Target layer signal-to-noise ratio calculation method and device, electronic equipment and medium

Abstract

The invention belongs to the technical field of geophysical exploration, and discloses a target stratum signal-to-noise ratio calculation method and device, electronic equipment and a medium, and the method comprises the steps: obtaining a reflection amplitude ratio of a target stratum to a marker stratum based on seismic data; obtaining a signal-to-noise ratio of a marker bed based on the seismic data; the signal-to-noise ratio of the target layer is equal to the signal-to-noise ratio of the marker layer * the reflection amplitude ratio of the target layer and the marker layer. According to the method, the signal-to-noise ratio of the target layer with weak reflection can be relatively accurately solved. The method is suitable for calculating the signal-to-noise ratio of the target layer with weak reflection.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of geophysical exploration, and relates to a signal-to-noise ratio calculation method, in particular to a target layer signal-to-noise ratio calculation method, device, electronic equipment and medium. BACKGROUND

[0002] In the field of geophysical exploration, signal-to-noise ratio is a key parameter in the process of data analysis. At present, the conventional signal-to-noise ratio calculation method commonly used is the correlation method. When the signal-to-noise ratio is high, the calculation result is relatively accurate. However, in the actual exploration process, many target layers are weak reflection, and the signal-to-noise ratio is generally low. The accuracy of the signal-to-noise ratio calculated by the conventional signal-to-noise ratio calculation method is poor. Especially when the signal-to-noise ratio is less than 1, since the correlation method cannot distinguish noise and signal, the correlation noise is also calculated as signal, resulting in greater error in the result calculated by the conventional signal-to-noise ratio calculation method. SUMMARY

[0003] In order to solve the above problems in the prior art, the present application aims to provide a target layer signal-to-noise ratio calculation method, device, electronic equipment and medium, which takes the marker layer with high signal-to-noise ratio in the seismic data as an intermediary, calculates the signal-to-noise ratio of the target layer according to the reflection amplitude ratio of the target layer and the marker layer, and calculates the signal-to-noise ratio of the target layer by calculating the signal-to-noise ratio of the marker layer, so as to improve the accuracy of the signal-to-noise ratio when the signal-to-noise ratio is less than or equal to 1.

[0004] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0005] A target layer signal-to-noise ratio calculation method, comprising the following steps:

[0006] Based on the seismic data, the reflection amplitude ratio of the target layer and the marker layer is obtained;

[0007] Based on the seismic data, the signal-to-noise ratio of the marker layer is obtained;

[0008] Then the signal-to-noise ratio of the target layer = the signal-to-noise ratio of the marker layer x the reflection amplitude ratio of the target layer and the marker layer.

[0009] The reflection amplitude ratio of the target layer and the marker layer, the signal-to-noise ratio of the marker layer and the signal-to-noise ratio of the target layer refer to the reflection amplitude ratio of the target layer and the marker layer, the signal-to-noise ratio of the marker layer and the signal-to-noise ratio of the target layer in the seismic profile.

[0010] The reflection amplitude ratio of the target layer and the marker layer = the reflection amplitude of the target layer ÷ the reflection amplitude of the marker layer.

[0011] The marker layer refers to a reflection layer with high signal-to-noise ratio.

[0012] The signal-to-noise ratio of the target layer is calculated by the formula: signal-to-noise ratio of the target layer = Am / An = (Am / Ab) × (Ab / An), wherein Am is the reflection amplitude of the target layer;

[0013] An is the noise amplitude;

[0014] Ab is the reflection amplitude of the marker layer;

[0015] Ab / An is the signal-to-noise ratio of the marker layer;

[0016] Am / Ab is the reflection amplitude ratio of the target layer to the marker layer.

[0017] The English abbreviation of the vertical seismic profile is VSP, the vertical seismic profile method is VSP method, and the vertical seismic profile record is VSP record.

[0018] As a limitation of the present application, when the target layer and the marker layer are in one well, the reflection amplitude ratio of the target layer to the marker layer is obtained by the logging data method.

