Speed modeling method and device for low-frequency loss of land data

Abstract

The invention relates to the technical field of seismic data processing, and particularly discloses a velocity modeling method and device for low-frequency loss of land data, and the method comprises the steps: constructing a low-frequency trend velocity model through logging information and horizon information; constructing an initial velocity model of full-waveform inversion based on the low-frequency trend velocity model; carrying out wavelet estimation based on full waveform inversion; and based on the initial velocity model, carrying out full waveform inversion on low-frequency effective data of 7hz and below and high-frequency data of 7hz and above. In order to solve the problem that full-waveform inversion falls into a local extreme value due to low-frequency loss of land data, a reasonable full-waveform inversion method and measurement are established by using various information such as logging, geology, horizon and the like; according to the method, a plurality of full-waveform inversion combination technologies based on early-arrival wave full-waveform inversion, multi-frequency multi-scale large-offset full-waveform inversion and full-waveform inversion based on logging and horizon constraint are formed, the inversion process is effectively prevented from falling into a local extreme value, and the convergence and stability of inversion are improved.

Description

Technical Field

[0001] This invention relates to the field of seismic data processing technology, specifically to a method and apparatus for velocity modeling of low-frequency missing land data. Background Technology

[0002] Full waveform inversion is a technique for high-precision velocity modeling of subsurface media using all information from the seismic wavefield. However, in practical applications, the lack of low-frequency information often poses a challenge to velocity modeling and avoiding local extrema in full waveform inversion. Currently, a series of methods for compensating for low-frequency data have been developed, but the reliability of low-frequency data is difficult to guarantee in real-world data. To compensate for the inversion problems caused by the lack of low-frequency information, methods such as travel-time-based full waveform inversion and envelope-based full waveform inversion have been developed. These methods have achieved good results with model data, but in practical applications, due to the complexity of the wavefield, while obtaining and matching the first arrival wave travel time and envelope is feasible, matching the travel time and envelope information of reflected waves from simulated data and actual data (observational data) is difficult, limiting their widespread application in real-world data.

[0003] Based on this technical background, this invention studies a velocity modeling method and apparatus for low-frequency missing land data. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a velocity modeling method and apparatus for low-frequency missing land data. This method addresses the problem of full waveform inversion getting trapped in local extrema caused by low-frequency missing land data. It utilizes multiple information sources such as well logging, geology, and stratigraphy to establish a reasonable full waveform inversion method and strategy. This results in a combination of various full waveform inversion techniques, including early arrival wave full waveform inversion, multi-frequency multi-scale large offset full waveform inversion, and full waveform inversion based on well logging and stratigraphic constraints. This effectively avoids the inversion process getting trapped in local extrema, improves the convergence and stability of the inversion, and promotes the practical application of full waveform inversion of land data.

[0005] To achieve the above objectives, a first aspect of the present invention provides a velocity modeling method for low-frequency missing land data, comprising:

[0006] A low-frequency trend velocity model was constructed using well logging and stratigraphic information.

[0007] An initial velocity model for full waveform inversion is constructed based on the aforementioned low-frequency trend velocity model.

[0008] Wavelet estimation is performed based on the full waveform inversion.

[0009] Based on the initial velocity model, full waveform inversion is performed on low-frequency effective data of 7 Hz and below, and high-frequency data of 7 Hz and above.

[0010] A second aspect of the present invention provides a velocity modeling apparatus for low-frequency missing land data, comprising:

[0011] The low-frequency trend velocity model construction module is used to construct a low-frequency trend velocity model using well logging information and stratigraphic information;

[0012] An initial velocity model construction module is used to construct an initial velocity model for full waveform inversion based on the low-frequency trend velocity model.

[0013] The wavelet estimation module is used to perform wavelet estimation based on the full waveform inversion;

[0014] The full waveform inversion module is used to perform full waveform inversion on low-frequency effective data of 7 Hz and below and high-frequency data of 7 Hz and above, based on the initial velocity model.

[0015] A third aspect of the present invention provides an electronic device, the electronic device comprising:

[0016] Memory, which stores executable instructions;

[0017] A processor that executes the executable instructions in the memory to implement the velocity modeling method for low-frequency missing land data as described in the first aspect.

[0018] A fourth aspect of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the velocity modeling method for low-frequency missing land data as described in the first aspect.

