A method and system for correcting closure errors of two-dimensional survey line seismic data

Abstract

The present invention proposes a correction method and system for the closure error of seismic data of a two-dimensional survey line, and belongs to the technical field of correction of closure error of seismic data. First, according to the original seismic data of the target area, a velocity model is obtained, and the final seismic profile data is generated; secondly, the intersection point of each seismic profile is selected as the closing point; then the velocity of the closing point on the two survey lines is analyzed, and the layers at the closing point where the layers are not aligned are aligned by fine-tuning the velocity to obtain the new velocity of the closing point; finally, the original velocity model is updated with the obtained new velocity to generate a new velocity model, and the seismic data is superimposed with the new velocity model to obtain the new final seismic profile data, and the correction of the closure error of the seismic data of the two-dimensional survey line is completed. The method of the present invention is simple and convenient, and can quickly realize the adjustment of the unaligned layers without changing the aligned layers, so that the final seismic profile layer alignment effect is good, and reliable data is provided for subsequent seismic interpretation.

Description

Technical Field

[0001] The invention relates to a method and system for correcting closure errors of seismic data of a two-dimensional survey line, belonging to the technical field of closure error correction of seismic data. Background Art

[0002] In the processing of seismic data, it is often necessary to process a large number of two-dimensional survey lines. When analyzing the data profiles in the survey line network, it is often seen that the seismic traces between the profiles at the intersections do not match. The mismatch of these intersections is usually called data closure error. Therefore, in order to meet the stratigraphic matching between the generated profile data, the closure error needs to be corrected. The accuracy of the closure error correction directly affects the accuracy of the structural map, the optimization of the drilling well location and even the detection of risk areas.

[0003] Among the existing methods for correcting the closure error of two-dimensional survey lines, the most common one is to move the layers on both sides of the closing point up and down as a whole. Although this method is simple, since the layers on both sides of the closing point are not one-to-one corresponding, although the overall movement aligns most of the layers, it will also cause individual layers to be misaligned; there is also a one-time correction of the closure error to ensure that the error of the correction result is within the allowable range, but this one-size-fits-all approach to the closure error will definitely restrict the accuracy; therefore, although the existing methods are simple, they cannot guarantee that all layers can be aligned after correction, which in turn affects the accuracy of subsequent seismic interpretation. Summary of the invention

[0004] The object of the present invention is to provide a method and system for correcting the closure error of two-dimensional survey line seismic data, so as to solve the problem of low correction accuracy of the closure error of two-dimensional survey line.

[0005] The present invention provides a method for correcting closure errors of two-dimensional survey line seismic data, the method comprising the following steps:

[0006] 1) Obtain the original seismic data of the target area, obtain the corresponding velocity model, and process it to generate the final seismic profile data;

[0007] 2) Select the intersection points of each section according to the seismic section data, and use the selected intersection points as closing points;

[0008] 3) Analyze the velocity of the closing point on the two intersecting survey lines, and fine-tune the velocity of the closing point on the two survey lines if the layers are not aligned, until the layers at the closing point are aligned, and obtain the new velocity of the closing point on the two survey lines;

[0009] 4) Using the new velocity obtained to update the original velocity model, a new velocity model is generated; and the new velocity model is then used to superimpose the seismic data to generate new final seismic profile data.

[0010] The present invention also provides a system for correcting closure errors of two-dimensional survey line seismic data, the system comprising a processor and a memory, the processor executing a computer program stored in the memory to implement the method for correcting closure errors of two-dimensional survey line seismic data as described in the present invention.

[0011] The present invention first solves the intersection of each seismic profile as a closing point, and analyzes the velocity of the closing point on two survey lines, aligns the two horizons by fine-tuning the closing point velocity of the unaligned horizon, updates the original velocity model with the generated new velocity to generate a new velocity model, and then superimposes the seismic data with the new velocity model to generate new final seismic profile data, thereby realizing the correction of the closure error of the two-dimensional survey line seismic data. The method takes into account the fact that the horizons on both sides of the closing point are not one-to-one corresponding, and fine-tunes the velocity of the closing point on the two survey lines, and re-superimposes the seismic profile with the fine-tuned velocity, and can adjust the horizons that are not aligned at the closing point without moving the horizon up and down as a whole, and realize the alignment of the horizons on both sides of the closing point. The method of the present invention is simple and convenient, and can quickly realize the adjustment of the unaligned horizons without changing the aligned horizons, so that the horizon alignment effect of the final seismic profile is good, and reliable data is provided for subsequent seismic interpretation.

[0012] Furthermore, in order to ensure the rationality of the speed fine-tuning, the speed fine-tuning in step 3) refers to adjusting the speed up or down according to a set adjustment threshold.

[0013] Furthermore, in order to improve the correction efficiency, in step 3), the entire layer is corrected before fine-tuning the closing point speed.

