Method for vc ternary sequence stratigraphic division and correlation

Abstract

The application provides a VC ternary sequence stratigraphic division and comparison method, which comprises the following steps: step 1, macro main interfaces are divided by adopting a Vail sequence research method under the guidance of a stratigraphic structure model; step 2, internal base level cycles are divided by adopting a Cross sequence research method under the frame of a three-level sequence; and step 3, a fine sequence stratigraphic framework is established by well-seismic integration, and a set of ternary sequence stratigraphic division and comparison method based on the VC theory method is formed. The VC ternary sequence stratigraphic division and comparison method is based on the V-C method as a theoretical basis, and is based on the geological model as a starting point. On the basis of the macro main interface constraint, the internal sequence characteristics are studied in detail, the applicability of various methods in the study area and the sequence interface response mode in different environments are focused on, so that the stratigraphic framework is more effectively established.

Description

Technical Field

[0001] This invention relates to the fields of energy exploration and development and geology, and in particular to a VC ternary sequence stratigraphic division and correlation method. Background Technology

[0002] In the process of oil and gas field exploration and development, establishing a high-precision isochronous sequence stratigraphic framework is of great significance, serving as the foundation for subsequent geological research. To date, sequence stratigraphy has developed into three main theoretical schools: Vail sequence stratigraphy, Galloway genetic sequence stratigraphy, and Cross high-resolution sequence stratigraphy. Among these, Vail sequence stratigraphy and Cross high-resolution sequence stratigraphy are the most widely used theories and techniques in my country's major oil and gas basins—continental rift basins and lacustrine basins. Vail sequence stratigraphy theory uses stratigraphic unconformities or their corresponding conformity surfaces as sequence boundaries. Based on seismic and well logging data, it establishes a basin or regional isochronous sequence stratigraphic framework by identifying seismic contact relationships and stratigraphic stacking pattern variations through a combination of well and seismic data. This method is widely used in oil and gas exploration, but its research accuracy is insufficient, and low-frequency sequences are difficult to meet the current needs of oil and gas exploration and development. The Cross high-resolution sequence stratigraphy method is based on the theory of base-level cycles. It treats strata formed during the "rise-fall" cycle of the base level as a sequence and uses the transition points of the base-level cycle changes as sequence boundaries. Since its introduction into China's petroleum exploration and development field, this method has broadened the research scope and scale of sequence stratigraphy, enabling the establishment of genetic stratigraphic correlation frameworks at the oilfield and even reservoir levels. However, it is less effective for regional isochronous stratigraphic frameworks.

[0003] Because Vail sequence stratigraphy originates from seismic sequence stratigraphy, and given the limitations of seismic data resolution, some consider Vail sequence stratigraphy to be low-resolution sequence stratigraphy and Cross sequence stratigraphy to be high-resolution sequence stratigraphy. This view is inaccurate. Vail sequence stratigraphy, as a theoretical method, can also utilize outcrop, core, and well logging data for high-level sequence analysis; while Cross sequence stratigraphy is a "high-resolution sequence stratigraphy" method, suitable for high-level sequence analysis, but "high resolution" does not equate to "high frequency" or "high precision." Overall, the Vail and Cross methods share a unified theoretical foundation: the cyclicity of stratigraphy. The Vail method is crucial for establishing macroscopic sequence stratigraphic frameworks in continental rift basins and lacustrine basins, while the Cross method is more advantageous for establishing sequence frameworks within conformable strata. Both can use unconformities (maximum discontinuities) as sequence boundaries and emphasize that the periodic variation of the base level controls sequence development. These characteristics provide theoretical support for the combined use of the two methods.

[0004] my country's eastern continental rift-lacustrine basins are rich in oil and gas resources, making them the main battleground for oil and gas exploration and development. The Dongying Depression, a typical example of a continental graben-shaped rift-lacustrine basin, features an asymmetrical, complex, semi-graben morphology with a northern fault and southern overburden (stripping) formation, belonging to a third-order tectonic unit within the Bohai Bay Basin. The Shahejie Formation red beds, located on the gentle slope of the southern part of the depression, are a typical area of ​​frequent overburden and stripping stratigraphy, with common erosion and overburden unconformities, making sequence stratigraphy and correlation difficult. Existing stratigraphic correlation schemes often exhibit time-dependent characteristics. Such problems are very common in the study of gentle slope zones in eastern continental rift-lacustrine basins in my country, hindering oil and gas exploration and development within the basins. There is an urgent need for targeted technical methods to establish accurate isochronous sequence stratigraphic frameworks.

