Consistency compensation method and system for overlying shielded earth surface and storage medium

Abstract

The invention provides a consistency compensation method and system for an overlying shielded earth surface, and a storage medium, and belongs to the field of geophysical exploration seismic data processing. The method comprises the following steps of: 1, inputting seismic data; 2, carrying out targeted amplitude spectrum analysis and earth surface consistency decomposition; 3, statistically calculating a target spectrum of a target layer; 4, designing an earth surface consistency compensation operator; and 5, carrying out consistency compensation on the overlying shielded earth surface. According to the method, the time window of spectral decomposition mainly aims at the underlying target layer, meanwhile, targeted compensation processing is carried out by ingeniously utilizing the characteristics of weak amplitude and low frequency of the seriously-shielded area, finally, overlying shielding energy compensation and frequency band recovery processing are achieved, and meanwhile, the AVO friendliness of the processing process is guaranteed through the earth surface consistency theory.

Description

Technical Field

[0001] The present invention belongs to the field of geophysical exploration seismic data processing, and in particular relates to a method, system and storage medium for compensating for overlying and shielding surface consistency. Background Art

[0002] Mesozoic coal seams are well developed in the Loess Plateau area in southern Hubei Province. When seismic waves propagate, they encounter a set of coal seams, which will cause energy shielding and frequency distortion, resulting in distortion of the amplitude and structure of the underlying strata, seriously affecting the true amplitude evaluation and analysis of the target layer, and is very unfavorable for finding favorable oil and gas traps and lithologic oil and gas layers.

[0003] The common practice nowadays is to perform complementary compensation based on the energy difference of coal seams after stacking. This approach can improve the energy consistency of the underlying strata to a certain extent. However, due to the limitations of post-stack data, reliance on differences in the degree of compensation may cause amplitude illusions, so it is still impossible to achieve fidelity and amplitude preservation processing. At the same time, the existence of coal seams not only shields energy, but also causes frequency distortion, and this method cannot eliminate frequency consistency differences. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and to provide a method, system and storage medium for compensating for the consistency of the overlying and obstructing surface.

[0005] One of the objects of the present invention is to provide a method for compensating for the consistency of the overlying obstructed surface.

[0006] A second object of the present invention is to provide a system for compensating for overlying and shielding surface consistency.

[0007] A third object of the present invention is to provide a computer-readable storage medium.

[0008] The present invention is achieved through the following technical solutions:

[0009] A first aspect of the present invention provides a method for compensating for surface consistency of an overlying obstruction, which specifically comprises the following steps:

[0010] The first step is to input earthquake data:

[0011] The second step is to conduct targeted amplitude spectrum analysis and surface consistency decomposition;

[0012] The third step is to statistically calculate the target spectrum of the target layer;

[0013] The fourth step is to design the surface consistency compensation operator;

[0014] The fifth step is to make consistency compensation for the overlying obscured surface.

[0015] A further improvement of the present invention is:

[0016] The seismic data in the first step are pre-processed pre-stack single shot or gather data.

[0017] A further improvement of the present invention is:

[0018] In the second step, the amplitude spectrum is analyzed and the surface consistency is decomposed. The specific operations include:

[0019] Select the time window for spectrum analysis and perform surface consistency decomposition. The seismic trace spectrum can be decomposed into shot point item P(src), receiver point item P(rcv), common center point item P(cmp), offset item P(offset), and other items P(extra) and noise item Pn. The expression is as follows:

[0020] P(trace)=P(src)●P(rcv)●P(cmp)●P(offset)●P(extra)●Pn.

[0021] A further improvement of the present invention is:

[0022] The third step statistically calculates the target spectrum of the target layer, and the specific operations include:

[0023] The shot point term P(src) and the detection point term P(rcv) are statistically analyzed to identify and remove the energy and frequency components that are seriously affected by the overburden shielding, and then the target spectrum to be restored is obtained using a weighted statistical method.