[0019] As a limitation of the present application, the reflection amplitude ratio of the target layer to the marker layer is obtained by the synthetic seismic record method or the vertical seismic profile method.

[0020] As a further limitation of the present application, the logging data method is to calculate the reflection amplitude ratio of the target layer to the marker layer according to the reflection coefficients of the target layer and the marker layer in the logging data.

[0021] As a further limitation of the present application, the synthetic seismic record method is to divide the synthetic target layer reflection amplitude by the corrected and calculated synthetic marker layer reflection amplitude to obtain the reflection amplitude ratio of the target layer to the marker layer.

[0022] As a further limitation of the present application, the vertical seismic profile method is to calculate the reflection amplitude ratio of the target layer to the marker layer according to the target layer reflection amplitude and the marker layer reflection amplitude in the vertical seismic profile record.

[0023] As a further limitation of the present application, the correction calculation is to perform spherical divergence correction and reflection loss correction on the synthetic marker layer reflection amplitude;

[0024] In the synthetic seismic record method, the calculation formula of the reflection amplitude ratio of the target layer to the marker layer is:

[0025] The reflection amplitude ratio of the target layer to the marker layer = synthetic target layer reflection amplitude ÷ (synthetic marker layer reflection amplitude ÷ spherical divergence attenuation coefficient of wave field propagation from the target layer to the marker layer ÷ reflection loss coefficient);

[0026] The calculation formula of the spherical divergence attenuation coefficient is:

[0027] Spherical diffraction attenuation coefficient = (T1 / T2) 2 ,

[0028] Wherein, T1 is the initial time of the target layer in the synthetic record,

[0029] T2 is the initial time of the marker layer in the synthetic record,

[0030] The formula for calculating the reflection loss coefficient is:

[0031] Reflection loss coefficient = (1-A1 2 ) x ··· x (1-A n 2 ),

[0032] Wherein, A1 is the reflection amplitude of the same phase axis 1 between the target layer and the marker layer in the synthetic record,

[0033] A n is the reflection amplitude of the same phase axis n between the target layer and the marker layer in the synthetic record,

[0034] n is the number of same phase axes between the target layer and the marker layer in the synthetic record.

[0035] The application also provides a target layer signal-to-noise ratio calculation device based on any one of the above technical solutions, comprising:

[0036] A first calculation module calculates the reflection amplitude ratio of the target layer and the marker layer based on seismic data;

[0037] A second calculation module calculates the signal-to-noise ratio of the marker layer based on seismic data;

[0038] A third calculation module calculates the signal-to-noise ratio of the target layer based on the reflection amplitude ratio of the target layer and the marker layer and the signal-to-noise ratio of the marker layer.

[0039] The application also provides an electronic device, comprising:

[0040] A memory storing executable instructions;

[0041] A processor running the executable instructions in the memory to implement the target layer signal-to-noise ratio calculation method in any one of the above technical solutions.

[0042] The application also provides a computer readable storage medium storing a computer program, which is executed by a processor to implement the target layer signal-to-noise ratio calculation method in any one of the above technical solutions.

[0043] The principle of the object layer signal-to-noise ratio calculation method is that the signal-to-noise ratio is the ratio of signal amplitude to noise amplitude. In most seismic profiles, there is generally a marker reflection layer with high signal-to-noise ratio, and the signal-to-noise ratio calculation accuracy of the marker layer is often higher. The reflection amplitude Am of the object layer and the reflection amplitude Ab of the marker layer are mainly determined by the respective reflection coefficients; the reflection amplitude ratio (Am / Ab) of the object layer and the marker layer in a certain range is a relatively stable value. In the same seismic data profile, the noise amplitudes An of the object layer and the marker layer are also basically the same; the signal-to-noise ratio (Am / An) of the object layer can be obtained by multiplying the signal-to-noise ratio (Ab / An) of the marker layer by the amplitude ratio (Am / Ab) of the object layer and the marker layer, that is, Am / An=(Ab / An)×(Am / Ab).

[0044] Compared with the prior art, the present application has the beneficial effects that:

[0045] The object layer signal-to-noise ratio calculation method of the present application can relatively accurately obtain the signal-to-noise ratio of the object layer with weak reflection, and the calculation principle is more scientific and the calculation result is more accurate.