[0014] Furthermore, the overall horizon correction method is a wavelet shaping method. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a flow chart of closure error correction of two-dimensional survey line seismic data of the present invention;

[0016] Figure 2 is the final seismic profile in the embodiment of the present invention;

[0017] Figure 3 It is the final seismic profile after closure error correction in the embodiment of the present invention. DETAILED DESCRIPTION

[0018] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0019] Method Embodiment

[0020] The present invention provides a method for correcting the closure error of two-dimensional survey line seismic data. The specific process is as follows: Figure 1 As shown. First, the original seismic data of the target area is obtained, the corresponding velocity model is obtained, and the final seismic profile data is generated; secondly, the intersection points of each seismic profile are selected and used as the closing point; then the velocity of the closing point on the two survey lines is analyzed, and the velocity of the closing point with misaligned layers is fine-tuned until the layers at the closing point are aligned, and the new velocity of the closing point on the two survey lines is obtained; finally, the original velocity model is updated with the obtained new velocity, and the seismic data is superimposed with the new velocity model to obtain the corrected final seismic profile data, completing the correction of the closure error of the two-dimensional survey line seismic data.

[0021] Step 1. Get the target area data

[0022] The data obtained by the present invention is the original seismic data in the target area, and a large number of two-dimensional survey lines in the target area are obtained. By analyzing these two-dimensional survey lines, a velocity model can be obtained, and the final seismic profile data can be generated after processing. Because the final seismic profile data will have a certain layer displacement, it is necessary to correct the overall layer. In this embodiment, the sub-wave shaping method is used to correct and obtain the initial corrected seismic profile data. In this embodiment, the initial corrected seismic profile data obtained is as follows Figure 2 As shown in the figure, it can be seen that the overall layers are generally aligned, and some layers are not aligned ( Figure 2 13053), the present invention is to correct some of the misaligned layers.

[0023] Step 2. Select the section closing point

[0024] According to the initial corrected seismic profile data generated in step 1, the intersection points of each profile are selected and these intersection points are used as closing points. Figure 2 The 13015, 13053, and 13091 in the figure are the intersection points of the various profiles selected based on the initial corrected seismic profile data, so 13015, 13053, and 13091 are called the two-dimensional survey line closing points.

[0025] Step 3. Fine-tune closing point speed

[0026] During field construction, due to factors such as instrument type, source type, source arrangement, etc., the layers of the intersection of the profiles are not aligned, and the mismatch of these intersections is called data closure error. In the present invention, the corresponding layers are adjusted by adjusting the speed of the closing point so that the layers at the final closing point are aligned. First, the speed of the closing point on the two survey lines is analyzed, and the speed at the closing point in the two survey lines can be obtained. The speed at the closing point is fine-tuned up and down, and the seismic data is superimposed with the fine-tuned speed to generate new seismic profile data. In the new seismic profile data, it is compared to show whether there is still a closure error at the closing point. If there is a closure error, the speed of the closing point on the two survey lines is constantly fine-tuned until the layers at both ends of the closing point are aligned, and the new speed of the closing point on the corresponding two survey lines is obtained. In this process, in order to ensure the rationality of the speed adjustment and avoid excessive speed adjustment, a speed adjustment threshold value needs to be set, and the speed is constantly fine-tuned under this threshold value to achieve alignment of the layers at both ends of the closing point.

[0027] In this embodiment, if Figure 2 As shown in the figure, the layers at both ends of the closing point 13055 are not aligned, and it can be clearly seen that there is an obvious layer dislocation, so it is necessary to perform a closure error correction on the closing point 13055. First, the speed of the closing point 13053 on the two survey lines is analyzed to obtain the speed of the closing point 13055 in the two survey lines, and then the speed at the closing point in the two survey lines is fine-tuned until the layers of the closing point 13055 are aligned.

[0028] During the fine-tuning process, one of the survey lines can be used as the reference survey line and the other survey line as the survey line to be corrected. The speed of the closing point on the reference survey line remains unchanged, and the speed of the closing point on the survey line to be corrected is continuously adjusted upward and downward within the set adjustment speed threshold. Taking the closing point 13053 as an example, if the speed of the closing point 13053 on the survey line to be corrected is adjusted upward first, it is found that the profile generated by the fine-tuned speed update still shows a closure error. If it is found that the speed adjustment of the closing point 13053 on the survey line to be corrected is too large, it is fine-tuned downward. If the speed adjustment is small, it is continued to be adjusted upward until the layers at both ends of the closing point 13053 are finally aligned.

