Earthquake imaging method and device for protecting low-frequency wave field information and electronic equipment

Abstract

The invention discloses a seismic imaging method and device for protecting low-frequency wave field information and electronic equipment. The method comprises the following steps: respectively calculating a shot point propagation wave field and a detection point back propagation wave field based on seismic data; at each moment of wave field propagation, performing multi-direction decomposition on a shot point propagation wave field and a detection point back propagation wave field to obtain wave field components of a full wave field in different directions; and respectively imaging wave field components of the full wave field in different directions by using time-space domain traveling wave multi-direction decomposition broadband imaging conditions to obtain imaging results. According to the invention, the problems of low-frequency noise and offset illusion can be effectively suppressed while the imaging precision is ensured, the protection of low-frequency information is realized, and the movement of an imaging profile spectrum to a high-frequency end is avoided.

Description

Technical Field

[0001] The present invention belongs to the field of pre-stack depth migration imaging of seismic data, and more specifically, relates to a seismic imaging method, device and electronic equipment for protecting low-frequency wave field information. Background Art

[0002] Prestack depth reverse time migration realizes the propagation of wave fields in underground media by solving wave equations. It can accurately describe the propagation of various types of seismic waves and achieve accurate seismic imaging at high and steep dip angles.

[0003] At present, the imaging condition used in reverse time migration is the conventional cross-correlation imaging condition. Its wave field is a complex two-way wave field. The directionality of the wave field is not considered, which will cause low-wavenumber and high-amplitude migration noise and migration artifacts in the imaging results, reducing the imaging accuracy of the migration section. In actual production applications, the solution is mainly to perform high-pass filtering after stacking, but conventional filtering will introduce artifacts; another solution is to perform Laplace filtering, but Laplace filtering can only suppress low-wavenumber and high-amplitude migration noise, and cannot effectively eliminate imaging artifacts. At the same time, it will change the imaging amplitude and frequency phase information, and is not amplitude-preserving, which is not conducive to subsequent seismic interpretation work. Summary of the invention

[0004] The purpose of the present invention is to propose a seismic imaging method, device and electronic equipment for protecting low-frequency wave field information, so as to effectively suppress low-frequency noise and offset illusion problems while ensuring imaging accuracy, and at the same time protect low-frequency information and avoid the movement of the imaging section spectrum to the high-frequency end.

[0005] To achieve the above objectives, in a first aspect, the present invention proposes a seismic imaging method for protecting low-frequency wave field information, comprising:

[0006] Based on the seismic data, the propagation wave field of the shot point and the reverse propagation wave field of the receiver point are calculated respectively;

[0007] At each moment of wave field propagation, the propagation wave field of the shot point and the reverse propagation wave field of the detection point are decomposed in multiple directions to obtain wave field components of the whole wave field in different directions;

[0008] The wave field components in different directions of the full wave field are imaged separately using the broadband imaging condition of multi-directional decomposition of traveling waves in the time-space domain to obtain the imaging results.

[0009] Optionally, multi-directional decomposition of the shot point propagation wavefield and the detection point reverse propagation wavefield is expressed by the following formula:

[0010]

[0011]

[0012] Among them, S d (w,k z ) represents the downgoing wave at the shot point in the frequency wavenumber domain, S u (w,k z ) represents the upgoing wave at the shot point in the frequency wavenumber domain, S + (w,k z ) represents the single wave at the shot point in the frequency wavenumber domain, S_(w, k z ) represents the single wave at the shot point in the frequency wavenumber domain, w represents the frequency, k z Indicates the wave number in the depth z direction.

[0013] Optionally, the time-space domain traveling wave multi-directional decomposition broadband imaging condition is:

[0014]

[0015] Where I(x, y, z) represents the wave field imaging result with the opposite propagation direction at the spatial position (x, y, z) at time t, T max is the maximum time of wave field extension, s + (t, z) represents the single wave of the shot point at time t in the time-space domain, s_(t, z) represents the single wave of the shot point at time t in the time-space domain, r + (t, z) represents a single wave at the detection point at time t in the time-space domain, and “*” represents the complex conjugate.

