As Figure 15 shown, Figure 15 in which angle A represents the azimuth angle. Set the coordinates of auxiliary ship 1 as [X S , 0], and set the range of the azimuth angle A to be between [-8 degrees, 8 degrees]. Then, the maximum value of X S can be calculated to be -3202 m, that is, the minimum distance between auxiliary ship 1 and the coordinate origin is 3202 m. According to the different distances between the main ship and the auxiliary ship, a statistical curve of the azimuth angle can be obtained as Figure 16 shown, Figure 16 in which the abscissa represents the azimuth angle in degrees, and the ordinate represents the proportion of the azimuth angle within a certain degree range when the distance between the auxiliary ship and the coordinate origin is 3525 m. Figure 16 In, the azimuth angle corresponding to the "meter" character is 8 degrees, and the proportion of the azimuth angle within 8 degrees reaches 100%. That is, when the distance between the auxiliary ship and the coordinate origin is 3525 m, the azimuth angle is concentrated within the range of [0, 8] degrees. Extending to the negative Y-axis direction, the azimuth angle is concentrated within the range of [-8, 8] degrees.

[0096] For the longitudinal full-waveform inversion mode where the auxiliary ship is directly ahead of the main ship, the concentration of the azimuth angle is determined by the distance X between the auxiliary ship's seismic source and the coordinate origin. S Decide, Figure 17 X is shown S The statistical results of the azimuth angle at 0.5 times, 1 times, 2 times, 3 times, and 4 times the cable length, specifically in X... S Equal to 0.5 times the cable length, that is, X S When the azimuth is equal to -3525m, the azimuth is concentrated in the range of [-8, 8] degrees, in X S Equal to 1 cable length, that is, X S When the azimuth is equal to -7050m, the azimuth is concentrated in the range of [-4, 4] degrees, in X S Equal to twice the cable length, that is, X S When the azimuth is equal to -14100m, the azimuth is concentrated in the range of [-2, 2] degrees, in X S Equal to 3 times the cable length, that is, X S When the azimuth is equal to -21150m, the azimuth is concentrated in the range of [-2, 2] degrees, in X S Equal to 4 times the cable length, that is, X S When the azimuth is equal to -28200m, the azimuth is concentrated in the range of [-1, 1] degrees. That is, as the distance between the auxiliary ship and the origin of the coordinate system increases, the azimuth gradually becomes concentrated.

[0097] Based on current understanding of full waveform inversion, a wider azimuth angle generally improves the accuracy of the inversion. However, in the longitudinal full waveform inversion mode, as the distance X... S As the azimuth increases, the azimuth becomes more concentrated, and due to the significant increase in data volume, the inversion accuracy improves in the azimuth concentration direction. This contradicts common understanding, therefore the longitudinal full waveform inversion mode is applied more often to relatively simple regions, based on the distance X between the auxiliary vessel and the coordinate origin. S Adjusting the azimuth angle improves inversion accuracy in a single direction. It is also applicable to longitudinal full-waveform inversion modes with the auxiliary vessel in front and behind.

[0098] Next, the determined inversion mode is set to a transverse full-waveform inversion mode, with the auxiliary ship located to the left or right of the main ship. The coordinates of the auxiliary ship are represented by [X...]. S Y S This indicates that the auxiliary ship's coordinates are set along the X-axis component X. S The component X of a detector's coordinates on the X-axis i When they are equal (where i is the i-th row of detectors aft of the main ship), the Y-component of the auxiliary ship's coordinates on the Y-axis can be obtained. S The range of coordinates is used to obtain the starting coordinate range of the auxiliary ship during the inversion process.

[0099] like Figure 18 As shown, auxiliary vessel 1 is located on the straight line where the first row of detectors are located behind the main vessel 2, that is, the coordinate component X of auxiliary vessel 1 on the X-axis. S =0, the corresponding azimuth range is an azimuth of 26 degrees, then Figure 18 The coordinates of auxiliary ship 1 are [X S =0m, Y S =3525m]; Again, as Figure 19 As shown, auxiliary vessel 1 is located in the middle of the cable towed by main vessel 2, that is, the coordinate component of auxiliary vessel 1 on the X-axis is X. S =3525m, the corresponding azimuth range is azimuth angle equal to 45 degrees, then Figure 19 The coordinates of auxiliary ship 1 are [X S =3525m, Y S =3525m).

