Oil gas detection method based on AVO attribute

Abstract

The invention provides an AVO attribute-based oil and gas detection method. The method comprises the following steps of: acquiring seismic data by adopting a two-width and one-height mode; performing OVT domain data processing on the seismic data, and extracting offset and azimuth angle information of the corresponding seismic data to obtain a spiral gather; co-azimuth amplitude superposition is carried out on the seismic data based on azimuth angle information in the spiral gather, and the two-way travel time of each group of co-azimuth amplitude superposition data is calculated; comparing the two-way travel time of each group of common-azimuth amplitude superposition data so as to determine a sensitive azimuth; determining near offset amplitude superposition energy and far offset amplitude superposition energy in the sensitive orientation according to a preset offset range; calculating an energy difference value between the near-offset amplitude superposition energy and the far-offset amplitude superposition energy to obtain a sensitive azimuth AVO attribute; and oil gas detection is carried out based on the sensitive orientation AVO attribute. By utilizing the AVO attribute, more gathers beneficial to oil gas detection can participate in calculation, so that the oil gas detection result is more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploration, and in particular to an oil and gas detection method based on AVO attributes. Background Art

[0002] AVO (Amplitude Versus Offset) technology was originally developed for natural gas exploration and was initially only used to qualitatively determine the gas-bearing property of formations. However, with in-depth research, it was found that the amplitude of common reflection point gathers not only changes with the incident angle but also with the azimuth angle, showing vector properties. That is to say, the change in AVO azimuth is closely related to formation anisotropy, so the method of using AVO attributes to identify reservoir fractures came into being. The AVO attributes and determination methods used in traditional technologies include:

[0003] 1) Conventional AVO attributes and their determination methods: Analyze the change in the amplitude of seismic wave data in each common reflection point gather with respect to the offset to determine the AVO attributes, and then obtain the conventional AVO attributes by taking the average of the AVO attributes of all common reflection point gathers; this method will mask information sensitive to oil and gas reservoirs.

[0004] 2) AVO attributes of partial azimuth gathers and their determination methods: First, determine the main fracture direction in the work area, select the azimuth gathers in the direction parallel to the main fracture direction for stacking, and then perform AVO analysis (for example: if the fracture is in the south-west direction, select the azimuth gathers within a certain range in the south-west direction for stacking and then perform AVO analysis), so as to only analyze the change in the amplitude of a part of the gathers with respect to the offset for oil and gas detection. Although this method reduces the influence of some fractures on oil and gas detection to a certain extent, it also misses a lot of useful gather information, and the fracture direction at each point underground changes continuously with depth. The AVO analysis of partial azimuth gathers implemented only based on the fracture direction at a certain depth underground cannot completely avoid the interference of fractures on seismic wave data.

[0005] Therefore, there is an urgent need in the art for reservoir fracture identification methods using some new AVO attributes. Summary of the Invention

[0006] In order to retain more of the most sensitive information about oil and gas reservoirs, the present invention proposes an oil and gas detection method based on AVO attributes. The method includes: collecting seismic data in a two-wide-one-high manner; performing OVT domain data processing on the seismic data, and extracting the offset and azimuth information of the corresponding seismic data to obtain a spiral gather; performing common-azimuth amplitude stacking on the seismic data based on the azimuth information in the spiral gather, and calculating the two-way travel time of each group of common-azimuth amplitude stacking data; comparing the magnitudes of the two-way travel times of each group of common-azimuth amplitude stacking data to determine the sensitive azimuth, where the sensitive azimuth includes one or more azimuth angles; determining the near-offset amplitude stacking energy and the far-offset amplitude stacking energy on the sensitive azimuth according to a preset offset range; calculating the energy difference between the near-offset amplitude stacking energy and the far-offset amplitude stacking energy to obtain the AVO attribute of the sensitive azimuth; and performing oil and gas detection based on the AVO attribute of the sensitive azimuth.

[0007] In one or more embodiments, the comparing the magnitudes of the two-way travel times of each group of common-azimuth amplitude stacking data to determine the sensitive azimuth includes: comparing the magnitudes of the two-way travel times of each group of common-azimuth amplitude stacking data; and determining the azimuth corresponding to the minimum two-way travel time as the sensitive azimuth.