[0005] In Chinese patent application No. CN202010196581.6, a deep-sea channel reservoir configuration unit hierarchical classification system is involved, which includes the following parts: (1) Configuration unit hierarchy: divided into 1-11 levels according to the scale from small to large; (2) Configuration unit type: Level 1 unit is micro-scale configuration; Level 2 unit is laminar; Level 3 unit is homogeneous section in rock strata; Level 4 unit is rock strata; Level 5 unit is rock strata group; Level 6 unit is secondary channel unit; Level 7 unit is single channel; Level 8 unit is composite channel; Level 9 unit is composite channel series; Level 10 unit is channel system; Level 11 unit is channel system series; (3) Configuration unit genesis; (4) Configuration unit formation time span; (5) Configuration unit structural style; (6) Configuration unit interface characteristics and scale; (7) Data used for underground identification of configuration units. This invention enables a complete, scientific, practical, and unified classification of deep-sea channel reservoir configuration levels.

[0006] Chinese patent application CN201910165769.1 discloses a method for fine prediction of beach-bar facies sand bodies in logging operations. The method includes: selecting a well adjacent to the design well in the beach-bar facies sand body area as a standard well; identifying and classifying different levels of reference surface cycles in the standard well; understanding the logging parameter characteristics and lithological and electrical superposition patterns of the reference surface cycles as they change; performing high-resolution sequence isochronous stratigraphy on adjacent wells one by one, then comparing different levels of reference surface cycles along and perpendicular to the provenance direction to ultimately establish a high-resolution sequence stratigraphic framework for the block; and determining the reference surface cycle location of the drilling well to guide stratigraphic analysis and hydrocarbon reservoir location prediction in the logging field. This invention addresses the problems of existing technologies relying heavily on personal experience, lacking understanding of the geological conditions and reservoir profile of the block where the design well is located, resulting in poor accuracy in stratigraphic division and correlation.

[0007] Chinese patent application CN201910536356.X discloses a method for determining sequence boundaries using acoustic transit time. The method includes: obtaining the acoustic logging values ​​from well logging curves; displaying the acoustic values ​​of the well logging curves in logarithmic form; plotting a cross-plot using the depth and logarithmic acoustic transit time values; and identifying the sequence boundary based on the variation patterns of the curves above and below the sequence boundary in the cross-plot. This invention identifies sequence boundaries based on anomalies in acoustic transit time corresponding to different depth points. Parameter selection is intuitive and reliable, and no function conversion is required, greatly improving the convenience and objectivity of sequence boundary identification.

[0008] The existing technologies described above are significantly different from the present invention and have failed to solve the technical problem we want to address. Therefore, we have invented a new VC ternary sequence stratigraphic division and correlation method. Summary of the Invention

[0009] The purpose of this invention is to provide a VC ternary sequence stratigraphic correlation method that combines the Vail sequence study method (“V” method) and the Cross sequence study method (“C” method), finds an effective combination point, and organizes them into three clear and easy-to-operate correlation steps, namely “ternary correlation”.

[0010] The objective of this invention can be achieved through the following technical measures: a VC ternary sequence stratigraphy correlation method, which includes:

[0011] Step 1: Guided by the stratigraphic structure model, the macroscopic main interface is delineated using the Vail sequence stratigraphic method;

[0012] Step 2: Using the three-level sequence as a framework, the Cross sequence study method is employed to delineate the internal reference surface cycles;

[0013] Step 3: Well-seismic integration is used to establish a fine sequence stratigraphic framework, forming a ternary sequence stratigraphic division and correlation method based on VC theory.

[0014] The objective of this invention can also be achieved through the following technical measures:

[0015] In step 1, the spatiotemporal method in Vail sequence stratigraphy is used to determine the third-order sequence boundary, i.e., the macroscopic master boundary.

