Field collection single shot comprehensive evaluation method based on indoor processing

Abstract

The invention discloses a field acquisition single shot comprehensive evaluation method based on indoor processing, and belongs to the field of seismic exploration. According to the field acquisition single shot comprehensive evaluation method based on indoor processing provided by the invention, external source interference has a great influence on seismic data quality, and detection and evaluation of the external source interference are beneficial to supervising and urging control of field acquisition interference sources and improving acquisition quality; the single shot quality inspection method is comprehensive reflection of external source interference control, field construction quality and excitation receiving conditions, and can quantitatively describe seismic original data quality; abnormal detectors and abnormal time periods can be detected through detector state detection, and a basis is provided for detector function evaluation. Detection of external source interference, evaluation of single shot quality and detector state detection can quantitatively describe noise development conditions, first arrival picking difficulty, denoising key points, signal-to-noise ratio conditions and the like of different areas. According to the characteristics, a targeted treatment flow and treatment parameters can be formulated, and an optimal treatment effect is achieved.

Description

Technical Field

[0001] The invention belongs to the field of seismic exploration, and in particular to a field acquisition single shot comprehensive evaluation method based on indoor processing. Background Art

[0002] With the continuous development of social economy, more and more interference noises are encountered in the process of field seismic data collection. Quarries, coal mines, passing vehicles, and even people passing by may interfere with seismic signals and affect seismic data. There is no obvious difference in geophysical characteristics between external interference signals and seismic source signals, and they also show obvious hyperbolic laws, with the same frequency range as effective seismic signals. Therefore, conventional processing methods are difficult to effectively suppress external interference, which has a great impact on the quality of seismic data.

[0003] The quality of seismic raw data is not affected by a single factor of external interference, and weak external interference does not mean high quality of a single shot. The placement of the detector, the excitation, the complexity of the near-surface, the attenuation and absorption of the near-surface, etc. will have a great impact on the quality of a single shot. The industry already has some methods for evaluating the quality of a single shot. Huang Youhui and other researchers quantitatively evaluate the quality of a single shot and seismic trace from aspects such as single shot energy, single channel energy, and environmental noise, and monitor in real time.

[0004] The number of detector points in a collection project is often tens of thousands. Due to factors such as the detector model and age, the performance of different detectors varies. The detector status detection mainly detects whether the detector is working normally during a certain period of time, which is conducive to the selection and evaluation of the detector. At present, the detector status detection is mainly focused on the inspection of continuous abnormal detectors in the artillery area (drop arrangement). It is not easy to detect abnormal reception of a detector for a long time in real time. Summary of the invention

[0005] The object of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a method for comprehensive evaluation of single-shot collected in the field based on indoor processing.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A comprehensive evaluation method for seismic acquisition raw single shot indoor includes the following operations: external interference detection, single shot quality evaluation and / or detector status evaluation.

[0008] Furthermore, when performing external interference detection, the specific operations are as follows:

[0009] (101) Calculate the single shot equalization factor: establish the single shot first arrival trend line, take the first arrival trend line as the top of the analysis time window, and the seismic record duration as the bottom of the analysis time window. Count the root mean square amplitude of each shot in the time window, and calculate the single shot equalization factor that equalizes the root mean square amplitude to 2000.

[0010] (102) Counting the root mean square amplitude of the background noise: for each channel in a shot, a single shot equalization factor is applied to perform equalization, and then for each seismic channel, the root mean square amplitude in the time window from 0 to the first arrival trend line is counted as the root mean square amplitude of the background noise of the channel;

[0011] (103) The original single-shot recorded seismic traces are evaluated and divided into non-interference traces and interference traces according to a first threshold value. When the root mean square amplitude of the background noise of the seismic trace is less than or equal to the first threshold value, the seismic trace is a non-interference trace, otherwise it is an interference trace. The proportion of the number of interference traces in the shot area is counted.

[0012] Furthermore, in step (102), the single shot balance factor calculation formula is:

[0013]

[0014] Among them, n is the total number of single shot channels, m represents the number of sampling points in each analysis window, Aij is the amplitude value of the jth sample point in the i-th channel of a single shot; i is the i-th seismic channel; j is the j-th sample point.