[0008] In one or more embodiments, the determining the near-offset amplitude stacking energy and the far-offset amplitude stacking energy on the sensitive azimuth according to a preset offset range includes: determining a near-offset range and a far-offset range according to the preset offset range; performing common-azimuth amplitude stacking on the seismic data within the near-offset range to obtain the near-offset amplitude stacking energy; and performing common-azimuth amplitude stacking on the seismic data within the far-offset range to obtain the far-offset amplitude stacking energy.

[0009] In one or more embodiments, the calculating the energy difference between the near-offset amplitude stacking energy and the far-offset amplitude stacking energy to obtain the AVO attribute of the sensitive azimuth includes: calculating the energy difference between the near-offset amplitude stacking energy and the far-offset amplitude stacking energy at the azimuth corresponding to the minimum two-way travel time to obtain the AVO attribute of the reservoir sensitive azimuth.

[0010] In one or more embodiments, the AVO-attribute-based oil and gas detection method of the present invention further includes: determining the near-offset amplitude stack energy and the far-offset amplitude stack energy in each azimuth according to a preset offset range, and calculating the energy difference between the near-offset amplitude stack energy and the far-offset amplitude stack energy in each azimuth; comparing the energy differences between the near-offset amplitude stack energy and the far-offset amplitude stack energy in all common azimuths, determining the maximum value of the energy differences as the azimuth maximum AVO attribute, and determining the minimum value of the energy differences as the azimuth minimum AVO attribute; performing oil and gas detection based on the azimuth maximum AVO attribute and / or the azimuth minimum AVO attribute.

[0011] In one or more embodiments, the spiral gather contains seismic data in the 0° to 360° directions reflected from reflection points at different depths on the same vertical line.

[0012] In one or more embodiments, the determining the near-offset amplitude stack energy and the far-offset amplitude stack energy in each azimuth according to a preset offset range, and calculating the energy difference between the near-offset amplitude stack energy and the far-offset amplitude stack energy in each azimuth includes: dividing a plurality of seismic data in the corresponding azimuth into near-offset seismic data and far-offset seismic data based on the offset of each seismic data and the preset offset range; performing common-azimuth amplitude stacking on the near-offset seismic data to obtain the near-offset amplitude stack energy; performing common-azimuth amplitude stacking on the far-offset seismic data to obtain the far-offset amplitude stack energy.

[0013] In one or more embodiments, the comparing the energy differences between the near-offset amplitude stack energy and the far-offset amplitude stack energy in all common azimuths, determining the maximum value of the energy differences as the azimuth maximum AVO attribute, and determining the minimum value of the energy differences as the azimuth minimum AVO attribute includes: comparing the magnitudes of the energy differences between the near-offset amplitude stack energy and the far-offset amplitude stack energy in the 0° to 360° directions; determining the maximum energy difference as the azimuth maximum AVO attribute; determining the minimum energy difference as the azimuth minimum AVO attribute.

[0014] In one or more embodiments, the AVO-attribute-based oil and gas detection method of the present invention further includes determining the offset range through the following steps: regularizing the offset-azimuth domain data of the spiral gather; determining the near-offset range and the far-offset range according to the offset distribution after regularization.

[0015] The oil and gas detection method based on AVO attributes of the present invention further includes: before performing common azimuth amplitude stacking on seismic data based on the azimuth information in the spiral gather, performing prestack data regularization on the seismic data, and the prestack data regularization includes bin homogenization or amplitude normalization based on the number of coverage times.

