Pre-stack space-time variant hyperbolic time window pickup method

Abstract

The invention provides a pre-stack space-time variant hyperbolic time window pickup method, which comprises the following steps of: 1, picking up a stratum top interface on a stack section, and counting into a channel head; 2, counting the average speed of a top interface; step 3, hyperbolic operation is carried out to obtain a hyperbolic time window upper boundary before space-time variation and stack; 4, a stratum bottom interface is picked up on the stacked section, and a road head is recorded; 5, counting the average speed of the bottom interface; step 6, performing hyperbolic operation to obtain a space-time variable pre-stack hyperbolic time window lower boundary; and step 7, generating a hyperbolic time window corresponding to the prestack space variant of the single shot. The invention discloses a pre-stack space-time variant hyperbolic time window pickup method.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas exploration seismic data processing, and in particular to a pre-stack space-time variable hyperbolic time window picking method. Background Art

[0002] Prestack hyperbolic time window is an important means of performing surface consistency calculations and attribute analysis in seismic data processing. It is a processing technology that obtains a time window by performing hyperbolic calculations on the time and velocity picked at zero offset, thereby analyzing the seismic data within the time window. However, in actual production, for areas with large structural changes, a single time window is difficult to take into account the same set of strata at different locations, thus affecting the analysis effect. At present, there is no technology for picking time-space variable hyperbolic time windows.

[0003] With the continuous deepening of oil and gas exploration, the impact of data quality differences caused by changes in stratum structure on fine seismic data processing has become increasingly prominent. However, due to the lack of a means of picking up a time-space hyperbolic time window for a certain layer in the existing processing software, analysis can only be performed through a single time window or multiple time windows, resulting in a large workload or lack of pertinence in the analysis results, thus affecting the processing efficiency.

[0004] In the Chinese patent application with application number: CN201710470477.X, a time window weighted coherent velocity inversion method and system is involved, which includes: picking up the main time layer data on the stacked section; calculating the travel time of the CMP gather; setting the weighting factor in the time window, whose length is the same as the time window length; calculating the coherence coefficient, and picking up the layer velocity of the layer. The method of the invention obtains the layer velocity in the depth domain, which is suitable for seismic data with low signal-to-noise ratio and has high accuracy; it is also applicable to strata with lateral velocity changes. Both theoretical model tests and actual data processing have achieved good results.

[0005] In the Chinese patent application with application number: CN201510572426.9, a method and device for determining pre-stack seismic horizons are involved. The method includes: dividing the pre-stack seismic trace set into N pre-stack seismic sub-trace sets; superimposing the data of each seismic trace in the pre-stack seismic sub-trace set to obtain the stacked seismic sub-trace set data; performing horizon tracking on the stacked seismic sub-trace set data to obtain the seismic horizon corresponding to the stacked seismic sub-trace set data; unfolding the seismic horizon on the pre-stack seismic sub-trace set, and determining the unfolded seismic horizon as the initial pre-stack seismic horizon corresponding to the pre-stack seismic sub-trace set; performing phase correction on the initial pre-stack seismic horizon to obtain the pre-stack seismic horizon corresponding to the pre-stack seismic sub-trace set. The method and device for determining pre-stack seismic horizons provided in this application embodiment can improve the efficiency of determining pre-stack seismic horizons while ensuring the accuracy of determining pre-stack seismic horizons.

[0006] In the Chinese patent application with application number: CN201710372337.9, a method and device for determining seismic prestack time migration velocity is involved, wherein the method includes: obtaining seismic data and well logging data; determining the seismic stacking velocity field and seismic wavelet according to the seismic data, and establishing the seismic layer velocity field; obtaining the well logging layer velocity in the time domain according to the well logging data and the seismic wavelet, and then determining the well logging layer velocity that meets the preset requirements to establish the well logging layer velocity field; establishing a well-seismic joint layer velocity field model according to the well logging layer velocity field, the seismic layer velocity field, and the seismic data; and then determining the seismic prestack time migration velocity. Since the scheme first determines the seismic layer velocity field and the well logging layer velocity field respectively, and then establishes the well-seismic joint layer velocity field model according to the above two layer velocity fields and the seismic data. Therefore, the technical problems existing in the existing methods that the determined seismic prestack time migration velocity is not accurate and the seismic velocity in the low signal-to-noise ratio area cannot be accurately picked up are solved.