[0015] Furthermore, in step (103), the first threshold value is obtained based on the statistics of multiple work areas, and a statistical graph of interference value-interference channel ratio is obtained, and the inflection point of the statistical graph is used as the first threshold value for external interference evaluation.

[0016] Furthermore, the first threshold value is 100.

[0017] Furthermore, when evaluating the quality of a single shot, the specific operations are as follows:

[0018] (201) Signal-to-Noise Ratio Calculation

[0019] Establish a single shot first arrival trend line, and count the root mean square amplitude in the time window determined by time 0-first arrival trend line as the background noise root mean square amplitude;

[0020] The RMS amplitude within the 4s window of the first arrival trend line-seismic record is counted as the RMS amplitude of the effective signal, and then the seismic trace noise signal ratio is calculated;

[0021] (202) The original single-shot recorded seismic traces are divided into qualified traces and unqualified traces according to a second threshold value. When the signal-to-noise ratio of the seismic trace is less than the second threshold value, the seismic trace is a qualified trace, otherwise it is an unqualified trace. At the same time, the number / proportion of unqualified traces in the shot area is counted.

[0022] Furthermore, in step (202), the second threshold value is determined according to the influence of background noise on the effective signal, and the amplitude ratio of the boundary between the first arrival that can be picked up and the first arrival that cannot be picked up is used as the second threshold value.

[0023] Furthermore, the second threshold value is

[0024] Furthermore, when evaluating the detector status, the specific operations are as follows:

[0025] (301) Separate the seismic data into the common detection point domain, perform automatic gain equalization on each channel to the same amplitude level, and remove 50 Hz industrial interference;

[0026] (302) Statistical Autocorrelation in the Co-detection Point Domain

[0027] For each channel in the common detection point domain, obtain the unilateral 300ms autocorrelation of each channel, and then stack them to obtain the detection point autocorrelation stacking channel;

[0028] (303) Extract the autocorrelation superposition channel of the detection point, and extract the root mean square amplitude value in the time window of 200 to 300 ms. When the root mean square amplitude value is less than or equal to 0.2, it is determined that the detector state is normal; otherwise, the detector signal with a root mean square amplitude value greater than 0.2 is sent for inspection to determine whether the detector is abnormal.

[0029] Furthermore, it also includes abnormal time period detection, specifically: detecting the abnormal time period of the detector according to the time recorded in the SPS.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention provides a comprehensive evaluation method for field acquisition single shot based on indoor processing. External interference has a great influence on the quality of seismic data. The detection and evaluation of external interference is conducive to supervising the control of interference sources in field acquisition and improving the acquisition quality. The single shot quality inspection method is a comprehensive reflection of external interference control, field construction quality, and excitation reception conditions, and can quantitatively describe the quality of seismic raw data. The detector state detection can detect abnormal detectors and abnormal time periods, providing a basis for the evaluation of detector functions. The detection of external interference, the evaluation of single shot quality, and the detector state detection can quantitatively describe the noise development in different regions, the difficulty of first arrival picking, the denoising focus, and the signal-to-noise ratio. According to these characteristics, targeted processing procedures and processing parameters can be formulated to achieve the best processing effect.

[0032] Furthermore, the influence of background noise on the effective signal is quantitatively described by the ratio of the root mean square amplitude of background noise to the effective signal (noise-to-signal ratio);

[0033] Furthermore, the detector status is determined by counting the autocorrelation sidelobe amplitude of the detection point domain gathers, providing a basis for the evaluation of the detector function. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a single shot that is disturbed in a certain work area;

[0035] Figure 2 This is the detection result of external interference of a single gun in a certain work area;

[0036] Figure 3 It is the statistical result of external interference channel in a certain survey line area;

[0037] Figure 4 The evaluation result of single shot quality (noise-to-signal ratio) in a certain work area;

[0038] Figure 5 This is the quality evaluation result of a single shot in a certain work area;

[0039] Figure 6 This is the abnormal road detection and evaluation result of a certain work area;

[0040] Figure 7 This is an abnormal detector signal detected in a certain work area. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0043] The invention provides an indoor comprehensive evaluation method for original single shot of seismic acquisition, including: external interference detection, single shot quality evaluation and detector state evaluation.