[0016] The beneficial effects of the present invention include: the present invention analyzes the gathers in each azimuth from 0° to 360° of each common reflection point in the spiral gather seismic data volume. First, the two-way travel time of the common azimuth amplitude stacking data in each azimuth from 0° to 360° is calculated to determine the AVO attributes in the sensitive azimuth, and then the extreme value of the energy difference between the near-offset amplitude stacking energy and the far-offset amplitude stacking energy of the common azimuth amplitude stacking data in each azimuth from 0° to 360° is compared to determine the maximum azimuth AVO attribute and the minimum azimuth AVO attribute. Using the AVO attributes determined in the above manner for seismic analysis can effectively avoid the problem that the AVO attributes of some azimuth gathers will cause the gathers that are not conducive to oil and gas detection to participate in the calculation, and make more gathers that are conducive to oil and gas detection participate in the calculation, making the oil and gas detection results more accurate. Brief Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other embodiments can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is the working flow chart of an oil and gas detection method based on AVO attributes according to an embodiment of the present invention;

[0019] Figure 2 It is the comparative analysis chart of the acquisition methods of the conventional AVO attributes, the reservoir sensitive azimuth AVO attributes, the maximum azimuth AVO attribute, and the minimum azimuth AVO attribute of the present invention;

[0020] Figure 3 It is the detection imaging result of the C2b layer section of Well SM03 in a known oil and gas field using the conventional AVO attributes according to an embodiment of the present invention;

[0021] Figure 4 It is the detection imaging result of the C2b layer section of Well SM03 in a known oil and gas field using the fault sensitive azimuth according to an embodiment of the present invention;

[0022] Figure 5 It is the detection imaging result of the C2b layer section of Well SM03 in a known oil and gas field using the reservoir sensitive azimuth AVO attributes according to an embodiment of the present invention;

[0023] Figure 6 The detection imaging result of the C2b interval of Well SM03 in a known oil and gas field using the maximum azimuth AVO attribute according to an embodiment of the present invention;

[0024] Figure 7 The detection imaging result of the C2b interval of Well SM03 in a known oil and gas field using the minimum azimuth AVO attribute according to an embodiment of the present invention. Specific Embodiments

[0025] To make the objectives, technical solutions and advantages of the present invention more clear and understandable, the following further describes the embodiments of the present invention in detail with reference to specific embodiments and the accompanying drawings.

[0026] It should be noted that all the expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities or non-identical parameters with the same name. It can be seen that "first" and "second" are only for the convenience of expression and should not be construed as a limitation on the embodiments of the present invention. This will not be elaborated in the subsequent embodiments one by one.

[0027] In order to retain more information most sensitive to oil and gas reservoirs, in some of the following embodiments, the present invention proposes an oil and gas detection method based on AVO attributes. By calculating the common-azimuth stack results at multiple azimuths from 0° to 360° based on the common reflection point spiral gather, and determining multiple AVO attribute combinations in the direction most sensitive to the oil and gas reservoir in multiple ways from the multiple common-azimuth stack results to retain more information most sensitive to the oil and gas reservoir. The following will combine the accompanying drawings to understand the technical solution of the present invention.

[0028] Please refer to the attached Figure 1 , which shows the workflow of an oil and gas detection method based on AVO attributes according to an embodiment of the present invention, including: Step S1, acquiring seismic data in the two-wide-one-high mode; Step S2, performing OVT domain data processing on the seismic data, and extracting the offset and azimuth information of the corresponding seismic data to obtain a spiral gather; Step S3, performing common-azimuth amplitude stacking on the seismic data based on the azimuth information in the spiral gather, and calculating the two-way travel time of each group of common-azimuth amplitude stacking data; Step S4, comparing the magnitudes of the two-way travel times of each group of common-azimuth amplitude stacking data to determine the sensitive azimuth, and the sensitive azimuth includes one or more azimuth angles; Step S5, determining the near-offset amplitude stacking energy and the far-offset amplitude stacking energy in the sensitive azimuth according to a preset offset range; Step S6, calculating the energy difference between the near-offset amplitude stacking energy and the far-offset amplitude stacking energy to obtain the sensitive azimuth AVO attribute; Step S7, performing oil and gas detection based on the sensitive azimuth AVO attribute.