[0007] The above existing technologies are greatly different from the present invention and fail to solve the technical problem we want to solve. Therefore, we have invented a new pre-stack space-time variable hyperbolic time window picking method. Summary of the invention

[0008] The purpose of the present invention is to provide a pre-stack space-time hyperbolic time window picking method for picking the space-time hyperbolic time window for a certain target layer.

[0009] The object of the present invention can be achieved by the following technical measures: a pre-stack space-time hyperbolic time window picking method, the pre-stack space-time hyperbolic time window picking method comprising:

[0010] Step 1, pick the top interface of the formation on the stacked section and include it in the trace head T1(0);

[0011] Step 2, calculating the average velocity V1 of the top interface;

[0012] Step 3, performing a hyperbolic operation to obtain the upper boundary T1(X) of the hyperbolic time window before the space-time stacking;

[0013] Step 4, pick up the bottom interface of the formation on the stacked section and include it in the trace head T2(0);

[0014] Step 5, calculating the average velocity V2 of the bottom interface;

[0015] Step 6, performing a hyperbolic operation to obtain the lower boundary T2(X) of the hyperbolic time window before the space-time stacking;

[0016] Step 7: Generate a hyperbolic time window of pre-stack space-variance corresponding to the single shot.

[0017] The purpose of the present invention can also be achieved by the following technical measures:

[0018] The pre-stack space-time hyperbolic time window picking method also includes, before step 1, preparing stacked sections of seismic data, control point single shots at different parts of the work area, stacked velocity fields, and geological stratum files to be analyzed.

[0019] Before step 1, the geological layer file is the preliminary interpretation result of the work area data. If the work area is a blank work area, it is necessary to manually pick the marker layer on the superimposed section for subsequent operations.

[0020] In step 1, the horizon is picked along the upper boundary marker stratum on the stacked section and counted into the trace header T1(0).

[0021] In step 1, when there is a previous geological layer file, the layer can be directly read.

[0022] In step 2, the trace header T1(0) is exported, and a layer file is formed by interpolation or the upper boundary layer file is directly read. The layer is projected into the velocity field, and the stacking velocity of the layer is counted as the average velocity V1 of the upper boundary marker formation.

[0023] In step 3, a hyperbolic operation is performed on the single shot data according to the upper boundary average velocity V1 and the upper boundary layer time value T1(0) in combination with the current track offset X to obtain the upper boundary T1(X) of the hyperbolic time window before the spatiotemporal stack and count it into the current track header.

[0024] In step 3, the calculation formula of T1(X) is:

[0025]

[0026] Where T1(X) is the time value corresponding to the upper boundary marker formation at offset X, DT is the boundary time delay, T1(0) is the time value of the upper boundary zero offset, V1 is the upper boundary average velocity, and X is the offset.

[0027] In step 4, the horizon is picked along the lower boundary marker stratum on the stacked section and counted into the trace header T2(0).

[0028] In step 4, when there is a previous geological layer file, the layer can be directly read.

[0029] In step 5, the trace header T2(0) is exported, and a layer file is formed by interpolation or the lower boundary layer file is directly read. The layer is projected into the stacking velocity field, and the stacking velocity of the layer is counted as the average velocity V2 of the lower boundary marker formation.

[0030] In step 6, a hyperbolic operation is performed on the single shot data according to the upper boundary average velocity V2 and the upper boundary layer time value T2(0) in combination with the current track offset X to obtain the upper boundary T2(X) of the hyperbolic time window before the spatiotemporal stacking and count it into the current track header.

[0031] In step 6, the calculation formula of T2(X) is:

[0032]

[0033] Where T2(X) is the time value corresponding to the lower boundary marker formation at offset X, DT is the boundary time delay, T2(0) is the time value of the lower boundary zero offset, V2 is the lower boundary average velocity, and X is the offset.

[0034] In step 7, the upper boundary trace head T1(X) and the lower boundary trace head T2(X) obtained on the single shot are used as the lower boundary to generate a pre-stack space-variant hyperbolic time window corresponding to the single shot.

[0035] Compared with other methods, the pre-stack space-time variable hyperbolic time window picking method of the present invention has the following advantages:

[0036] 1. The method is stable and reliable. This method comprehensively considers the impact of the temporal and spatial changes of the stratum on a single shot, thereby picking the time window for the target layer in the shot area.

[0037] Second, the operation is simple and easy. The process and parameter settings of this method are simple, the calculation efficiency is high, no assumptions are required, and it is not restricted by data.