[0100] Furthermore, based on the different coordinates of the auxiliary vessel, statistical curves of the azimuth angle can be obtained, such as... Figure 20 As shown, Figure 20 The dashed line in the middle represents the coordinates of the auxiliary ship as [X]. S =0m, Y S The statistical curve of the azimuth angle when [=3525m], from Figure 20 It can be seen that the auxiliary ship's coordinates are [X S =0m, Y S When the azimuth is 3525m, the azimuth angle is distributed between 25-90°; Figure 20 The solid line in the center indicates the coordinates of the auxiliary ship as [X]. S =3525m, Y S The statistical curve of the azimuth angle when [=3525m], from Figure 20 It can be seen that the auxiliary ship's coordinates are [X S =3525m, Y S When [m = 3525m], the azimuth angle is distributed between 40-90°. According to... Figure 20 The following conclusions can be drawn: In the transverse full waveform inversion mode, at the longitudinal distance Y... S Under certain conditions, the lateral distance X can be adjusted. S This expands the range of azimuth angles.

[0101] In the transverse full-waveform inversion mode, for the X-axis component X of the auxiliary ship coordinates S The same, but the Y-axis component Y S In different cases, the coordinates of one of the auxiliary ships are [X] S =3525m, Y S =3525m] and the coordinates of another auxiliary ship are [X S =3525m,Y STaking [7050m] as an example, the statistical curve of the azimuth angle obtained is as follows: Figure 21 As shown, Figure 21 The solid line in the center indicates the coordinates of the auxiliary ship as [X]. S =3525m, Y S The statistical curve of the azimuth angle when [=3525m], from Figure 21 It can be seen that the auxiliary ship's coordinates are [X S =0m, Y S When the azimuth is 3525m, the azimuth angle is distributed between 40-90°; Figure 21 The dashed line in the middle represents the coordinates of the auxiliary ship as [X]. S =3525m,Y S The statistical curve of the azimuth angle at [7050m] is from... Figure 21 It can be seen that the auxiliary ship's coordinates are [X S =3525m,Y S When [7050m], the azimuth angle is distributed between 60-90°. According to Figure 21 The following conclusions can be drawn: In the transverse full waveform inversion mode, at the transverse distance X S Under certain conditions, the further the auxiliary vessel deviates longitudinally from the center of the cable, the narrower the corresponding azimuth angle distribution range becomes.

[0102] Furthermore, in specific implementation of this embodiment of the invention, the main ship also carries a seismic source so that the detector on the main ship can receive the reflected waves from the seismic source on the main ship, so as to perform offset imaging based on the reflected waves.

[0103] Since the detectors on the main ship receive refracted waves from the seismic source on the auxiliary ship and reflected waves from the seismic source on the main ship, the refracted wave data and reflected wave data will be mixed. Therefore, in actual processing, common detector domain denoising algorithms and transform domain feature extraction methods are used. The signal basis of these two types of algorithms is to highlight the features of the effective signal and weaken the features of the background signal.

[0104] Secondly, when acquiring refracted waves, multiple ships can work together to complete the acquisition in one go, or multiple acquisitions can be made by two ships, namely a main ship and an auxiliary ship, to achieve multi-ship refracted wave acquisition. During data acquisition, a pseudo-continuous acquisition method can be used. This method is proposed when the main ship lacks a continuous acquisition configuration. Based on conventional acquisition, the traditional single-source recordings from the main ship are connected according to the accurately recorded source times, with missing data between sources filled with zeros. Then, the records from the auxiliary ship used for full waveform inversion are extracted according to the firing time of the auxiliary ship.

