A correction method for the deviation of the actual excitation point from the center in radial arrangement experiments

Abstract

The present invention belongs to the field of seismic exploration technology and discloses a method for correcting the deviation of the actual excitation point from the center in a radial arrangement test, comprising collecting the coordinates of the actual excitation point; collecting the apparent velocity of the first arrival wave of the receiving point; collecting the coordinates of the receiving point; calculating the distance from the actual excitation point to each receiving point on the concentric circle; calculating the difference between the distance from the actual excitation point to each receiving point on the concentric circle and the distance from the theoretical excitation point to each receiving point on the concentric circle; calculating the correction amount of the first arrival wave of each receiving point on the concentric circle; and applying the correction amount to correct the deviation of the actual excitation point from the center in the radial arrangement test. The method of the present invention is simple and lays a good foundation for subsequent data analysis. The present invention is suitable for correcting the deviation of the actual excitation point from the center in a radial arrangement test.

Description

Technical Field

[0001] The invention belongs to the technical field of seismic exploration, and in particular is a method for correcting deviation of actual excitation points of a radial arrangement test from the center. Background Art

[0002] In the 1960s, polarized seismic sources and geophones for reflecting shear waves were developed. In the 1970s, shear wave sources were further improved, allowing for the combined exploration of reflected P- and S-waves. In the 1980s, nine-component seismic exploration research and experiments were conducted on land, focusing on shear wave splitting and anisotropy. Conversion wave experiments began in the 1990s, but their widespread adoption was limited due to the difficulty of data processing. Currently, seismic exploration technology is rapidly developing, and nine-component (3D3C) seismic exploration projects using combined P- and S-wave excitation and reception with three-component geophones are increasing. In 2019, Oriental Geophysical Company improved and upgraded the performance of its S-wave vibrator and manufactured six EV56S seismic instruments, providing equipment for further development of 3D3C three-dimensional acquisition. However, the 3D3C seismic exploration project was developed relatively late, and people's understanding of the data is not very complete. In order to better understand the characteristics of the data, various forms of experiments must be conducted to help people understand the 3D3C seismic exploration data more intuitively and accurately and grasp its characteristics.

[0003] like Figure 1 The radial arrangement shown is a good test form for studying the characteristics of shear wave data. At present, the first wave point of the test is usually analyzed. Through the test of the first wave point, many properties of the 3D3C seismic exploration data can be understood. In the radial arrangement test, according to the design requirements, the excitation point should be at the center of the circle of the arrangement. However, during the construction process, many data lines will pass through the center of the circle. The source is a relatively heavy special vehicle and it is difficult to move to the center of the circle. The most common analysis for the radial arrangement test is the common offset concentric circle (seismic exploration is usually called offset, for ease of understanding, it is hereinafter referred to as concentric circle) data. However, if the actual excitation point deviates from the center of the circle, such as Figure 2 As shown in the figure, the theoretical excitation point at the center of the circle is at equal distances from the concentric circles. However, as the excitation point deviates from the center, the distances from the actual excitation point to the concentric circles also vary. If not adjusted, these unequal distances will cause the concentric circle data to be off-level, significantly impacting data analysis. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for correcting the deviation of the actual excitation point from the center of a radial arrangement test, so as to correct the phenomenon that the same reflection layers of concentric circle data are not on the same horizontal plane due to the deviation of the actual excitation point from the center of the circle.

[0005] In order to achieve the above-mentioned purpose, the technical methods adopted by the present invention are as follows:

[0006] A method for correcting deviation of an actual excitation point from a center in a radial arrangement test is provided, based on the radial arrangement test, and includes the following steps:

[0007] S1. Collect the coordinates of the actual excitation points in the radial arrangement test;

[0008] S2, collect the first arrival apparent velocity of each receiving point on the concentric circle;

[0009] S3. Determine the distance from the theoretical excitation point to each receiving point on the concentric circle, and collect the coordinates of each receiving point on the concentric circle;

[0010] S4. Calculate the distance from the actual excitation point to each receiving point on the concentric circle based on the coordinates of the actual excitation point and the coordinates of each receiving point on the concentric circle;

[0011] S5. Calculate the difference between the distance from the actual excitation point to each receiving point on the concentric circle and the distance from the theoretical excitation point to each receiving point on the concentric circle;

[0012] S6. Calculate the correction amount of the first arrival wave at each receiving point on the concentric circle based on the apparent velocity of the first arrival wave at each receiving point on the concentric circle and the difference between the distance from the actual excitation point to each receiving point on the concentric circle and the distance from the theoretical excitation point to each receiving point on the concentric circle;

[0013] S7. Apply the correction amount to correct the deviation of the actual excitation point from the center in the radial arrangement test.

