Method for determining the direction of a seismic source excitation
By acquiring and analyzing nine-component seismic data, and combining the excitation of P-wave and S-wave sources, the orientation angle of the three-component geophone and the excitation direction of the S-wave source were determined. This solved the problem of insufficient seismic data, achieved both accuracy and richness of seismic data, and facilitated data processing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA NAT PETROLEUM CORP
- Filing Date
- 2022-07-29
- Publication Date
- 2026-07-21
AI Technical Summary
Existing technologies only consider P-wave source excitation, resulting in insufficient seismic data, a lack of S-wave source excitation data, and a lack of correction for the S-wave source excitation direction, leading to inaccurate wavefield characteristics in the seismic data.
By acquiring nine-component seismic data, including P-wave and S-wave source data, the orientation angle of the three-component geophone is determined by P-wave first-arrival energy analysis, and the excitation direction of the S-wave source is determined by S-wave first-arrival energy analysis. Combined with coordinate transformation and retargeting correction processing, richer seismic data is obtained.
It achieves accuracy and richness in seismic data, provides sufficient data support, and facilitates a more accurate description of the wavefield characteristics of seismic data.
Smart Images
Figure CN117518236B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of earthquake data processing, and in particular to a method for determining the excitation direction of an earthquake source. Background Technology
[0002] During seismic data acquisition, a controlled seismic source is used to excite vibrations, and a three-component geophone is used to receive the seismic data.
[0003] In related technologies, when acquiring seismic data, most methods utilize controllable seismic sources to excite P-wave sources, obtain three-component P-wave data through three-component geophones, and perform polarization analysis on the three-component P-wave source data to obtain the orientation angle of the three-component geophones.
[0004] However, considering only P-wave source excitation results in insufficient seismic data, lack of S-wave source excitation data, and lack of correction for S-wave source excitation direction, leading to inaccurate wavefield characteristics in the acquired seismic data. Summary of the Invention
[0005] In view of this, this application provides a method for determining the excitation direction of a seismic source, so as to determine the orientation angle of a three-component detector and the excitation direction of a shear wave source.
[0006] Specifically, the following technical solutions are included:
[0007] This application provides a method for determining the excitation direction of a seismic source, the method comprising:
[0008] Nine-component seismic data is acquired, including P-wave source data and S-wave source data. The P-wave source data is data excited by the P-wave source received by a three-component geophone along the survey line direction, perpendicular to the survey line direction, and vertically. The S-wave source data is data excited by the S-wave source received by a three-component geophone along the survey line direction, perpendicular to the survey line direction, and vertically.
[0009] Perform P-wave first arrival energy analysis on the P-wave source data to determine the orientation angle of the three-component detector;
[0010] The shear wave source data is subjected to shear wave first arrival energy analysis to determine the excitation direction of the shear wave source.
[0011] In some embodiments, before performing P-wave first-arrival energy analysis on the P-wave source data to determine the orientation angle of the three-component detector, the method further includes:
[0012] The longitudinal wave source data is subjected to a coordinate transformation, converting the rectangular coordinate system into a cylindrical coordinate system. The formula used for the coordinate transformation is as follows:
[0013]
[0014] In the formula, j is the current receiver point number, j = 1, 2, ..., N, N is the total number of receiver points, i is the shot sequence number of the current common receiver point gather, i = 1, 2, ..., M, M is the total number of shots in the common receiver point gather. This is the three-component recording vector of the P-wave source in the Cartesian coordinate system (X, Y, Z) corresponding to receiver point number j and shot point number i. for Rotate to cylindrical coordinates (R, T, Z) to the three-component longitudinal wave source vector, θ ij Let j be the receiver azimuth corresponding to the receiver number j and the shot number i, and t be the time sample number of the seismic record, where t = 0, 1, 2, ..., Tr, and Tr is the number of time samples of the seismic record.
[0015] In some embodiments, performing P-wave first-arrival energy analysis on the P-wave source data to determine the orientation angle of the three-component detector includes:
[0016] The P-wave source data is subjected to redirection correction processing to obtain redirected P-wave source data;
[0017] Using the data after the redirection correction, the orientation angle of the three-component detector is calculated.
[0018] In some embodiments, the P-wave source data is redirected and corrected according to the following correction formula to obtain the redirected and corrected P-wave source data:
[0019]
[0020] In the formula, The three-component recording vector of the redirected P-wave source. Let φ be the horizontal deflection angle of the three-component detector, and φ be the vertical deflection angle of the three-component detector. The initial value of φ is 0. The initial value is 0. Let be the three-component P-wave source vector in cylindrical coordinate system (R, T, Z), j be the current receiver point number, j = 1, 2, ..., N, N be the total number of receiver points, i be the shot number of the current common receiver point gather, i = 1, 2, ..., M, M be the total number of shots in the common receiver point gather, and t be the seismic record time sample number, t = 0, 1, 2, ..., Tr, Tr be the number of seismic record time samples.
