A method and system for identifying abandoned channels and deterioration zones inside a river sand body

Abstract

The application discloses a method for identifying abandoned river channels and deterioration zones in sand bodies in a river channel, and comprises the following steps: selecting original seismic data, and establishing a fine isochronous stratigraphic framework of well-seismic combination in a typical block; on the basis of the fine isochronous stratigraphic framework, geological parameters of different types of sand bodies are extracted, a forward modeling model based on distribution characteristics of different types of sand bodies in a target layer is established, and forward modeling is completed; according to the forward modeling result, seismic response characteristics of a point bar, an abandoned river channel and a deterioration zone in the point bar are analyzed; the spectrum of a seismic attribute volume in the original seismic data is converted from a time domain to a frequency domain; according to the seismic response characteristics, a plurality of single-frequency volumes are selected from the converted seismic attribute volume; RGB attribute fusion is performed on the plurality of single-frequency volumes; and according to an obtained RGB attribute fusion image, the point bar, the abandoned river channel and the deterioration zone are identified. The application is based on forward modeling, and the wave group characteristics of the abandoned river channel and the deterioration zone are clear, so that longitudinal profile identification of the abandoned river channel and the deterioration zone is realized.

Description

Technical Field

[0001] This invention belongs to the field of oilfield reservoir configuration prediction technology, and in particular relates to a method and system for identifying abandoned channels and variation zones inside channel sand bodies. Background Technology

[0002] As oilfield development progresses, the distribution of remaining oil becomes increasingly fragmented, leading to a greater need for detailed reservoir analysis. Meandering river deposits, as important fluvial reservoirs, rely heavily on the identification of abandoned channels and degradation zones for efficient development of remaining oil potential. An abandoned channel refers to a section of a river that gradually or abruptly ceases operation during its evolution, later filled with mud. A degradation zone refers to the area within the point-bar sand bodies within a meandering river where the physical properties deteriorate. The presence of abandoned channels and degradation zones can create seepage barriers during water injection into individual sand bodies within the channel, resulting in an imbalance between injection and production, and consequently, the formation of remaining oil. Therefore, improving the accuracy of identifying abandoned channels and degradation zones within river sand bodies can provide reliable geological data for oilfield development adjustments and the tapping of remaining oil potential.

[0003] Existing technologies have limited research on the identification of variation zones. There are two main categories of methods for identifying abandoned channels within channel sand bodies. The first category is abandoned channel identification technology based on well point data, specifically divided into two techniques: one is based on the characteristics of well logging curves, generally selecting spontaneous potential curves and resistivity curves, and identifying abandoned channels based on their specific response characteristics; the other is based on sand top data from well points, using the mudstone thickness between the sand top and the top surface of a small layer to predict abandoned channels, with areas of greater thickness indicating favorable locations for abandoned channel development. The second category is abandoned channel identification technology based on seismic attribute slices. This involves extracting seismic slices sensitive to lithological changes, identifying high-value areas as point bars, analyzing the seismic waveform profiles at their boundaries, and then identifying abandoned channels.

[0004] In summary, the existing technology has the following problems:

[0005] In the first type of method, identifying abandoned channels based on well point data has high vertical resolution. However, its accuracy depends on the density of the well point data; the fewer the well points, the greater the ambiguity in the inter-well distribution of abandoned channels. Therefore, limited by the lateral resolution of the well point data, it is difficult to determine the boundaries and planar combinations of abandoned channels. In the second type of method, identifying abandoned channels using along-layer amplitude attribute slices requires manual adjustment of the color scale of the attribute slices to highlight channel characteristics. If the color scale adjustment is unreasonable, it can easily create sedimentary artifacts, requiring a high level of seismic interpretation skills from the technicians. In addition, amplitude attribute slices cannot predict the variation zones within composite channel sand bodies, and the identified abandoned channels are discontinuous and have unclear boundaries on the plane, especially indistinguishable from inter-channel information, requiring further manual analysis, which is a significant workload.

[0006] To address the aforementioned issues, this patent proposes a method and system for identifying abandoned river channels and variation zones within river sand bodies. Summary of the Invention

[0007] To overcome the shortcomings of the existing technology, the present invention aims to solve the problems of inaccurate identification of abandoned channels and difficulty in identifying variability zones in reservoir configuration research. To achieve the above objective, the present invention provides the following technical solution:

[0008] A method for identifying abandoned channels and variation zones within river sand bodies includes the following steps:

[0009] Select raw seismic data and establish a fine isochronous stratigraphic framework combining well-seismic data for typical blocks;

[0010] Based on the detailed isochronous stratigraphic framework, geological parameters of different types of sand bodies are extracted, and a forward modeling model based on the distribution characteristics of different types of sand bodies in the target interval is established to complete the forward modeling simulation.