[0024] A further improvement of the present invention is:

[0025] The shot point term P(src) and the receiver point term P(rcv) are statistically analyzed to identify and remove the energy and frequency components that are severely affected by the overburden shielding. Specifically:

[0026] Based on the spectrum decomposition in the second step, the decomposition results of different shot points and detection points are obtained, and the results are displayed on the plane. The spectrum of the area affected by the coal seam and the abnormal spectrum at the boundary of the work area are eliminated, and finally the target spectrum with relatively high quality is circled and selected.

[0027] A further improvement of the present invention is:

[0028] The target spectrum to be restored is obtained using a weighted statistical method, specifically:

[0029] The final target spectrum is obtained by statistically averaging the circled and selected target spectrum.

[0030] A further improvement of the present invention is:

[0031] In the fourth step, a surface consistency compensation operator is designed, and the specific operations include:

[0032] Based on the seismic trace spectrum in the second step and the target spectrum in the third step, the surface consistency amplitude, frequency and phase operators are designed using the surface consistency L2 norm principle. According to the error formula between the seismic trace and the simulated seismic trace, E(trace) = ‖L(trace)-L m (trace)‖, find the minimum error to obtain the operator containing frequency and phase information, which is the surface consistency compensation operator;

[0033] Among them, L(trace) represents the actual acquired seismic trace, including amplitude, frequency and phase information; L m (trace) represents the simulated seismic trace obtained based on the operator. Seeking the minimum error between the two ensures the amplitude preservation and AVO-friendly characteristics of amplitude processing.

[0034] A further improvement of the present invention is:

[0035] In the fifth step, consistency compensation is performed on the overlying obstructed surface, and the specific operations include:

[0036] The corresponding surface consistency operator is applied to the seismic data to achieve the purpose of overburden masking consistency compensation.

[0037] A second aspect of the present invention provides a system for compensating for overlying and shielding surface consistency, comprising:

[0038] Input unit, used to input earthquake data:

[0039] Decomposition unit, used for targeted amplitude spectrum analysis and surface consistency decomposition;

[0040] A target spectrum calculation unit, used for statistically calculating the target spectrum of the target layer;

[0041] A design unit, used for designing a surface consistency compensation operator;

[0042] Compensation unit, used to compensate for the consistency of the overlying obscured surface.

[0043] The third object of the present invention is to provide a computer-readable storage medium, which stores at least one computer-executable program, and when the at least one program is executed by the computer, the computer executes the steps in the method for compensating for surface consistency of overlying shading as described above.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The present invention has achieved good application results in solving the problem of Mesozoic coal seam shielding in the southern Hubei loess plateau. After the application of the technology, the amplitude and frequency consistency of the target layer have been improved to a certain extent, and the seismic data can better meet the needs of subsequent reservoir prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a flow chart of the overlying obscured surface consistency compensation method of the present invention;

[0047] Figure 2 is the shot point item spectrum (top) and the corresponding target spectrum (bottom);

[0048] Figure 3 is the spectrum of the detection point item (upper) and the corresponding target spectrum (lower);

[0049] Figure 4 It is the stacked section before compensation for consistency of the overlying obscured surface;

[0050] Figure 5 It is a superimposed profile after consistency compensation for the overlying obstructed surface. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0052] The present invention provides a compensation method for overburden shielding based on surface consistency and applied to prestack. The method has made targeted improvements and upgrades on the basis of traditional surface consistency processing ideas. It also needs to decompose the amplitude and frequency of the shot check points of the seismic data spectrum, but the time window of the spectrum decomposition is mainly for the underlying target layer. At the same time, it cleverly uses the characteristics of weak amplitude and low frequency in the severely shielded area to perform targeted compensation processing, and finally realizes overburden shielding energy compensation and frequency band recovery processing. At the same time, the surface consistency theory ensures that the processing process is AVO-friendly.

[0053] There are many ways to analyze the impact of overlying coal seams on underlying layers. For example, the spatial inconsistency of underlying energy can be visually observed from the superimposed profile itself. Another more sophisticated way is to perform a root mean square amplitude analysis on the coal seam opening time window, and then perform a root mean square amplitude analysis on the underlying target layer opening time window, and compare the similarity between the two. If the target layer attributes have the shadow of coal seam distribution, it means there is an impact.