[0016] Optionally, in the fk domain, the shot point propagation wavefield and the detection point reverse propagation wavefield are decomposed in multiple directions.

[0017] In a second aspect, the present invention provides an electronic device, the electronic device comprising:

[0018] at least one processor; and,

[0019] a memory communicatively connected to the at least one processor; wherein,

[0020] The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the seismic imaging method for protecting low-frequency wavefield information described in any one of the first aspects.

[0021] In a third aspect, the present invention provides a non-transitory computer-readable storage medium storing computer instructions for causing a computer to execute any of the seismic imaging methods for protecting low-frequency wavefield information described in the first aspect.

[0022] In a fourth aspect, the present invention provides a seismic imaging device for protecting low-frequency wave field information, comprising:

[0023] A wave field calculation module, used to calculate the propagation wave field of the shot point and the reverse propagation wave field of the receiver point based on the seismic data;

[0024] A wave field decomposition module is used to perform multi-directional decomposition of the shot point propagation wave field and the detection point reverse propagation wave field at each moment of wave field propagation to obtain wave field components of the whole wave field in different directions;

[0025] The wave field components in different directions of the full wave field are imaged separately using the broadband imaging condition of multi-directional decomposition of traveling waves in the time-space domain to obtain the imaging results.

[0026] Optionally, multi-directional decomposition of the shot point propagation wavefield and the detection point reverse propagation wavefield is expressed by the following formula:

[0027]

[0028]

[0029] Among them, S d (w,k z ) represents the downgoing wave at the shot point in the frequency wavenumber domain, Su(w, k z ) represents the upgoing wave at the shot point in the frequency wavenumber domain, S + (w,k z ) represents the single-travel wave at the shot point in the frequency wavenumber domain, S-(w, k z ) represents the single wave at the shot point in the frequency wavenumber domain, w represents the frequency, k z Indicates the wave number in the depth z direction.

[0030] Optionally, the time-space domain traveling wave multi-directional decomposition broadband imaging condition is:

[0031]

[0032] Where I(x, y, z) represents the wave field imaging result with the opposite propagation direction at the spatial position (x, y, z) at time t, T max is the maximum time of wave field extension, s + (t, z) represents the single wave of the shot point at time t in the time-space domain, s_(t, z) represents the single wave of the shot point at time t in the time-space domain, r + (t, z) represents a single wave at the detection point at time t in the time-space domain, and “*” represents the complex conjugate.

[0033] Optionally, in the fK domain, the shot point propagation wavefield and the detection point reverse propagation wavefield are decomposed in multiple directions.

[0034] The beneficial effects of the present invention are:

[0035] The present invention uses wave field components in different directions of the full wave field for separate imaging, thereby constructing a seismic imaging algorithm that protects low-frequency wave field information. This method can effectively suppress low-frequency noise and offset artifacts while ensuring imaging accuracy, and can also protect low-frequency information, avoiding the movement of the imaging profile spectrum to the high-frequency end, providing technical support for broadband seismic imaging.

[0036] The system of the present invention has other characteristics and advantages, which will be apparent from the drawings incorporated herein and the following detailed description, or will be described in detail in the drawings incorporated herein and the following detailed description, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which like reference numerals generally represent like components.

[0038] Figure 1 A step diagram of a seismic imaging method for protecting low-frequency wave field information according to the present invention is shown.

[0039] Figure 2 A processing flow chart of a seismic imaging method for protecting low-frequency wavefield information according to an embodiment of the present invention.

[0040] Figure 3a The reverse time migration results obtained by the conventional method for a simple flat layer model are shown.

[0041] Figure 3b The reverse time migration result obtained by the method of the present invention is shown.

[0042] Figure 4a and Figure 4b They are the wave fields before decomposition in the shot point and receiver point directions respectively.

[0043] Figure 5 The multi-directional wave field at the shot point end after separation by the method of the present invention.

[0044] Figure 6 This is the result of conventional reverse time migration imaging.

[0045] Figure 7a This is the reverse time migration result of the present invention.