[0014] Due to the adoption of the above solution, the present invention has the following beneficial effects compared with the prior art:

[0015] The present invention provides a method for correcting the deviation of the actual excitation point from the center in a radial arrangement test. By collecting coordinate data of the actual excitation point and the receiving points on the concentric circles, and based on the distance difference between the theoretical excitation point and the actual excitation point to each receiving point on the concentric circles, the same reflection layer of the concentric circle data excited from the center of the circle is corrected to the same horizontal plane. The method is simple, saves manpower and time, and the calculation results are not affected by human subjective factors. The results are more accurate, laying a good foundation for subsequent data analysis.

[0016] The present invention is suitable for correcting the deviation of the actual excitation point from the center in a radial arrangement test. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0018] Figure 1 Schematic diagram of radial arrangement test;

[0019] Figure 2 This is a schematic diagram of a radial arrangement test where the actual excitation point deviates from the center of the circle;

[0020] Figure 3 Schematic diagram of the apparent velocity of the first arrival wave of the receiving points on the concentric circles according to an embodiment of the present invention;

[0021] Figure 4 This is the position diagram of the actual excitation points of the concentric circles before correction;

[0022] Figure 5 This is a diagram showing the positions of the actual excitation points of the concentric circles after correction according to an embodiment of the present invention; DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the following embodiments. However, those skilled in the art should understand that the present invention is not limited to the following embodiments, and any improvements and equivalent changes made based on the specific embodiments of the present invention are within the scope of protection of the claims of the present invention.

[0024] Example 1: A method for correcting the deviation of the actual excitation point from the center in a radial arrangement test

[0025] A method for correcting deviation of an actual excitation point from a center in a radial arrangement test is provided, based on the radial arrangement test, and includes the following steps:

[0026] S1. Collect the actual excitation points S in the radial arrangement test i The coordinates (x si ,,y si ), i represents the serial number of the actual excitation point, i>0, and i is an integer;

[0027] S2, determine the theoretical excitation point S0 to reach each receiving point R on the concentric circle j The distance L0 collects each receiving point R on the concentric circle j The coordinates (x rj ,y rj ), j represents the receiving point R on the concentric circle j , j>0, and j is an integer;

[0028] S3, collect data from each receiving point R on the concentric circle through the seismic data processing system. j The apparent velocity of the first arrival wave v ij ,like Figure 3 As shown;

[0029] S4, according to the actual excitation point S i The coordinates (x si ,,y si ) and the coordinates of each receiving point on the concentric circle (x rj ,y rj), calculate the actual excitation point S i Arrives at each receiving point R on the concentric circle j Distance L ij , the calculation formula is:

[0030] S5. Calculate the actual excitation point S i To each receiving point R on the concentric circle j Distance L ij From the theoretical excitation point S0 to each receiving point R on the concentric circle j The difference ΔL of the distance L0 ij , the calculation formula is: ΔL ij =L ij -L0;

[0031] S6, according to each receiving point R on the concentric circle j The apparent velocity of the first arrival wave v ij and the actual excitation point S i To each receiving point R on the concentric circle j Distance L ij From the theoretical excitation point S0 to each receiving point R on the concentric circle j The difference ΔL of the distance L0 ij , calculate each receiving point R on the concentric circle j Correction value of first arrival wave Δt ij , the calculation formula is:

[0032] S7, apply the correction value to the time correction module of the seismic data processing system, and perform the actual excitation point S of the radial arrangement test. i Correction is done off-center.

