OVT data set division method and system and storage medium

Abstract

The invention provides an OVT data set division method and system and a storage medium, and belongs to the field of geophysical exploration seismic data processing. The method comprises the following steps: firstly, preprocessing original seismic data, projecting the data into an OVT domain by taking a detection line distance and a shot line distance as scales to complete division of vector slices, then recombining and dividing the vector slices into OVT vector slices with the same number as the actual coverage times, and performing pre-stack time migration processing to obtain an offset gather with amplitude fidelity and high signal-to-noise ratio. According to the method, the five-dimensional pre-stack gather with high signal-to-noise ratio, amplitude fidelity and accurate orientation details can be obtained, so that the imaging precision is improved, and AVO inversion and crack prediction are facilitated.

Description

Technical Field

[0001] The present invention belongs to the field of geophysical exploration seismic data processing, and in particular relates to an OVT data set partitioning method, system and storage medium. Background Art

[0002] As the observation azimuth changes, the azimuthal anisotropy of seismic data, such as the change of velocity and travel time difference with azimuth and dip, becomes more prominent. Therefore, obtaining five-dimensional prestack gathers with azimuth attributes and applying AVO analysis, fracture prediction and other technologies are important for studying fractured oil and gas reservoirs, improving exploration success rate and development efficiency, playing a greater role in complex structural seismic imaging and reservoir description, and providing an important basis for drilling and increasing oil well production. At present, the mainstream approach to obtaining five-dimensional prestack gathers with azimuth attributes is to process data in the OVT (offset vector) domain.

[0003] OVT is a data subset within the cross arrangement, and its size is equal to the area between two adjacent receiving lines and two adjacent shot lines. Ideally, for a wide azimuth observation system with N coverage times, the area of ​​the cross arrangement can be subdivided into N OVTs, that is, the number of OVT vector slices is equal to the number of coverage times. Each OVT is composed of a limited range of shot points along the shot line and a limited range of detection points along the receiving line. These two limited ranges determine that each OVT has a limited azimuth and shot offset range. At this time, the cross arrangement distribution is symmetrical about the intersection of the shot line and the detection line.

[0004] In fact, due to the design of the old data collection observation system, the cross arrangement of some observation systems is not centrally symmetrical, and some cross arrangements even have detection lines and shot lines that do not intersect. The number of OVT vector slices of this type of observation system after division is far greater than the actual coverage of the observation system, and the vector slices of the far offset distance on the cross arrangement are incomplete (the so-called complete means that the scale of a single vector slice in the cross arrangement is a complete rectangle with the shot line distance and the detection line as the long and short sides respectively). The difference between the data volume of an incomplete single vector slice and the data volume of a complete vector slice causes the number of observations of the prestack gather of the same underground reflection point to be different, resulting in relatively weak imaging energy of the incomplete vector slice after prestack time migration, which is reflected in the poor spatial energy consistency on the spiral gather, thereby reducing the imaging accuracy.

[0005] Therefore, it is necessary to develop an optimized OVT vector slice partitioning method and system suitable for non-ideal observation systems. Summary of the invention

[0006] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and to provide an OVT data set partitioning method, system and storage medium, which can obtain a five-dimensional pre-stack gather with high signal-to-noise ratio, amplitude fidelity and accurate azimuthal details, thereby improving imaging accuracy and facilitating AVO inversion and fracture prediction.

[0007] One of the objectives of the present invention is to provide an OVT data set partitioning method.

[0008] A second objective of the present invention is to provide an OVT data set partitioning system.

[0009] A third object of the present invention is to provide a computer-readable storage medium.

[0010] The present invention is achieved through the following technical solutions:

[0011] The first aspect of the present invention provides an OVT data set division method, which first pre-processes the original seismic data, projects the data into the OVT domain based on the detection line spacing and shot line spacing, completes the division of vector slices, and then recombines and divides the vector slices into the same number of OVT vector slices as the actual coverage times, and undergoes pre-stack time migration processing to obtain an offset track set with amplitude fidelity and high signal-to-noise ratio.