[0054] [Example 1]

[0055] The embodiment of the present invention provides a method for compensating for the consistency of the overlying and shielding surface. Figure 1 As shown, the specific steps include:

[0056] The first step is to input earthquake data:

[0057] The seismic data are pre-processed pre-stack single shot or gather data.

[0058] The acquisition and preprocessing methods of seismic data are all acquired or processed using existing technologies, which will not be described in detail here.

[0059] The second step is to conduct targeted amplitude spectrum analysis and surface consistency decomposition:

[0060] Specific operations include:

[0061] Select the time window for spectrum analysis and perform surface consistency decomposition. The seismic trace spectrum can be decomposed into shot point item P(src), receiver point item P(rcv), common center point item P(cmp), offset item P(offset), and other items P(extra) and noise item Pn. The expression is as follows:

[0062] P(trace)=P(src)●P(rcv)●P(cmp)●P(offset)●P(extra)●Pn

[0063] The surface consistency decomposition of the present invention adopts the existing classic seismic data consistency processing and decomposition method. The process is to convert the seismic data into the frequency domain and decompose it according to the composition of the seismic trace spectrum. The expression is as follows:

[0064] W(ω)=S(ω)R(ω)M(ω)O(ω)

[0065] Where ω is the frequency in the angle domain, S is the shot point spectrum, R is the receiver point spectrum, M is the underground center point spectrum, and O is the offset distance spectrum.

[0066] The third step is to statistically calculate the target spectrum of the target layer:

[0067] Specific operations include:

[0068] The shot point term P(src) and the detection point term P(rcv) are statistically analyzed to identify and remove the energy and frequency components that are seriously affected by the overburden shielding, and then the target spectrum to be restored is obtained using a weighted statistical method.

[0069] The shot point term P(src) and the receiver point term P(rcv) are statistically analyzed to identify and remove the energy and frequency components that are severely affected by the overburden shielding. Specifically:

[0070] Based on the spectrum decomposition in the second step, the decomposition results of different shot points and detection points can be obtained, and the results can be displayed on the plane. The spectrum of the area affected by the coal seam and the abnormal spectrum at the boundary of the work area are eliminated, and finally the target spectrum with relatively high quality is circled and selected.

[0071] The target spectrum to be restored is obtained using a weighted statistical method, specifically:

[0072] The final target spectrum is obtained by statistically averaging the circled and selected target spectrum.

[0073] Figure 2 is the shot point item spectrum (top) and the corresponding target spectrum (bottom); Figure 3 is the detection point spectrum (upper) and the corresponding target spectrum (lower).

[0074] The fourth step is to design the surface consistency compensation operator;

[0075] Based on the seismic trace spectrum in the second step and the target spectrum in the third step, the surface consistency amplitude, frequency and phase operators are designed using the surface consistency L2 norm principle. According to the error formula between the seismic trace and the simulated seismic trace, E(trace) = ‖L(trace)-L m (trace)‖, find the minimum error to obtain the operator containing frequency and phase information, which is the surface consistency compensation operator;

[0076] Among them, L(trace) represents the actual acquired seismic trace, including amplitude, frequency and phase information; L m (trace) represents the simulated seismic trace obtained based on the operator. Seeking the minimum error between the two ensures the amplitude preservation and AVO-friendly characteristics of amplitude processing.

[0077] Step 5: Compensate for the consistency of the overlying obscured surface:

[0078] The corresponding surface consistency operator is applied to the seismic data to achieve the purpose of overburden masking consistency compensation.

[0079] The meaning applied here is the convolution operation.

[0080] Figure 4 To compensate for the consistency of the overlying obscuration surface, the profile is stacked before. Figure 5 The sections are superimposed after compensating for the consistency of the overlying obscuration surface.