[0029] Specifically, compared with the conventional 3D seismic recording acquisition technology, the "two-width and one-height" seismic recording acquisition technology emphasizes more on accuracy and fidelity. Instead of aiming to improve the quality of single-shot record data, it mainly aims to reflect the characteristics of full (wide) azimuth, full (wide) frequency band, high density, high coverage, and full wave field. Among them, full (wide) azimuth means collecting seismic records using a wide-azimuth observation system with an aspect ratio greater than 0.5. When the aspect ratio is 1, it is an omnidirectional acquisition observation system, that is, uniform acquisition at each azimuth angle. Full (wide) frequency band means aiming to broaden the high and low frequency bands of the seismic wave and enhance the effective octave of the seismic system, paying attention to the excitation and reception of seismic information at the high and low frequency ends and frequency extension processing, and using single-point small charge excitation and single-point digital geophone reception according to local conditions. High density means increasing the spatial sampling density in the field, reducing the surface element scale, and increasing the effective coverage times of the target layer to achieve high coverage, ensuring alias-free sampling of various wave fields, making the surface element attributes uniform, and combining point acquisition technology to ensure the fidelity of seismic information through point excitation and point reception acquisition. For step S1, the common reflection point gather obtained by the "two-width and one-height" method will contain seismic data propagating in all directions (0° to 360°) centered on a certain reflection point, which is also the basis for the implementation of the technical solution of the present invention.

[0030] For step S2, OVT domain extraction is a data partitioning method that is used for the "two-width and one-height" seismic data to comprehensively consider the optimization results of azimuth and offset. The OVT domain data partitioning is carried out based on the cross-equalization gather. The collected seismic records are extracted into a single-fold cross-equalization arrangement gather according to the common shot line and common receiver line, and then OVT slices are partitioned and numbered according to the offset and receiver line distance. Finally, the same OVT slices in each cross-equalization gather are extracted into the same OVT subset, and then a spiral gather is obtained through steps such as pre-stack processing of the OVT domain gather and pre-stack migration of the OVT domain gather. Among them, since the OVT subset is a set of seismic traces controlled within a certain range of offset and azimuth, the spiral gather has the characteristic of uniform sampling in space, and adjacent traces have good coherence. More specifically, the characteristic of uniform sampling in space of the spiral gather is specifically manifested as that the spiral gather contains seismic data at different formation depths in multiple azimuths from 0° to 360°.

[0031] For step S3, different from the traditional technology, in this embodiment, it no longer takes the fracture direction at a certain depth point as the reference and only stacks the gather data formed in a specific direction (such as the vertical fracture direction), but utilizes the characteristics of the anisotropic seismic data contained in the spiral gather, and stacks in each direction within the azimuth range of 360° existing in the spiral gather. By using the stacking result - the two-way travel time of each group of common-azimuth amplitude stacking data, the direction most sensitive to the oil and gas reservoir is found, so as to achieve the purpose of retaining more seismic data sensitive to the oil and gas reservoir. Specifically, the specific method of performing common-azimuth amplitude stacking in step S3 can be to perform common-azimuth amplitude stacking based on each azimuth angle. When the seismic data at this azimuth is too small, it can be further considered to perform common-azimuth amplitude stacking of the seismic data at the azimuth angle adjacent to this azimuth angle with the seismic data at this azimuth angle. Therefore, the sensitive azimuth determined by using the two-way travel time after common-azimuth amplitude stacking can include one azimuth angle or multiple azimuth angles.

[0032] In one embodiment, the specific process of step S4 for comparing the two-way travel times of each group of common-azimuth amplitude stacking data to determine the sensitive azimuth includes: comparing the two-way travel times of each group of common-azimuth amplitude stacking data; determining the azimuth corresponding to the minimum two-way travel time as the sensitive azimuth; The specific steps of step S5 for determining the near-offset amplitude stacking energy and the far-offset amplitude stacking energy on the sensitive azimuth according to the preset offset range include: determining the near-offset range and the far-offset range according to the preset offset range; performing common-azimuth amplitude stacking on the seismic data within the near-offset range to obtain the near-offset amplitude stacking energy; performing common-azimuth amplitude stacking on the seismic data within the far-offset range to obtain the far-offset amplitude stacking energy; Step S6, calculating the energy difference between the near-offset amplitude stacking energy and the far-offset amplitude stacking energy to obtain the AVO attribute of the sensitive azimuth, including: calculating the energy difference between the near-offset amplitude stacking energy and the far-offset amplitude stacking energy at the azimuth corresponding to the minimum two-way travel time to obtain the AVO attribute of the reservoir-sensitive azimuth. In the process of using step S4 to determine the sensitive azimuth above, the azimuth corresponding to the maximum two-way travel time can also be determined, and this azimuth is the fault-sensitive azimuth and can be used for fault detection. Among them, the offset range is determined in advance by regularizing the offset-azimuth domain data of the spiral gather; and then the near-offset range and the far-offset range are determined according to the offset distribution after regularization.