[0012] A further improvement of the present invention is:

[0013] The steps of the method are as follows:

[0014] Step 1, preprocessing the original seismic data to obtain CMP gathers;

[0015] Step 2: Project the CMP gather data into the OVT domain based on the detection line spacing and shot line spacing to complete the OVT gather extraction and the division of conventional vector slices;

[0016] Step 3: Count the number of vector slices and perform statistical analysis on the amount of single-slice data for each OVT data set to form a graph;

[0017] Step 4, delete the vector slices divided by the acquisition change view;

[0018] Step 5: Optimize and reorganize the OVT vector slices;

[0019] Step 6: Perform prestack time migration processing on the optimized OVT dataset.

[0020] A further improvement of the present invention is:

[0021] The preprocessing in step 1 refers to processing the acquired original seismic data through static correction, amplitude fidelity denoising, amplitude compensation, resolution improvement, and residual static correction to obtain a CMP gather with high signal-to-noise ratio, good amplitude consistency, and high resolution.

[0022] A further improvement of the present invention is:

[0023] In step 4, the vector slices divided by the acquisition change view are deleted, and the specific operation is as follows:

[0024] The vector slices are spirally numbered and marked with headers, and the vector slices composed of very few scattered points caused by serious acquisition changes are deleted, where the data volume is ≤500.

[0025] A further improvement of the present invention is:

[0026] The optimization principle in step 5 is:

[0027] Several far-off vector slices with similar offset distances and azimuth angles are reassembled to form a target vector slice.

[0028] A further improvement of the present invention is:

[0029] The operations in step 5 include:

[0030] With the theoretical coverage times equal to the number of vector slice divisions as the goal, for a wide-azimuth observation system with N coverage times, the cross-arranged area is subdivided into N OVTs, with 2i coverage times in the horizontal direction and 2j coverage times in the vertical direction, N=2i*2j.

[0031] A further improvement of the present invention is:

[0032] The operations in step 5 include:

[0033] With the main survey line offset of the center point of the OVT vector slice as the horizontal coordinate or vertical coordinate, and the contact survey line offset as the vertical coordinate or horizontal coordinate, all OVT vector slices are projected onto the same plane.

[0034] A further improvement of the present invention is:

[0035] The operations in step 5 include:

[0036] Taking the point (0,0) where the offset of the main survey line and the offset of the contact survey line are both zero as the origin, the vector slices on the offset distribution plane are divided into four quadrants, and the OVT vector slices of the far offset in the four quadrants are optimized and reorganized respectively:

[0037] The vector slice at position (i,j) in the first quadrant: i=1, 2, 3,…; j=1, 2, 3,…;

[0038] The vector slice at position (i,-j) in the second quadrant: i=1, 2, 3,…; j=1, 2, 3,…;

[0039] The third quadrant position (-i, -j) vector slice: i=1, 2, 3,…; j=1, 2, 3,…;

[0040] The vector slice at the fourth quadrant position (-i, j): i=1, 2, 3,…; j=1, 2, 3,…;

[0041] Position (-i,y) vector slice:

[0042] Position (i,y) vector slice:

[0043] Position (x,j) vector slice:

[0044] Position (x,-j) vector slice:

[0045] Where: T (i,j) is the vector patch at position (i, j);

[0046] T ( ' i,j) is the vector slice at position (i, j) after optimization;

[0047] 2k is the number of horizontal vector slices after processing in step 4, 2p is the number of vertical vector slices after processing in step 4; 2i is the number of horizontal coverage times, and 2j is the number of vertical coverage times.

[0048] A second aspect of the present invention provides an OVT data set partitioning system, comprising:

[0049] A preprocessing unit, used for preprocessing the original seismic data to obtain CMP gathers;

[0050] The data projection unit is used to project the CMP gather data into the OVT domain based on the detection line spacing and shot line spacing, and complete the OVT gather extraction and the division of conventional vector slices;

[0051] The statistical unit is used to count the number of vector slices and perform statistical analysis on the single-slice data volume of each OVT data set to generate a graph;

[0052] A vector slice deletion unit is used to delete the vector slices divided by the acquisition change view;

[0053] Optimization and reorganization unit, used to optimize and reorganize OVT vector slices;

[0054] The migration processing unit is used to perform prestack time migration processing on the optimized OVT data set.

[0055] According to a third aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores at least one computer-executable program, and when the at least one program is executed by the computer, the computer executes the steps in the OVT data set partitioning method as described above.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] The present invention can be applied to solve the problem that the imaging energy of a single vector slice at a long offset is weak after prestack time migration, thereby causing the energy inconsistency of the spiral gather at the same underground reflection point in space.