[0019] The beneficial effects of this invention include:

[0020] The velocity modeling method for low-frequency missing land data proposed in this invention addresses the problem of full waveform inversion getting trapped in local extrema caused by low-frequency missing land data. It establishes a reasonable full waveform inversion method and strategy by utilizing multiple information such as well logging, geology, and stratigraphy. It forms a combination of various full waveform inversion techniques, including full waveform inversion based on early arrival waves, multi-frequency multi-scale large offset full waveform inversion, and full waveform inversion based on well logging and stratigraphy constraints. This effectively avoids getting trapped in local extrema during the inversion process, improves the convergence and stability of the inversion, and promotes the practical application of full waveform inversion of land data.

[0021] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0022] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings.

[0023] Figure 1 This is a flowchart illustrating the velocity modeling method for low-frequency missing land data proposed in this invention.

[0024] Figure 2 This is a flowchart illustrating a specific implementation of the velocity modeling method for low-frequency missing land data proposed in this invention.

[0025] Figure 3 This is a schematic diagram of the frequency bands of seismic data below 6 Hz and the original data in a specific implementation of the velocity modeling method for low-frequency missing land data proposed in this invention.

[0026] Figure 4 This is a schematic diagram of the initial velocity model in a specific implementation of the velocity modeling method for low-frequency missing land data proposed in this invention.

[0027] Figure 5 This is a schematic diagram of full waveform inversion of large offset data in a specific implementation of the velocity modeling method for low-frequency missing land data proposed in this invention.

[0028] Figure 6 This is a schematic diagram of full waveform inversion based on well logging stratigraphic constraints for full offset data, in a specific implementation of the velocity modeling method for low-frequency missing land data proposed in this invention.

[0029] Figure 7 This is a schematic diagram of full waveform inversion of high-frequency full offset data logging layer constraints in a specific implementation of the velocity modeling method for low-frequency missing land data proposed in this invention. Detailed Implementation

[0030] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0031] This invention provides a velocity modeling method for low-frequency missing land data, such as... Figure 1 As shown, it includes:

[0032] A low-frequency trend velocity model was constructed using well logging and stratigraphic information.

[0033] An initial velocity model for full waveform inversion is constructed based on a low-frequency trend velocity model;

[0034] Wavelet estimation is performed based on full waveform inversion;

[0035] Based on the initial velocity model, full waveform inversion is performed on low-frequency effective data at 7 Hz and below, and high-frequency data above 7 Hz.

[0036] This invention addresses the problem of full waveform inversion falling into local extrema due to the lack of low-frequency data in terrestrial data. It establishes a reasonable full waveform inversion method and strategy by utilizing various information such as well logging, geology, and stratigraphy. This results in a combination of multiple full waveform inversion techniques, including early arrival wave full waveform inversion, multi-frequency multi-scale large offset full waveform inversion, and full waveform inversion based on well logging and stratigraphic constraints. These techniques effectively avoid falling into local extrema during the inversion process, improve the convergence and stability of the inversion, and promote the practical application of full waveform inversion of terrestrial data.

[0037] According to the present invention, the initial velocity model for full waveform inversion based on the low-frequency trend velocity model includes:

[0038] First-arrival tomographic velocity modeling was performed using a low-frequency trend velocity model as the initial model.

[0039] After initial arrival wave tomography velocity modeling, reflected wave tomography is used to obtain the full waveform inversion initial velocity model.

[0040] According to the present invention, when performing wavelet estimation based on full waveform inversion, one wavelet is obtained from each shot data.

[0041] According to the present invention, performing full waveform inversion on low-frequency effective data of 7 Hz and below and high-frequency data of above 7 Hz includes:

[0042] Determine whether the data contains valid low-frequency data of 7Hz and below;

[0043] If the data contains effective low-frequency data of 7 Hz and below, perform full waveform inversion on the effective low-frequency data of 7 Hz and below first; otherwise, perform full waveform inversion directly on the high-frequency data above 7 Hz.

[0044] According to the present invention, performing full waveform inversion on effective low-frequency data of 7 Hz and below includes:

[0045] Large-scale background velocity model full waveform inversion was performed using large offset data with an offset / target layer depth ratio greater than 2 at 7 Hz and below.

[0046] Preferably, performing full waveform inversion on high-frequency data above 7 Hz includes:

[0047] Based on the full waveform inversion results of offset data of 7 Hz and below, or by directly using large offset data of 8-9 Hz with a target layer depth ratio greater than 2, full waveform inversion can be performed on large-scale background data.

[0048] Based on the full waveform inversion results of 8-9 Hz offset data, we carried out full waveform inversion of 8-10 Hz full offset data based on well logging and stratigraphic constraints.

