Multi-scale establishment method for velocity field of multi-channel seismic data

Abstract

The present application relates to a multi-scale establishment method for the velocity field of multi-channel seismic data. Multiple velocity spectra are made from data with different offsets and data in different frequency bands, and the multiple made velocity spectra are combined to form a new velocity spectrum. This method has strong practicability, high efficiency and good effect, and can efficiently and accurately obtain the velocity field of ultra-high resolution multi-channel seismic data. The innovative velocity picking point library of this method has determined time values and velocity values, but the intervals of different velocity picking points are variable; based on the imaging quality corresponding to the velocity, the optimization of velocity picking points is carried out, thereby determining the optimal velocity field of ultra-high resolution multi-channel seismic data.

Description

Technical Field

[0001] The present invention relates to the field of seismic exploration and data processing, and particularly relates to a multi-scale establishment method for a velocity field of multi-channel seismic data. Background Art

[0002] Seismic exploration is an important means to understand the underground geological conditions. It is the most important and effective method for solving oil and gas exploration problems in geophysical exploration. The propagation velocity of seismic waves in the medium is a very important kinematic characteristic parameter in many aspects of seismic exploration. For example, dynamic correction, migration processing, time-depth conversion, multiple suppression, seismic data inversion, etc.

[0003] In the field of seismic exploration, a velocity spectrum is calculated through multi-channel seismic data (as shown in Figure 2 ), and the corresponding velocity value is obtained through the center point of the strong energy group (i.e., the velocity picking point), and then the velocity field is established. Due to the influence of noise and complex wave fields, the result obtained by the method of picking the center point of the strongest energy group is single, lacking the comparison of multiple picking results, and the obtained result is often not the best result.

[0004] In order to obtain an accurate velocity field, a velocity picking method of velocity scanning is carried out on the basis of picking the center point of the maximum energy group. This method obtains multiple groups of velocities by setting a specified step size and range, and it is not easy to determine the velocity scanning range and step size. The larger the scanning range and the smaller the step size, the more accurate the result of the velocity field, but the efficiency is extremely low; the smaller the scanning range and the larger the step size, the relatively higher the efficiency, but the accuracy of the obtained velocity field is often lower; this method has the disadvantages of large influence of human factors and poor operability for accurately and efficiently obtaining the velocity field. Summary of the Invention

[0005] The object of the present invention is to provide a multi-scale establishment method for a velocity field of multi-channel seismic data in view of the above deficiencies.

[0006] To solve the above technical problems, the first aspect of the present invention provides a multi-scale establishment method for a velocity field of multi-channel seismic data, which is to make multiple velocity spectra from data with different offsets and data with different frequency bands, and merge the multiple made velocity spectra to form a new velocity spectrum.

[0007] Further, it includes the following steps:

[0008] S1: Select at least two different offset ranges to make multiple velocity spectra;

[0009] S2: Establish a target time window on each velocity spectrum, and use the maximum energy point of the independent energy group within the target time window as the velocity picking point;

[0010] S3: Select the horizontal and vertical coordinates of any velocity spectrum as the horizontal and vertical coordinates of the new velocity picking library, and plot all velocity picking points into this new velocity picking library;

[0011] S4: In the new velocity picking library, partition and classify the velocity picking points;

[0012] S5: Select the velocity representative points of each partition, and the level of the velocity representative point is the same as the level of the partition where it is located;

[0013] S6: Compare the imaging results of the highest-level velocity representative point and the second-highest-level velocity representative point respectively;

[0014] S7: According to the imaging results, take the velocity representative point with high imaging quality as the high-level velocity representative point, and eliminate the velocity representative point with low imaging quality;

[0015] S8: Sort the velocity representative points lower than the second-highest-level velocity representative point in descending order of level, upgrade the velocity representative points one by one to the second-highest-level velocity representative point in the sorted order, and repeat steps S6 and S7 one by one in the sorted order until all velocity representative points with poor imaging quality are eliminated, and retain the only velocity representative point with the best imaging quality;

[0016] S9: Repeat steps S1 - S8, and establish a velocity field after obtaining multiple different velocity representative points.

[0017] Further, in step S2, the target time window takes the center of the energy cluster group as the center of the target time window, and the upper and lower boundaries of the target time window are at 3 / f of the upper and lower limit differences (the time window has only upper and lower boundaries, no left and right boundaries), where f is the main frequency.