[0046] Figure 7b This is the reverse time migration result after conventional filtering. DETAILED DESCRIPTION

[0047] At present, the separation of the full wave field is usually carried out in the frequency-wavenumber domain. The direction of the wave field can be separated by using the sign of the product of frequency and wave number. However, the conventional three-dimensional Fourier transform has a huge amount of calculation. At the same time, all the time slice wave fields of the shot points and the detection points need to be saved to disk. Therefore, the directional decomposition of the wave field in the frequency-wavenumber domain has huge requirements on the data I / O and hard disk storage, which cannot meet the needs of actual production at this stage.

[0048] The present invention proposes a wavefield propagation algorithm based on full wavefield separation. By applying the wavefield components in different directions of the full wavefield for separate imaging, a seismic imaging algorithm that protects low-frequency wavefield information is constructed. While ensuring the imaging accuracy, the low-frequency noise and offset artifact problems can be effectively suppressed. At the same time, the low-frequency information can be protected and the imaging profile spectrum can be prevented from moving to the high-frequency end. This is of great significance for promoting high-precision broadband seismic imaging.

[0049] The present invention will be described in more detail below with reference to the accompanying drawings. Although preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0050] Example 1

[0051] like Figure 1 As shown, this embodiment provides a seismic imaging method for protecting low-frequency wave field information, including:

[0052] S1: Calculate the propagation wave field of the shot point and the reverse propagation wave field of the receiver point based on the seismic data;

[0053] S2: At each moment of wave field propagation, the wave field propagated by the shot point and the wave field propagated in the reverse direction by the receiver point are decomposed in multiple directions to obtain the wave field components of the whole wave field in different directions;

[0054] In this step, in the fK domain, the shot point propagation wavefield and the detection point reverse propagation wavefield are decomposed in multiple directions. The multi-directional decomposition of the shot point propagation wavefield and the detection point reverse propagation wavefield is expressed by the following formula:

[0055]

[0056]

[0057] Among them, S d (w,k z ) represents the downgoing wave at the shot point in the frequency wavenumber domain, S u (w,k z ) represents the upgoing wave at the shot point in the frequency wavenumber domain, S +(w,k z ) represents the single wave at the shot point in the frequency wavenumber domain, S_(w, k z ) represents the single wave at the shot point in the frequency wavenumber domain, w represents the frequency, k z Indicates the wave number in the depth z direction.

[0058] S3: Use the time-space domain traveling wave multi-directional decomposition broadband imaging condition to image the wave field components in different directions of the full wave field respectively to obtain the imaging results.

[0059] In this step, the conditions for multi-directional decomposition of broadband imaging of traveling waves in the time-space domain are:

[0060]

[0061] Where I(x, y, z) represents the wave field imaging result with the opposite propagation direction at the spatial position (x, y, z) at time t, T max is the maximum time of wave field extension, s + (t, z) represents the single wave of the shot point at time t in the time-space domain, s-(t, z) represents the single wave of the shot point at time t in the time-space domain, r + (t, z) represents a single wave at the detection point at time t in the time-space domain, and “*” represents the complex conjugate.

[0062] Example 2

[0063] The present embodiment provides a seismic imaging method for protecting low-frequency wave field information, specifically a wave field decomposition method based on multi-order wave field simulation theory in the time-space domain, which can realize the decomposition of the wave field in multiple directions and perform correlation imaging on the wave field in a specific direction, and can effectively suppress the offset noise and offset illusion, and realize the protection of low-frequency information.

[0064] The derivation process of the time-space domain traveling wave multi-directional decomposition broadband reverse time migration imaging conditions involved in this embodiment is as follows:

[0065] Reverse time migration realizes wavefield extrapolation by solving the acoustic wave equation. The conventional full wavefield cross-correlation imaging condition is:

[0066]

[0067] Where s(t, x) and r(t, x) represent the forward wave field of the earthquake source and the reverse wave field of the detection point at the spatial position x = (x, y, z) at time t, respectively. max It is the maximum time of wave field extension.

[0068] The wave fields of the shot point and the receiver point are decomposed in multiple directions to obtain:

[0069] s(t,x)=s d (t,x)+su(t,x)

[0070] r(t,x)=r d (t,x)+r u (t, x) (2)

[0071] Where: s d (t, x-, su(t, x-, are the downgoing and upgoing waves of the shot point, respectively, r d (t,x),r u (t, x) are the downgoing wave and upgoing wave of the detection point respectively.