[0046] The present application is suitable for calculating the signal-to-noise ratio of the object layer with weak reflection. BRIEF DESCRIPTION OF DRAWINGS

[0047] The present application will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0048] Figure 1 It is a seismic data forward profile graph using logging data in Example 1 of the present application;

[0049] Figure 2 It is a schematic diagram of the signal-to-noise ratio of the marker layer measured by the correlation method in Example 1 of the present application;

[0050] Figure 3 It is a schematic diagram of the signal-to-noise ratio of the object layer measured by the correlation method in Comparative Example 1 of the present application;

[0051] Figure 4 It is a corridor stack profile graph in VSP recording in Example 2 of the present application;

[0052] Figure 5 It is a seismic data profile graph in synthetic recording in Example 3 of the present application. DETAILED DESCRIPTION

[0053] The present application will be described in further detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the described embodiments are only for explaining the present application and do not limit the present application.

[0054] Example 1: A signal-to-noise ratio calculation method for an object layer

[0055] This embodiment describes a method for calculating the signal-to-noise ratio of a target layer. The target layer and the marker layer are located in a single well, and the reflection coefficient ratio between the target layer and the marker layer is obtained from well logging data. An example is a forward-modeled seismic profile from the well logging data. Figure 1 As shown, in the forward modeling profile of seismic data, the target layer and the marker layer are adjacent, with the target layer above the marker layer. Based on the composite record of the target layer and the marker layer, the reflection amplitude of the target layer is 0.2, and the reflection amplitude of the marker layer is 1. After adding 50% noise, theoretically, the signal-to-noise ratio of the marker layer is 2, and the signal-to-noise ratio of the target layer is 0.4.

[0056] The signal-to-noise ratio of the marker layer, measured using the correlation method, is 2.1. Figure 2 As shown, it is basically close to the theoretical value of 2.

[0057] The reflection amplitude ratio between the target layer and the marker layer is 0.2 ÷ 1 = 0.2. The signal-to-noise ratio of the target layer is calculated using the target layer signal-to-noise ratio calculation method of this invention.

[0058] The signal-to-noise ratio of the target layer is 2.1 × 0.2 = 0.42, which is close to the theoretical value of 0.4.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 1 is that the signal-to-noise ratio of the target layer is calculated using the correlation method.

[0061] The comparative example shows that the signal-to-noise ratio of the target layer measured by the correlation method is 0.98. Figure 3 As shown, the value differs significantly from the theoretical value of 0.4.

[0062] Example 2: A method for calculating the signal-to-noise ratio of the target layer

[0063] This embodiment presents a method for calculating the signal-to-noise ratio of a target layer. It uses the Vertical Seismic Profile (VSP) method to obtain the reflection amplitude ratio between the target layer and the marker layer. Taking a corridor-stacked profile from a VSP record as an example, ... Figure 4 As shown, the reflection amplitude of the target layer in the superimposed profile of the corridor is 0.25, and the reflection amplitude of the marker layer is 1.

[0064] The signal-to-noise ratio of the marker layer was calculated to be 4 using the correlation method.

[0065] The reflection amplitude ratio between the target layer and the marker layer is 0.25 ÷ 1 = 0.25. The signal-to-noise ratio of the target layer is calculated using the target layer signal-to-noise ratio calculation method of this invention.

[0066] The signal-to-noise ratio of the target layer = 4 × 0.25 = 1.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 2 is that the signal-to-noise ratio of the target layer is calculated using the correlation method.

[0069] The purpose layer signal-to-noise ratio of the present comparative example is calculated by the correlation method to be 1.