[0049] According to the present invention, performing full waveform inversion on high-frequency data above 7 Hz further includes:

[0050] If a higher frequency inversion is required, then based on the full waveform inversion results of the 8-10 Hz offset data, a higher frequency full waveform inversion based on well logging and stratigraphic constraints should be carried out.

[0051] The present invention will be described in more detail below through embodiments.

[0052] Example 1:

[0053] like Figure 2 As shown, this embodiment proposes a velocity modeling method for low-frequency missing land data. Due to the limitations of the seismic acquisition environment and excitation and receiving equipment, land data usually lacks low-frequency information. Typically, the frequencies below 6 Hz are basically noise and do not contain effective signals, which hinders the full waveform inversion of land data.

[0054] The specific steps of this method are as follows:

[0055] Step 1: Construct a low-frequency trend velocity model v using well logging and stratigraphic information. w lf ;

[0056] Step 2: Using this low-frequency model as the initial model, perform first-arrival tomography velocity modeling;

[0057] Step 3: After initial arrival wave tomography velocity modeling, reflected wave tomography is used to obtain the full waveform inversion initial velocity model v. initia l;

[0058] Step 4: Wavelet estimation is performed using full waveform inversion, and one wavelet is obtained from each shot's data;

[0059] Step 5: Using v initia l As the initial velocity model, full-wave inversion velocity modeling of the early arrival wave is carried out;

[0060] Step 6: Perform this step when the data contains low-frequency effective data at 7 Hz and below, and use large offset data with an offset / target layer depth ratio greater than 2 to perform large-scale background velocity model full waveform inversion;

[0061] Step 7: If Step 6 was performed, then based on this, large-scale background velocity full waveform inversion is performed using large offset data with an 8-9 Hz offset / target layer depth ratio greater than 2 to obtain the velocity vf. w i _ 1 ;

[0062] Step 8: Using VF wi _ 1 As the initial velocity model, full waveform inversion was performed using 8-10 Hz full offset data and well logging and stratigraphic constraints.

[0063] Step 9: If a higher frequency inversion is required, then perform a full waveform inversion based on well logging and stratigraphic constraints based on the results of Step 8.

[0064] In this embodiment, Figure 3 The spectrum of raw data collected in a certain onshore work area and the seismic signal situation at 6Hz and below; it can be seen that the effective signal starting frequency is about 7Hz. In this embodiment, early arrival wave full waveform inversion, large offset full waveform inversion, full offset logging and layer-constrained full waveform inversion were performed in sequence; from Figures 4-7 The full waveform inversion results are shown in sequence. It can be seen that the full waveform inversion of the large migration data constructs the large-scale low wavenumber background velocity of the velocity model. The thrust structure characteristics of this work area are inverted on the velocity model. With the addition of near-offset data and high-frequency data in the full offset, the high wavenumber in the velocity is gradually characterized, which improves the velocity resolution below the thrust structure and makes the velocity model more consistent with geological understanding.

[0065] Example 2:

[0066] This embodiment provides a velocity modeling method for low-frequency missing land data, such as... Figure 1 As shown, it includes:

[0067] A low-frequency trend velocity model was constructed using well logging and stratigraphic information.

[0068] An initial velocity model for full waveform inversion is constructed based on a low-frequency trend velocity model;

[0069] Wavelet estimation is performed based on full waveform inversion;

[0070] Based on the initial velocity model, full waveform inversion is performed on low-frequency effective data at 7 Hz and below, and high-frequency data above 7 Hz.

[0071] In this embodiment, the initial velocity model for full waveform inversion based on the low-frequency trend velocity model includes:

[0072] First-arrival tomographic velocity modeling was performed using a low-frequency trend velocity model as the initial model.

[0073] After initial arrival wave tomography velocity modeling, reflected wave tomography is used to obtain the full waveform inversion initial velocity model;

[0074] In this embodiment, when performing wavelet estimation based on full waveform inversion, each shot data yields a wavelet;

[0075] In this embodiment, the full waveform inversion for effective low-frequency data at 7 Hz and below, and high-frequency data above 7 Hz includes:

[0076] Determine whether the data contains valid low-frequency data of 7Hz and below;

[0077] If the data contains effective low-frequency data of 7 Hz and below, perform full waveform inversion on the effective low-frequency data of 7 Hz and below first; otherwise, perform full waveform inversion directly on the high-frequency data above 7 Hz.

