A five-dimensional seismic gather flattening correction method and device based on a two-step method
The two-step five-dimensional seismic gather flattening and correction method solves the problem of the difficulty in accurately calculating the dynamic correction speed in five-dimensional seismic data processing, and achieves a high-precision, distortion-free flattening effect, ensuring the accuracy of five-dimensional seismic data in fracture detection and oil and gas identification.
Patent Information
- Application Number
- CN202311337671.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-16
- Publication Date
- 2025-11-07
- Estimated Expiration
- 2043-10-16
AI Technical Summary
Existing technologies struggle to accurately calculate dynamic correction velocities in five-dimensional seismic data processing, leading to reduced stacked profile resolution. Furthermore, the correlation between far and near channels in five-dimensional seismic data is poor, making distortion and stretching more likely.
A two-step five-dimensional seismic gather flattening correction method is adopted. By acquiring the relatively flattened gather and the final flattened gather, the relative time shift and the residual time shift are used for correction to eliminate the time difference caused by velocity anisotropy and ensure distortion-free stretching.
It achieves high-precision flattening of five-dimensional seismic gathers, preserves type II OVT features, eliminates time differences caused by velocity anisotropy, restores the anisotropic characteristics of amplitude, and ensures the accuracy and effectiveness of five-dimensional seismic data in fracture detection and oil and gas identification.
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Figure CN119846715B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of physical exploration, in particular to a five-dimensional seismic gather flattening correction method and device based on a two-step method. BACKGROUND
[0002] Currently, small-scale lithology and subtle oil and gas reservoirs have become the focus of current exploration and development. From the perspective of technical development, the technical direction of land oil and gas seismic exploration is single-source, single-detection, high-density and wide-azimuth seismic data acquisition and imaging processing technology. At present, the international special wide-azimuth five-dimensional seismic data processing technology is mainly OVT processing technology. OVT (Offset Vector Tile) is usually translated as "shot-receiver distance vector tile technology", which was first proposed by Vermeer when studying the minimum data set expression of the acquisition work area; Cary almost simultaneously proposed the Common Offset Vector COV concept.
[0003] In seismic data processing, stack processing is an effective denoising method. However, in actual OVT seismic data processing, the moveout correction velocity is based on the NMO algorithm of the flat layer assumption, and it is a discrete point interpolation velocity, which is difficult to accurately calculate. In addition, due to the anisotropy of the velocity, when there are non-uniform bodies in the seismic ray path, even the pre-stack time migration algorithm cannot obtain a flattened gather. Therefore, there will be a certain amount of residual moveout correction on the data after moveout correction, which will reduce the resolution of the stack profile when doing the same phase stack.
[0004] The commonly used flattening method is to take the near trace stack as the reference trace, and the rest of the traces are compared and flattened with the reference trace. Due to the poor correlation of five-dimensional seismic far traces and near traces, distortion stretching is easily generated. SUMMARY
[0005] In view of the above technical problems in the related art, the present application provides a five-dimensional seismic gather flattening correction method and device based on a two-step method, which can overcome the above shortcomings of the prior art.
[0006] To achieve the above technical purposes, the technical solution of the present application is as follows:
[0007] On the one hand, a five-dimensional seismic gather flattening correction method based on a two-step method is provided, comprising:
[0008] Obtaining a relative flattened gather of a plurality of five-dimensional seismic gathers;
[0009] Based on the relative flattened gather, a final flattened gather is calculated;
[0010] Repeat the above steps to complete the flattening correction of the five-dimensional seismic gather data body.
[0011] Further, the obtaining of the relative flattened gathers of the five-dimensional seismic gathers comprises:
[0012] From the five-dimensional seismic data volume, a first five-dimensional spiral gather is obtained;
[0013] According to the spiral arrangement order of the first five-dimensional seismic gather, the current gather is compared with the previous gather in sequence to calculate a relative time shift amount;
[0014] The relative time shift amounts of all the gathers in front of the current gather are accumulated and added to obtain an absolute time shift amount of the current gather;
[0015] The relative flattened gathers of the five-dimensional seismic gathers are obtained by time shifting according to the absolute time shift amount of the current gather.
[0016] Further, the obtaining of the relative flattened gathers of the five-dimensional seismic gathers comprises:
[0017] Based on the relative flattened gathers and the reference gather, a residual time shift amount is calculated, a residual flattened gather of the relative time shift amount is calculated, and the final flattened gather is obtained.