[0018] Further, in step S3, the horizontal and vertical coordinates of different velocity spectra are the same.

[0019] Further, in step S4, the partitioning rule is:

[0020] The area where the independent point is located is defined as a target area;

[0021] The area where points are in contact or overlap is defined as a target area.

[0022] In step S4, the grading rule is:

[0023] For different target areas, the higher the number of velocity picking points in the target area, the higher its level;

[0024] If the number of velocity picking points in the target areas of two same target areas is the same, the target area closer to the center of the time window has a higher level.

[0025] Further, in step S5, within a target area, the velocity pick-up point closest to the center of the target time window is used as the velocity representative point for this target area, and other velocity pick-up points in the target area are excluded.

[0026] Further, in step S6, the imaging result is the calculation result of Kirchhoff migration for the corresponding velocity representative point.

[0027] Further, in step S7, the imaging result with more focused event energy has higher imaging quality.

[0028] To solve the above technical problems, a second aspect of the present invention provides a terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above multi-scale establishment method for the velocity field of multi-channel seismic data is implemented.

[0029] To solve the above technical problems, a third aspect of the present invention provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the above multi-scale establishment method for the velocity field of multi-channel seismic data is implemented.

[0030] Compared with the prior art, the present invention has the following beneficial effects: strong practicability, high efficiency, good effect, and can obtain the velocity field of ultra-high resolution multi-channel seismic data efficiently and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The following further describes the present invention with reference to the drawings.

[0032] Figure 1 It is the processing flow chart of this method.

[0033] Figure 2 They are velocity spectra obtained for three different offset groups.

[0034] Figure 3 It is the full-window display diagram of the velocity spectrum established by the multi-scale method.

[0035] Figure 4 It is for Figure 3 The partial enlarged display diagram.

[0036] Figure 5 It is the imaging result diagram of the highest-level picked velocity points.

[0037] Figure 6 It is the imaging result diagram of the second-highest-level picked velocity points. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The preferred embodiments of the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art. It should be understood that the specific embodiments described herein are merely for explaining the present invention and not for limiting the present invention.

[0039] Seismic exploration is an important means to understand the geological conditions underground. Seismic exploration is the most important and effective method for solving oil and gas exploration problems in geophysical exploration. The propagation speed of seismic waves in the medium is a very important kinematic characteristic parameter in many aspects of seismic exploration. For example, dynamic correction, migration processing, time-depth conversion, multiple suppression, seismic data inversion, etc.

[0040] In the field of seismic exploration, a velocity spectrum is calculated from multi-channel seismic data (as shown in Figure 2 ), and the center point of the strong energy cluster (i.e., the velocity picking point) is picked up. The corresponding velocity value is obtained through the velocity picking point, and then a velocity field is established. Due to the influence of noise and complex wave fields, the result obtained by the method of picking up the center point of the strongest energy cluster is single, lacking the comparison of multiple picking results, and the obtained result is often not the best result.

[0041] In order to obtain an accurate velocity field, a velocity picking method of velocity scanning is carried out on the basis of picking up the center point of the maximum energy cluster. This method obtains multiple sets of velocities by setting a specified step size and range, and it is not easy to determine the velocity scanning range and step size, which has the disadvantages of large influence of human factors and poor operability for accurately and efficiently obtaining the velocity field.

[0042] Example 1:

[0043] To solve the above technical problems, Example 1 provides a multi-scale establishment method for the velocity field of multi-channel seismic data.

[0044] Example 1 selects 3 groups of offset groups, with ranges of 4 meters to 76 meters, 4 meters to 113 meters, and 4 meters to 151 meters respectively. Three corresponding velocity spectra are made as examples to illustrate the multi-scale establishment method for the velocity field of multi-channel seismic data.

[0045] A multi-scale establishment method for the velocity field of multi-channel seismic data, which makes multiple velocity spectra from different offset data and different frequency band data, and combines the multiple made velocity spectra to form a new velocity spectrum.

[0046] Traditional velocity spectra obtain individual velocity spectra through the hyperbolic travel-time property of seismic reflection waves and coherence calculation methods. The innovative method of this patent creates multiple velocity spectra from data with different offsets and different frequency bands, and combines the multiple created velocity spectra to form a new velocity spectrum.