[0078] In this embodiment, performing full waveform inversion on effective low-frequency data of 7Hz and below includes:

[0079] Large-scale background velocity model full waveform inversion was performed using large offset data with an offset / target layer depth ratio greater than 2 at 7 Hz and below.

[0080] In this embodiment, performing full waveform inversion on high-frequency data above 7 Hz includes:

[0081] Based on the full waveform inversion results of offset data of 7 Hz and below, or by directly using large offset data of 8-9 Hz with a target layer depth ratio greater than 2, full waveform inversion can be performed on large-scale background data.

[0082] Based on the full waveform inversion results of 8-9 Hz offset data, we carried out full waveform inversion of 8-10 Hz full offset data based on well logging and stratigraphic constraints.

[0083] In this embodiment, performing full waveform inversion on high-frequency data above 7 Hz also includes:

[0084] If a higher frequency inversion is required, then based on the full waveform inversion results of the 8-10 Hz offset data, a higher frequency full waveform inversion based on well logging and stratigraphic constraints should be carried out.

[0085] Example 3:

[0086] This embodiment provides a velocity modeling device for low-frequency missing land data, including:

[0087] The low-frequency trend velocity model construction module is used to construct a low-frequency trend velocity model using well logging information and stratigraphic information;

[0088] The initial velocity model construction module is used to construct an initial velocity model for full waveform inversion based on a low-frequency trend velocity model.

[0089] The wavelet estimation module is used for wavelet estimation based on full waveform inversion;

[0090] The full waveform inversion module is used to perform full waveform inversion on low-frequency effective data of 7 Hz and below, and high-frequency data of 7 Hz and above, based on the initial velocity model.

[0091] In this embodiment, the initial velocity model for full waveform inversion based on the low-frequency trend velocity model includes:

[0092] First-arrival tomographic velocity modeling was performed using a low-frequency trend velocity model as the initial model.

[0093] After initial arrival wave tomography velocity modeling, reflected wave tomography is used to obtain the full waveform inversion initial velocity model;

[0094] In this embodiment, when performing wavelet estimation based on full waveform inversion, each shot data yields a wavelet;

[0095] In this embodiment, the full waveform inversion for effective low-frequency data at 7 Hz and below, and high-frequency data above 7 Hz includes:

[0096] Determine whether the data contains valid low-frequency data of 7Hz and below;

[0097] If the data contains effective low-frequency data of 7 Hz and below, perform full waveform inversion on the effective low-frequency data of 7 Hz and below first; otherwise, perform full waveform inversion directly on the high-frequency data above 7 Hz.

[0098] In this embodiment, performing full waveform inversion on effective low-frequency data of 7Hz and below includes:

[0099] Large-scale background velocity model full waveform inversion was performed using large offset data with an offset / target layer depth ratio greater than 2 at 7 Hz and below.

[0100] In this embodiment, performing full waveform inversion on high-frequency data above 7 Hz includes:

[0101] Based on the full waveform inversion results of offset data of 7 Hz and below, or by directly using large offset data of 8-9 Hz with a target layer depth ratio greater than 2, full waveform inversion can be performed on large-scale background data.

[0102] Based on the full waveform inversion results of 8-9 Hz offset data, we carried out full waveform inversion of 8-10 Hz full offset data based on well logging and stratigraphic constraints.

[0103] In this embodiment, performing full waveform inversion on high-frequency data above 7 Hz also includes:

[0104] If a higher frequency inversion is required, then based on the full waveform inversion results of the 8-10 Hz offset data, a higher frequency full waveform inversion based on well logging and stratigraphic constraints should be carried out.

[0105] Example 4:

[0106] This invention provides an electronic device including a memory and a processor, comprising:

[0107] Memory, which stores executable instructions;

[0108] The processor runs executable instructions in memory to implement a speed modeling method for low-frequency missing land data.

[0109] This memory is used to store non-transitory computer-readable instructions. Specifically, the memory may include one or more computer program products, which 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 random access memory (RAM) and / or cache memory. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, etc.

[0110] The processor may be a central processing unit (CPU) or other form of processing unit with 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 invention, the processor is used to execute computer-readable instructions stored in the memory.

[0111] Those skilled in the art should understand that, in order to solve the technical problem of how to achieve a good user experience, this embodiment may also include well-known structures such as communication buses and interfaces, and these well-known structures should also be included within the protection scope of this invention.