[0105] In this embodiment of the invention, the actual acquisition direction during the inversion process is obtained from the spatial coordinates of the target layer using Fourier transform, resulting in an actual acquisition direction that more closely matches the structural attitude. The geophones on the main ship receive refracted waves from the seismic source on the auxiliary ship to establish a velocity model, thus improving the modeling accuracy of the velocity model.

[0106] Figure 22 A schematic diagram of an embodiment of the device for improving the accuracy of velocity models in full waveform inversion according to the present invention is shown. Figure 22 As shown, the device includes a Fourier transform module 310 and an auxiliary vessel starting coordinate range determination module 320, specifically:

[0107] The Fourier transform module 310 is used to calculate the actual acquisition direction and azimuth range of the inversion process based on the spatial coordinates of the target layer after selecting the target layer for inversion.

[0108] The auxiliary vessel starting coordinate range determination module 320 is used to obtain the starting coordinate range of the auxiliary vessel during the inversion process based on the azimuth range and the parameters of the main vessel, so that any position of the target layer can be used as the starting position of the main vessel, and inversion can be performed within the target layer according to the starting coordinate range of the auxiliary vessel and the actual acquisition direction, so that the detector on the main vessel can receive the refracted wave of the seismic source on the auxiliary vessel, and a velocity model can be established based on the refracted wave.

[0109] In this embodiment, both the actual acquisition direction and the azimuth range during the inversion process are calculated using Fourier transform based on the spatial coordinates of the target stratum. In existing technologies, the actual acquisition direction is obtained statistically based on the attitude of the underground structures at the starting point; therefore, the actual acquisition direction obtained in this embodiment is more accurate.

[0110] Currently, in addition to high-quality seismic data, high-quality velocity modeling is also an important guarantee for high-precision seismic exploration. The refracted wave information of the auxiliary vessel collected in this embodiment of the invention is used to establish a high-quality velocity model.

[0111] In an optional approach, after selecting the target layer for inversion, the Fourier transform module 310 calculates the actual acquisition direction and azimuth range of the inversion process using Fourier transform based on the spatial coordinates of the target layer, further including:

[0112] The Fourier transform module 310 uses any point as the origin of the coordinate system, takes the due north direction as the positive y-axis direction, and the due east direction as the positive x-axis direction, and establishes a three-dimensional coordinate system according to the right-hand rule to obtain the spatial coordinates of the target layer.

[0113] The Fourier transform module 310 performs a two-dimensional Fourier transform on the spatial coordinates to obtain a wavenumber domain Fourier spectrum.

[0114] The Fourier transform module 310 obtains the construction direction based on the distribution characteristics of the energy field in the wavenumber domain Fourier spectrum;

[0115] The Fourier transform module 310 determines the actual acquisition direction and azimuth range of the inversion process based on the constructed orientation direction.

[0116] Based on the energy distribution characteristics of the wavenumber domain amplitude spectrum in space, the direction of the structure can be determined. The direction perpendicular to the direction of the structure is the actual acquisition direction, which is also the direction of the main ship's movement during the inversion process. The azimuth range of the inversion process is determined based on the deflection angle and error accuracy. For example, if the error accuracy is dθ, then the azimuth range is θ±dθ.

[0117] Secondly, there are two perpendicular directions to the actual structural orientation, which means there are two actual acquisition directions, which are 180 degrees apart. Therefore, in actual inversion, the inversion is generally completed by going back and forth between the two actual acquisition directions that are 180 degrees apart.

[0118] In one alternative approach, the auxiliary vessel's starting coordinate range determination module 320, based on the azimuth range and the main vessel's parameters, obtains the specific starting coordinate range of the auxiliary vessel during the inversion process as follows:

[0119] If two azimuth ranges are determined based on the construction direction, an inversion mode combining longitudinal full waveform inversion and transverse full waveform inversion is adopted. The auxiliary ship starting coordinate range determination module 320 obtains the starting coordinate range of one auxiliary ship based on one of the azimuth ranges and the parameters of the main ship, and obtains the starting coordinate range of the other auxiliary ship based on the other azimuth range and the parameters of the main ship.