[0011] Based on the forward modeling results, the seismic response characteristics of the point dam and its internal abandoned river channels and variability zones are analyzed.

[0012] Convert the seismic attribute volume spectrum in the original seismic data from the time domain to the frequency domain;

[0013] Based on the seismic response characteristics, select several single-frequency volumes from the transformed seismic attribute volumes;

[0014] Perform RGB attribute fusion on several single-frequency volumes;

[0015] Based on the obtained RGB attribute fusion map, point dams, abandoned river channels, and variation zones are identified.

[0016] Furthermore, the selection of raw seismic data specifically includes: conducting a quality survey of the raw seismic data, and selecting data that meets the preset conditions or the target segment with the optimal signal-to-noise ratio based on the survey results.

[0017] Furthermore, the seismic response characteristics are selected from several single-frequency volumes in the transformed seismic attribute volume, including the following steps:

[0018] Determine the cyclic characteristics of different lithologies on well logging curves to identify the sedimentary microfacies of the target layer;

[0019] Conduct detailed reservoir calibration and analyze the seismic reflection characteristics of reservoirs with different microfacies, lithologies, and thickness levels;

[0020] Sensitive frequency bands for frequency domain seismic attribute volumes were selected for reservoirs with different microfacies, lithologies, and thickness levels.

[0021] Find the optimal frequency bands of reservoirs with different microfacies, lithology, and thickness levels, and then screen out the sensitive frequency bands of point dams, abandoned channels, and variation zones in the target layer.

[0022] Furthermore, when selecting several single-frequency volumes from the transformed seismic attribute volumes based on seismic response characteristics, three single-frequency volumes are selected.

[0023] Furthermore, when performing RGB attribute fusion, the three single-frequency bodies correspond to the three primary colors respectively.

[0024] Furthermore, when converting the seismic attribute volume spectrum from the time domain to the frequency domain, a time window is selected based on the frequency; the higher the frequency, the shorter the time window.

[0025] Furthermore, when converting the seismic attribute volume spectrum from the time domain to the frequency domain, wavelet transform technology is used.

[0026] Furthermore, when performing wavelet transform, the following formula is used for calculation:

[0027]

[0028] Where: f(t) is the signal; t is time; Ψ is the mother wavelet; τ is the Fourier transform of the mother wavelet; σ is the time shift factor; σ is the scaling factor; Ψ σ,τ (t) represents the basic wavelet; F w (σ,τ) is the wavelet transform of f(t).

[0029] Furthermore, when identifying point dams, abandoned channels, and variability zones, based on a geological concept model of modern sedimentation, and constrained by well point logging curve facies patterns, the microfacies types of geological bodies represented by different colors are determined by combining wave group characteristics on different geological body profiles and distribution characteristics on the plane, ultimately identifying point dams, abandoned channels, and variability zones.

[0030] Furthermore, after identifying point dams, abandoned channels, and variation zones, a quantitative relationship between point dams and abandoned channels within high-low meandering channels is established.

[0031] Furthermore, the steps to establish a quantitative relationship between point dams and abandoned channels within high- to low-slender meandering rivers include:

[0032] Obtain the actual length and width of the prototype geological model from the original seismic data, including: river channel length, river channel width, valley length, and valley width;

[0033] Based on the ratio of river channel length to valley length, low-meandering rivers and high-meandering rivers can be identified.

[0034] Quantitative relationships were established between the length and width of point dams in meandering rivers at different elevations and widths of abandoned river channels.

[0035] A system for identifying abandoned channels and variation zones within river sand bodies, comprising:

[0036] Storage module, used to store raw seismic data;

[0037] The isochronous stratigraphic grid module is used to establish an isochronous stratigraphic grid based on the original seismic data.

[0038] The parameter extraction module is used to extract geological parameters of different types of sand bodies based on a fine isochronous stratigraphic framework.

[0039] The forward modeling module is used to establish and complete forward modeling simulations based on the isochronous stratigraphic framework.

[0040] The results analysis module is used to analyze the seismic response characteristics of the point dam and its internal abandoned river channels and variability zones based on the forward modeling results.