[0072] Then the reverse time migration imaging condition can be rewritten as:

[0073]

[0074] Where: I 1 (x) and I 2 (x) is the wave field imaging result in the opposite propagation direction, reflecting the underground interface imaging information; I 3 (x) and I 4 (x) is the wave field imaging result with the same propagation direction, which does not contribute to the underground structure imaging result. Therefore, the wave field decomposition cross-correlation imaging condition after eliminating noise in the imaging process is obtained as follows:

[0075]

[0076] From formula (4), we can see that the key to the reverse time migration result is to obtain the wave field with opposite propagation directions between the shot point and the receiver point and to perform cross-correlation along time. If the wave equation can be solved once in the time-space domain, the wave field can be decomposed and the storage and calculation amount can be reduced.

[0077] The wave field decomposition cross-correlation imaging condition is extended to the frequency domain, and its expression is:

[0078]

[0079] in “*” indicates complex conjugation.

[0080] In the fk domain, the multi-directional wave field is decomposed into the form:

[0081]

[0082]

[0083] From the above formula, it can be seen that the direction of the decomposed wave field depends on the sign of the current frequency.

[0084] Substitute the inverse Fourier transform result of equation (6) into equation (4). At this time, no matter whether the sign of the current frequency is positive or negative, the following equation always holds:

[0085]

[0086] The above formula (7) is the imaging condition of broadband reverse time migration by multi-directional decomposition of traveling waves in the time-space domain. The migration imaging result obtained under this imaging condition can suppress the migration noise. Compared with the conventional filtering method, this method does not change the phase and amplitude of the wavelet, has better amplitude preservation, and effectively protects the low-frequency information.

[0087] like Figure 2 As shown, the specific implementation process of the method in this embodiment is:

[0088] Step 1: Calculate the forward propagation wave field of the shot point;

[0089] Step 2: Calculate the reverse propagation wave field of the detection point;

[0090] Step 3: At each moment of wave field propagation, perform multi-directional directional decomposition of the imaging wave fields of the shot point and the receiver point based on formula (6);

[0091] Step 4: Use the time-space domain traveling wave multi-directional decomposition broadband imaging condition of the above formula (7) to image the decomposed wave field data respectively to obtain the imaging results.

[0092] Through the application of simple theoretical models and actual data, it is verified that this method has a good suppression effect on the migration noise existing in conventional cross-correlation reverse time migration. At the same time, compared with post-stack filtering, it well protects the low-frequency information in the data and improves the imaging accuracy of reverse time migration.

[0093] Figure 3a This is the conventional reverse time migration result of a simple flat model. Figure 3b This is the final imaging result obtained by the method of the present invention. It can be seen that since the shot point and the detection point contain traveling waves in different directions at the same time, when imaging is performed using the cross-correlation imaging condition, the waves with opposite propagation directions at the shot point and the detection point can be effectively imaged, while the wave fields with the same propagation direction form high-amplitude low-frequency noise, which interferes with the imaging result. The method of the present invention achieves effective suppression of noise. Figure 4a and Figure 4b They are the wave fields before decomposition of the shot point and the detection point, including the full wave field information. Figure 5 In order to realize the wave field after multi-directional decomposition at the shot point end, the wave field can be decomposed in the upward, downward, left and right directions, or even in any specified direction. Applying this decomposed traveling wave to broadband imaging conditions can obtain better imaging results and avoid the damage of conventional filtering processing to low-frequency signals. Figure 6-7b For the application effect of actual data, Figure 7a Relative to Figure 6 The imaging accuracy is higher and the imaging artifacts are suppressed; at the same time, compared with Figure 7b The conventional filtering results show that the low-frequency information is richer and the continuity of the event axis is enhanced, especially the imaging accuracy of high-steep structures is higher.

[0094] The application results of the theoretical model and actual data show that the protective low-frequency imaging method of the present invention can effectively improve the accuracy of imaging profiles.