[0021] In some embodiments, calculating the orientation angle of the three-component detector using the redirected and corrected data includes:
[0022] Using the data after the redirection correction, calculate the sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiving point gather;
[0023] The orientation angle of the three-component detector is calculated based on the minimum sum of the energy ratios of the R and T components of all shots within the first arrival time window of the common receiving point gather with receiving point number j.
[0024] In some embodiments, the sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiving point gather is calculated according to the following formula:
[0025]
[0026] In the formula, T1 ij and T2 ij The start and end times of the calculation window for the seismic trace with receiver point number j and shot point number i are the sample point numbers. φ is the horizontal deflection angle of the three-component detector, and φ is the vertical deflection angle of the three-component detector. This is the sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiver gather with receiver number j. and is the P-wave source vector in the corrected cylindrical coordinate system, j is the current receiver point number, j = 1, 2, ..., N, N is the total number of receiver points, i is the shot number of the current common receiver point gather, i = 1, 2, ..., M, M is the total number of shots in the common receiver point gather, t is the seismic record time sample number, t = 0, 1, 2, ..., Tr, Tr is the number of seismic record time samples.
[0027] In some embodiments, calculating the orientation angle of the three-component detector based on the minimum sum of the energy ratios of the R and T components within the first arrival time windows of all shots in the common receiving point gather with receiving point number j includes:
[0028] Given υ∈[0°, 180°], Calculate different orientation angles within the angular range. The sum of the energy ratios of the corresponding R and T components within a given time window Statistical analysis of receiving point number j The minimum value and the corresponding orientation angle
[0029] Where φ0 is the initial value of φ. Let φ be the initial value, δφ be the angular interval, and k1 = 1, 2…K1. Let the horizontal deflection be the calculated angle of the three-component detector with receiver number j. The vertical deflection angle of the three-component detector with receiver point number j is calculated.
[0030] The sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiving point gather is calculated using the following formula:
[0031]
[0032] In the formula, T1 ij and T2 ij The start and end times of the calculation window for the seismic trace with receiver point number j and shot point number i are the sample point numbers. φ is the horizontal deflection angle of the three-component detector, and φ is the vertical deflection angle of the three-component detector. This is the sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiver gather with receiver number j. and is the P-wave source vector in the corrected cylindrical coordinate system, j is the current receiver point number, j = 1, 2, ..., N, N is the total number of receiver points, i is the shot number of the current common receiver point gather, i = 1, 2, ..., M, M is the total number of shots in the common receiver point gather, t is the seismic record time sample number, t = 0, 1, 2, ..., Tr, Tr is the number of seismic record time samples.
[0033] In some embodiments, performing shear wave first arrival energy analysis on the shear wave source data to determine the excitation direction of the shear wave source includes:
[0034] Using the aforementioned orientation angle, the receiving direction of the shear wave source data is corrected respectively;
[0035] The excitation direction of the shear wave source is determined by using the horizontal component of the corrected shear wave source data.
[0036] In some embodiments, the receiving direction of the shear wave source data is corrected using the orientation angle according to the following formula:
[0037]
[0038]
[0039] in, The three-component recording vector is generated along the survey line direction by the shear wave source with receiving point number j and shot point number i. The three-component recording vector is generated by the shear wave source with receiving point number j and shot point number i in a direction perpendicular to the survey line direction. and These are data from the shear wave source. and The three-component recording vector after three-component detector retargeting. Let the horizontal deflection be the calculated angle of the three-component detector with receiver number j. Let t be the vertical deflection angle of the three-component geophone with receiver point number j, where j is the current receiver point number, j = 1, 2, ..., N, N is the total number of receiver points, i is the shot sequence number of the current common receiver point gather, i = 1, 2, ..., M, M is the total number of shots in the common receiver point gather, and t is the seismic record time sample number, t = 0, 1, 2, ..., Tr, Tr is the number of seismic record time samples.
[0040] In some embodiments, the excitation direction of the shear wave source is determined using the horizontal component of the corrected shear wave source data according to the following formula:
[0041]
[0042]
[0043] In the formula, and T1 represents the direction of excitation along the survey line and perpendicular to the survey line direction at the i-th shot point of the shear wave source, respectively. ij and T2 ij The start and end time sample numbers are the calculation time windows for the direction-corrected seismic trace with receiver point number j and shot point number i. and The horizontal component of the corrected shear wave source data is denoted by j, which is the current receiver point number, j = 1, 2, ..., N, where N is the total number of receiver points. The shot number of the current common receiver point gather is denoted by i, i = 1, 2, ..., M, where M is the total number of shots in the common receiver point gather. The time sample number of the seismic record is denoted by t, t = 0, 1, 2, ..., Tr, where Tr is the number of time samples in the seismic record.