[0044] 1. External interference detection

[0045] (1) Calculation of single shot balance factor: Establish a single shot first arrival trend line, take the first arrival line as the top of the analysis window, and record the duration as the bottom of the analysis window. Statistically calculate the root mean square amplitude of each shot in the analysis window, and calculate the single shot balance factor that will balance the amplitude to 2000.

[0046] Balance factor calculation formula:

[0047] n is the total number of channels in a single shot, m represents the number of sampling points in each analysis window (the number of analysis points in each channel may be different), and Aij is the amplitude value of the jth sample point in the ith channel of a single shot.

[0048] Calculate the root mean square amplitude of background noise: For each channel in a shot, apply the single shot equalization factor. For each channel, calculate the root mean square amplitude in the time window from 0 to the first arrival trend line as the root mean square amplitude of the background noise of the channel.

[0049] The original single-shot recorded seismic traces are divided into two levels according to the threshold value: non-interference traces and interference traces. Taking 100 as the threshold value, when the root mean square amplitude of the background noise of the seismic trace is less than or equal to 100, the seismic trace is a non-interference trace, otherwise it is an interference trace, and the number / proportion of interference traces in the shot area is counted.

[0050] 2. Single shot quality evaluation

[0051] (1) Calculation of signal-to-noise ratio: Establish a single shot first arrival trend line, and calculate the RMS amplitude in the time window from time 0 to the first arrival trend line, which represents the RMS amplitude of the background noise. Calculate the RMS amplitude in the 4s time window from the first arrival trend line to the seismic record, which represents the RMS amplitude of the effective signal, and calculate the signal-to-noise ratio.

[0052] The most fundamental difference from external interference evaluation is that single-shot quality evaluation quantitatively reflects the impact of background noise on the effective signal.

[0053] (2) According to the threshold value, the original single-shot seismic traces are divided into two levels: qualified traces and unqualified traces. is the threshold value. When the signal-to-noise ratio of the seismic channel is less than If the seismic trace is , then it is qualified, otherwise it is unqualified, and the number / proportion of unqualified traces in the blast area are counted.

[0054] 3. Detector status detection method

[0055] (1) Sorting. Seismic data are sorted into the common detection point domain, and automatic gain is performed to equalize each channel to the same amplitude level, and 50 Hz industrial interference is removed in a targeted manner.

[0056] (2) Statistical autocorrelation in the common detection point domain: For each trace of the common detection point gather, the unilateral autocorrelation of 300 ms is calculated and then superimposed to obtain the detection point autocorrelation superposition trace.

[0057] (3) Detection standard. The detector status evaluation is divided into two levels: normal and abnormal. Extract the autocorrelation superposition channel of the detection point and extract the root mean square amplitude value in the time window of 200ms to 300ms. When the root mean square amplitude value is less than or equal to 0.2, the detector status is considered normal. Manually confirm the detector signal with a root mean square amplitude value greater than 0.2 to determine whether the detector is abnormal.

[0058] (4) Abnormal period detection: Based on the time recorded in the SPS, the abnormal period of the detector can be detected.

[0059] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0060] Example 1

[0061] Example 1 is an external interference evaluation, which quantitatively describes the external interference of seismic traces through the strength of the RMS amplitude of the seismic data background noise (the background noise is above the initial arrival) after amplitude equalization. The greater the background noise, the more serious the interference to the seismic data;

[0062] See also Figure 1 , Figure 1 This is a single shot in a certain work area that was disturbed. From the data, we can see that the seismic signal was seriously disturbed.

[0063] See also Figure 2 , Figure 2 This is the result of the external interference detection of a single shot in a certain work area. After the external interference detection, the external interference size (gray line) and the threshold (black line) are superimposed on the seismic data. The lower the gray line, the stronger the interference.