[0095] Example 3

[0096] This embodiment provides a seismic imaging device for protecting low-frequency wave field information, including:

[0097] A wave field calculation module, used to calculate the propagation wave field of the shot point and the reverse propagation wave field of the receiver point based on the seismic data;

[0098] A wave field decomposition module is used to perform multi-directional decomposition of the shot point propagation wave field and the detection point reverse propagation wave field at each moment of wave field propagation to obtain wave field components of the whole wave field in different directions;

[0099] The wave field components in different directions of the full wave field are imaged separately using the broadband imaging condition of multi-directional decomposition of traveling waves in the time-space domain to obtain the imaging results.

[0100] In this embodiment, the multi-directional decomposition of the wave field propagated by the shot point and the wave field propagated in the reverse direction by the detection point is expressed by the following formula:

[0101]

[0102]

[0103] Among them, S d (w,k z ) represents the downgoing wave at the shot point in the frequency wavenumber domain, S u (w,k z ) represents the upgoing wave at the shot point in the frequency wavenumber domain, S + (w,k z ) represents the single-travel wave at the shot point in the frequency wavenumber domain, S - (w,k z ) represents the single wave at the shot point in the frequency wavenumber domain, w represents the frequency, k z In this embodiment, the time-space domain traveling wave multi-directional decomposition broadband imaging condition is:

[0104]

[0105] Where I(x, y, z) represents the wave field imaging result with the opposite propagation direction at the spatial position (x, y, z) at time t, T max is the maximum time of wave field extension, s +(t, z) represents the single-travel wave of the shot point at time t in the time-space domain, s - (t, z) represents the single wave of the shot point at time t in the time-space domain, r + (t, z) represents a single wave at the detection point at time t in the time-space domain, and “*” represents the complex conjugate.

[0106] In this embodiment, in the fk domain, the propagation wavefield of the shot point and the reverse propagation wavefield of the detection point are decomposed in multiple directions.

[0107] Example 4

[0108] This embodiment provides an electronic device, the electronic device comprising:

[0109] at least one processor; and,

[0110] a memory communicatively connected to the at least one processor; wherein,

[0111] The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the seismic imaging method for protecting low-frequency wavefield information described in any one of the first aspects.

[0112] The electronic device according to an embodiment of the present disclosure includes a memory and a processor, and the memory is used to store non-temporary computer-readable instructions. Specifically, the memory may include one or more computer program products, and the computer program product may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include a random access memory (RAM) and / or a cache memory (cache), etc. The non-volatile memory may, for example, include a read-only memory (ROM), a hard disk, a flash memory, etc.

[0113] The processor may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. In one embodiment of the present disclosure, the processor is used to run the computer-readable instructions stored in the memory.

[0114] Those skilled in the art should be able to understand that in order to solve the technical problem of how to obtain a good user experience, the present embodiment may also include well-known structures such as a communication bus and an interface, and these well-known structures should also be included in the protection scope of the present disclosure.

[0115] For detailed description of this embodiment, reference may be made to the corresponding descriptions in the aforementioned embodiments, which will not be repeated here.

[0116] Example 5

[0117] This embodiment provides a non-transitory computer-readable storage medium, which stores computer instructions, and the computer instructions are used to enable a computer to execute any of the seismic imaging methods for protecting low-frequency wavefield information described in the first aspect.

[0118] According to the computer-readable storage medium of the embodiment of the present disclosure, non-transitory computer-readable instructions are stored thereon. When the non-transitory computer-readable instructions are executed by a processor, all or part of the steps of the above-mentioned methods of each embodiment of the present disclosure are executed.

[0119] The above-mentioned computer-readable storage media include, but are not limited to: optical storage media (e.g., CD-ROM and DVD), magneto-optical storage media (e.g., MO), magnetic storage media (e.g., magnetic tape or mobile hard disk), media with built-in rewritable non-volatile memory (e.g., memory card) and media with built-in ROM (e.g., ROM box).