[0044] The method for determining the excitation direction of a seismic source provided in this application utilizes a controllable seismic source to excite both P-wave and S-wave sources, and combines this with a three-component geophone for receiving seismic data. This method acquires not only P-wave source data but also S-wave source data, obtaining a total of nine seismic data components. Compared with related technologies, the acquired information is richer, providing ample data support for seismic data analysis. P-wave first-arrival energy analysis of the P-wave source data determines the orientation angle of the three-component geophone, ensuring the accuracy of the received seismic data. Similarly, S-wave first-arrival energy analysis of the S-wave source data determines the excitation direction of the S-wave source. This method determines the orientation angle of the three-component geophone and the excitation direction of the S-wave source, facilitating data processing personnel to more accurately describe the wavefield characteristics of the seismic data. Attached Figure Description
[0045] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0046] Figure 1 A flowchart illustrating a method for determining the excitation direction of a seismic source, provided as an embodiment of this application;
[0047] Figure 2 A flowchart illustrating another method for determining the excitation direction of a seismic source, provided in an embodiment of this application;
[0048] Figure 3 A schematic diagram of a three-component common receiver gather excited by a longitudinal wave source, provided in an embodiment of this application;
[0049] Figure 4 A schematic diagram of the three-component common receiving point gather excited by the longitudinal wave source after coordinate transformation, provided in an embodiment of this application;
[0050] Figure 5 The flowchart illustrates the process of determining the orientation angle of a three-component geophone by performing P-wave first arrival energy analysis on P-wave source data in a method for determining the excitation direction of a seismic source provided in this application embodiment.
[0051] Figure 6 A schematic diagram of a three-component common receiver gather excited by a longitudinal wave source in a cylindrical coordinate system after receiving direction correction, provided in an embodiment of this application.
[0052] Figure 7 The flowchart illustrates a method for determining the excitation direction of a seismic source by performing shear wave first arrival energy analysis on shear wave source data to determine the excitation direction of the shear wave source, as provided in an embodiment of this application.
[0053] Figure 8 A schematic diagram of a common receiving point gather excited along the survey line direction by a transverse wave source after receiving direction correction, as provided in an embodiment of this application.
[0054] Figure 9 A schematic diagram of a common receiver gather excited by a transverse wave source with the receiving direction corrected along a direction perpendicular to the survey line, as provided in an embodiment of this application.
[0055] Figure 10 A schematic diagram of the common receiving point gather excited along the survey line direction by the shear wave source after excitation direction correction provided in the embodiments of this application;
[0056] Figure 11 This is a schematic diagram of a common receiving point gather excited by a transverse wave source after excitation direction correction along a direction perpendicular to the survey line, as provided in an embodiment of this application. Detailed Implementation
[0057] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0058] During seismic data acquisition, controlled source vibration excitation is required, and three-component geophones are used to receive the seismic data. Controlled source excitation includes P-wave and S-wave source excitation. Unlike conventional P-wave source excitation, the seismic record wavefield received by the three-component geophone during S-wave source excitation exhibits significant vector characteristics. Its polarity and energy distribution are not only directly related to the shot-receiver azimuth and the placement direction of the three-component geophone, as with the P-wave source excitation wavefield, but are also directly influenced by the S-wave source excitation direction. Therefore, the excitation direction of the S-wave source is an extremely important parameter in S-wave source exploration, directly affecting the processing and application of S-wave source data. However, in actual construction, due to limitations in construction conditions and equipment performance, just as it is difficult to ensure that the three-component geophones are deployed exactly according to design requirements, it is also difficult to strictly adhere to the designed excitation direction during S-wave source exploration. Therefore, determining the excitation direction of the S-wave source and performing quality control and direction correction on the acquired S-wave source data is a key task in S-wave source data processing.
[0059] The wave field recorded by a shear wave source is affected by both the detector placement direction and the excitation direction of the shear wave source. Therefore, when analyzing the excitation direction of shear wave source data, it is necessary to first analyze the shear wave source data to check for any three-component detector orientation issues. If there are obvious three-component detector orientation issues, it is necessary to first perform three-component detector orientation analysis and correction on the shear wave source data, and then use the shear wave source data after detector orientation correction to analyze the excitation direction of the shear wave source.