[0016] In step 1, the core step of the Vail sequence method is to use paleontological and cuttings logging data to identify third-order sequence boundaries and, through the calibration of synthetic records, to transfer the temporal significance they represent onto seismic and well logging curves. By tracking seismic data and comparing well logging curves, the spatial distribution characteristics of third-order sequence boundaries in the entire area are determined.

[0017] In step 2, within the framework of the isochronous third-order sequence strata determined by the Vail sequence method, the base-level cycle method in the Cross high-resolution sequence stratigraphy theory is used to determine the internal sequence characteristics, namely the fourth-order sequence or even higher-level sequences.

[0018] In step 2, the core datum cycle in the Cross sequence method is divided into long-term, medium-term, and short-term datum cycles. The long-term datum cycle is correlated with the three-level sequence in the Vail sequence method, and then the medium-term or short-term datum cycles are divided in sequence. The boundary of the medium-term or short-term datum cycle cannot cross the boundary of the long-term datum cycle.

[0019] In step 2, the identification and division of the base surface cycle follows the principle of hierarchical division from macro to micro and from large scale to small scale. The transition point of the base surface cycle can be an unconformity or a discontinuity in sedimentary processes, or it can be a transition surface or a sedimentary continuum in stratigraphy.

[0020] In step 2, during the partitioning process, sedimentary response is used to determine medium- and short-term base-level cycles, which specifically includes the identification of lithological cycles, well logging response of sedimentary sequences, and wavelet transform method to determine the cycle partitioning scheme.

[0021] In step 2, wavelet energy spectrum and wavelet curve method are the core methods of this step. Different cycles show obvious discontinuities in energy clusters. The number of energy clusters appearing vertically can well represent the order of occurrence of base surface cycles. Based on sedimentary sequence analysis, and under the constraint of seismic data, the lateral correlation of strata is carried out by the similarity of energy clusters.

[0022] In step 3, through steps 1 and 2, the single-well sequence division of VC is completed. The division results fully consider the isochronism of the stratigraphic deposition and conform to the regularity of the spatial development of sedimentary cycles.

[0023] In step 3, multi-well logging and high-resolution seismic data interpretation techniques are used to track and compare each sequence boundary in descending order of size. The comparison results are repeatedly verified with the stratigraphic structure model to ensure the accuracy and precision of the comparison results.

[0024] The VC ternary sequence stratigraphy correlation method in this invention combines the Vail sequence stratigraphy (“V” method) and the Cross sequence stratigraphy (“C” method), finding an effective point of convergence and organizing them into three clear and convenient correlation steps, namely the “ternary correlation.” This systematic method is applied to the gentle slope zone of a continental rift basin for verification, establishing an effective sequence stratigraphy correlation method. This invention, the “VC ternary sequence stratigraphy correlation method,” is based on the VC method and uses a geological model as a starting point. Under the constraint of the macroscopic main interface, it conducts a detailed study of the internal sequence characteristics. It emphasizes the applicability of various methods in the study area and the sequence interface response modes in different environments, thereby more effectively establishing a stratigraphic framework. Attached Figure Description

[0025] Figure 1 This is a schematic diagram illustrating the main idea of ​​the VC ternary sequence stratigraphy correlation method in a specific embodiment of the present invention;

[0026] Figure 2 This is a flowchart illustrating the establishment of a sequence stratigraphic grid in a specific embodiment of the present invention;

[0027] Figure 3 This is a flowchart of a specific embodiment of the VC ternary sequence stratigraphy method of the present invention. Detailed Implementation

[0028] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.

[0030] like Figure 3 As shown, Figure 3 This is a flowchart of the VC ternary sequence stratigraphy correlation method of the present invention. The VC ternary sequence stratigraphy correlation method includes the following steps:

[0031] Step 101: Guided by the stratigraphic structure model, use the "V" method to delineate the macroscopic main interface;

[0032] Step 102: Using the three-level sequence as a framework, the internal reference surface cycle is divided using the "C" method;

[0033] Step 103: Well-seismic integration establishes a fine sequence stratigraphic framework, forming a ternary sequence stratigraphic division and correlation method based on VC theory.