[0064] See also Figure 3 , Figure 3 It is the statistical result of external interference channel in a certain survey line area; Figure 3 The left picture is the superposition of the earthquake source type and the satellite image, the middle picture is the statistics of the interference channels recorded for each shot, and the display is based on the shot point coordinates and the number of interference channels, and the right picture is the distribution of interference sources in the work area. It can be clearly seen that there is an obvious correspondence between the external interference detection results and the earthquake source type and the distribution of interference sources, indicating that the detection results are reasonable.

[0065] Example 2

[0066] Example 2 is a single shot quality evaluation, which determines the quality of seismic trace data by the first arrival upper and lower root mean square amplitude ratio. The weaker the background noise and the stronger the effective signal, the higher the data quality (e.g. Figure 4 ). Single shot quality evaluation is a comprehensive reflection of external interference control, excitation reception conditions, construction quality, and near-surface conditions. It can quantitatively describe the difficulty of first arrival picking, denoising, and other processing. At the same time, it can be applied to detect empty channels, abnormally weak amplitudes, abnormally strong amplitudes, and other situations.

[0067] See also Figure 4 , Figure 4 This is the quality evaluation result of a single shot in a certain work area; Figure 4 After the single shot quality evaluation is performed, the single shot quality (noise-to-signal ratio) and threshold are superimposed on the seismic data. The higher the black curve, the better the single shot quality.

[0068] See also Figure 5 , Figure 5 This is the quality evaluation result of a single shot in a certain work area; Figure 5 The left side is the superposition diagram of the source type and the satellite image, and the middle is the single-channel root mean square amplitude ratio of each shot record greater than After counting the number of seismic channels, the images are displayed according to the shot point coordinates and the number of statistical channels, and the right side shows the distribution of interference sources in the work area. It can be clearly seen that the single shot quality evaluation results have a certain correspondence with the source type and the distribution of interference sources, but there are differences with the external interference detection results, indicating that the strength of external interference cannot fully reflect the impact of external interference on seismic signals.

[0069] Example 3

[0070] Example 3 is the detector state detection. Based on the assumption that the reflection coefficient is a random sequence, the detector state is determined by the autocorrelation sidelobe amplitude of the common detection point domain gather. Seismic data can be defined as the convolution of seismic wavelets and reflection coefficients plus a certain degree of background noise. Under normal circumstances, seismic data is not correlated (except in areas with multiple wave development). Abnormal detectors often appear as regular mechanical signals (such as Figure 7 ), the autocorrelation sidelobe amplitude is strong, thus distinguishing the detector status.

[0071] See also Figure 6 , Figure 6 It is an abnormal detector signal detected in a certain work area; Figure 6 Figure 2 shows an earthquake record (upper side) and its autocorrelation spectrum (lower side). It can be seen that the performance of the abnormal signal in the autocorrelation spectrum is significantly different from that of the conventional earthquake record. This difference can be used to automatically detect the abnormal detector signal.

[0072] See also Figure 7 , Figure 7 This is the abnormal detector signal in a certain work area. Figure 7 It is to extract the seismic data into the common detection point domain, calculate the single-channel autocorrelation spectrum in the detection point domain, and finally superimpose all the autocorrelation spectra of the common detection points to detect the abnormal detector signal according to the abnormal detector detection standard.

[0073] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A comprehensive evaluation method for seismic acquisition of original single-shot chamber, characterized in that: Includes the following operations: external interference detection, single shot quality evaluation and / or detector status evaluation; When performing external interference detection, the following steps are included: (101) Calculate the single-shot balance factor; (102) Calculate the root mean square amplitude of the background noise; (103) evaluating the original single shot record seismic traces into non-interference traces and interference traces according to a first threshold value; When evaluating the quality of a single shot, the following steps are included: (201) Signal-to-noise ratio calculation; (202) dividing the original single-shot recorded seismic traces into qualified traces and unqualified traces according to a second threshold value; When evaluating the status of the detector, the detector status is determined by statistically analyzing the autocorrelation sidelobe amplitude of the detection point domain gather.