[0038] 3. The layers can be adjusted at any time according to needs to meet the analysis requirements of multiple layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of picking the boundary of the post-stack horizon time window in a specific embodiment of the present invention;

[0040] Figure 2 A schematic diagram of counting the picking boundary time into the track header in a specific embodiment of the present invention;

[0041] Figure 3 It is a schematic diagram for statistically analyzing the average velocity of the upper and lower boundary formations in a specific embodiment of the present invention;

[0042] Figure 4 A schematic diagram of calculating a hyperbolic time window according to boundary velocity and time in a specific embodiment of the present invention;

[0043] Figure 5 It is a schematic diagram of the application of space-time variable hyperbolic time window in a specific embodiment of the present invention;

[0044] Figure 6 The flowchart is a specific embodiment of the pre-stack space-time hyperbolic time window picking method of the present invention. DETAILED DESCRIPTION

[0045] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0046] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0047] Hyperbolic time window is an important analysis tool in seismic data processing. Through the relationship between velocity and offset, a hyperbolic time window parallel to the event axis of the single-shot hyperbolic morphology can be obtained, thereby improving the analysis accuracy. At present, a single hyperbolic time window is usually used for analysis in the single-shot data analysis process. When the information such as the formation depth and structural trend changes, the single hyperbolic time window cannot change with the formation, and the analysis accuracy will inevitably be affected, resulting in inaccurate analysis results. Therefore, the present invention uses the post-stack hyperbolic time window to pick up the boundary of the hyperbolic time window along the target layer, and reversely obtains the pre-stack hyperbolic time window through velocity calculation, so as to obtain a hyperbolic time window that changes along the target layer and improve the accuracy of single-shot analysis.

[0048] The essence of the pre-stack space-time variable hyperbolic time window picking technology is to pick the time window boundary on the stacked data, and to reverse the post-stack time window to a single shot through velocity calculation to form a hyperbolic time window, thereby realizing the pre-stack application of the post-stack time window.

[0049] When operating, it is necessary to prepare the stacked profile of seismic data, the control point single shot at different parts of the work area, the stacked velocity field, and the geological layer file to be analyzed. The geological layer file is the preliminary interpretation result of the work area data. If the work area is a blank work area, it is necessary to manually pick the marker layer on the stacked profile for subsequent operations. The pre-stack space-time hyperbolic time window picking method of the present invention includes the following steps:

[0050] (1) Pick up the horizon along the upper boundary marker stratum on the stacked section (if there is a previous geological horizon file, the horizon can be read directly) and include it in the trace header T1(0).

[0051] (2) Export the trace header T1(0), form a layer file by interpolation (or directly read the upper boundary layer file), project the layer into the velocity field, and calculate the stacking velocity of the layer as the average velocity V1 of the upper boundary marker formation.

[0052] (3) Based on the single-shot data, a hyperbolic operation is performed according to the upper boundary average velocity V1 and the upper boundary layer time value T1(0) in combination with the current track offset X to obtain the upper boundary T1(X) of the hyperbolic time window before the spatiotemporal stacking and include it in the current track header.

[0053]

[0054] Where T1(X) is the time value corresponding to the upper boundary marker formation at offset X, DT is the boundary time delay, T1(0) is the time value of the upper boundary zero offset, V1 is the upper boundary average velocity, and X is the offset.

[0055] (4) Pick up the horizon along the lower boundary marker stratum on the superimposed section (if there is a previous geological horizon file, the horizon can be read directly) and include it in the trace header T2(0).

[0056] (5) The trace header T2(0) is exported, and a layer file is formed by interpolation (or the lower boundary layer file is directly read). The layer is projected into the stacking velocity field, and the stacking velocity of the layer is calculated as the average velocity V2 of the lower boundary marker formation.

[0057] (6) Based on the single-shot data, a hyperbolic operation is performed based on the upper boundary average velocity V2 and the upper boundary layer time value T2(0) in combination with the current track offset X to obtain the upper boundary T2(X) of the hyperbolic time window before the spatiotemporal stacking and include it in the current track header.

[0058]

[0059] Where T2(X) is the time value corresponding to the lower boundary marker formation at offset X, DT is the boundary time delay, T2(0) is the time value of the lower boundary zero offset, V2 is the lower boundary average velocity, and X is the offset.

[0060] (7) The upper boundary trace head T1(X) and the lower boundary trace head T2(X) obtained on a single shot can be used as the lower boundary to generate a hyperbolic time window of the pre-stack space-variant corresponding to the single shot.

[0061] The following are several specific embodiments of the present invention.