[0060] Figure 1 A flowchart illustrating a method for determining the excitation direction of a seismic source, as provided in this application embodiment, can be found here. Figure 1 The method includes:
[0061] 101. Acquire 9-component seismic data. The 9-component seismic data includes P-wave source data and S-wave source data. The P-wave source data is the data excited by the P-wave source received by the three-component geophone along the survey line direction, perpendicular to the survey line direction, and vertical direction. The S-wave source data is the data excited by the S-wave source received by the three-component geophone along the survey line direction, perpendicular to the survey line direction, and vertical direction.
[0062] 102. Perform initial arrival energy analysis on the longitudinal wave source data to determine the orientation angle of the three-component detector.
[0063] 103. Perform shear wave first arrival energy analysis on the shear wave source data to determine the excitation direction of the shear wave source.
[0064] The method for determining the excitation direction of a seismic source provided in this application utilizes a controllable seismic source to excite both P-wave and S-wave sources, and combines this with a three-component geophone for receiving seismic data. This method acquires not only P-wave source data but also S-wave source data, obtaining a total of nine seismic data components. Compared with related technologies, the acquired information is richer, providing ample data support for seismic data analysis. P-wave first-arrival energy analysis of the P-wave source data determines the orientation angle of the three-component geophone, ensuring the accuracy of the received seismic data. Similarly, S-wave first-arrival energy analysis of the S-wave source data determines the excitation direction of the S-wave source. This method determines the orientation angle of the three-component geophone and the excitation direction of the S-wave source, facilitating data processing personnel to more accurately describe the wavefield characteristics of the seismic data.
[0065] In some embodiments, before performing P-wave first-arrival energy analysis on the P-wave source data to determine the orientation angle of the three-component detector, the method further includes:
[0066] The longitudinal wave source data undergoes a coordinate transformation, converting the Cartesian coordinate system to a cylindrical coordinate system. The formula used for this coordinate transformation is as follows:
[0067]
[0068] In the formula, j is the current receiver point number, j = 1, 2, ..., N, N is the total number of receiver points, i is the shot sequence number of the current common receiver point gather, i = 1, 2, ..., M, M is the total number of shots in the common receiver point gather. This is the three-component recording vector of the P-wave source in the Cartesian coordinate system (X, Y, Z) corresponding to receiver point number j and shot point number i. for Rotate to cylindrical coordinates (R, T, Z) to the three-component longitudinal wave source vector, θ ij Let j be the receiver azimuth corresponding to the receiver number j and the shot number i, and t be the time sample number of the seismic record, where t = 0, 1, 2, ..., Tr, and Tr is the number of time samples of the seismic record.
[0069] In some embodiments, performing P-wave first-arrival energy analysis on P-wave source data to determine the orientation angle of the three-component detector includes:
[0070] The P-wave source data is redirected and corrected to obtain the redirected and corrected P-wave source data.
[0071] Using the data after redirection correction, the orientation angle of the three-component detector is calculated.
[0072] In some embodiments, the P-wave source data is redirected and corrected according to the following correction formula to obtain the redirected and corrected P-wave source data:
[0073]
[0074] In the formula, The three-component recording vector of the redirected P-wave source. Let φ be the horizontal deflection angle of the three-component detector, and φ be the vertical deflection angle of the three-component detector. The initial value of φ is 0. The initial value is 0. The three-component longitudinal wave source vector is given in the cylindrical coordinate system (R, T, Z).
[0075] In some embodiments, the orientation angle of the three-component detector is calculated using the redirected and corrected data, including:
[0076] Using the data after redirection correction, calculate the sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiving point gather;
[0077] The orientation angle of the three-component detector is calculated based on the minimum sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiver gather with receiver number j.
[0078] In some embodiments, the sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiving point gather is calculated according to the following formula:
[0079]
[0080] In the formula, T1 ij and T2 ij The start and end times of the calculation window for the seismic trace with receiver point number j and shot point number i are the sample point numbers. φ is the horizontal deflection angle of the three-component detector, and φ is the vertical deflection angle of the three-component detector. This is the sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiver gather with receiver number j. and It is the longitudinal wave source vector of the corrected cylindrical coordinate system.
[0081] In some embodiments, the orientation angle of the three-component detector is calculated based on the minimum sum of the energy ratios of the R and T components within the first arrival time windows of all shots in the common receiver gather with receiver point number j, including:
[0082] Given φ∈[0°, 180°], Calculate different orientation angles within the angular range. The sum of the energy ratios of the corresponding R and T components within a given time window Statistical analysis of receiving point number j Minimum value and corresponding orientation angle
[0083] Where φ0 is the initial value of φ. Let φ be the initial value, δφ be the angular interval, and k1 = 1, 2...K1. Let the horizontal deflection be the calculated angle of the three-component detector with receiver number j. The vertical deflection angle of the three-component detector with receiver point number j is calculated.
[0084] It is understandable that different orientation angles include multiple different angle values.