[0033] In a further embodiment, in order to utilize more seismic data sensitive to oil and gas, in addition to using the AVO attributes in the sensitive azimuth, the embodiment of the present invention also proposes to determine the azimuth maximum AVO attribute and the azimuth minimum AVO attribute by comparing the extreme values of the energy differences between the near-offset amplitude stack energy and the far-offset amplitude stack energy of the common-azimuth amplitude stack data in each azimuth from 0° to 360°. The specific steps are as follows: Determine the near-offset amplitude stack energy and the far-offset amplitude stack energy in each azimuth according to a preset offset range, and calculate the energy difference between the near-offset amplitude stack energy and the far-offset amplitude stack energy in each azimuth; Compare the energy differences between the near-offset amplitude stack energy and the far-offset amplitude stack energy in all common-azimuths, determine the maximum value of the energy differences as the azimuth maximum AVO attribute, and determine the minimum value of the energy differences as the azimuth minimum AVO attribute; Perform oil and gas detection based on the azimuth maximum AVO attribute and / or the azimuth minimum AVO attribute. In an optional embodiment, the present invention can perform oil and gas detection using the above-mentioned sensitive azimuth AVO attributes, azimuth maximum AVO attributes, and / or azimuth minimum AVO attributes.

[0034] In a further embodiment, the spiral gather contains seismic data in the 0° to 360° direction reflected from reflection points at different depths on the same vertical line. Specifically, the azimuth maximum AVO attribute and the azimuth minimum AVO attribute determined by the method of this embodiment are obtained by extreme value screening from the energy differences of many azimuths, which represent the azimuths with the largest geological structure changes among many azimuths, such as the existence of large fractures. And since the seismic data in this embodiment is collected by geophones arranged at different formation depths, it is possible to detect different formation depths of 360°, and to understand the interference of fractures at different depths on the seismic wave data, so as to perform targeted denoising on each seismic data.

[0035] In a further embodiment, determining the near-offset amplitude stack energy and the far-offset amplitude stack energy in each azimuth according to a preset offset range, and calculating the energy difference between the near-offset amplitude stack energy and the far-offset amplitude stack energy in each azimuth includes: Dividing the multiple seismic data in the corresponding azimuth into near-offset seismic data and far-offset seismic data based on the offset of each seismic data and the preset offset range; Performing common-azimuth amplitude stacking on the near-offset seismic data to obtain the near-offset amplitude stack energy; Performing common-azimuth amplitude stacking on the far-offset seismic data to obtain the far-offset amplitude stack energy.

[0036] In a further embodiment, energy differences between near-offset amplitude stacking energies and far-offset amplitude stacking energies in all common azimuths are compared, a maximum value among the energy differences is determined as the azimuth maximum AVO attribute, and a minimum value among the energy differences is determined as the azimuth minimum AVO attribute, including: comparing the energy differences between near-offset amplitude stacking energies and far-offset amplitude stacking energies in the directions of 0° to 360°; determining the maximum energy difference as the azimuth maximum AVO attribute; and determining the minimum energy difference as the azimuth minimum AVO attribute.

[0037] See also Figure 2 , which shows the comparative analysis of the conventional AVO attribute, reservoir sensitive azimuth AVO attribute, maximum azimuth AVO attribute and minimum azimuth AVO attribute acquisition methods of the present invention. Figure 2 As shown, compared with the acquisition method of the azimuthal maximum / minimum AVO attributes of the present invention, the conventional AVO attributes will not perform co-azimuthal superposition of near-offset and far-offset distances respectively, nor will they perform extreme value screening, so as to determine a set of azimuthal maximum / minimum AVO attributes with opposite attributes; and compared with the reservoir sensitive azimuthal AVO attributes of the present invention, the conventional AVO attributes will not judge the sensitive azimuth; and the acquisition methods of the above three AVO attributes of the present invention are different from the traditional acquisition methods of the AVO attributes of partial azimuthal gathers. The judgment of the sensitive azimuth of the present invention is not limited to the direction of the fracture, but a more reasonable judgment is made by actually comparing the two-way travel time of the amplitude superposition energy in different azimuths.