[0062] Example 1

[0063] In a specific embodiment 1 of the present invention, the three-dimensional seismic data of the GL area of ​​the XX oil field is used as the target area in this study, and the method is applied to process the data to verify the effect of the method. The specific flow chart is shown in Figure 6 .

[0064] 1) First, go to step 1. Since this work area is a new acquisition work area and lacks layer files, manual layer picking is performed. The upper boundary of the target layer is picked on the superimposed section of the work area, such as Figure 1 shown.

[0065] 2) Then according to step 2, the picked upper boundary time value is recorded in the stacking trace header in the form of a trace header, and interpolated to obtain the upper boundary layer file, such as Figure 2 shown.

[0066] 3) According to step 3, the upper boundary layer file is projected to the stacking velocity field. The average velocity of the upper boundary of the target layer is 2350 m / s from the stacking velocity field, and verified on the control point single shot, such as Figure 3 shown.

[0067] 4) According to steps 4-6, pick up the lower boundary of the target layer on the stacked section of the work area, count it into the stacked trace head, and interpolate to obtain the lower boundary horizon file. Project the lower boundary horizon file to the stacked velocity field. The average velocity of the lower boundary of the target layer is 2650m / s from the stacked velocity field, and verify it on the control point single shot, such as Figure 3 shown.

[0068] 5) According to step 7, the obtained space-time hyperbolic time window upper and lower boundaries are used to generate the pre-stack space-time hyperbolic time window, such as Figure 4 shown.

[0069] 6) Figure 5 In order to pick up the results of time windows on different single shots, the application of this technology can realize the picking of spatiotemporal time windows for a certain target layer.

[0070] Through the application of time-space variable time windows, the application of single shot data in this work area in surface consistency processing has achieved more ideal processing than conventional methods. Compared with conventional methods, this technology can achieve targeted time window picking, the method is simple and easy, and has more technical advantages.

[0071] Example 2

[0072] In the specific embodiment 2 of the present invention, the target processing is performed on the T6 formation of the GL area of ​​the XX oil field. The depth of the formation in this analysis is quite different. The formation is thin in the convex part, and the time length is only 500ms, while the formation in the concave part is thicker, and the time length exceeds 2000ms. If a single hyperbolic time window is used, the convex part will contain too much other layer information, and the analysis results will be quite different. This method is used to process the data to verify the effect of this method. The specific flow chart is shown in Figure 6 .

[0073] 1) Since this work area has previous data and previous layer files, skip step 1 and proceed directly to step 2. The upper boundary time value of the previous layer is included in the superimposed trace header in the form of a trace header, and interpolation is performed to obtain the upper boundary layer file.

[0074] 2) According to step 3, the upper boundary layer file is projected onto the stacking velocity field. The average velocity of the upper boundary of the target layer is calculated to be 2500 m / s from the stacking velocity field and verified on a single shot at the control point.

[0075] 3) Skip step 4 and, according to steps 5-6, count the lower boundary time value of the previous layer into the stacking trace header in the form of a trace header, and interpolate to obtain the lower boundary layer file. Project the lower boundary layer file to the stacking velocity field, and calculate the average velocity of the lower boundary of the target layer from the stacking velocity field as 2950m / s, and verify it on the control point single shot, such as Figure 3 shown.

[0076] 4) According to step 7, the obtained upper and lower boundaries of the space-time-variant hyperbolic time window are used to generate a pre-stack space-time-variant hyperbolic time window.

[0077] The application of this technology can realize the picking of the target layer in time-space varying time window according to the characteristics of large changes in the thickness of the stratum in this work area. When the subsequent target processing is carried out according to the time-space varying hyperbolic time window, a more reasonable processing effect is achieved than the previous single time window deconvolution.

[0078] Example 3

[0079] In the specific embodiment 3 of the present invention, it is necessary to perform attribute analysis on the single-shot target layer in the LJ work area of ​​XX Oilfield. Since the target layer has large fluctuations, the results of the analysis in a single time window have large differences in space, which affects the analysis effect. The present method is used to produce a new analysis time window.

[0080] This work area was a blank work area in the early stage, and its operation steps are the same as those in Example 1, which will not be repeated here. Through the operation of steps 1-7, a spatiotemporal hyperbolic time window that matches the target layer is generated. The original single analysis time window includes information of other strata at the location of structural mutation, resulting in large differences in analysis results. After the introduction of the spatiotemporal hyperbolic time window, the spatial consistency of the obtained single shot attributes is better.

[0081] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0082] Except for the technical features described in the specification, all other technical features are known technologies to those skilled in the art.