[0112] For a detailed description of this embodiment, please refer to the corresponding descriptions in the foregoing embodiments, which will not be repeated here.

[0113] Example 5:

[0114] This invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements a method for velocity modeling of low-frequency missing land data.

[0115] A computer-readable storage medium according to embodiments of the present invention stores non-transitory computer-readable instructions. When these non-transitory computer-readable instructions are executed by a processor, all or part of the steps of the methods described in the foregoing embodiments of the present invention are performed.

[0116] The aforementioned 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 portable hard drive), media with built-in rewritable non-volatile memory (e.g., memory card), and media with built-in ROM (e.g., ROM cartridge).

[0117] The velocity modeling method for low-frequency missing land data proposed in the embodiments of this invention addresses the problem of full waveform inversion getting trapped in local extrema caused by low-frequency missing land data. It establishes a reasonable full waveform inversion method and strategy by utilizing multiple information such as well logging, geology, and stratigraphy. It forms a combination of various full waveform inversion techniques, including full waveform inversion based on early arrival waves, multi-frequency multi-scale large offset full waveform inversion, and full waveform inversion based on well logging and stratigraphy constraints. This effectively avoids the inversion process getting trapped in local extrema, improves the convergence and stability of the inversion, and promotes the practical application of full waveform inversion of land data.

[0118] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A velocity modeling method for low-frequency missing land data, characterized in that, include: A low-frequency trend velocity model was constructed using well logging and stratigraphic information. An initial velocity model for full waveform inversion is constructed based on the aforementioned low-frequency trend velocity model. Wavelet estimation is performed based on the full waveform inversion. Based on the initial velocity model, full waveform inversion is performed on low-frequency effective data of 7 Hz and below, and high-frequency data of 7 Hz and above.

2. The method according to claim 1, characterized in that, The initial velocity model for full waveform inversion based on the low-frequency trend velocity model includes: First-arrival tomography velocity modeling is performed using the aforementioned low-frequency trend velocity model as the initial model. After initial arrival wave tomography velocity modeling, reflected wave tomography is used to obtain the full waveform inversion initial velocity model.

3. The method according to claim 2, characterized in that, When performing wavelet estimation based on the full waveform inversion, one wavelet is obtained for each shot data.

4. The method according to claim 3, characterized in that, Full waveform inversion is performed on effective low-frequency data of 7 Hz and below, and high-frequency data of above 7 Hz, including: Determine whether the data contains valid low-frequency data of 7Hz and below; If the data contains effective low-frequency data of 7 Hz and below, perform full waveform inversion on the effective low-frequency data of 7 Hz and below first; otherwise, perform full waveform inversion directly on the high-frequency data above 7 Hz.

5. The method according to claim 4, characterized in that, Full waveform inversion of effective low-frequency data at 7 Hz and below includes: Large-scale background velocity model full waveform inversion was performed using large offset data with an offset / target layer depth ratio greater than 2 at 7 Hz and below.

6. The method according to claim 5, characterized in that, Full waveform inversion for high-frequency data above 7 Hz includes: Based on the full waveform inversion results of offset data of 7 Hz and below, or by directly using large offset data of 8-9 Hz with a target layer depth ratio greater than 2, full waveform inversion can be performed on large-scale background data. Based on the full waveform inversion results of 8-9 Hz offset data, we carried out full waveform inversion of 8-10 Hz full offset data based on well logging and stratigraphic constraints.

7. The method according to claim 6, characterized in that, Full waveform inversion of high-frequency data above 7 Hz also includes: If a higher frequency inversion is required, then based on the full waveform inversion results of the 8-10 Hz offset data, a higher frequency full waveform inversion based on well logging and stratigraphic constraints should be carried out.

8. A velocity modeling device for low-frequency missing land data, characterized in that, include: The low-frequency trend velocity model construction module is used to construct a low-frequency trend velocity model using well logging information and stratigraphic information; An initial velocity model construction module is used to construct an initial velocity model for full waveform inversion based on the low-frequency trend velocity model. The wavelet estimation module is used to perform wavelet estimation based on the full waveform inversion; The full waveform inversion module is used to perform full waveform inversion on low-frequency effective data of 7 Hz and below and high-frequency data of 7 Hz and above, based on the initial velocity model.

9. An electronic device, characterized in that, The electronic device includes: Memory, which stores executable instructions; A processor that executes the executable instructions in the memory to implement the velocity modeling method for low-frequency missing land data according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the velocity modeling method for low-frequency missing land data as described in any one of claims 1-7.

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