[0038] In a further embodiment, before performing co-azimuth amplitude stacking on seismic data based on each azimuth, pre-stack data regularization is performed on the seismic data, and the pre-stack data regularization includes bin averaging or amplitude normalization based on the number of coverages. Pre-stack regularization can effectively remove abnormal data in the seismic data, so that the co-azimuth stacking effect is better.

[0039] Practical application to the known oil and gas field SM03 well

[0040] In this example, the detection effects of various AVO attributes are as follows: it has been proven that the C2b layer of the SM03 well is a gas-bearing layer. The prediction results using conventional AVO attributes and partial azimuth gather AVO attributes do not contain gas, and the prediction fails; while the minimum azimuth AVO attribute, the maximum azimuth AVO attribute, and the reservoir sensitive azimuth AVO attribute can all predict that the C2b layer of the SM03 well contains gas. For specific detection results, please refer to Figures 3 - 7 , which respectively show the detection imaging results of the C2b layer segment using conventional AVO attributes, fault-sensitive azimuth AVO attributes, reservoir-sensitive azimuth AVO attributes, maximum azimuth AVO attributes, and minimum azimuth AVO attributes in the embodiment of the present invention. Figures 3 - 7It can be seen that the imaging result using the reservoir-sensitive azimuth AVO attribute - Figure 5 , is significantly better than the imaging results obtained using other AVO attributes, indicating that the reservoir-sensitive azimuth AVO attribute can effectively detect oil and gas in the reservoir; while the imaging result using the fault-sensitive azimuth AVO attribute - Figure 4 shows that the C2b layer section contains no gas and the prediction fails, which verifies from the side that the fault-sensitive azimuth data is not applicable to oil and gas detection.

[0041] The above are exemplary embodiments disclosed by the present invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments disclosed by the present invention as defined by the claims. The functions, steps, and / or actions of the method claims according to the disclosed embodiments herein do not need to be performed in any specific order. In addition, although the elements disclosed by the embodiments of the present invention can be described or claimed in individual form, they can also be understood as plural unless explicitly limited to the singular.

[0042] It should be understood that, as used herein, unless the context clearly supports the exception, the singular form "a" is also intended to include the plural form. It should also be understood that the "and / or" used herein refers to any and all possible combinations of one or more of the associated listed items.

[0043] The serial numbers of the disclosed embodiments of the present invention above are only for description and do not represent the superiority or inferiority of the embodiments.

[0044] Those of ordinary skill in the art should understand that: the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the embodiments disclosed by the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features between the above embodiments or different embodiments can also be combined, and there are many other variations in different aspects of the embodiments of the present invention as above, which are not provided in detail for the sake of brevity. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present invention shall be included in the protection scope of the embodiments of the present invention.

Claims

1. An oil and gas detection method based on AVO attributes, characterized in that, The method includes: Collecting seismic data in a two-wide-one-high manner; Performing OVT domain data processing on the seismic data, and extracting offset and azimuth information of the corresponding seismic data to obtain a spiral gather; Performing common-azimuth amplitude stacking on the seismic data based on the azimuth information in the spiral gather, and calculating the two-way travel time of each group of common-azimuth amplitude stacked data; Comparing the two-way travel times of each group of common-azimuth amplitude stacked data to determine the sensitive azimuth, where the sensitive azimuth includes one or more azimuth angles; Determining the near-offset amplitude stacked energy and the far-offset amplitude stacked energy on the sensitive azimuth according to a preset offset range; Calculating the energy difference between the near-offset amplitude stacked energy and the far-offset amplitude stacked energy to obtain the AVO attribute of the sensitive azimuth; Performing oil and gas detection based on the AVO attribute of the sensitive azimuth.