Claims

1. A pre-stack space-time hyperbolic time window picking method, characterized in that: The pre-stack space-time hyperbolic time window picking method includes: Step 1, pick the top interface of the formation on the stacked section and include it in the trace head T1(0); Step 2, calculating the average velocity V1 of the top interface; Step 3, performing a hyperbolic operation to obtain the upper boundary T1(X) of the hyperbolic time window before the space-time stacking; Step 4, pick up the bottom interface of the formation on the stacked section and include it in the trace head T2(0); Step 5, calculating the average velocity V2 of the bottom interface; Step 6, performing a hyperbolic operation to obtain the lower boundary T2(X) of the hyperbolic time window before the space-time stacking; Step 7: Generate a hyperbolic time window of pre-stack space-variance corresponding to the single shot.

2. The pre-stack space-time hyperbolic time window picking method according to claim 1, characterized in that: The pre-stack space-time hyperbolic time window picking method also includes, before step 1, preparing stacked sections of seismic data, control point single shots at different parts of the work area, stacked velocity fields, and geological stratum files to be analyzed.

3. The pre-stack space-time hyperbolic time window picking method according to claim 2 is characterized in that: Before step 1, the geological layer file is the preliminary interpretation result of the work area data. If the work area is a blank work area, it is necessary to manually pick the marker layer on the superimposed section for subsequent operations.

4. The pre-stack space-time hyperbolic time window picking method according to claim 1, characterized in that: In step 1, the horizon is picked along the upper boundary marker stratum on the stacked section and counted into the trace header T1(0).

5. The pre-stack space-time hyperbolic time window picking method according to claim 4, characterized in that: In step 1, when there is a previous geological layer file, the layer can be directly read.

6. The pre-stack space-time hyperbolic time window picking method according to claim 1, characterized in that: In step 2, the trace header T1(0) is exported, and a layer file is formed by interpolation or the upper boundary layer file is directly read. The layer is projected into the velocity field, and the stacking velocity of the layer is counted as the average velocity V1 of the upper boundary marker formation.

7. The pre-stack space-time hyperbolic time window picking method according to claim 1, characterized in that: In step 3, a hyperbolic operation is performed on the single shot data according to the upper boundary average velocity V1 and the upper boundary layer time value T1(0) in combination with the current track offset X to obtain the upper boundary T1(X) of the hyperbolic time window before the spatiotemporal stack and count it into the current track header.

8. The pre-stack space-time hyperbolic time window picking method according to claim 7, characterized in that: In step 3, the calculation formula of T1(X) is: Where T1(X) is the time value corresponding to the upper boundary marker formation at offset X, DT is the boundary time delay, T1(0) is the time value of the upper boundary zero offset, V1 is the upper boundary average velocity, and X is the offset.

9. The pre-stack space-time hyperbolic time window picking method according to claim 1, characterized in that: In step 4, the horizon is picked along the lower boundary marker stratum on the stacked section and counted into the trace header T2(0).

10. The pre-stack space-time hyperbolic time window picking method according to claim 9, characterized in that: In step 4, when there is a previous geological layer file, the layer can be directly read.

11. The pre-stack space-time hyperbolic time window picking method according to claim 1, characterized in that: In step 5, the trace header T2(0) is exported, and a layer file is formed by interpolation or the lower boundary layer file is directly read. The layer is projected into the stacking velocity field, and the stacking velocity of the layer is counted as the average velocity V2 of the lower boundary marker formation.

12. The pre-stack space-time hyperbolic time window picking method according to claim 1, characterized in that: In step 6, a hyperbolic operation is performed on the single shot data according to the upper boundary average velocity V2 and the upper boundary layer time value T2(0) in combination with the current track offset X to obtain the upper boundary T2(X) of the hyperbolic time window before the spatiotemporal stacking and count it into the current track header.

13. The pre-stack space-time hyperbolic time window picking method according to claim 12, characterized in that: In step 6, the calculation formula of T2(X) is: Where T2(X) is the time value corresponding to the lower boundary marker formation at offset X, DT is the boundary time delay, T2(0) is the time value of the lower boundary zero offset, V2 is the lower boundary average velocity, and X is the offset.

14. The pre-stack space-time hyperbolic time window picking method according to claim 1, characterized in that: In step 7, the upper boundary trace head T1(X) and the lower boundary trace head T2(X) obtained on the single shot are used as the lower boundary to generate a pre-stack space-variant hyperbolic time window corresponding to the single shot.

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