[0085] In some embodiments, shear wave first arrival energy analysis is performed on shear wave source data to determine the excitation direction of the shear wave source, including:
[0086] Using the orientation angle, the receiving direction of the shear wave source data is corrected.
[0087] The excitation direction of the shear wave source is determined by using the horizontal component of the corrected shear wave source data.
[0088] In some embodiments, the receiving direction of the shear wave source data is corrected using the orientation angle according to the following formula:
[0089]
[0090]
[0091] in, This is the three-component recording vector excited along the survey line by the shear wave source with receiver number j and shot number i. The three-component recording vector is generated by the shear wave source with receiver number j and shot number i in a direction perpendicular to the survey line. and These are data from the shear wave source. and The three-component recording vector after the three-component detector is redirected.
[0092] In some embodiments, the excitation direction of the shear wave source is determined using the horizontal component of the corrected shear wave source data according to the following formula:
[0093]
[0094]
[0095] In the formula, and T1 represents the excitation directions along the survey line and perpendicular to the survey line direction at the i-th shot point of the shear wave source, respectively. ij and T2 ij The start and end time sample numbers are the calculation time windows for the direction-corrected seismic trace with receiver point number j and shot point number i. and The horizontal component of the corrected shear wave source data is denoted as j, where j = 1, 2, ..., N, and N is the total number of receivers. i is the shot sequence number of the current common receiver gather, where i = 1, 2, ..., M, and M is the total number of shots within the common receiver gather. t is the seismic record time sample number, where t = 0, 1, 2, ..., Tr, and Tr is the number of seismic record time samples.
[0096] Figure 2 A flowchart of another method for determining the excitation direction of a seismic source provided in this application embodiment is available. Figure 2 The method includes:
[0097] 201. Obtain 9-component seismic data.
[0098] The 9-component seismic data includes P-wave source data and S-wave source data. The P-wave source data comprises three components: data received by three geophones along the seismic line, perpendicular to the seismic line, and vertically, respectively, showing the vibration excitation of the P-wave source in the vertical direction. The S-wave source data includes two types of three-component data. One type includes data received by three geophones along the seismic line, perpendicular to the seismic line, and vertically, respectively, showing the vibration excitation of the S-wave source in the direction perpendicular to the seismic line. The other type includes data received by three geophones along the seismic line, perpendicular to the seismic line, and vertically, respectively, showing the vibration excitation of the S-wave source in the direction perpendicular to the seismic line. Here, the seismic line direction refers to the route used for seismic exploration fieldwork on the ground.
[0099] It is understandable that the 9-component seismic data is obtained by controlled source excitation, which includes P-wave source excitation and S-wave source excitation. P-wave source excitation is vibration excitation carried out in the vertical direction, while S-wave source excitation is vibration excitation carried out in the direction along the survey line and in the direction perpendicular to the survey line.
[0100] 202. Perform coordinate transformation on the longitudinal wave source data to convert the rectangular coordinate system into a cylindrical coordinate system.
[0101] By performing coordinate transformation on the P-wave source data, we can prepare for subsequent data processing.
[0102] In this embodiment of the application, the longitudinal wave source data is transformed into a cylindrical coordinate system. The coordinate transformation can be performed using the following formula:
[0103]
[0104] In the formula, j is the current receiver point number, j = 1, 2, ..., N, where N is the total number of receiver points, and i is the shot sequence number of the current common receiver point gather, i = 1, 2, ..., M, where M is the total number of shots within the common receiver point gather. This is the three-component recording vector of the P-wave source in the Cartesian coordinate system (X, Y, Z) corresponding to receiver point number j and shot point number i. for Rotate to cylindrical coordinates (R, T, Z) to the three-component longitudinal wave source vector, θ ij Let j be the receiver azimuth corresponding to the receiver number j and the shot number i, and t be the time sample number of the seismic record, where t = 0, 1, 2, ..., Tr, and Tr is the number of time samples of the seismic record.
[0105] Figure 3 This is a schematic diagram of a three-component common receiver gather excited by a longitudinal wave source, provided in an embodiment of this application. See also... Figure 3 The areas selected by the dashed boxes in the figure are the distribution ranges of the Z, X, and Y components, respectively. It can be seen that the distribution of the three components of the common receiving point gather excited by the longitudinal wave source in the X, Y, and Z components is as follows.
[0106] Figure 4 This is a schematic diagram of the three-component common receiver gather excited by the longitudinal wave source after coordinate transformation, provided in an embodiment of this application. See also... Figure 4 The areas selected by the dashed boxes in the figure represent the distribution ranges of the Z, R, and T components. It can be seen that since the X and Y components of the three-component geophone are not in the designed directions along and perpendicular to the survey line, there is a strong P-wave first arrival energy in the T component on the ZRT gather after coordinate transformation. It is necessary to perform P-wave first arrival energy analysis on the P-wave source data to determine the orientation angle of the three-component geophone.