[0041] The wavelet frequency division module is used to convert the seismic attribute volume spectrum in the original seismic data from the time domain to the frequency domain.

[0042] The RGB attribute fusion module is used to perform RGB attribute fusion on the spectrum of the converted seismic attribute volume.

[0043] The identification module is used to identify point dams, abandoned river channels, and variation zones based on the RGB attribute fusion map.

[0044] Furthermore, the wavelet frequency division module includes a calculation module for calculating the basic wavelet and wavelet transform, and the specific calculation process is as follows:

[0045]

[0046] Where: f(t) is the signal; t is time; Ψ is the mother wavelet; τ is the Fourier transform of the mother wavelet; σ is the time shift factor; σ is the scaling factor; Ψ σ,τ (t) represents the basic wavelet; F w (σ,τ) is the wavelet transform of f(t).

[0047] The technical effects and advantages of this invention are as follows:

[0048] This application clarifies the wave group characteristics of abandoned river channels and variation zones based on forward modeling, and realizes the longitudinal profile identification of abandoned river channels and variation zones;

[0049] Based on an objective understanding of seismic resolution, this application leverages the advantage of high lateral seismic resolution and innovates wavelet frequency division RGB attribute fusion technology to achieve objective and accurate planar identification of abandoned channels and variability zones. This solves the problems of low lateral prediction accuracy of abandoned channels based on well point data and unclear boundaries of variability zones and abandoned channels when using conventional attribute slices in existing technologies. It further provides a reliable technical foundation for quantitative prediction and provides a geological model close to the underground geological prototype for accurate tapping of residual oil hidden by abandoned channels inside point dam sand bodies. Attached Figure Description

[0050] Figure 1 This is a flowchart of a method for identifying abandoned river channels and variation zones within river sand bodies according to the present invention.

[0051] Figure 2 This refers to the wavelet frequency division process in Example 1;

[0052] Figure 3 These are the results of the forward simulation in Example 1;

[0053] Figure 4 This refers to the wavegroup characteristics of the abandoned river channel within the dam in Example 1;

[0054] Figure 5 This refers to the differential band wave group characteristics within the dam in Example 1;

[0055] Figure 6 This is a diagram showing the earthquake attribute prediction results in the prior art of Example 1;

[0056] Figure 7 This is the RGB fusion image based on wavelet frequency division in Example 1;

[0057] Figure 8 This is a distribution map of the meandering river with high-low bends in Example 1;

[0058] Figure 9 This is the quantitative relationship of the river engineering parameters of the meandering river channel with high-low curvature in Example 1. Detailed Implementation

[0059] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Example 1:

[0061] like Figure 1 As shown, a method for identifying abandoned channels and variation zones within river sand bodies is as follows:

[0062] Step 1: Select raw seismic data and establish a fine isochronous stratigraphic framework combining well and seismic data for typical blocks;

[0063] Step 2: Extract geological parameters of different types of sand bodies, establish a forward model based on the distribution characteristics of different types of sand bodies in the target interval, and complete the forward modeling simulation;

[0064] Step 3: Based on the forward modeling results, analyze the seismic response characteristics of the point dam and its internal abandoned river channels and variation zones;

[0065] Step 4: Convert the seismic attribute volume spectrum from the time domain to the frequency domain;

[0066] Step 5: Select three single-frequency volumes from the seismic attribute volume spectrum based on the seismic response characteristics;

[0067] Step 6: Perform RGB attribute fusion on the seismic attribute volume spectrum;

[0068] Step 7: Identify point dams, abandoned river channels, and variation zones based on the obtained RGB attribute fusion map.

[0069] Specifically:

[0070] When selecting raw seismic data, a quality survey should be conducted first. Based on the survey results, the target layer with the best relative quality data or the best signal-to-noise ratio should be selected. Well logging, seismic and development dynamic data should be fully utilized to establish a fine isochronous stratigraphic framework for well-seismic co-location in typical blocks.

[0071] Based on the isochronous stratigraphic framework, and according to the stratigraphic development characteristics of the target section, a corresponding forward model is established. By extracting the impedance parameters of sandstone and mudstone, the forward simulation is completed, clarifying the seismic response of various geological bodies, such as... Figure 3 As shown.