[0120] If only one azimuth range can be determined based on the aforementioned structural orientation, then the auxiliary vessel's starting coordinate range determination module 320 obtains the starting coordinate range of the auxiliary vessel during the inversion process based on the azimuth range and the parameters of the main vessel.

[0121] In the case of a single orthogonal strong energy field, a deflection angle can be obtained, and only an azimuth range can be determined. Based on the determined azimuth range and the parameters of the main ship, the starting coordinate range of the auxiliary ship in the inversion process can be obtained.

[0122] However, for cases with two orthogonal strong energy fields, i.e., two deflection angles, the actual acquisition direction is determined based on the two deflection angles. Under the actual acquisition direction, two azimuth ranges are determined. Then, an inversion mode combining longitudinal full waveform inversion and lateral full waveform inversion is adopted. Based on one of the azimuth ranges and the parameters of the main ship, the starting coordinate range of one auxiliary ship is obtained. Based on the other azimuth range and the parameters of the main ship, the starting coordinate range of the other auxiliary ship is obtained. Thus, an inversion mode of two auxiliary ships and one main ship is used for inversion.

[0123] In an alternative approach, if only one azimuth range can be determined based on the construction direction, the auxiliary vessel's starting coordinate range determination module 320, based on the azimuth range and the main vessel's parameters, further determines the auxiliary vessel's starting coordinate range during the inversion process, including:

[0124] The auxiliary vessel's starting coordinate range determination module 320 determines the inversion mode of the inversion process based on the relationship between the actual acquisition direction and the preset acquisition direction, as well as the accuracy requirements in the inversion process. The inversion mode includes a longitudinal full waveform inversion mode and a transverse full waveform inversion mode.

[0125] The auxiliary vessel's starting coordinate range determination module 320 determines the starting coordinate range of the auxiliary vessel during the inversion process based on the azimuth range and the parameters of the main vessel, combined with the inversion mode.

[0126] Specifically, the preset acquisition direction will be suggested in the early stage of the observation system design; however, the starting coordinate range of the auxiliary ship will be different depending on the inversion mode. Therefore, in this embodiment, the inversion mode of the inversion process is first determined based on the relationship between the actual acquisition direction and the preset acquisition direction, as well as the accuracy requirements in the inversion process. Then, based on the azimuth range, the parameters of the main ship, and the determined inversion mode, the starting coordinate range of the auxiliary ship in the inversion process can be obtained.

[0127] In one alternative approach, the auxiliary vessel's starting coordinate range determination module 320 determines the inversion mode of the inversion process based on the relationship between the actual acquisition direction and the preset acquisition direction, as well as the accuracy requirements during the inversion process:

[0128] If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the first direction, and the actual acquisition direction is parallel to the preset acquisition direction or parallel to the opposite direction of the preset acquisition direction, then the auxiliary ship's starting coordinate range determination module 320 determines to adopt the transverse full waveform inversion mode; the first direction refers to the direction perpendicular to the structure orientation direction;

[0129] If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the first direction, and the actual acquisition direction is orthogonal to the preset acquisition direction, then the auxiliary ship's starting coordinate range determination module 320 determines to adopt the longitudinal full waveform inversion mode.

[0130] If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the second direction, and the actual acquisition direction is parallel to the preset acquisition direction or parallel to the opposite direction of the preset acquisition direction, then the auxiliary ship's starting coordinate range determination module 320 determines to adopt the longitudinal full waveform inversion mode; the second direction refers to the direction parallel to the construction direction.

[0131] If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the second direction, and the actual acquisition direction is orthogonal to the preset acquisition direction, then the auxiliary ship's starting coordinate range determination module 320 determines to adopt the transverse full waveform inversion mode.

[0132] Specifically, this embodiment considers two cases: improving the accuracy of the velocity model in the first direction and improving the accuracy of the velocity model in the second direction. In each case, the relationship between the actual acquisition direction and the preset acquisition direction is considered, thus obtaining a more suitable inversion mode.