[0107] 203. Perform initial arrival energy analysis on the P-wave source data to determine the orientation angle of the three-component detector.
[0108] See Figure 5 This step may include:
[0109] 2031, the P-wave source data is redirected and corrected to obtain the redirected and corrected P-wave source data.
[0110] Because the P-wave source data has strong initial P-wave energy in the T component, it indicates that there is a orientation problem of the three-component detector. Therefore, it is necessary to perform redirection correction on the P-wave source data to obtain the redirected P-wave source data, in order to prepare for determining the orientation angle of the three-component detector.
[0111] To obtain the P-wave source data after redirection correction, the P-wave source data can be redirected and corrected according to the following correction formula:
[0112]
[0113] In the formula, The three-component recording vector of the redirected P-wave source. Let φ be the horizontal deflection angle of the three-component detector, and φ be the vertical deflection angle of the three-component detector. The initial value of φ is 0. The initial value is 0. The three-component vector of the longitudinal wave source in cylindrical coordinate system (R, T, Z).
[0114] 2032, using the data after redirection correction, calculate the orientation angle of the three-component detector.
[0115] Using the data after redirection correction, the orientation angle of the three-component detector is calculated to determine the orientation angle of the three-component detector and to prepare for the subsequent determination of the excitation direction of the shear wave source.
[0116] Specifically, the calculation of the orientation angle of the three-component detector using the redirected and corrected data includes: using the redirected and corrected data, calculating the sum of the energy ratios of the R and T components within the first arrival time windows of all shots in the common receiving point gather; and calculating the orientation angle of the three-component detector based on the minimum value of the sum of the energy ratios of the R and T components within the first arrival time windows of all shots in the common receiving point gather with receiving point number j.
[0117] Using the data after redirection correction, the sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiver gather can be calculated according to the following formula:
[0118]
[0119] In the formula, T1 ij and T2 ij The start and end times of the calculation window for the seismic trace with receiver point number j and shot point number i are the sample point numbers. φ is the horizontal deflection angle of the three-component detector, and φ is the vertical deflection angle of the three-component detector. This is the sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiver gather with receiver number j. and It is the longitudinal wave source vector of the corrected cylindrical coordinate system.
[0120] Based on the minimum sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiver gather with receiver number j, calculate the orientation angle of the three-component detector, including: given φ∈[0°, 180°], Calculate different orientation angles within the angular range. The sum of the energy ratios of the corresponding R and T components within a given time window Statistical analysis of receiving point number j Minimum value and corresponding orientation angle
[0121] Where φ0 is the initial value of φ. Let φ be the initial value, δφ be the angular interval, and k1 = 1, 2…K1. Let the horizontal deflection be the calculated angle of the three-component detector with receiver number j. Let be the vertical deflection angle of the three-component detector with receiver number j.
[0122] It is understandable that different orientation angles include multiple different angle values.
[0123] Figure 6 This is a schematic diagram of a three-component common receiver gather excited by a longitudinal wave source in cylindrical coordinates after receiving direction correction, provided in an embodiment of this application. See also... Figure 6 The areas selected by the dashed boxes in the figure represent the distribution ranges of the Z, R, and T components. It can be seen that after receiving direction correction, the initial arrival energy of the longitudinal wave is correctly positioned in the T component.
[0124] 204. Perform shear wave first arrival energy analysis on the shear wave source data to determine the excitation direction of the shear wave source.
[0125] See Figure 7 This step can specifically include:
[0126] 2041. Using the orientation angle, the receiving direction of the shear wave source data is corrected.
[0127] By using the orientation angle of the three-component detector, the receiving direction of the shear wave source data is corrected, in order to determine the excitation direction of the shear wave source.
[0128] The receiving direction of shear wave source data is corrected using the orientation angle according to the following formula:
[0129]
[0130]
[0131] in, This is the three-component recording vector excited along the survey line by the shear wave source with receiver number j and shot number i. The three-component recording vector is generated by the shear wave source with receiver number j and shot number i in a direction perpendicular to the survey line. and These are data from the shear wave source. and The three-component recording vector after the three-component detector is redirected.
[0132] Figure 8 This is a schematic diagram of a common receiver gather excited along the survey line direction by a transverse wave source after receiving direction correction, as provided in an embodiment of this application. See also... Figure 8 The areas selected by the dashed boxes in the figure are the distribution ranges of the Z, X, and Y components, respectively. It can be seen that there is a strong first arrival energy of the transverse wave in the Y component, indicating that there is a problem with the excitation direction correction in this record.