[0070] Example 3: a purpose layer signal-to-noise ratio calculation method

[0071] The present example is a purpose layer signal-to-noise ratio calculation method, the reflection amplitude ratio of the purpose layer and the marker layer is obtained by the synthetic recording method, taking one seismic data section in the synthetic recording as an example, as shown in the figure, the synthetic purpose layer reflection amplitude is 0.2, and the synthetic marker layer reflection amplitude is 1. Figure 5

[0072] In the seismic data section, the purpose layer is at 2.07s, and the marker layer is at 2.11s, the marker layer signal-to-noise ratio is calculated by the correlation method to be 4, the number of in-phase axes between the purpose layer and the marker layer is 2, and the reflection amplitudes are 0.4 and 0.6 respectively, the marker layer reflection propagation distance is longer than that of the purpose layer, the spherical diffusion attenuation coefficient and the reflection loss coefficient are respectively:

[0073] Spherical diffusion attenuation coefficient = (2.07 ÷ 2.11) 2 = 0.96,

[0074] Reflection loss coefficient = (1-0.4 2 )×(1-0.6 2 ) = 0.54,

[0075] Therefore, the reflection amplitude ratio of the purpose layer and the marker layer = 0.2 ÷ (1 ÷ 0.96 ÷ 0.54) = 0.104, the purpose layer signal-to-noise ratio is calculated by the purpose layer signal-to-noise ratio calculation method of the present application:

[0076] Purpose layer signal-to-noise ratio = 4 × 0.104 = 0.416.

[0077] Comparative example 3

[0078] The difference between the present comparative example and example 3 is that the purpose layer signal-to-noise ratio is calculated by the synthetic recording before correction = 4 × (0.2 ÷ 1) = 0.8.

[0079] Result analysis

[0080] The results of example 1 and comparative example 1 show that when the marker layer signal-to-noise ratio is 2, the signal-to-noise ratio calculated by the correlation method is 2.1, the result is more accurate; when the purpose layer signal-to-noise ratio is 0.4, the signal-to-noise ratio calculated by the correlation method is 0.98, the result error is larger, and the purpose layer signal-to-noise ratio calculated by the purpose layer signal-to-noise ratio calculation method of the present application is 0.42, the result is more accurate; it is shown that when the purpose layer signal-to-noise ratio is calculated by the purpose layer signal-to-noise ratio calculation method of the present application, compared with the conventional signal-to-noise ratio calculation method, the signal-to-noise ratio calculated by the present application is more accurate.

[0081] ​The results of Example 2 and Comparative Example 2 show that when the signal-to-noise ratio is high, the signal-to-noise ratio calculated by applying the correlation method is basically consistent with that calculated by applying the present invention.

[0082] The results of Example 3 and Comparative Example 3 show that, compared with the target layer signal-to-noise ratio calculated using the target layer signal-to-noise ratio calculation method of the present invention, the target layer signal-to-noise ratio calculated using the synthetic record before correction has a larger error because the synthetic record before correction does not consider the loss of seismic waves during propagation. Therefore, the target layer signal-to-noise ratio calculation method of the present invention has higher accuracy.

[0083] The above results show that the target layer signal-to-noise ratio calculation method of the present invention is applicable to calculating the target layer with a low signal-to-noise ratio, and can significantly improve the accuracy of the calculated target layer signal-to-noise ratio.

[0084] Example 4: A target layer signal-to-noise ratio calculation device

[0085] This embodiment provides a target layer signal-to-noise ratio (SNR) calculation device based on the target layer SNR calculation method described in any one of embodiments 1-3. The target layer SNR calculation device includes:

[0086] The first calculation module, based on seismic data, calculates the reflection amplitude ratio between the target layer and the marker layer;

[0087] The second calculation module calculates the signal-to-noise ratio of the marker layer based on seismic data;

[0088] The third calculation module calculates the signal-to-noise ratio of the target layer based on the reflection amplitude ratio of the target layer and the marker layer and the signal-to-noise ratio of the marker layer.

[0089] Example 5: An electronic device

[0090] This embodiment provides an electronic device, which includes: a memory storing executable instructions; and a processor that executes the executable instructions in the memory to implement the target layer signal-to-noise ratio calculation method as described in any one of embodiments 1-3.

[0091] 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.

[0092] The processor may be a central processing unit (CPU) or other processing unit with data processing and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. In one embodiment disclosed in this application, the processor is used to execute computer-readable instructions stored in the memory.