[0018] Further, the obtaining of the relative flattened gathers of the five-dimensional seismic gathers comprises:
[0019] Based on the relative flattened gathers, the near gather is added as the reference gather, and the remaining gathers are compared with the reference gather to calculate the residual time shift amount.
[0020] Further, the calculation formula of the absolute time shift amount of the current gather by accumulating and adding the relative time shift amounts of all the gathers in front of the current gather is:
[0021]
[0022] In the formula, Δτ j is the relative time shift amount of the current gather and the previous gather, and τ i is the absolute time shift amount of the current gather.
[0023] On the other hand, a five-dimensional seismic gather flattening correction device based on a two-step method is provided, comprising:
[0024] An obtaining module is configured to obtain relative flattened gathers of a plurality of five-dimensional seismic gathers;
[0025] A calculation module is configured to calculate a final flattened gather based on the relative flattened gathers;
[0026] A correction module is configured to repeatedly perform the above steps to complete the flattening correction of the five-dimensional seismic gather data volume.
[0027] Further, the obtaining of the relative flattened gathers of the five-dimensional seismic gathers comprises:
[0028] from the five-dimensional seismic data volume, a first five-dimensional seismic spiral gather is obtained;
[0029] According to the spiral arrangement order of the first five-dimensional seismic gather, the current trace is correlated with the previous trace in turn to calculate the relative time shift amount;
[0030] The relative time shift amounts of all the traces in front of the current trace are cumulatively added to obtain the absolute time shift amount of the current trace;
[0031] According to the absolute time shift amount of the current trace, time shifting is performed to obtain the relative flattened gather of the five-dimensional seismic gather.
[0032] Further, the final flattened gather is calculated based on the relative flattened gather, comprising:
[0033] Based on the relative flattened gather and the reference trace, the residual time shift amount is calculated, the residual flattened gather of the relative time shift amount is calculated, and the final flattened gather is obtained.
[0034] Further, the residual time shift amount is calculated based on the relative flattened gather and the reference trace, comprising:
[0035] Based on the relative flattened gather, the near trace is added as the reference trace, and the remaining traces are correlated with the reference trace to calculate the residual time shift amount.
[0036] Further, the calculation formula of the absolute time shift amount of the current trace by cumulatively adding the relative time shift amounts of all the traces in front of the current trace is:
[0037]
[0038] In the formula, Δτ j is the relative time shift amount of the current trace and the previous trace, τ i is the absolute time shift amount of the current trace.
[0039] The present application has the following beneficial effects: the present application calculates the relative time difference of each trace in the trace set with the adjacent trace, and corrects the residual time difference of each trace with the near trace to perform the flattening correction processing on the trace set data, and the same as the flattening of the same phase axis, the second OVT feature is retained while ensuring no stretching distortion; while ensuring the flattening of the same phase axis of the five-dimensional seismic gather, the second OVT feature is retained while ensuring no stretching distortion, the time difference caused by the velocity anisotropy of the five-dimensional seismic data is eliminated, the anisotropy feature of the amplitude is restored, and the correctness and effectiveness of the five-dimensional seismic data in the anisotropy fracture detection and oil and gas identification are ensured; the present application proposes a two-step flattening method, which not only overcomes the cumulative error of the adjacent trace flattening, but also eliminates the stretching distortion caused by the near and far traces, ensures the high-precision and distortion-free five-dimensional seismic flattening effect, and makes the five-dimensional seismic truly play an advantage in the anisotropy fracture identification and fluid prediction. BRIEF DESCRIPTION OF DRAWINGS
[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed in the embodiments will be briefly introduced as follows. Obviously, the accompanying drawings in the following description only represent some embodiments of the present application, and can provide other drawings based on these drawings for those skilled in the art without any creative effort.
[0041] Figure 1 is a flowchart of a five-dimensional seismic trace set flattening correction method based on a two-step method according to an embodiment of the present application;
[0042] Figure 2 In order to obtain a five-dimensional seismic trace set from the entire five-dimensional seismic trace set data body by using the method according to the embodiment of the present application;
[0043] Figure 3 A calculation of relative time difference and trace-by-trace flattening diagram in the method according to the embodiment of the present application;
[0044] Figure 4 A calculation of absolute time difference flattening diagram in the method according to the embodiment of the present application;
[0045] Figure 5 A five-dimensional seismic flattened trace set obtained by using the method according to the embodiment of the present application. DETAILED DESCRIPTION
[0046] The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.