[0033] In this embodiment, the theoretical excitation point S0 reaches each receiving point R on the concentric circle. j The distance L0 = 1100m, the apparent velocity v of the first arrival wave at each receiving point on the concentric circle ij =780m / s, actual excitation point S i The coordinates (x si ,,y si ) as shown in Table 1; Each receiving point R on the concentric circle j The coordinates (x rj ,y rj ) as shown in Table 2; Due to the large amount of data, this embodiment takes the actual excitation point S1 as an example for explanation, the actual excitation point S i Arrives at each receiving point R on the concentric circle j Distance L ij , and the actual excitation point S i To each receiving point R on the concentric circle jDistance L ij From the theoretical excitation point S0 to each receiving point R on the concentric circle j The difference ΔL of the distance L0 ij As shown in Table 3, each receiving point R on the concentric circle j Correction value of first arrival wave Δt ij As shown in Table 4; the position diagram of the actual excitation points of the concentric circles before correction is as follows Figure 4 As shown in the figure, the position diagram of the actual excitation points of the concentric circles after correction in this embodiment is as follows Figure 5 As shown by Figure 4 It can be seen that before correction, the actual excitation point deviates from the center of the circle, and the initial arrivals of the obtained data are not on the same horizontal plane, which is not conducive to subsequent data analysis. Figure 5 It can be seen that after correction, the influence of the actual excitation point deviating from the center of the circle is eliminated, and the first arrival is corrected to the same horizontal plane, which is convenient for subsequent various analyses.

[0034] Table 1 Coordinates of actual excitation points collected

[0035]

[0036]

[0037] Table 2 Each receiving point R on the concentric circles collected j Coordinates

[0038]

[0039]

[0040] Table 3 The distance between the actual excitation point and each receiving point on the concentric circle

[0041]

[0042]

[0043]

[0044] Table 4 First arrival correction values between the actual excitation point and each receiving point on the concentric circle

[0045]

[0046]

Claims

1. A method for correcting the deviation of the actual excitation point from the center in a radial arrangement test, based on the radial arrangement test, characterized in that: The following steps are involved: S1. Collect the coordinates of the actual excitation points in the radial arrangement test; S2, collect the first arrival apparent velocity of each receiving point on the concentric circle; S3. Determine the distance from the theoretical excitation point to each receiving point on the concentric circle, and collect the coordinates of each receiving point on the concentric circle; S4. Calculate the distance from the actual excitation point to each receiving point on the concentric circle based on the coordinates of the actual excitation point and the coordinates of each receiving point on the concentric circle; S5. Calculate the difference between the distance from the actual excitation point to each receiving point on the concentric circle and the distance from the theoretical excitation point to each receiving point on the concentric circle; S6. Calculate the correction amount of the first arrival wave at each receiving point on the concentric circle based on the apparent velocity of the first arrival wave at each receiving point on the concentric circle and the difference between the distance from the actual excitation point to each receiving point on the concentric circle and the distance from the theoretical excitation point to each receiving point on the concentric circle; S7. Apply the correction amount to correct the deviation of the actual excitation point from the center in the radial arrangement test.

2. The method for correcting the deviation of the actual excitation point from the center in a radial arrangement test according to claim 1, characterized in that: The calculation formula for the distance from the actual excitation point to each receiving point on the concentric circle in step S4 is: Among them, L ij is the distance from the actual excitation point to each receiving point on the concentric circle. The coordinates of the actual excitation point are (x si ,y si ), the coordinates of each receiving point on the concentric circles (x rj ,y rj ), i represents the serial number of the actual excitation point, i>0, and i is an integer, j represents the receiving point R on the concentric circle j The serial number, j>0, and j is an integer; the calculation formula of the difference between the distance from the actual excitation point to each receiving point on the concentric circle and the distance from the theoretical excitation point to each receiving point on the concentric circle in step S5 is: ΔL ij =L ij -L0, where ΔL ij L is the difference between the distance from the actual excitation point to each receiving point on the concentric circle and the distance from the theoretical excitation point to each receiving point on the concentric circle. ij is the distance from the actual excitation point to each receiving point on the concentric circle, and L0 is the distance from the theoretical excitation point to each receiving point on the concentric circle. The calculation formula for the correction amount of the first arrival wave of each receiving point on the concentric circle in step S6 is: Where Δt ij is the correction value of the first arrival wave at each receiving point on the concentric circle, v ij is the apparent velocity of the first arrival wave at each receiving point on the concentric circles.

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