[0072] Further utilize existing drilling data to analyze the wave group characteristics of abandoned river channels and variation zones: such as Figure 4 As shown, when horizontal well A encountered an abandoned river channel inside a dam, it exhibited increased amplitude energy; as... Figure 5 As shown, the horizontal well B encountered a variation zone inside the dam, where the energy of the same phase axis decreased and the energy of the variation zone increased.

[0073] By using wavelet frequency division technology, the original seismic data volume is transformed from the time domain to the frequency domain. Specifically:

[0074] Wavelet frequency division provides multi-scale resolution. Different time windows are used in the calculation: short time windows for high-frequency components and long time windows for low-frequency components, improving the resolution of reservoir responses across different frequency bands. The seismic data is processed and converted from the time domain to the frequency domain using the following formula. The amplitude spectrum in the frequency domain is then used to identify temporal thickness variations and sedimentary facies changes in the reservoir.

[0075]

[0076] Where: f(t) is the signal; t is time; Ψ is the mother wavelet; τ is the Fourier transform of the mother wavelet; σ is the time shift factor; σ is the scaling factor; Ψ σ,τ (t) represents the basic wavelet; F w (σ,τ) is the wavelet transform of f(t).

[0077] like Figure 2 As shown, the original seismic data volume is converted into a single-frequency volume of 0-100Hz, and based on the analysis of the frequency band distribution of river sand bodies in the target layer, three single-frequency volumes of 40Hz, 60Hz and 80Hz are selected.

[0078] The method for selecting a single-frequency body is:

[0079] Determine the cyclic characteristics of different lithologies on well logging curves to identify the sedimentary microfacies of the target layer;

[0080] Conduct detailed reservoir calibration and analyze the seismic reflection characteristics of reservoirs with different microfacies, lithologies, and thickness levels;

[0081] Sensitive frequency bands of frequency domain seismic attribute bodies are selected for reservoirs with different microfacies, lithologies, and thickness levels. The optimal frequency bands of frequency attribute bodies for reservoirs with different microfacies, lithologies, and thickness levels are found, and the sensitive frequency bands of point bars, abandoned channels, and variation zones in the target layer are selected from them.

[0082] By using RGB color fusion, the colors of three single-frequency volume data are non-linearly transformed to highlight the data volume within the target range and reveal more geological details. No manual adjustment of color scales is required in this process.

[0083] See Figure 7 Wavelet frequency division RGB color fusion result image;

[0084] contrast Figure 6 Map showing the results of earthquake attribute prediction using existing technology;

[0085] Figure 7 In this process, wavelet frequency division and RGB color fusion can identify more, more accurate and continuous abandoned river channels.

[0086] It should be noted that when identifying point dams, abandoned channels, and variability zones, it is necessary to rely on geological concept models based on modern sedimentation, constrained by well point logging curve facies patterns, and combine wave group characteristics on different geological body profiles and distribution characteristics on the plane to determine the microfacies types of geological bodies represented by different colors, and finally identify point dams, abandoned channels, and variability zones.

[0087] See Figure 8 and Figure 9 After identifying point dams, abandoned river channels, and variation zones, low-slender meandering rivers and high-slender meandering rivers were identified based on the ratio of river channel length to valley length. Through actual measurements of underground prototype geological models of high- and low-slender meandering rivers, as shown in Figure 7, quantitative relationships between the length and width of point dams and the width of abandoned river channels were established for high- and low-slender meandering rivers, which can be applied to the study of the internal configuration of meandering rivers under the same geological background.

[0088] like Figure 9 As shown in the figure, the relationship between the length of the point dam and the width of the abandoned river channel, the relationship between the width of the point dam and the width of the abandoned river channel, and the relationship between the width of the point dam and the length of the point dam are respectively displayed.

[0089] In summary, this invention, based on an objective understanding of seismic resolution, leverages the high lateral resolution of seismic data to solve the problem of low lateral prediction accuracy for identifying abandoned river channels based on well point data. This invention innovatively employs wavelet frequency division RGB attribute fusion technology to identify more, more accurate, and continuous abandoned river channels, resolving the issue of unclear boundaries in conventional attribute slices. Furthermore, it newly identifies internal variation zones within the river channels, guiding horizontal well trajectory design with significant results. In addition, this invention can accurately describe the distribution of abandoned river channels, ensuring the accuracy of actual measurement data from underground prototype geological models and providing technical support for quantitative prediction.