[0081] The technology of the present invention has made targeted improvements and upgrades on the basis of the traditional surface consistency processing ideas. It also needs to decompose the amplitude and frequency of the shot check points of the seismic data spectrum, but the time window of the spectrum decomposition is mainly for the underlying target layer. At the same time, it cleverly uses the characteristics of weak amplitude and low frequency in the severely shielded area to perform targeted compensation processing, and finally realizes the overlying shielding energy compensation and frequency band recovery processing. At the same time, the surface consistency theory ensures that the processing process is AVO-friendly.

[0082] The technology of the present invention is also applicable to any underlying inconsistency caused by overlying shielding, and has a very wide range of application scenarios, such as the problem of underlying energy shielded by volcanic rocks, the inconsistency problem caused by shallow gas chimneys, etc. Therefore, the technology of the present invention has good practical application value and prospects.

[0083] [Example 2]

[0084] The embodiment of the present invention provides a system for compensating for overlying and shielding surface consistency, comprising:

[0085] An input unit, used for inputting earthquake data;

[0086] The seismic data are pre-processed pre-stack single shot or gather data.

[0087] The acquisition and preprocessing methods of seismic data are all acquired or processed using existing technologies, which will not be described in detail here.

[0088] The decomposition unit is used for targeted amplitude spectrum analysis and surface consistency decomposition, and performs the following operations:

[0089] Select the time window for spectrum analysis and perform surface consistency decomposition. The seismic trace spectrum can be decomposed into shot point item P(src), receiver point item P(rcv), common center point item P(cmp), offset item P(offset), and other items P(extra) and noise item Pn. The expression is as follows:

[0090] P(trace)=P(src)●P(rcv)●P(cmp)●P(offset)●P(extra)●Pn

[0091] The surface consistency decomposition of the present invention adopts the existing classic seismic data consistency processing and decomposition method. The process is to convert the seismic data into the frequency domain and decompose it according to the composition of the seismic trace spectrum. The expression is as follows:

[0092] W(ω)=S(ω)R(ω)M(ω)O(ω)

[0093] Where ω is the frequency in the angle domain, S is the shot point spectrum, R is the receiver point spectrum, M is the underground center point spectrum, and O is the offset distance spectrum.

[0094] The target spectrum calculation unit is used to statistically calculate the target spectrum of the destination layer and perform the following operations:

[0095] The shot point term P(src) and the detection point term P(rcv) are statistically analyzed to identify and remove the energy and frequency components that are seriously affected by the overburden shielding, and then the target spectrum to be restored is obtained using a weighted statistical method.

[0096] The shot point term P(src) and the receiver point term P(rcv) are statistically analyzed to identify and remove the energy and frequency components that are severely affected by the overburden shielding. Specifically:

[0097] Based on the spectrum decomposition in the second step, the decomposition results of different shot points and detection points can be obtained, and the results can be displayed on the plane. The spectrum of the area affected by the coal seam and the abnormal spectrum at the boundary of the work area are eliminated, and finally the target spectrum with relatively high quality is circled and selected.

[0098] The target spectrum to be restored is obtained using a weighted statistical method, specifically:

[0099] The final target spectrum is obtained by statistically averaging the circled and selected target spectrum.

[0100] The design unit is used to design the surface consistency compensation operator and perform the following operations:

[0101] Based on the seismic trace spectrum in the second step and the target spectrum in the third step, the surface consistency amplitude, frequency and phase operators are designed using the surface consistency L2 norm principle. According to the error formula between the seismic trace and the simulated seismic trace, E(trace) = ‖L(trace)-L m (trace)‖, find the minimum error to obtain the operator containing frequency and phase information, which is the surface consistency compensation operator;

[0102] Among them, L(trace) represents the actual acquired seismic trace, including amplitude, frequency and phase information; L m (trace) represents the simulated seismic trace obtained based on the operator. Seeking the minimum error between the two ensures the amplitude preservation and AVO-friendly characteristics of amplitude processing.

[0103] The compensation unit is used to compensate for the consistency of the overlying obstructed surface and performs the following operations:

[0104] The corresponding surface consistency operator is applied to the seismic data to achieve the purpose of overburden masking consistency compensation. The application here means the convolution operation.