[0034] The VC ternary sequence stratigraphy correlation method of this invention combines the Vail sequence theory (“V” method) and the Cross sequence theory (“C” method) to find an effective point of convergence between the two. It then comprehensively utilizes geological, paleontological, well logging, and seismic analysis methods, as well as wavelet transform technology, to establish a stratigraphic structure model of a rift basin with a gentle slope. Using this model as a guide, it identifies the macroscopic main interfaces within the sequence stratigraphy, ultimately determining the sequence characteristics within the stratigraphic structure. The effectively integrated method is applied to a typical continental rift basin with a gentle slope for oil and gas exploration and verification, thus establishing a VC ternary sequence stratigraphy correlation method.

[0035] The following are several specific embodiments of the application of the present invention.

[0036] Example 1

[0037] In a specific embodiment 1 of the present invention, the VC ternary sequence stratigraphy correlation method includes the following steps:

[0038] (1) Guided by the stratigraphic structure model, the macroscopic main interface was delineated using the "V" method.

[0039] In terrestrial lacustrine basins, factors such as tectonic activity, climate, and sediment supply control the rise and fall of the base level, thereby affecting changes in the accommodation space. This process determines sediment volume distribution and facies differentiation, ultimately shaping the sequence structure. Therefore, stratigraphic models are fundamental to sequence stratigraphy. First, the spatiotemporal method from Vail's sequence stratigraphy theory is used to determine the third-order sequence boundaries, i.e., the macroscopic master boundaries. The core step of this method is to identify the third-order sequence boundaries using paleontological and cuttings logging data, and then, through synthetic record calibration, transfer their temporal significance to seismic and well logging curves. By tracking seismic activity and comparing well logging curves, the spatial distribution characteristics of the third-order sequence boundaries across the entire region are determined.

[0040] (2) Using a three-level hierarchical sequence as a framework, the internal reference surface cycle is divided using the "C" method.

[0041] Within the framework of the isochronous third-order sequence stratigraphy determined by the "V" method, the base-level cycle method in Cross high-resolution sequence stratigraphy theory is used to determine internal sequence characteristics, i.e., fourth-order sequences and even higher-level sequences. The core base-level cycles in the "C" method are often divided into long-term, medium-term, and short-term base-level cycles. Long-term base-level cycles can be correlated with the third-order sequence in the "V" method, and then medium-term or short-term base-level cycles can be subdivided sequentially. The boundaries of medium-term or short-term base-level cycles cannot cross the boundaries of long-term base-level cycles. The identification and subdivision of base-level cycles follows a step-by-step subdivision principle from macro to micro and from large scale to small scale. The transition points of base-level cycles can be unconformities or sedimentary discontinuities, or transition surfaces or sedimentary continuities in stratigraphy.

[0042] In the process of classification, this invention mainly uses sedimentary response to determine medium- and short-term base-level cycles. Specifically, this includes lithological cycle identification, well logging response of sedimentary sequences, and wavelet transform to determine the cycle classification scheme. Among these, wavelet energy spectrum and wavelet curve methods are the core methods in this step. Different cycles exhibit obvious discontinuities in energy clusters, and the number of vertically occurring energy clusters effectively represents the order of occurrence of base-level cycles. Based on sedimentary sequence analysis and constrained by seismic data, lateral stratigraphic correlation can be performed through the similarity of energy clusters.

[0043] (3) A fine sequence stratigraphic framework was established by combining well and seismic data, forming a three-dimensional sequence stratigraphic division and correlation method based on VC theory.

[0044] Through steps (1) and (2), single-well sequence stratigraphy based on VC was completed. The stratigraphic results fully considered the isochronism of the sedimentary formations and conformed to the spatial development regularity of sedimentary cycles. On this basis, using multi-well logging and high-resolution seismic data interpretation techniques, each sequence boundary was tracked and compared in descending order of size. The comparison results were repeatedly verified with the stratigraphic structure model to ensure the accuracy and precision of the comparison results.

[0045] Example 2

[0046] In a specific embodiment 2 of the present invention, such as Figure 1As shown, this method combines the overall sequence structure of the stratigraphy with high-precision internal sequence boundaries, organically integrating the theory of the VC method into each step of sequence delineation. First, based on the basin structure of the selected area, a stratigraphic model of the target layer is established. This model guides the determination of sequence boundaries of order three and above, i.e., the macroscopic master boundaries, through well-seismic synthesis. Then, using the macroscopic master boundaries as constraints, the characteristics of order 4-5 sequences within the order three are determined by integrating fine characterization methods based on rock, electrical, and seismic data. The established set of sequence boundaries can be verified against the stratigraphic model to ensure that the sequence delineation results conform to the basin's structural patterns. This series of methods effectively combines the V method and the C method and can be applied to the establishment of stratigraphic frameworks, such as the red beds on the southern slope of the Dongying Depression.