[0047] As shown in Figures 1-5 A five-dimensional seismic trace set flattening correction method based on a two-step method is provided, which comprises:
[0048] Obtaining a relative flattened trace set of a plurality of five-dimensional seismic trace sets;
[0049] Based on the relative flattened trace set, a final flattened trace set is calculated;
[0050] The above steps are repeated multiple times to complete the flattening correction of the five-dimensional seismic trace set data body.
[0051] In some embodiments of the present application, the relative flattened trace set of the five-dimensional seismic trace set comprises:
[0052] Obtaining a first five-dimensional spiral trace set from the five-dimensional seismic data body;
[0053] According to the first five-dimensional seismic trace set spiral arrangement order, the current trace is compared with the previous trace in turn to calculate the relative time shift amount;
[0054] The relative time shift amounts of all the traces in front of the current trace are accumulated and added to obtain the absolute time shift amount of the current trace;
[0055] According to the absolute time shift amount of the current trace, the time shift is performed to obtain the relative flattened trace set of the five-dimensional seismic trace set.
[0056] In some embodiments of the present application, the final flattened trace set is calculated based on the relative flattened trace set, and the method comprises:
[0057] The residual time shift amount is calculated based on the relative flattened trace set and the reference trace, the residual flattened trace set of the relative time shift amount is calculated, and the final flattened trace set is obtained.
[0058] In some embodiments of the present application, the residual time shift amount is calculated based on the relative flattened trace set and the reference trace, and the method comprises:
[0059] The residual time shift amount is calculated based on the relative flattened trace set, the near trace is added as the reference trace, and the residual time shift amount is calculated by correlating the reference trace with the remaining traces.
[0060] In some embodiments of the present application, the calculation formula of the absolute time shift amount of the current trace by accumulating and adding the relative time shift amounts of all the traces in front of the current trace is:
[0061]
[0062] In the formula, Δτ j is the relative time shift amount of the current trace and the previous trace, τ i is the absolute time shift amount of the current trace.
[0063] In another aspect, a five-dimensional seismic trace set flattening correction device based on a two-step method is provided, which comprises:
[0064] An acquisition module is configured to acquire a relative flattened trace set of a plurality of five-dimensional seismic trace sets;
[0065] A calculation module is configured to calculate a final flattened trace set based on the relative flattened trace set;
[0066] A correction module is configured to repeatedly perform the above steps to complete the flattening correction of the five-dimensional seismic trace set data body.
[0067] In some embodiments of the present application, the relative flattened trace set of the five-dimensional seismic trace set is acquired, and the method comprises:
[0068] A first five-dimensional seismic spiral trace set is acquired from a five-dimensional seismic data body;
[0069] According to the first five-dimensional seismic trace set spiral arrangement order, the current trace is compared with the previous trace in turn to calculate the relative time shift amount;
[0070] The relative time shift amounts of all the traces in front of the current trace are accumulated and added to obtain the absolute time shift amount of the current trace;
[0071] According to the absolute time shift amount of the current trace, the relative flattened trace set of the five-dimensional seismic trace set is obtained through time shifting.
[0072] In some embodiments of the present application, the final flattened trace set is calculated based on the relative flattened trace set, and includes:
[0073] Based on the relative flattened trace set and the reference trace, the residual time shift amount is calculated, the residual flattened trace set of the relative time shift amount is calculated, and the final flattened trace set is obtained.
[0074] In some embodiments of the present application, the residual time shift amount is calculated based on the relative flattened trace set and the reference trace, and includes:
[0075] Based on the relative flattened trace set, the near trace is added as the reference trace, and the remaining traces are compared with the reference trace to calculate the residual time shift amount.
[0076] In some embodiments of the present application, the calculation formula of the absolute time shift amount of the current trace by accumulating and adding the relative time shift amounts of all the traces in front of the current trace is:
[0077]
[0078] In the formula, Δτ j is the relative time shift amount of the current trace and the previous trace, τ i is the absolute time shift amount of the current trace.