[0058] The method of the present invention can obtain a five-dimensional pre-stack gather with high signal-to-noise ratio, amplitude fidelity and accurate azimuth details, thereby improving imaging accuracy and being beneficial to AVO inversion and fracture prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 The present invention provides a flow chart of an OVT data set partitioning method;

[0060] Figure 2 The conventional method is used to divide the OVT data set into the offset plane distribution and the single-slice data volume statistics, where the white numbers are the total number of single vector slice data, and the vector slices in the yellow box are vector slices with a data volume of ≤500;

[0061] Figure 3 The offset plane distribution diagram of the OVT data set partitioned by the conventional method (after deleting vector slices with data volume ≤ 500) is shown in the figure. The numbers in the figure are the spiral numbers of the vector slices.

[0062] Figure 4 This is the offset plane distribution diagram after the OVT data set is divided by the method of the present invention, and the numbers in the figure are the spiral numbers of the vector slices;

[0063] Figure 5 This is a statistical bar chart of the data volume before (blue) and after (red) the optimization partitioning of the OVT data set. The horizontal axis corresponds to Figure 3 The vector slice spiral number, the ordinate is the vector slice data volume;

[0064] Figure 6 Comparison of prestack time migration spiral gathers before (left) and after (right) optimization of OVT data set partitioning;

[0065] Figure 7Comparison of the first coverage section before (left) and after (right) the optimization of the OVT data set partitioning and prestack time migration. DETAILED DESCRIPTION

[0066] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0067] The present invention provides an OVT data set division method. First, the original seismic data is subjected to a series of conventional preprocessing such as static correction, amplitude fidelity denoising, amplitude compensation, resolution improvement, residual static correction, etc., and then the data is projected into the OVT domain based on the detection line spacing and shot line spacing as the scale to complete the division of conventional vector slices. Then, the vector slices are recombined and divided into the same number of OVT vector slices as the actual coverage times, and pre-stack time migration processing is performed to obtain a migration track gather with amplitude fidelity and high signal-to-noise ratio.

[0068] The method of the present invention can be applied to obtain a five-dimensional pre-stack gather with high signal-to-noise ratio, amplitude fidelity, and accurate azimuth details, thereby improving imaging accuracy. The present invention can be applied to provide pre-stack gathers with high signal-to-noise ratio, amplitude fidelity, and accurate azimuth details for AVO inversion and fracture prediction, and has a good application prospect in fracture oil and gas reservoir exploration.

[0069] [Example 1]

[0070] The embodiment of the present invention provides an OVT data set partitioning method, such as Figure 1 As shown, the steps of the method are as follows:

[0071] Step 1, preprocessing the original seismic data to obtain CMP gathers;

[0072] Preprocessing refers to a series of conventional preprocessing of the acquired raw seismic data, including static correction, amplitude fidelity denoising, amplitude compensation, resolution improvement, residual static correction, etc., to obtain CMP gathers with high signal-to-noise ratio, good amplitude consistency and high resolution.

[0073] Among them, pre-processing methods such as static correction, amplitude-fidelity denoising, amplitude compensation, resolution improvement, and residual static correction all adopt existing technical methods and will not be described in detail here.

[0074] Step 2: Project the CMP gather data into the OVT domain based on the detection line spacing and shot line spacing to complete the OVT gather extraction and the division of conventional vector slices;

[0075] Step 3: Count the number of vector slices and perform statistical analysis on the amount of single-slice data for each OVT data set to form a graph;

[0076] Step 4, delete the vector slices divided by the acquisition change view;

[0077] The specific operations are:

[0078] The vector slices are spirally numbered and marked with trace headers, and the vector slices composed of very few scattered points caused by serious acquisition changes are deleted, where the data volume is ≤ 500 traces;

[0079] Step 5: Optimize and reorganize the OVT vector slices;

[0080] Optimization principle: Several far-offset vector slices with similar offset distances and azimuth angles are recombined to form a target vector slice (Note: OVT data set and OVT vector slice are equivalent concepts in this invention);

[0081] With the theoretical coverage times equal to the number of vector slice divisions as the goal, for a wide azimuth observation system with N coverage times, the cross-arranged area can be subdivided into N OVTs, with 2i horizontal coverage times and 2j vertical coverage times, N = 2i*2j;

[0082] An OVT dataset consists of seismic traces with approximately the same shot offset and azimuth, and extends to the entire work area. It is a single coverage data volume covering the entire work area. Therefore, when multiple OVT datasets are expressed in geodetic coordinates, it is impossible to display all datasets in the entire plane.