[0047] like Figure 2 As shown, the process of determining the internal sequence structure from the macroscopic main interface was comprehensively utilized using detailed characterization methods from geology, logging, and seismic analysis. Geologically, core data was fully utilized for high-frequency cycle division and internal interface identification, and paleontological data was used to determine key time interfaces. In logging, based on the interface identification using conventional logging data, methods such as mudstone sonic transit time analysis, wavelet transform analysis, and Gr curve mirror analysis were employed to identify and divide logging cycles. Using geological and logging data, the internal sequence interfaces of individual wells could be precisely identified. Between wells, high-resolution 3D seismic data was used to interpret isochronous sequence interfaces. By mutually constraining these three methods and fully leveraging the advantages of each, a precise and accurate sequence stratigraphic framework was established.

[0048] Example 3

[0049] In a specific embodiment 3 of the present invention, the red bed deposits on the southern slope of the Dongying Depression in the Jiyang Depression of the Bohai Bay Basin were selected as the research object. The study area covers approximately 500 km². 2 The Lower Sha-4 Member of the Paleogene – Kongdian Formation – features extensive red sandstone and mudstone deposits. These red strata lack paleontology and are commonly referred to as "dumb strata," making stratigraphic and geological dating difficult. Due to the significant lateral variations in the red strata and the lack of stable lithological and electrical indicators, effective methods for isochronous correlation are scarce, hindering sedimentary and reservoir studies and oil and gas exploration within the isochronous framework.

[0050] The key technical steps of this invention include the following three steps:

[0051] (1) Guided by the stratigraphic structure model, the macroscopic main interface was delineated using the "V" method.

[0052] In terrestrial lacustrine basins, factors such as tectonic activity, climate, and sediment supply control the rise and fall of the base level, thereby affecting changes in the accommodation space. This process determines sediment volume distribution and facies differentiation, ultimately determining the sequence structure. Therefore, stratigraphic models are the foundation of sequence stratigraphy. Guided by the red bed structure model on the southern slope of the Dongying Depression, this study first uses the spatiotemporal method in Vail sequence stratigraphy to determine the third-order sequence boundary, i.e., the macroscopic main boundary. The core step of this method is to use paleontological and cuttings logging data to identify the boundary between the lower top and bottom of the Sha-4 Formation and the Kongdian Formation, i.e., the third-order sequence boundary. The temporal significance represented by this boundary is then mapped onto seismic and well logging curves through synthetic record calibration. By tracking seismic data and comparing well logging curves, the spatial distribution characteristics of the third-order sequence boundary in the entire region are determined.

[0053] (2) Using a three-level hierarchical sequence as a framework, the internal reference surface cycle is divided using the "C" method.

[0054] Within the framework of the isochronous third-order sequence stratigraphy determined by the "V" method, the base-level cycle method in Cross high-resolution sequence stratigraphy theory is used to determine internal sequence characteristics, i.e., fourth-order sequences and even higher-level sequences. The core base-level cycles in the "C" method are often divided into long-term, medium-term, and short-term base-level cycles. Long-term base-level cycles can be correlated with the third-order sequence in the "V" method, and then medium-term or short-term base-level cycles can be subdivided sequentially. The boundaries of medium-term or short-term base-level cycles cannot cross the boundaries of long-term base-level cycles. The identification and subdivision of base-level cycles follows a step-by-step subdivision principle from macro to micro and from large scale to small scale. The transition points of base-level cycles can be unconformities or sedimentary discontinuities, or transition surfaces or sedimentary continuities in stratigraphy.

[0055] In the process of classification, this invention mainly uses sedimentary response to determine medium- and short-term base-level cycles, specifically including lithological cycle identification, well logging response of sedimentary sequences, and wavelet transform to determine the cycle classification scheme. Among these, wavelet energy spectrum and wavelet curve methods are the core methods in this step. Different cycles exhibit obvious discontinuities in energy clusters, and the number of vertically occurring energy clusters effectively represents the order of occurrence of base-level cycles. Based on sedimentary sequence analysis and constrained by seismic data, lateral stratigraphic correlation can be performed through the similarity of energy clusters, achieving excellent identification results on the southern slope of the Dongying Depression.