[0093] Those skilled in the art will 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 disclosure.

[0094] Example 6: A computer-readable storage medium

[0095] This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the target layer signal-to-noise ratio calculation method described in any one of embodiments 1-3.

[0096] The computer-readable storage medium stores non-transitory computer-readable instructions thereon. When the non-transitory computer-readable instructions are executed by a processor, all or part of the steps of the methods described in the foregoing embodiments are performed.

[0097] 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).

[0098] It should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for calculating the signal-to-noise ratio of a target layer, characterized in that, Includes the following steps: Based on seismic data, the reflection amplitude ratio between the target layer and the marker layer was obtained; Based on seismic data, the signal-to-noise ratio of the marker layer is obtained; Then the target layer signal-to-noise ratio = the marker layer signal-to-noise ratio × the ratio of reflection amplitudes of the target layer and the marker layer.

2. The target layer signal-to-noise ratio calculation method according to claim 1, characterized in that, When the target layer and the marker layer are in the same well, the reflection amplitude ratio of the target layer and the marker layer is obtained by well logging data.

3. The target layer signal-to-noise ratio calculation method according to claim 1, characterized in that, The reflection amplitude ratio between the target layer and the marker layer is obtained by synthetic seismic recording or vertical seismic profiling.

4. The target layer signal-to-noise ratio calculation method according to claim 2, characterized in that, The well logging data method calculates the reflection amplitude ratio of the target layer and the marker layer based on the reflection coefficients of the target layer and the marker layer in the well logging data.

5. The target layer signal-to-noise ratio calculation method according to claim 3, characterized in that, The synthetic seismic record method obtains the ratio of the reflection amplitudes of the target layer and the marker layer by dividing the synthetic reflection amplitude of the target layer in the synthetic record by the synthetic reflection amplitude of the marker layer after correction calculation.

6. The target layer signal-to-noise ratio calculation method according to claim 3, characterized in that, The vertical seismic profiling method calculates the ratio of the reflection amplitudes of the target layer and the marker layer based on the reflection amplitudes of the target layer and the marker layer in the vertical seismic profiling record.

7. The target layer signal-to-noise ratio calculation method according to claim 5, characterized in that, The correction calculation involves performing spherical diffusion correction and reflection loss correction on the synthesized marker layer reflection amplitude; In synthetic seismic recordings, the formula for calculating the reflection amplitude ratio between the target layer and the marker layer is: The ratio of the reflection amplitude of the target layer to that of the marker layer = the synthesized reflection amplitude of the target layer ÷ (the synthesized reflection amplitude of the marker layer ÷ the spherical diffusion attenuation coefficient of the wave field propagating from the target layer to the marker layer ÷ the reflection loss coefficient); The formula for calculating the spherical diffusion attenuation coefficient is as follows: Spherical diffusion attenuation coefficient = (T1 / T2) 2 , Where T1 is the first arrival time of the target layer in the synthetic record. T2 is the first arrival time of the marker layer in the synthetic record. The formula for calculating the reflection loss coefficient is as follows: Reflection loss coefficient = (1-A1) 2 )×······×(1-A n 2 ), Where A1 is the reflection amplitude of the in-phase axis 1 between the target layer and the marker layer in the synthetic record. A n This represents the reflection amplitude of the in-phase axis n between the target layer and the marker layer in the synthetic record. n is the number of in-phase axes between the target layer and the marker layer in the synthetic record.

8. A target layer signal-to-noise ratio (SNR) calculation apparatus based on the target layer SNR calculation method according to any one of claims 1-7, characterized in that, include: The first calculation module, based on seismic data, calculates the reflection amplitude ratio between the target layer and the marker layer; The second calculation module calculates the signal-to-noise ratio of the marker layer based on seismic data; The third calculation module calculates the signal-to-noise ratio of the target layer based on the reflection amplitude ratio of the target layer and the marker layer and the signal-to-noise ratio of the marker layer.

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 target layer signal-to-noise ratio calculation method 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 target layer signal-to-noise ratio calculation method according to any one of claims 1-7.

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