[0047] As Figure 1 shown, the specific steps are as follows:

[0048] S1: Select at least two different offset ranges to create multiple velocity spectra;

[0049] Specifically, select 3 offset groups with ranges of 4 meters to 76 meters, 4 meters to 113 meters, and 4 meters to 151 meters respectively, and thus create 3 corresponding velocity spectra (the velocity spectra of the left 1 - 24 channels, Figure 2 the middle 1 - 36 channels, Figure 2 and the right 1 - 48 channels) in Figure 2 respectively.

[0050] S2: Establish a target time window on each velocity spectrum, and use the maximum energy point of the independent energy cluster within the target time window as the picked-up velocity point;

[0051] In step S2, the target time window takes the center of the energy cluster group as the center of the target time window, and the upper and lower boundaries of the target time window are at 3 / f where f is the main frequency;

[0052] S3: Select the horizontal and vertical coordinates of any one velocity spectrum as the horizontal and vertical coordinates of the new velocity picking library, and plot all the velocity picking points into this new velocity picking library. As Figure 3 shown, V0 - V7 in the figure are the velocity picking points;

[0053] In step S3, the horizontal and vertical coordinates of different velocity spectra are the same;

[0054] S4: In the new velocity picking library, partition and classify the velocity picking points;

[0055] The partitioning rule is:

[0056] The area where the independent point is located is defined as a target area;

[0057] The area where points are in contact or coincide is defined as a target area.

[0058] The grading rule is:

[0059] For different target areas, the higher the number of velocity picking points in the target area, the higher its level;

[0060] If the number of velocity picking points in the target areas of two same target areas is the same, the target area closer to the time window center has a higher level.

[0061] S5: Select the velocity representative points of each target area, where the level of the velocity representative point is the same as that of the target area where it is located;

[0062] In step S5, within one target area, the velocity pick-up point closest to the center of the target time window is taken as the velocity representative point of this target area, and other velocity pick-up points in the target area are excluded;

[0063] S6: Compare the imaging results of the highest-level velocity representative point ( Figure 4 the V1 velocity point in

[0064] In step S6, as shown in Figure 5 and Figure 6 ), the imaging result is the calculation result of Kirchhoff migration for the corresponding velocity representative point;

[0065] S7: According to the imaging results, take the velocity representative point with high imaging quality as the high-level velocity representative point, and exclude the velocity representative points with low imaging quality;

[0066] In step S7, the imaging result with more focused event energy has higher imaging quality, as shown in Figure 5 and Figure 6 at the middle circle;

[0067] S8: Sort the velocity representative points lower than the second-highest level velocity representative point in descending order of level, upgrade the velocity representative points one by one in the sorted order to the second-highest level velocity representative point, and repeat steps S6 and S7 one by one in the sorted order until all velocity representative points with poor imaging quality are excluded, and retain the velocity representative point with the best and unique imaging quality (the best velocity representative point obtained here is a coordinate position and a depth);

[0068] S9: Repeat steps S1 - S8, and establish a velocity field after obtaining the best velocity representative points at multiple different positions and different depths.

[0069] By using this method to obtain the best velocity representative points at different coordinate positions and different depths, a high-quality velocity field corresponding to the velocity values of the best velocity representative points at different positions and different depths can be efficiently and accurately obtained.

[0070] In this embodiment, the Kirchhoff prestack depth migration technology adopted in step 6 is one of the most important depth-domain imaging methods in the process of seismic data processing for geophysical exploration. This method has higher imaging quality than time migration and has the advantages of being not restricted by the field data acquisition method, etc. The Kirchhoff prestack depth migration technology belongs to the technology well known in the art and will not be elaborated here.

[0071] The innovative speed pick-up point library of this method has definite time values and speed values, but the intervals of different speed pick-up points are variable. Based on the imaging quality corresponding to the speed, the speed pick-up points are optimized, thereby determining the optimal speed field of ultra-high resolution multi-channel seismic data.

[0072] Embodiment 2:

[0073] Embodiment 2 provides a terminal, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the multi-scale establishment method of the multi-channel seismic data speed field described above.

[0074] Embodiment 3:

[0075] Embodiment 3 provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the multi-scale establishment method of the multi-channel seismic data speed field.

[0076] In this embodiment, the computer-readable storage medium may include any medium capable of storing or transmitting information. Examples of computer-readable storage media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical discs, hard disks, fiber optic media, radio frequency (RF) links, and so on. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0077] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of this application. In all the examples shown and discussed here, any specific value should be construed as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: similar reference numerals and letters denote similar items, and thus, once an item is defined, it does not need to be further discussed subsequently.