[0133] Figure 9 This is a schematic diagram of a common receiver gather excited by a transverse wave source with the receiver direction corrected along a direction perpendicular to the survey line, as provided in an embodiment of this application. See also... Figure 9 The areas selected by the dashed boxes in the figure are the distribution ranges of the Z, X, and Y components, respectively. It can be seen that there is a strong first arrival energy of the transverse wave in the X component, indicating that there is a problem with the excitation direction correction in this record.
[0134] 2042. The excitation direction of the shear wave source is determined by using the horizontal component of the corrected shear wave source data.
[0135] To obtain the wavefield characteristics of seismic data more fully, it is necessary to determine the excitation direction of the shear wave source.
[0136] The excitation direction of the shear wave source is determined using the horizontal component of the corrected shear wave source data according to the following formula:
[0137]
[0138]
[0139] In the formula, and T1 represents the excitation directions along the survey line and perpendicular to the survey line direction at the i-th shot point of the shear wave source, respectively. ij and T2 ij The start and end time sample numbers are the calculation time windows for the direction-corrected seismic trace with receiver point number j and shot point number i. and This refers to the horizontal component of the corrected shear wave source data.
[0140] Figure 10 This is a schematic diagram of the common receiver gather excited along the survey line direction by the shear wave source after excitation direction correction, as provided in an embodiment of this application. See also... Figure 10 The areas selected by the dashed boxes in the figure represent the distribution ranges of the Z, X, and Y components, respectively. It can be seen that the initial arrival energy of the transverse wave has been correctly allocated.
[0141] Figure 11 This is a schematic diagram of a common receiver gather excited by a transverse wave source with excitation direction correction along a direction perpendicular to the survey line, as provided in an embodiment of this application. See also... Figure 11 The areas selected by the dashed boxes in the figure represent the distribution ranges of the Z, X, and Y components, respectively. It can be seen that the initial arrival energy of the transverse wave has been correctly allocated.
[0142] The method for determining the source excitation direction provided in this application involves using a controllable seismic source to excite a P-wave source along the vertical direction and a S-wave source along and perpendicular to the seismic line direction. A three-component geophone receives data along the vertical, seismic line, and seismic line directions, acquiring a total of nine seismic data components. Compared with related technologies, this method provides richer information and sufficient data support for seismic data analysis. First-arrival energy analysis of the P-wave source data determines the orientation angle of the three-component geophone, ensuring the accuracy of the received seismic data. First-arrival energy analysis of the S-wave source data determines the excitation direction of the S-wave source. This method determines the orientation angle of the three-component geophone and the excitation direction of the S-wave source, facilitating data processing personnel to more accurately describe the wavefield characteristics of the seismic data.
[0143] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only.
[0144] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.
Claims
1. A method for determining the excitation direction of a seismic source, characterized in that, The method includes: Nine-component seismic data is acquired, including P-wave source data and S-wave source data. The P-wave source data is data excited by the P-wave source received by a three-component geophone along the survey line direction, perpendicular to the survey line direction, and vertically. The S-wave source data is data excited by the S-wave source received by a three-component geophone along the survey line direction, perpendicular to the survey line direction, and vertically. Perform P-wave first arrival energy analysis on the P-wave source data to determine the orientation angle of the three-component detector; Using the aforementioned orientation angle, the receiving direction of the shear wave source data is corrected respectively; The excitation direction of the shear wave source is determined by using the horizontal component of the corrected shear wave source data. Specifically, the receiving direction of the shear wave source data is corrected using the orientation angle according to the following formula: in, For the receiving point sequence number is The firing point number is The three-component recording vector excited by the transverse wave source along the direction of the survey line. For the receiving point sequence number is The firing point number is The transverse wave source excites a three-component recording vector in a direction perpendicular to the survey line direction. and These are data from the shear wave source. and The three-component recording vector after three-component detector retargeting The receiver number to be calculated is The horizontal deflection angle of the three-component detector, The receiver number to be calculated is The vertical deflection angle of the three-component detector. This is the current receiving point number. , The total number of receiving points. This is the shot sequence number of the current common receiving point gather. , This represents the total number of shots fired within the common receiving point gather. This refers to the sequence number of the earthquake record time sample point. , This represents the number of time samples in the earthquake record. The excitation direction of the shear wave source is determined using the horizontal component of the corrected shear wave source data according to the following formula: In the formula, and These are the first two terms used to determine the source of the transverse wave. The firing directions of each shot point along the survey line and perpendicular to the survey line direction. and For the receiving point sequence number is The firing point number is The start and end time sample point numbers of the calculation window for the direction-corrected seismic trace. and For the horizontal component of the corrected shear wave source data, This is the current receiving point number. , The total number of receiving points. This is the shot sequence number of the current common receiving point gather. , This represents the total number of shots fired within the common receiving point gather. This refers to the sequence number of the earthquake record time sample point. , This represents the number of time samples in the earthquake record.