[0133] In one alternative approach, the auxiliary vessel's starting coordinate range determination module 320, based on the azimuth range and the main vessel's parameters, combined with the inversion mode, obtains the specific starting coordinate range of the auxiliary vessel during the inversion process as follows:

[0134] The auxiliary vessel's starting coordinate range determination module 320 establishes a coordinate system with the opposite direction of the main vessel's travel direction as the X-axis direction and the center of symmetry of the first row of detectors behind the main vessel as the origin, thereby obtaining the coordinate set of all detectors behind the main vessel.

[0135] The auxiliary vessel's starting coordinate range determination module 320 obtains the starting coordinate range of the auxiliary vessel during the inversion process based on the coordinate set of all detectors behind the main vessel, the azimuth range, and the inversion mode.

[0136] Specifically, the parameters of the main ship refer to the coordinate set of all the detectors behind the main ship. For example, if the cable towed by the main ship is 7050m long and the spacing between two adjacent detectors on each cable is 12.5m, then each cable towed by the main ship carries 565 detectors. Assuming there are 10 cables towed by the main ship, with a spacing of 100m between adjacent cables, then taking the center of symmetry of the first row of detectors behind the main ship as the origin O, and setting the X-axis to have an angle of 180 degrees with the direction of the main ship's travel, the Y-axis can be obtained according to the right-hand rule. Thus, the coordinate set [X...] of all the detectors behind the main ship can be obtained in the XOY coordinate system. RY R ].

[0137] Again, based on the coordinate set of all detectors behind the main ship [X] R Y R The starting coordinate range of the auxiliary vessel can be obtained by determining the inversion mode and the range of azimuth angles.

[0138] First, the determined inversion mode is set as the longitudinal full-waveform inversion mode, and the coordinates of the auxiliary ship are set as [X]. S If the azimuth angle A is set to the range of [-8 degrees, 8 degrees], then X can be calculated. S The maximum value is -3202m, which means the minimum distance between the auxiliary ship and the origin of the coordinate system is 3202m.

[0139] Next, the determined inversion mode is set to a transverse full-waveform inversion mode, with the auxiliary ship located to the left or right of the main ship. The coordinates of the auxiliary ship are represented by [X...]. S Y S This indicates that the auxiliary ship's coordinates are set along the X-axis component X. S The component X of a detector's coordinates on the X-axis i When they are equal (where i is the i-th row of detectors aft of the main ship), the Y-component of the auxiliary ship's coordinates on the Y-axis can be obtained. S The range of coordinates is used to obtain the starting coordinate range of the auxiliary ship during the inversion process.

[0140] Furthermore, in specific implementation of this embodiment of the invention, the main ship also carries a seismic source so that the detector on the main ship can receive the reflected waves from the seismic source on the main ship, so as to perform offset imaging based on the reflected waves.

[0141] Since the detectors on the main ship receive refracted waves from the seismic source on the auxiliary ship and reflected waves from the seismic source on the main ship, the refracted wave data and reflected wave data will be mixed. Therefore, in actual processing, common detector domain denoising algorithms and transform domain feature extraction methods are used. The signal basis of these two types of algorithms is to highlight the features of the effective signal and weaken the features of the background signal.

[0142] Secondly, when acquiring refracted waves, multiple ships can work together to complete the acquisition in one go, or multiple acquisitions can be made by two ships, namely a main ship and an auxiliary ship, to achieve multi-ship refracted wave acquisition. During data acquisition, a pseudo-continuous acquisition method can be used. This method is proposed when the main ship lacks a continuous acquisition configuration. Based on conventional acquisition, the traditional single-source recordings from the main ship are connected according to the accurately recorded source times, with missing data between sources filled with zeros. Then, the records from the auxiliary ship used for full waveform inversion are extracted according to the firing time of the auxiliary ship.

[0143] This invention provides a non-volatile computer storage medium storing at least one executable instruction that can execute the method for improving the accuracy of the velocity model in full waveform inversion in any of the above method embodiments.

[0144] Figure 23 The diagram shows a structural schematic of an embodiment of a computing device according to the present invention. The specific embodiments of the present invention do not limit the specific implementation of the computing device.