[0056] (3) A fine sequence stratigraphic framework was established by combining well and seismic data, forming a three-dimensional sequence stratigraphic division and correlation method based on VC theory.

[0057] Through steps (1) and (2), single-well sequence stratigraphy based on VC was completed. The stratigraphic results fully considered the isochronism of the sedimentary formations and conformed to the spatial development regularity of sedimentary cycles. On this basis, using multi-well logging and high-resolution seismic data interpretation techniques, each sequence boundary was tracked and compared in descending order of size. The comparison results were repeatedly verified with the stratigraphic structure model to ensure the accuracy and precision of the comparison results.

[0058] By streamlining and integrating the above three steps, a ternary sequence stratigraphic correlation method combining VC theory and technology was established. This method was applied to the red beds on the southern slope of the Dongying Depression, and exploration verification showed good results, proving the application value of this technology in the gentle slope zones of continental rift basins and lacustrine basins in my country.

[0059] Finally, it should be noted that the above description is merely 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.

[0060] Except for the technical features described in the specification, all other technologies are known to those skilled in the art.

Claims

1. A VC ternary sequence stratigraphic correlation method, characterized in that, The VC ternary sequence stratigraphic correlation method includes: Step 1: Guided by the stratigraphic structure model, the macroscopic main interface is delineated using the Vail sequence stratigraphic method; Step 2: Using the three-level sequence as a framework, the Cross sequence study method is employed to delineate the internal reference surface cycles; Step 3: Well-seismic integration is used to establish a fine sequence stratigraphic framework, forming a ternary sequence stratigraphic division and correlation method based on VC theory. In step 1, the spatiotemporal method in Vail sequence stratigraphy is used to determine the third-order sequence boundary, i.e., the macroscopic master boundary; In step 1, the core step of the Vail sequence method is to use paleontological and cuttings logging data to identify third-order sequence boundaries and, through the calibration of synthetic records, to transfer the temporal significance they represent onto seismic and well logging curves. By tracking seismic data and comparing well logging curves, the spatial distribution characteristics of third-order sequence boundaries in the entire area are determined. In step 2, within the framework of the isochronous third-order sequence strata determined by the Vail sequence method, the base-level cycle method in the Cross high-resolution sequence stratigraphy theory is used to determine the internal sequence characteristics, namely the fourth-order sequence or even higher-level sequences. In step 2, the core datum cycle in the Cross sequence method is divided into long-term, medium-term, and short-term datum cycles. The long-term datum cycle is correlated with the three-level sequence in the Vail sequence method, and then the medium-term or short-term datum cycles are divided in turn. The boundary of the medium-term or short-term datum cycle cannot cross the boundary of the long-term datum cycle. In step 2, the identification and division of the base surface cycle follows the principle of hierarchical division from macro to micro and from large scale to small scale. The transition point of the base surface cycle can be an unconformity or a discontinuity in sedimentary processes, or it can be a transition surface or a sedimentary continuum in stratigraphy. In step 2, during the partitioning process, sedimentary response is used to determine medium- and short-term base-level cycles, which specifically includes the identification of lithological cycles, well logging response of sedimentary sequences, and wavelet transform method to determine the cycle partitioning scheme. In step 2, wavelet energy spectrum and wavelet curve method are the core methods of this step. Different cycles show obvious discontinuities in energy clusters. The number of energy clusters appearing vertically can well represent the order of occurrence of base surface cycles. Based on sedimentary sequence analysis, and under the constraint of seismic data, the lateral correlation of strata is carried out through the similarity of energy clusters. In step 3, through steps 1 and 2, the single-well sequence division of VC is completed. The division results fully consider the isochronism of the stratigraphic deposition and conform to the regularity of the spatial development of sedimentary cycles. In step 3, multi-well logging and high-resolution seismic data interpretation techniques are used to track and compare each sequence boundary in descending order of size. The comparison results are repeatedly verified with the stratigraphic structure model to ensure the accuracy and precision of the comparison results.

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