[0079] Referring to Figure 1 , a five-dimensional seismic trace set flattening correction method based on a two-step method according to the present embodiment includes the following specific steps:
[0080] S10, a five-dimensional seismic trace set is obtained from the entire five-dimensional seismic trace set data body. Figure 2 is a five-dimensional seismic trace set obtained from a five-dimensional seismic work area in the Bohai Bay Basin. From the entire trace set, especially the anisotropic moveout at 2450ms, the trace set is curved and uneven, which will destroy the anisotropy characteristics of the amplitude and the amplitude change relationship with the offset, affect the fracture identification and oil and gas prediction, and need to be flattened under the premise of ensuring no distortion.
[0081] S20, according to the spiral arrangement order of the five-dimensional seismic trace set, the current trace is compared with the previous trace in turn to calculate the relative time shift amount, as shown in Figure 3As shown, the relative time shift amount of the second trace to the first trace, the relative time shift amount of the third trace to the second trace, and the relative time shift amount of all the traces are calculated in sequence, and since the signal characteristics of adjacent traces are basically consistent, no distortion error exists.
[0082] In S30, the relative time shift amounts of all the traces in front of the current trace are accumulated and added to obtain the absolute time shift amount of the current trace; the absolute time shift amount of the current trace is realized by using the following formula:
[0083]
[0084] In the formula, Δτ j is the relative time shift amount of the current trace to the previous trace, τ i is the absolute time shift amount of the current trace.
[0085] As shown in Figure 3 , the absolute time shift amount of the fourth trace is the accumulation of the time shift amounts of the second, third and fourth traces.
[0086] In S40, time shift is performed according to the absolute time shift amount of the current trace to obtain the relative flattened trace set of the first step; although the relative time shift amount calculation does not have distortion error, there is a small error due to the influence of noise and other factors, and the five-dimensional seismic trace set has a large number of traces, so there is often a large cumulative error.
[0087] In S50, based on the relative flattened trace set, the near trace is added as a reference trace, the remaining traces are compared with the reference trace, the remaining time shift amount is calculated, the second step of remaining flattening is performed, the cumulative error in the first step of flattening is eliminated, and the final flattened trace set is obtained. Figure 3 is a schematic diagram for calculating the absolute time difference flattening, the first to fourth traces are superimposed as a flattening reference trace, and the remaining traces are aligned with the reference trace for flattening.
[0088] In S60, the steps S10 to S50 are repeated to process the entire five-dimensional seismic trace set flattening data body.
[0089] Here, one five-dimensional seismic trace set shown in Figure 2 is repeated with the steps S20 to S50 to obtain the corresponding flattened trace set as shown in Figure 5 , compared with Figure 2 , it can be seen that Figure 5 not only the remaining time difference is eliminated, but also there is no distortion phenomenon, and the effect of the change of the five-dimensional seismic amplitude with the azimuth angle and the offset distance is obvious, which shows that the flattening effect of the method of the present application is very good, and the five-dimensional seismic data is real and effective.
[0090] In some embodiments of the present application, firstly, a five-dimensional seismic spiral trace set is obtained from a five-dimensional seismic data volume; then, according to the spiral arrangement order of the five-dimensional seismic trace set, the relative time shift amount is calculated by correlating the current trace with the previous trace in turn; then, the relative time shift amount of all the traces in front of the current trace is accumulated and added to obtain the absolute time shift amount of the current trace; secondly, the relative time shift amount is time-shifted to obtain the relative flattened trace set of the first step; finally, based on the relative flattened trace set, the near trace addition is taken as a reference trace, the remaining traces are correlated with the reference trace to calculate the remaining time shift amount, and the second step of remaining flattening is performed to obtain the final flattened trace set. Compared with the prior art, the present application is aimed at the five-dimensional seismic trace set, and can overcome the problems of large signal difference between near and far traces and the misalignment of the far trace with the near trace; at the same time, the present application can overcome the problems of large cumulative error of relative flattening due to the large number of five-dimensional seismic traces and low signal-to-noise ratio. The two-step flattening method is a reliable method for flattening the five-dimensional seismic trace set, and can provide correct data for five-dimensional seismic fracture detection and oil and gas prediction.