[0145] like Figure 23 As shown, the computing device may include: a processor 402, a communications interface 404, a memory 406, and a communications bus 408.

[0146] The processor 402, communication interface 404, and memory 406 communicate with each other via communication bus 408. Communication interface 404 is used to communicate with other network elements, such as clients or other servers. Processor 402 executes program 410, specifically performing the relevant steps in the above-described method embodiment for improving the accuracy of the velocity model in full waveform inversion for computing devices.

[0147] Specifically, program 410 may include program code that includes computer operation instructions.

[0148] Processor 402 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. The apparatus for improving the accuracy of the speed model in full waveform inversion includes one or more processors, which may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0149] Memory 406 is used to store program 410. Memory 406 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0150] Specifically, program 410 can be used to cause processor 402 to execute the method for improving the accuracy of the velocity model in full waveform inversion in any of the above method embodiments.

[0151] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. Various general-purpose systems can also be used in conjunction with the teachings herein. The required structure for constructing such systems is apparent from the above description. Furthermore, the embodiments of the present invention are not directed to any particular programming language. It should be understood that the content of the invention described herein can be implemented using various programming languages, and the above description of specific languages ​​is for the purpose of disclosing the best mode of implementation of the invention.

[0152] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0153] Similarly, it should be understood that, in order to simplify the invention and aid in understanding one or more of the various inventive aspects, features of the embodiments of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into this detailed description, wherein each claim itself is a separate embodiment of the invention.

[0154] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0155] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0156] The various component embodiments of the present invention can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. Those skilled in the art will understand that microprocessors or digital signal processors (DSPs) can be used in practice to implement some or all of the functions of some or all of the components according to the embodiments of the present invention. The present invention can also be implemented as a device or apparatus program (e.g., a computer program and computer program product) for performing part or all of the methods described herein. Such programs implementing the present invention can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0157] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

Claims

1. A method for improving the accuracy of velocity models in full waveform inversion, characterized in that, include: Select the target layer for inversion, and calculate the actual acquisition direction and azimuth range of the inversion process using Fourier transform based on the spatial coordinates of the target layer. Based on the azimuth range and the parameters of the main ship, the starting coordinate range of the auxiliary ship during the inversion process is obtained, so that any position of the target layer can be used as the starting position of the main ship. The inversion is carried out within the target layer according to the starting coordinate range of the auxiliary ship and the actual acquisition direction, so that the detector on the main ship can receive the refracted wave of the seismic source on the auxiliary ship, and a velocity model can be established based on the refracted wave.

2. The method for improving the accuracy of the velocity model in full waveform inversion according to claim 1, characterized in that, The step of selecting the target stratum for inversion, and calculating the actual acquisition direction and azimuth range of the inversion process using Fourier transform based on the spatial coordinates of the target stratum, further includes: Select the target stratigraphic level for the inversion; Using any point as the origin of the coordinate system, and taking due north as the positive y-axis and due east as the positive x-axis, a three-dimensional coordinate system is established according to the right-hand rule to obtain the set of spatial coordinates of the target layer. A two-dimensional Fourier transform is performed on the set of spatial coordinates to obtain the wavenumber domain Fourier spectrum; The orientation of the structure is determined based on the distribution characteristics of the energy field in the wavenumber domain Fourier spectrum. The actual acquisition direction and azimuth range of the inversion process are determined based on the structural orientation.

3. The method for improving the accuracy of the velocity model in full waveform inversion according to claim 2, characterized in that, The specific details of obtaining the starting coordinate range of the auxiliary ship during the inversion process based on the azimuth range and the parameters of the main ship are as follows: If two azimuth ranges are determined based on the aforementioned structural orientation, an inversion mode combining longitudinal full waveform inversion and transverse full waveform inversion is adopted. Based on one of the azimuth ranges and the parameters of the main ship, the starting coordinate range of one auxiliary ship is obtained, and based on the other azimuth range and the parameters of the main ship, the starting coordinate range of the other auxiliary ship is obtained. If only one azimuth range can be determined based on the aforementioned structural orientation, then the starting coordinate range of the auxiliary ship during the inversion process can be obtained based on the azimuth range and the parameters of the main ship.