2. The method for determining the excitation direction of a seismic source according to claim 1, characterized in that, Before performing P-wave first-arrival energy analysis on the P-wave source data to determine the orientation angle of the three-component detector, the method further includes: The longitudinal wave source data is subjected to a coordinate transformation, converting the rectangular coordinate system into a cylindrical coordinate system. The formula used for the coordinate transformation is as follows: In the formula, This is the current receiving point number. , The total number of receiving points. This is the shot sequence number of the current common receiving point gather. , This represents the total number of shots fired within the common receiving point gather. For the receiving point sequence number is The firing point number is The corresponding three-component recording vector of the longitudinal wave source in the rectangular coordinate system (X, Y, Z) for Rotate to the cylindrical coordinate system (R, T, Z) to define the three components of the longitudinal wave source vector. For the receiving point sequence number is The firing point number is The corresponding azimuth of the shot receiver. This refers to the sequence number of the earthquake record time sample point. , This represents the number of time samples in the earthquake record.
3. The method for determining the excitation direction of a seismic source according to claim 1, characterized in that, The step of performing P-wave first-arrival energy analysis on the P-wave source data to determine the orientation angle of the three-component detector includes: The P-wave source data is subjected to redirection correction processing to obtain redirected P-wave source data; Using the data after the redirection correction, the orientation angle of the three-component detector is calculated.
4. The method for determining the excitation direction of a seismic source according to claim 3, characterized in that, The P-wave source data is then redirected and corrected according to the following correction formula to obtain the redirected and corrected P-wave source data: In the formula, The three-component recording vector of the redirected P-wave source. The horizontal deflection angle of the three-component detector. The vertical deflection angle of the three-component detector. The initial value is 0. The initial value is 0. The three-component vector of the longitudinal wave source in cylindrical coordinates (R, T, Z) is... This is the current receiving point number. , The total number of receiving points. This is the shot sequence number of the current common receiving point gather. , This represents the total number of shots fired within the common receiving point gather. This refers to the sequence number of the earthquake record time sample point. , This represents the number of time samples in the earthquake record.
5. The method for determining the excitation direction of a seismic source according to claim 3, characterized in that, The step of calculating the orientation angle of the three-component detector using the redirected and corrected data includes: Using the data after the redirection correction, calculate the sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiving point gather; According to the receiving point sequence number The minimum sum of the energy ratios of the R and T components of all shots within the first arrival time window of the common receiving point gather is used to calculate the orientation angle of the three-component detector.
6. The method for determining the excitation direction of a seismic source according to claim 5, characterized in that, The sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiving point gather is calculated using the following formula: In the formula, and For the receiving point sequence number is The firing point number is The start and end time sample point numbers of the calculation window for the seismic trace. The horizontal deflection angle of the three-component detector. The vertical deflection angle of the three-component detector. For the receiving point sequence number is The sum of the energy ratios of the R and T components of all shots within the first arrival time window of the common receiving point gather. and It is the longitudinal wave source vector in the corrected cylindrical coordinate system. This is the current receiving point number. , The total number of receiving points. This is the shot sequence number of the current common receiving point gather. , This represents the total number of shots fired within the common receiving point gather. This refers to the sequence number of the earthquake record time sample point. , This represents the number of time samples in the earthquake record.
7. The method for determining the excitation direction of a seismic source according to claim 5, characterized in that, The calculation of the orientation angle of the three-component detector based on the minimum sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiving point gather with receiving point number j includes: In the given Within the angular range, calculate different orientation angles ( , The sum of the energy ratios of the corresponding R and T components within a given time window. The serial number of the receiving point is... of The minimum value and the corresponding orientation angle ( , ); in, for initial value, for initial value, For angular intervals, , , , The receiver number to be calculated is The horizontal deflection angle of the three-component detector, The receiver number to be calculated is The vertical deflection angle of the three-component detector; The sum of the energy ratios of the R and T components within the first arrival time window of all shots in the common receiving point gather is calculated using the following formula: In the formula, and For the receiving point sequence number is The firing point number is The start and end time sample point numbers of the calculation window for the seismic trace. The horizontal deflection angle of the three-component detector. The vertical deflection angle of the three-component detector. For the receiving point sequence number is The sum of the energy ratios of the R and T components of all shots within the first arrival time window of the common receiving point gather. and It is the longitudinal wave source vector in the corrected cylindrical coordinate system. This is the current receiving point number. , The total number of receiving points. This is the shot sequence number of the current common receiving point gather. , This represents the total number of shots fired within the common receiving point gather. This refers to the sequence number of the earthquake record time sample point. , This represents the number of time samples in the earthquake record.