[0120] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A seismic imaging method for protecting low-frequency wave field information, It is characterized in that include: Based on the seismic data, the propagation wave field of the shot point and the reverse propagation wave field of the receiver point are calculated respectively; At each moment of wave field propagation, the propagation wave field of the shot point and the reverse propagation wave field of the detection point are decomposed in multiple directions to obtain wave field components of the whole wave field in different directions; The wave field components in different directions of the full wave field are imaged separately using the broadband imaging condition of multi-directional decomposition of traveling waves in the time-space domain to obtain the imaging results.

2. The seismic imaging method for protecting low-frequency wavefield information according to claim 1, It is characterized in that The multi-directional decomposition of the wave field propagated by the shot point and the wave field propagated in reverse by the detection point is expressed by the following formula: Among them, S d (w,k z ) represents the downgoing wave at the shot point in the frequency wavenumber domain, S u (w,k z ) represents the upgoing wave at the shot point in the frequency wavenumber domain, S + (w,k z ) represents the single-travel wave at the shot point in the frequency wavenumber domain, S - (w,k z ) represents the single wave at the shot point in the frequency wavenumber domain, w represents the frequency, k z Indicates the wave number in the depth z direction.

3. The seismic imaging method for protecting low-frequency wavefield information according to claim 1, It is characterized in that The time-space domain traveling wave multi-directional decomposition broadband imaging condition is: Where I(x,y,z) represents the wave field imaging result with the opposite propagation direction at the spatial position (x,y,z) at time t, T max is the maximum time of wave field extension, s + (t,z) represents the single-travel wave of the shot point at time t in the time-space domain, s - (t,z) represents the single wave of the shot point at time t in the time-space domain, r + (t,z) represents a single wave at the detection point at time t in the time-space domain, and "*" represents the complex conjugate.

4. The seismic imaging method for protecting low-frequency wavefield information according to claim 1, It is characterized in that In the fk domain, the propagation wavefield of the shot point and the reverse propagation wavefield of the detection point are decomposed in multiple directions.

5. An electronic device, It is characterized in that The electronic device comprises: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the seismic imaging method for protecting low-frequency wavefield information according to any one of claims 1-4.

6. A non-transitory computer-readable storage medium, It is characterized in that The non-transitory computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the seismic imaging method for protecting low-frequency wavefield information as described in any one of claims 1-4.

7. A seismic imaging device for protecting low-frequency wave field information, It is characterized in that include: A wave field calculation module, used to calculate the propagation wave field of the shot point and the reverse propagation wave field of the receiver point based on the seismic data; A wave field decomposition module is used to perform multi-directional decomposition of the shot point propagation wave field and the detection point reverse propagation wave field at each moment of wave field propagation to obtain wave field components of the whole wave field in different directions; The wave field components in different directions of the full wave field are imaged separately using the broadband imaging condition of multi-directional decomposition of traveling waves in the time-space domain to obtain the imaging results.

8. The seismic imaging device for protecting low-frequency wave field information according to claim 7, It is characterized in that The multi-directional decomposition of the wave field propagated by the shot point and the wave field propagated in reverse by the detection point is expressed by the following formula: Among them, S d (w,k z ) represents the downgoing wave at the shot point in the frequency wavenumber domain, S u (w,k z ) represents the upgoing wave at the shot point in the frequency wavenumber domain, S + (w,k z ) represents the single-travel wave at the shot point in the frequency wavenumber domain, S - (w,k z ) represents the single wave at the shot point in the frequency wavenumber domain, w represents the frequency, k z Indicates the wave number in the depth z direction.

9. The seismic imaging device for protecting low-frequency wave field information according to claim 7, It is characterized in that The time-space domain traveling wave multi-directional decomposition broadband imaging condition is: Where I(x,y,z) represents the wave field imaging result with the opposite propagation direction at the spatial position (x,y,z) at time t, T max is the maximum time of wave field extension, s + (t,z) represents the single-travel wave of the shot point at time t in the time-space domain, s - (t,z) represents the single wave of the shot point at time t in the time-space domain, r + (t,z) represents a single wave at the detection point at time t in the time-space domain, and "*" represents the complex conjugate.

10. The seismic imaging device for protecting low-frequency wave field information according to claim 7, It is characterized in that In the fk domain, the propagation wavefield of the shot point and the reverse propagation wavefield of the detection point are decomposed in multiple directions.

Images