2. The oil and gas detection method based on AVO attributes according to claim 1, characterized in that, The comparing the two-way travel times of each group of common-azimuth amplitude stacked data to determine the sensitive azimuth includes: Comparing the two-way travel times of each group of common-azimuth amplitude stacked data, and determining the azimuth corresponding to the minimum two-way travel time as the sensitive azimuth.

3. The oil and gas detection method based on AVO attributes according to claim 2, characterized in that, The determining the near-offset amplitude stacked energy and the far-offset amplitude stacked energy on the sensitive azimuth according to a preset offset range includes: Determining a near-offset range and a far-offset range according to a preset offset range; Performing common-azimuth amplitude stacking on the seismic data within the near-offset range to obtain the near-offset amplitude stacked energy; Performing common-azimuth amplitude stacking on the seismic data within the far-offset range to obtain the far-offset amplitude stacked energy.

4. The oil and gas detection method based on AVO attributes according to claim 3, characterized in that, The calculating the energy difference between the near-offset amplitude stacked energy and the far-offset amplitude stacked energy to obtain the AVO attribute of the sensitive azimuth includes: Calculating the energy difference between the near-offset amplitude stacked energy and the far-offset amplitude stacked energy at the azimuth corresponding to the minimum two-way travel time to obtain the AVO attribute of the reservoir sensitive azimuth.

5. The oil and gas detection method based on AVO attributes according to claim 1, characterized in that, The method further includes: Determining the near-offset amplitude stacked energy and the far-offset amplitude stacked energy at each azimuth according to a preset offset range, and calculating the energy difference between the near-offset amplitude stacked energy and the far-offset amplitude stacked energy at each azimuth; Comparing the energy differences between the near-offset amplitude stacked energy and the far-offset amplitude stacked energy at all common-azimuths, determining the maximum value of the energy differences as the maximum AVO attribute of the azimuth, and determining the minimum value of the energy differences as the minimum AVO attribute of the azimuth; Performing oil and gas detection based on the maximum AVO attribute of the azimuth and / or the minimum AVO attribute of the azimuth.

6. The oil and gas detection method based on AVO attributes according to claim 5, characterized in that, The spiral gather contains seismic data in the 0° to 360° direction reflected from reflection points at different depths on the same vertical line.

7. The oil and gas detection method based on AVO attributes according to claim 5, characterized in that, The determining the near-offset amplitude stacked energy and the far-offset amplitude stacked energy at each azimuth according to a preset offset range, and calculating the energy difference between the near-offset amplitude stacked energy and the far-offset amplitude stacked energy at each azimuth includes: Dividing the multiple seismic data at the corresponding azimuth into near-offset seismic data and far-offset seismic data based on the offset of each seismic data and the preset offset range; Performing common-azimuth amplitude stacking on the near-offset seismic data to obtain near-offset amplitude stacked energy; Performing common-azimuth amplitude stacking on the far-offset seismic data to obtain far-offset amplitude stacked energy.

8. The oil and gas detection method based on AVO attributes according to claim 7, characterized in that, The comparing the energy differences between the near-offset amplitude stacked energy and the far-offset amplitude stacked energy at all common azimuths, determining the maximum value in the energy differences as the azimuth maximum AVO attribute, and determining the minimum value in the energy differences as the azimuth minimum AVO attribute includes: Comparing the magnitudes of the energy differences between the near-offset amplitude stacked energy and the far-offset amplitude stacked energy in the direction of 0° to 360°; Determining the maximum energy difference as the azimuth maximum AVO attribute; Determining the minimum energy difference as the azimuth minimum AVO attribute.

9. The oil and gas detection method based on AVO attributes according to claim 1, characterized in that, The method further includes determining the offset range through the following steps: Regularizing the offset-azimuth domain data of the spiral gather; Determining the near-offset range and the far-offset range according to the offset distribution after regularization.

10. The oil and gas detection method based on AVO attributes according to claim 1, characterized in that, The method further includes: before performing common-azimuth amplitude stacking on the seismic data based on the azimuth angle information in the spiral gather, Performing pre-stack data regularization on the seismic data, where the pre-stack data regularization includes bin homogenization or amplitude normalization based on the fold number.

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