4. The method for improving the accuracy of the velocity model in full waveform inversion according to claim 3, characterized in that, If only one azimuth range can be determined based on the structural orientation, then the starting coordinate range of the auxiliary ship during the inversion process, based on the azimuth range and the parameters of the main ship, further includes: The inversion mode of the inversion process is determined based on the relationship between the actual acquisition direction and the preset acquisition direction, as well as the accuracy requirements in the inversion process. The inversion mode includes a longitudinal full waveform inversion mode and a transverse full waveform inversion mode. Based on the azimuth range and the parameters of the main ship, combined with the inversion mode, the starting coordinate range of the auxiliary ship during the inversion process is obtained.

5. The method for improving the accuracy of the velocity model in full waveform inversion according to claim 4, characterized in that, The specific steps for determining the inversion mode of the inversion process based on the relationship between the actual acquisition direction and the preset acquisition direction, as well as the accuracy requirements during the inversion process, are as follows: If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the first direction, and the actual acquisition direction is parallel to the preset acquisition direction or parallel to the opposite direction of the preset acquisition direction, then the transverse full waveform inversion mode is adopted; the first direction refers to the direction perpendicular to the construction direction. If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the first direction, and the actual acquisition direction is orthogonal to the preset acquisition direction, then the longitudinal full waveform inversion mode is adopted. If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the second direction, and the actual acquisition direction is parallel to the preset acquisition direction or parallel to the opposite direction of the preset acquisition direction, then the longitudinal full waveform inversion mode is adopted; the second direction refers to the direction parallel to the construction direction. If the accuracy requirement in the inversion process is to improve the accuracy of the velocity model in the second direction, and the actual acquisition direction is orthogonal to the preset acquisition direction, then the transverse full waveform inversion mode is adopted.

6. The method for improving the accuracy of the velocity model in full waveform inversion according to claim 4, characterized in that, The specific details of obtaining the starting coordinate range of the auxiliary ship during the inversion process, based on the azimuth range and the parameters of the main ship, combined with the inversion mode, are as follows: With the direction opposite to the main ship's direction of travel as the X-axis and the center of symmetry of the first row of detectors at the rear of the main ship as the origin, a coordinate system is established to obtain the coordinate set of all detectors at the rear of the main ship. The starting coordinate range of the auxiliary ship is obtained based on the coordinate set of all the detectors behind the main ship, the azimuth range, and the inversion mode.

7. The method for improving the accuracy of the velocity model in full waveform inversion according to claim 1, characterized in that, The main ship also carries a seismic source so that a detector on the main ship can receive the reflected waves from the seismic source on the main ship, so as to perform offset imaging based on the reflected waves.

8. A device for improving the accuracy of velocity models in full waveform inversion, characterized in that, include: The Fourier transform module is used to calculate the actual acquisition direction and azimuth range of the inversion process based on the spatial coordinates of the selected target layer after inversion. The auxiliary vessel's starting coordinate range determination module is used to obtain the starting coordinate range of the auxiliary vessel during the inversion process based on the azimuth range and the parameters of the main vessel, so that any position of the target layer can be used as the starting position of the main vessel, and inversion can be performed within the target layer according to the starting coordinate range of the auxiliary vessel and the actual acquisition direction, so that the detector on the main vessel can receive the refracted wave from the seismic source on the auxiliary vessel, and a velocity model can be established based on the refracted wave.

9. A computing device, comprising: The processor, memory, communication interface, and communication bus are provided, wherein the processor, memory, and communication interface communicate with each other via the communication bus. The memory is used to store at least one executable instruction that causes the processor to perform the operation corresponding to the method for improving the accuracy of the velocity model in full waveform inversion as described in any one of claims 1-7.

10. A computer storage medium storing at least one executable instruction that causes a processor to perform an operation as claimed in any one of claims 1-7, corresponding to improving the accuracy of a velocity model in full waveform inversion.

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