[0083] Therefore, the present invention uses the main survey line offset of the center point of the OVT vector slice as the horizontal coordinate (or vertical coordinate) and the connection survey line offset as the vertical coordinate (or horizontal coordinate), and can project all OVT vector slices onto the same plane.

[0084] Taking the point (0,0) where the offset of the main survey line and the offset of the contact survey line are both zero as the origin, the vector slices on the offset distribution plane are divided into four quadrants, and the OVT vector slices of the far offset in the four quadrants are optimized and reorganized respectively:

[0085] The vector slice at position (i,j) in the first quadrant: i=1, 2, 3,…; j=1, 2, 3,…;

[0086] The vector slice at position (i,-j) in the second quadrant: i=1, 2, 3,…; j=1, 2, 3,…;

[0087] The third quadrant position (-i, -j) vector slice: i=1, 2, 3,…; j=1, 2, 3,…;

[0088] The vector slice at the fourth quadrant position (-i, j): i=1, 2, 3,…; j=1, 2, 3,…;

[0089] Position (-i,y) vector slice:

[0090] Position (i,y) vector slice:

[0091] Position (x,j) vector slice:

[0092] Position (x,-j) vector slice:

[0093] Where: T (i,j) is the vector patch at position (i, j);

[0094] T ( ' i,j) is the vector slice at position (i, j) after optimization;

[0095] 2k is the number of horizontal vector slices after processing in step 4, 2p is the number of vertical vector slices after processing in step 4; 2i is the number of horizontal coverage times, and 2j is the number of vertical coverage times.

[0096] According to the above formula, the number of optimized OVT data sets is equal to the number of coverages designed by the observation system. The amount of data between the optimized OVT data sets is at the same level.

[0097] Step 6: Perform prestack time migration processing on the optimized OVT data set to analyze the lateral energy distribution of the spiral gather and the imaging quality of the first coverage profile.

[0098] Figure 2 The conventional method is used to divide the OVT data set into the offset plane distribution and the single-slice data volume statistics, where the white numbers are the total number of single vector slice data, and the vector slices in the yellow box are vector slices with a data volume of ≤500; Figure 3 The offset plane distribution diagram of the OVT data set partitioned by the conventional method (after deleting vector slices with data volume ≤ 500) is shown in the figure. The numbers in the figure are the spiral numbers of the vector slices. Figure 4 This is the offset plane distribution diagram after the OVT data set is divided by the method of the present invention. The numbers in the figure are the spiral numbers of the vector slices. Figure 4 As shown in , the number of optimized OVT data sets is equal to the number of coverages designed by the observation system. The amount of data between the optimized OVT data sets is at the same level, see Figure 5 After prestack time migration of the optimized OVT data set, the lateral energy distribution of the spiral gather is more uniform and the consistency is enhanced, and the imaging quality of the one-time coverage profile is significantly improved. Figure 6 , Figure 7The experiment shows that the application of the present invention can significantly improve the amplitude fidelity of the pre-stack gathers.

[0099] [Example 2]

[0100] An embodiment of the present invention provides an OVT data set partitioning system, including:

[0101] A preprocessing unit, used for preprocessing the original seismic data to obtain CMP gathers;

[0102] The data projection unit is used to project the CMP gather data into the OVT domain based on the detection line spacing and shot line spacing, and complete the OVT gather extraction and the division of conventional vector slices;

[0103] The statistical unit is used to count the number of vector slices and perform statistical analysis on the single-slice data volume of each OVT data set to generate a graph;

[0104] A vector slice deletion unit is used to delete the vector slices divided by the acquisition change view;

[0105] Optimization and reorganization unit, used to optimize and reorganize OVT vector slices;

[0106] The migration processing unit is used to perform prestack time migration processing on the optimized OVT data set.

[0107] [Example 3]

[0108] An embodiment of the present invention provides a computer-readable storage medium, which stores at least one computer-executable program. When the at least one program is executed by the computer, the computer executes the steps in the OVT data set partitioning method described in Example 1.