2. The comprehensive evaluation method for seismic acquisition original single shot chamber according to claim 1 is characterized in that: When performing external interference detection, the specific operations are as follows: (101) Calculate the single shot equalization factor: establish the single shot first arrival trend line, take the first arrival trend line as the top of the analysis time window, and the seismic record duration as the bottom of the analysis time window. Count the root mean square amplitude of each shot in the time window, and calculate the single shot equalization factor that equalizes the root mean square amplitude to 2000. (102) Counting the root mean square amplitude of the background noise: for each channel in a shot, a single shot equalization factor is applied to perform equalization, and then for each seismic channel, the root mean square amplitude in the time window from 0 to the first arrival trend line is counted as the root mean square amplitude of the background noise of the channel; (103) The original single-shot recorded seismic traces are evaluated and divided into non-interference traces and interference traces according to a first threshold value. When the root mean square amplitude of the background noise of the seismic trace is less than or equal to the first threshold value, the seismic trace is a non-interference trace, otherwise it is an interference trace. The proportion of the number of interference traces in the shot area is counted.

3. The comprehensive evaluation method for seismic acquisition original single shot chamber according to claim 2 is characterized in that: In step (102), the single shot balance factor calculation formula is: Among them, n is the total number of single shot channels, m represents the number of sampling points in each analysis window, Aij is the amplitude value of the jth sample point in the i-th channel of a single shot; i is the i-th seismic channel; j is the j-th sample point.

4. The comprehensive evaluation method for seismic acquisition original single shot chamber according to claim 2 is characterized in that: In step (103), the first threshold value is obtained based on the statistics of multiple work areas, and a statistical graph of interference value-interference channel ratio is obtained, and the inflection point of the statistical graph is used as the first threshold value for external interference evaluation.

5. The comprehensive evaluation method for seismic acquisition original single shot chamber according to claim 4 is characterized in that: The first threshold value is 100.

6. The comprehensive evaluation method for seismic acquisition original single shot chamber according to claim 1 is characterized in that: When evaluating the quality of a single shot, the specific operations are as follows: (201) Signal-to-Noise Ratio Calculation Establish a single shot first arrival trend line, and count the root mean square amplitude in the time window determined by time 0-first arrival trend line as the background noise root mean square amplitude; The RMS amplitude within the 4s window of the first arrival trend line-seismic record is counted as the RMS amplitude of the effective signal, and then the seismic trace noise signal ratio is calculated; (202) The original single-shot recorded seismic traces are divided into qualified traces and unqualified traces according to a second threshold value. When the signal-to-noise ratio of the seismic trace is less than the second threshold value, the seismic trace is a qualified trace, otherwise it is an unqualified trace. At the same time, the number / proportion of unqualified traces in the shot area is counted.

7. The comprehensive evaluation method for seismic acquisition original single shot chamber according to claim 6 is characterized in that: In step (202), the second threshold value is determined according to the influence of background noise on the effective signal, and the amplitude ratio of the first arrival that can be picked up and that cannot be picked up is used as the second threshold value.

8. The comprehensive evaluation method for seismic acquisition original single shot chamber according to claim 7 is characterized in that: The second threshold value is 9. The comprehensive evaluation method for seismic acquisition original single shot chamber according to claim 1, characterized in that: When evaluating the detector status, the specific operations are as follows: (301) Separate the seismic data into the common detection point domain, perform automatic gain equalization on each channel to the same amplitude level, and remove 50 Hz industrial interference; (302) Statistical Autocorrelation in the Co-detection Point Domain For each channel in the common detection point domain, obtain the unilateral 300ms autocorrelation of each channel, and then stack them to obtain the detection point autocorrelation stacking channel; (303) extracting the autocorrelation superposition channel of the detection point, extracting the root mean square amplitude value in the time window of 200 to 300 ms, and when the root mean square amplitude value is less than or equal to 0.2, determining that the detector is in a normal state; Otherwise, the detector signal with a root mean square amplitude value greater than 0.2 is sent for inspection to determine whether the detector is abnormal.

10. The comprehensive evaluation method for seismic acquisition original single shot chamber according to claim 9, characterized in that: It also includes abnormal period detection, specifically: detecting the abnormal period of the detector according to the time recorded in the SPS.

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