[0091] In summary, the present application calculates the relative time difference of each trace in the trace set with the adjacent trace, and corrects the trace set data by calculating the remaining time difference of each trace with the near trace, thereby performing flattening correction processing, flattening the phase axis, retaining the second type of OVT feature, and ensuring no stretching distortion; while ensuring the flattening of the phase axis of the five-dimensional seismic trace set, retaining the second type of OVT feature, ensuring no stretching distortion, eliminating the time difference of the five-dimensional seismic data due to velocity anisotropy, restoring the anisotropy characteristics of the amplitude, and ensuring the correctness and effectiveness of the five-dimensional seismic data in anisotropic fracture detection and oil and gas identification; the present application proposes a two-step flattening method, which can overcome the cumulative error of adjacent trace flattening and eliminate the stretching distortion caused by near and far traces, ensure high-precision five-dimensional seismic flattening effect without distortion, and make the five-dimensional seismic truly play an advantage in anisotropic fracture identification and fluid prediction.
[0092] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims
1. A five-dimensional seismic gather flattening correction method based on a two-step approach, characterized in that, The method comprises the following steps: (1) obtaining a plurality of relative flattened traces of five-dimensional seismic trace sets; (2) calculating a final flattened trace based on the relative flattened traces; (3) repeatedly performing steps (1) and (2) to complete the flattening correction of the five-dimensional seismic trace data volume, wherein: the step of obtaining a plurality of relative flattened traces of five-dimensional seismic trace sets comprises: obtaining a first five-dimensional spiral seismic trace set from a five-dimensional seismic data volume; comparing the current trace with the previous trace in turn according to the spiral arrangement order of the first five-dimensional seismic trace set to calculate a relative time shift amount; cumulatively adding the relative time shift amounts of all the traces in front of the current trace to obtain an absolute time shift amount of the current trace; time shifting according to the absolute time shift amount of the current trace to obtain the relative flattened trace of the five-dimensional seismic trace set; the step of calculating a final flattened trace based on the relative flattened trace comprises: calculating a residual time shift amount based on the relative flattened trace and a reference trace, calculating a residual flattened trace of the relative time shift amount, and obtaining the final flattened trace.
2. The five-dimensional seismic gather flattening correction method based on two-step method according to claim 1, characterized in that, the step of calculating a residual time shift amount based on the relative flattened trace and a reference trace comprises: adding the near trace as the reference trace, and comparing the remaining traces with the reference trace to calculate the residual time shift amount.
3. The five-dimensional seismic gather flattening correction method based on two-step method according to claim 1, characterized in that, the calculation formula of cumulatively adding the relative time shift amounts of all the traces in front of the current trace to obtain the absolute time shift amount of the current trace is: where Δτ j is the relative time shift of the current track from the previous track, τ i is the absolute time shift of the current track.
4. A five-dimensional seismic gather flattening correction device based on a two-step method, characterized in that, The method comprises the following steps: an obtaining module is configured to obtain a plurality of relative flattened traces of five-dimensional seismic trace sets in step (1); a calculating module is configured to calculate a final flattened trace based on the relative flattened traces in step (2); a correction module is configured to repeatedly perform steps (1) and (2) to complete the flattening correction of the five-dimensional seismic trace data volume, wherein: the step of obtaining a plurality of relative flattened traces of five-dimensional seismic trace sets comprises: obtaining a first five-dimensional spiral seismic trace set from a five-dimensional seismic data volume; comparing the current trace with the previous trace in turn according to the spiral arrangement order of the first five-dimensional seismic trace set to calculate a relative time shift amount; cumulatively adding the relative time shift amounts of all the traces in front of the current trace to obtain an absolute time shift amount of the current trace; time shifting according to the absolute time shift amount of the current trace to obtain the relative flattened trace of the five-dimensional seismic trace set; the step of calculating a final flattened trace based on the relative flattened trace comprises: calculating a residual time shift amount based on the relative flattened trace and a reference trace, calculating a residual flattened trace of the relative time shift amount, and obtaining the final flattened trace.
5. A five-dimensional seismic gather flattening correction device based on a two-step method according to claim 4, characterized in that, the step of calculating a residual time shift amount based on the relative flattened trace and a reference trace comprises: adding the near trace as the reference trace, and comparing the remaining traces with the reference trace to calculate the residual time shift amount.
6. A five-dimensional seismic gather flattening correction device based on a two-step method according to claim 4, characterized in that, the calculation formula of cumulatively adding the relative time shift amounts of all the traces in front of the current trace to obtain the absolute time shift amount of the current trace is: where Δτ j is the relative time shift of the current track from the previous track, τ i is the absolute time shift of the current track.