[0090] Example 2:

[0091] Example 1 provides a method for identifying abandoned channels and variation zones within river sand bodies. In this example, an identification system for abandoned channels and variation zones within river sand bodies will be provided to execute the identification method in Example 1. Since the identification system embodiment is basically similar to the identification method embodiment, it is described in a relatively simple way. For details of the relevant technical features, please refer to the corresponding description of the identification method embodiment provided above. The following description of the identification system embodiment is merely illustrative.

[0092] A system for identifying abandoned channels and variation zones within river sand bodies, comprising:

[0093] Storage module, used to store raw seismic data;

[0094] The isochronous stratigraphic grid module is used to establish an isochronous stratigraphic grid based on the original seismic data.

[0095] The parameter extraction module is used to extract geological parameters of different types of sand bodies based on a fine isochronous stratigraphic framework.

[0096] The forward modeling module is used to establish and complete forward modeling simulations based on the isochronous stratigraphic framework.

[0097] The results analysis module is used to analyze the seismic response characteristics of the point dam and its internal abandoned river channels and variability zones based on the forward modeling results.

[0098] The wavelet frequency division module is used to convert the seismic attribute volume spectrum in the original seismic data from the time domain to the frequency domain.

[0099] The RGB attribute fusion module is used to perform RGB attribute fusion on the spectrum of the converted seismic attribute volume.

[0100] The identification module is used to identify point dams, abandoned river channels, and variation zones based on the RGB attribute fusion map.

[0101] Furthermore, the wavelet frequency division module includes a calculation module for calculating the basic wavelet and wavelet transform, and the specific calculation process is as follows:

[0102]

[0103] Where: f(t) is the signal; t is time; Ψ is the mother wavelet; τ is the Fourier transform of the mother wavelet; σ is the time shift factor; σ is the scaling factor; Ψ σ,τ (t) represents the basic wavelet; F w (σ,τ) is the wavelet transform of f(t).

[0104] The RGB attribute fusion of the converted seismic attribute volume spectrum includes: selecting three single-frequency volumes from the seismic attribute volume. During RGB attribute fusion, the three single-frequency volumes correspond to three primary colors respectively. That is, by using RGB color fusion, the colors of the three single-frequency volume data are nonlinearly transformed to highlight the data volume within the target range, so as to show more geological details.

[0105] Finally, it should be noted that the above description 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 foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for identifying abandoned channels and variation zones within river sand bodies, characterized in that, Includes the following steps: Select raw seismic data and establish a fine isochronous stratigraphic framework combining well-seismic data for typical blocks; Based on the detailed isochronous stratigraphic framework, geological parameters of different types of sand bodies are extracted, and a forward modeling model based on the distribution characteristics of different types of sand bodies in the target interval is established to complete the forward modeling simulation. Based on the forward modeling results, the seismic response characteristics of the point dam and its internal abandoned river channels and variability zones are analyzed. Convert the seismic attribute volume spectrum in the original seismic data from the time domain to the frequency domain; Based on the seismic response characteristics, select several single-frequency volumes from the transformed seismic attribute volumes; Selecting several single-frequency volumes from the transformed seismic attribute volumes based on seismic response characteristics includes the following steps: Determine the cyclic characteristics of different lithologies on well logging curves to identify the sedimentary microfacies of the target layer; Conduct detailed reservoir calibration and analyze the seismic reflection characteristics of reservoirs with different microfacies, lithologies, and thickness levels; Sensitive frequency bands for frequency domain seismic attribute volumes were selected for reservoirs with different microfacies, lithologies, and thickness levels. Find the optimal frequency bands of the body of reservoirs with different microfacies, different lithologies, and different thickness levels, and screen out the sensitive frequency bands of point dams, abandoned channels, and variation zones in the target layer; Perform RGB attribute fusion on several single-frequency volumes; Based on the obtained RGB attribute fusion map, identify point dams, abandoned river channels, and variation zones; After identifying point dams, abandoned channels, and variation zones, a quantitative relationship between point dams and abandoned channels within high-low meandering channels is established. The steps to establish a quantitative relationship between point dams and abandoned channels within high- to low-slender meandering rivers include: Obtain the actual length and width of the prototype geological model from the original seismic data, including: river channel length, river channel width, valley length, and valley width; Based on the ratio of river channel length to valley length, low-meandering rivers and high-meandering rivers can be identified. Quantitative relationships were established between the length and width of point dams in meandering rivers at different elevations and widths of abandoned river channels.