[0105] [Example 3]

[0106] An embodiment of the present invention provides a computer-readable storage medium, which stores at least one computer-executable program. When the at least one program is executed by the computer, the computer executes the steps in the method for compensating for overlying surface consistency as described in Example 1.

[0107] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0108] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A method for compensating for surface consistency of overlying obstruction, characterized in that: The specific steps include: The first step is to input earthquake data; The second step is to conduct targeted amplitude spectrum analysis and surface consistency decomposition; The third step is to statistically calculate the target spectrum of the target layer; The fourth step is to design the surface consistency compensation operator; The fifth step is to make consistency compensation for the overlying obscured surface.

2. The method for compensating for overlying surface consistency according to claim 1, characterized in that: The seismic data in the first step are pre-processed pre-stack single shot or gather data.

3. The method for compensating for overlying and shielding surface consistency according to claim 1, characterized in that: In the second step, the amplitude spectrum is analyzed and the surface consistency is decomposed. The specific operations include: Select the time window for spectrum analysis and perform surface consistency decomposition. The seismic trace spectrum can be decomposed into shot point item P(src), receiver point item P(rcv), common center point item P(cmp), offset item P(offset), and other items P(extra) and noise item Pn. The expression is as follows: P(trace)=P(src)●P(rcv)●P(cmp)●P(offset)●P(extra)●Pn.

4. The method for compensating for overlying and shielding surface consistency according to claim 3, characterized in that: The third step statistically calculates the target spectrum of the target layer, and the specific operations include: The shot point term P(src) and the detection point term P(rcv) are statistically analyzed to identify and remove the energy and frequency components that are seriously affected by the overburden shielding, and then the target spectrum to be restored is obtained using a weighted statistical method.

5. The method for compensating for overlying and shielding surface consistency according to claim 4, characterized in that: The shot point term P(src) and the receiver point term P(rcv) are statistically analyzed to identify and remove the energy and frequency components that are severely affected by the overburden shielding. Specifically: Based on the spectrum decomposition in the second step, the decomposition results of different shot points and detection points are obtained, and the results are displayed on the plane. The spectrum of the area affected by the coal seam and the abnormal spectrum at the boundary of the work area are eliminated, and finally the target spectrum with relatively high quality is circled and selected.

6. The method for compensating for overlying and shielding surface consistency according to claim 5, characterized in that: The target spectrum to be restored is obtained using a weighted statistical method, specifically: The final target spectrum is obtained by statistically averaging the circled and selected target spectrum.

7. The method for compensating for consistency of overlying and shielding ground surface according to claim 6, characterized in that: In the fourth step, a surface consistency compensation operator is designed, and the specific operations include: Based on the seismic trace spectrum in the second step and the target spectrum in the third step, the surface consistency amplitude, frequency and phase operators are designed using the surface consistency L2 norm principle. According to the error formula between the seismic trace and the simulated seismic trace, E(trace) = ‖L(trace)-L m (trace)‖, find the minimum error to obtain the operator containing frequency and phase information, which is the surface consistency compensation operator; Among them, L(trace) represents the actual acquired seismic trace, including amplitude, frequency and phase information; L m (trace) represents the simulated seismic trace obtained based on the operator.

8. The method for compensating for consistency of overlying and shielding ground surface according to claim 7, characterized in that: In the fifth step, consistency compensation is performed on the overlying obstructed surface, and the specific operations include: The corresponding surface consistency operator is applied to the seismic data to achieve the purpose of overburden masking consistency compensation.

9. A system for compensating for overlying surface consistency, characterized in that: include: Input unit, used to input earthquake data: Decomposition unit, used for targeted amplitude spectrum analysis and surface consistency decomposition; A target spectrum calculation unit, used for statistically calculating the target spectrum of the target layer; A design unit, used for designing a surface consistency compensation operator; Compensation unit, used to compensate for the consistency of the overlying obscured surface.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one computer-executable program, and when the at least one program is executed by the computer, the computer executes the steps in the method for compensating for overlying surface consistency as described in any one of claims 1-8.

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