[0109] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0110] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A method for partitioning an OVT data set, characterized in that: First, after preprocessing the original seismic data, the data is projected into the OVT domain based on the detection line spacing and shot line spacing to complete the division of vector slices. Then the vector slices are recombined and divided into the same number of OVT vector slices as the actual coverage times, and after prestack time migration processing, the migration gathers with amplitude fidelity and high signal-to-noise ratio are obtained.

2. The OVT data set partitioning method according to claim 1, characterized in that: The steps of the method are as follows: Step 1, preprocessing the original seismic data to obtain CMP gathers; Step 2: Project the CMP gather data into the OVT domain based on the detection line spacing and shot line spacing to complete the OVT gather extraction and the division of conventional vector slices; Step 3: Count the number of vector slices and perform statistical analysis on the amount of single-slice data for each OVT data set to form a graph; Step 4, delete the vector slices divided by the acquisition change view; Step 5: Optimize and reorganize the OVT vector slices; Step 6: Perform prestack time migration processing on the optimized OVT dataset.

3. The OVT data set partitioning method according to claim 2, characterized in that: The preprocessing in step 1 refers to processing the acquired original seismic data through static correction, amplitude fidelity denoising, amplitude compensation, resolution improvement, and residual static correction to obtain a CMP gather with high signal-to-noise ratio, good amplitude consistency, and high resolution.

4. The OVT data set partitioning method according to claim 2, characterized in that: In step 4, the vector slices divided by the acquisition change view are deleted, and the specific operation is as follows: The vector slices are spirally numbered and marked with headers, and the vector slices composed of very few scattered points caused by serious acquisition changes are deleted, where the data volume is ≤500.

5. The OVT data set partitioning method according to claim 2, characterized in that: The optimization principle in step 5 is: Several far-off vector slices with similar offset distances and azimuth angles are reassembled to form a target vector slice.

6. The OVT data set partitioning method according to claim 5, characterized in that: The operations in step 5 include: With the theoretical coverage times equal to the number of vector slice divisions as the goal, for a wide-azimuth observation system with N coverage times, the cross-arranged area is subdivided into N OVTs, with 2i coverage times in the horizontal direction and 2j coverage times in the vertical direction, N=2i*2j.

7. The OVT data set partitioning method according to claim 6, characterized in that: The operations in step 5 include: With the main survey line offset of the center point of the OVT vector slice as the horizontal coordinate or vertical coordinate, and the contact survey line offset as the vertical coordinate or horizontal coordinate, all OVT vector slices are projected onto the same plane.

8. The OVT data set partitioning method according to claim 7, characterized in that: The operations in step 5 include: Taking the point (0,0) where the offset of the main survey line and the offset of the contact survey line are both zero as the origin, the vector slices on the offset distribution plane are divided into four quadrants, and the OVT vector slices of the far offset in the four quadrants are optimized and reorganized respectively: The vector slice at position (i,j) in the first quadrant: The vector slice at position (i,-j) in the second quadrant: The third quadrant position (-i, -j) vector slice: The fourth quadrant position (-i, j) vector slice: Position (-i,y) vector slice: Position (i,y) vector slice: Position (x,j) vector slice: Position (x,-j) vector slice: Where: T (i,j) is the vector patch at position (i, j); T ( ' i,j) is the vector slice at position (i, j) after optimization; 2k is the number of horizontal vector slices after processing in step 4, 2p is the number of vertical vector slices after processing in step 4; 2i is the number of horizontal coverage times, and 2j is the number of vertical coverage times.

9. An OVT data set partitioning system, characterized in that: include: A preprocessing unit, used for preprocessing the original seismic data to obtain CMP gathers; The data projection unit is used to project the CMP gather data into the OVT domain based on the detection line spacing and shot line spacing, and complete the OVT gather extraction and the division of conventional vector slices; The statistical unit is used to count the number of vector slices and perform statistical analysis on the single-slice data volume of each OVT data set to generate a graph; A vector slice deletion unit is used to delete the vector slices divided by the acquisition change view; Optimization and reorganization unit, used to optimize and reorganize OVT vector slices; The migration processing unit is used to perform prestack time migration processing on the optimized OVT data set.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one computer-executable program, and when the at least one program is executed by the computer, the computer executes the steps in the OVT data set partitioning method according to any one of claims 1 to 8.

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