[0078] In the description of this application, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom" are usually based on the shown orientation or positional relationships, and are only for the convenience of describing this application and simplifying the description. Without contrary explanations, these orientation words do not indicate and imply that the devices or elements referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus should not be construed as limiting the protection scope of this application; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0079] For ease of description, spatial relative terms such as "above", "over", "on the upper surface", "upper" etc. may be used herein to describe the spatial positional relationship of features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation described.

[0080] In addition, it should be noted that the use of terms such as "first", "second" etc. to limit components is only for the convenience of differentiating the corresponding components. Without additional statements, the above terms have no special meanings, and thus should not be construed as limiting the protection scope of the present application.

[0081] If the present application discloses or involves components or structural members that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, using bolts or screws), or can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutually fixed connection can also be replaced by an integral structure (for example, manufactured by integral forming using casting process, except where integral forming process is clearly not applicable).

[0082] The above preferred embodiments have further elaborated on the purpose, technical solutions and advantages of the present invention. It should be understood that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A multi-scale establishment method for the velocity field of multi-channel seismic data, characterized in that: Make multiple velocity spectra from data with different offsets and different frequency bands, and merge the multiple made velocity spectra to form a new velocity spectrum; It includes the following steps: S1: Select at least two groups of different offset ranges to make multiple velocity spectra; S2: Establish a target time window on each velocity spectrum, and use the maximum energy point of the independent energy cluster within the target time window as the picked-up velocity point; S3: Select the horizontal and vertical coordinates of any one velocity spectrum as the horizontal and vertical coordinates of the new velocity picked-up library, and plot all the velocity picked-up points into this new velocity picked-up library; S4: In the new velocity picked-up library, partition and grade the velocity picked-up points; S5: Select the velocity representative points of each partition, and the level of the velocity representative point is the same as the level of the partition where it is located; S6: Compare the imaging results of the highest-level velocity representative point and the second-highest-level velocity representative point respectively; S7: According to the imaging results, use the velocity representative point with high imaging quality as the high-level velocity representative point, and eliminate the velocity representative point with low imaging quality; S8: Sort the velocity representative points with levels lower than the second-highest-level velocity representative point in descending order of level, upgrade the velocity representative points to the second-highest-level velocity representative point one by one in the sorted order, and repeat steps S6 and S7 one by one in the sorted order until all the velocity representative points with poor imaging quality are eliminated, and keep the only velocity representative point with the best imaging quality; S9: Repeat steps S1 - S8, and establish a velocity field after obtaining multiple different velocity representative points.

2. The multi-scale establishment method of the multi-channel seismic data velocity field according to claim 1, characterized in that: In step S2, the target time window takes the center of the energy cluster group as the center of the target time window, and the upper and lower boundaries of the target time window are at 3 / f of the upper and lower limit differences, where f is the main frequency.

3. The multi-scale establishment method of the multi-channel seismic data velocity field according to claim 1, characterized in that: In step S3, the horizontal and vertical coordinates of different velocity spectra are the same.

4. The multi-scale establishment method of the multi-channel seismic data velocity field according to claim 1, characterized in that: In step S4, The partitioning rule is: The area where the independent point is located is defined as a target area; The area where points are in contact or coincide is defined as a target area; The grading rule is: For different target areas, the higher the number of velocity picked-up points in the target area, the higher its level; If the number of velocity picked-up points in the target areas of two same target areas is the same, the target area closer to the center of the time window has a higher level.

5. The multi-scale establishment method of the multi-channel seismic data velocity field according to claim 1, characterized in that: In step S5, within one target area, use the velocity picked-up point closest to the center of the target time window as the velocity representative point of this target area, and eliminate other velocity picked-up points in the target area.

6. The multi-scale establishment method of the multi-channel seismic data velocity field according to claim 1, characterized in that: In step S6, the imaging result is the calculation result of Kirchhoff migration for the corresponding velocity representative point.

7. The multi-scale establishment method of the multi-channel seismic data velocity field according to claim 1, characterized in that: In step S7, the imaging result with more focused event energy has higher imaging quality.

8. A terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements the multi-scale establishment method of the multi-channel seismic data velocity field as described in any one of claims 1 to 7.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the multi-scale establishment method of the multi-channel seismic data velocity field as described in any one of claims 1 to 7.

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