[0029] During the fine-tuning process, the speed of the closing points on the two survey lines can also be adjusted at the same time. Taking the closing point 13053 as an example, the upper and lower layers corresponding to the closing points of the two survey lines can be obtained. The closing point of the survey line corresponding to the upper layer needs to be adjusted downward, and the closing point of the lower layer needs to be adjusted upward. Therefore, the speed of the closing point 13053 on the two survey lines can be adjusted at the same time. For example, the speed of the closing point on one survey line is fine-tuned upward, and the speed of the closing point on another survey line is fine-tuned downward. If in the profile generated by the speed update after fine-tuning, it is found that the layers of the closing points of the two survey lines are close, but the corresponding layer positions have not changed up and down, then the speed that is fine-tuned upward continues to be adjusted upward, and the speed that is fine-tuned downward continues to be adjusted downward; if the layers of the closing points of the two survey lines are found to be displaced in the opposite direction, the speed that is fine-tuned upward needs to be adjusted downward, and the speed that is fine-tuned downward needs to be adjusted upward, until the layers at both ends of the closing point 13053 are finally aligned. Finally, the new speed of the closing point at the two survey lines can be obtained.

[0030] Step 4. Generate new seismic profile data

[0031] The new velocities of the closing points on the two survey lines obtained in step 3 are used to update the original velocity model to generate a new velocity model; the generated new velocity model is then used to superimpose the seismic data to generate new final seismic profile data.

[0032] In this embodiment, the new velocity of the closing point 13053 on the two survey lines is obtained through step 3), and the original velocity model is updated with the new velocity to generate a new velocity model; the seismic data is then superimposed with the generated new velocity model to generate new final seismic profile data. The obtained new final seismic profile is shown in FIG. Figure 3 As shown. Figure 2 The obvious layer dislocation at the closing point 13053 Figure 3 It can be clearly seen that there is no layer dislocation at the corresponding closing point 13053, and the layer dislocation disappears after the closure error correction. The intersection of the two survey lines has a smooth transition without any trace of dislocation, which proves that the method of the present invention is effective in correcting the closure error of two-dimensional survey line seismic data.

[0033] System Example

[0034] The system proposed in this embodiment includes a processor and a memory, wherein a computer program that can be run on the processor is stored in the memory, and the processor implements the method of the above method embodiment when executing the computer program. That is to say, the method in the above embodiment should be understood as a process of a correction method for closure error of two-dimensional survey line seismic data that can be implemented by computer program instructions. These computer program instructions can be provided to the processor so that the processor executes these instructions to generate functions specified by the above method flow.

[0035] The processor referred to in this embodiment refers to a processing device such as a microprocessor MCU or a programmable logic device FPGA; the memory referred to in this embodiment includes a physical device for storing information, which usually digitizes the information and then stores it in an electrical, magnetic or optical manner. For example: various memories that use electrical energy to store information, such as RAM, ROM, etc.; various memories that use magnetic energy to store information, such as hard disks, floppy disks, tapes, magnetic core memories, bubble memories, and U disks; various memories that use optical methods to store information, such as CDs or DVDs. Of course, there are other types of memories, such as quantum memories, graphene memories, and so on.

[0036] The device is composed of the above-mentioned memory, processor and computer program, and the processor executes corresponding program instructions in the computer to achieve the above-mentioned. The processor can be equipped with various operating systems, such as Windows operating system, Linux system, Android, iOS system, etc. As another embodiment, the device can also include a display, and the display is used to display the correction result for reference by the staff.

Claims

1. A method for correcting closure errors of two-dimensional survey line seismic data, characterized in that: The method comprises the following steps: 1) Obtain the original seismic data of the target area, obtain the corresponding velocity model, and process it to generate the final seismic profile data; 2) Select the intersection points of each section according to the seismic section data, and use the selected intersection points as closing points; 3) Analyze the velocity of the closing point on the two intersecting survey lines, set the velocity adjustment threshold, and fine-tune the velocity of the closing point on the two survey lines where the layers are not aligned under the velocity threshold. Use the fine-tuned velocity to superimpose the seismic data to generate new seismic profile data. In the new seismic profile data, compare and show whether there is still a closure difference at the closing point. If there is a closure difference, the velocity of the closing point on the two survey lines is continuously fine-tuned until the layers at the closing point are aligned, and the new velocity of the closing point on the two survey lines is obtained; 4) Use the new velocity obtained to update the original velocity model and generate a new velocity model; then use the new velocity model to superimpose the seismic data to generate new final seismic profile data.

2. The method for correcting closure errors of two-dimensional survey line seismic data according to claim 1, characterized in that: The speed fine-tuning in step 3) refers to adjusting the speed up or down according to the set adjustment threshold.

3. The method for correcting closure errors of two-dimensional survey line seismic data according to claim 1, characterized in that: In step 3), before fine-tuning the closing point velocity, the overall layer is corrected by wavelet shaping.

4. A correction system for closure error of two-dimensional survey line seismic data, characterized in that: The system comprises a processor and a memory, wherein the processor executes a computer program stored in the memory to implement the method for correcting closure errors of two-dimensional survey line seismic data as described in any one of claims 1 to 3.

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