2. The method for identifying abandoned channels and variation zones within river sand bodies according to claim 1, characterized in that, The selection of raw seismic data specifically includes: conducting a quality survey of the raw seismic data, and selecting data that meets the preset conditions or the target segment with the best signal-to-noise ratio based on the survey results.

3. The method for identifying abandoned channels and variation zones within river sand bodies according to claim 1, characterized in that, When selecting several single-frequency volumes from the transformed seismic attribute volumes based on seismic response characteristics, three single-frequency volumes are selected.

4. The method for identifying abandoned river channels and variation zones within river sand bodies according to claim 3, characterized in that, When performing RGB attribute fusion, the three single-frequency bodies correspond to the three primary colors respectively.

5. The method for identifying abandoned channels and variation zones within river sand bodies according to claim 1, characterized in that, When converting the seismic attribute volume spectrum from the time domain to the frequency domain, the time window is selected according to the frequency; the higher the frequency, the shorter the time window.

6. The method for identifying abandoned channels and variation zones within river sand bodies according to claim 5, characterized in that, When converting the seismic attribute volume spectrum from the time domain to the frequency domain, wavelet transform technology is used.

7. The method for identifying abandoned channels and variation zones within river sand bodies according to claim 6, characterized in that, When performing wavelet transform, the following formula is used for calculation: ； ； in: t is the signal; t is time; Mother wavelet; Fourier transform of the mother wavelet; It is the time shift factor; Scale factor; For basic wavelets; for Wavelet transform.

8. The method for identifying abandoned channels and variation zones within river sand bodies according to claim 1, characterized in that, When identifying point dams, abandoned channels, and variability zones, a geological concept model based on modern sedimentation is used, constrained by well point logging curve facies patterns, and combined with wave group characteristics on different geological body profiles and planar distribution characteristics to determine the microfacies types of geological bodies represented by different colors, ultimately identifying point dams, abandoned channels, and variability zones.

9. A system for identifying abandoned river channels and variation zones within river sand bodies, characterized in that, include: Storage module, used to store raw seismic data; The isochronous stratigraphic grid module is used to establish an isochronous stratigraphic grid based on the original seismic data. The parameter extraction module is used to extract geological parameters of different types of sand bodies based on a fine isochronous stratigraphic framework. The forward modeling module is used to establish and complete forward modeling simulations based on the isochronous stratigraphic framework. The results analysis module is used to analyze the seismic response characteristics of the point dam and its internal abandoned river channels and variability zones based on the forward modeling results. The wavelet frequency division module is used to convert the spectrum of seismic attribute volumes in the original seismic data from the time domain to the frequency domain, and select several single-frequency volumes from the converted seismic attribute volumes according to the seismic response characteristics. Selecting several single-frequency volumes from the transformed seismic attribute volumes based on seismic response characteristics includes the following steps: Determine the cyclic characteristics of different lithologies on well logging curves to identify the sedimentary microfacies of the target layer; Conduct detailed reservoir calibration and analyze the seismic reflection characteristics of reservoirs with different microfacies, lithologies, and thickness levels; Sensitive frequency bands for frequency domain seismic attribute volumes were selected for reservoirs with different microfacies, lithologies, and thickness levels. Find the optimal frequency bands of the body of reservoirs with different microfacies, different lithologies, and different thickness levels, and screen out the sensitive frequency bands of point dams, abandoned channels, and variation zones in the target layer; The RGB attribute fusion module is used to fuse the RGB attributes of several single-frequency bodies. The identification module is used to identify point dams, abandoned river channels, and variation zones based on the RGB attribute fusion map; After identifying point dams, abandoned channels, and variation zones, a quantitative relationship between point dams and abandoned channels within high-low meandering channels is established. The steps to establish a quantitative relationship between point dams and abandoned channels within high- to low-slender meandering rivers include: Obtain the actual length and width of the prototype geological model from the original seismic data, including: river channel length, river channel width, valley length, and valley width; Based on the ratio of river channel length to valley length, low-meandering rivers and high-meandering rivers can be identified. Quantitative relationships were established between the length and width of point dams in meandering rivers at different elevations and widths of abandoned river channels.

10. A system for identifying abandoned river channels and variation zones within a river sand body according to claim 9, characterized in that, The wavelet frequency division module includes a calculation module for calculating the basic wavelet and wavelet transform. The specific calculation process is as follows: ； ； in: t is the signal; t is time; Mother wavelet; Fourier transform of the mother wavelet; It is the time shift factor; Scale factor; For basic wavelets; for Wavelet transform.

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