Improved multiple formation mechanism analysis method and device

Abstract

The application provides an improved multiple wave formation mechanism analysis method, comprising the following steps: constructing a complex seismic geological model by using a four-approximation principle for a research area; and performing multiple wave generation mechanism forward quantitative analysis on the complex seismic geological model to determine basic conditions and wave field characteristics of free surface multiple waves and interlayer multiple waves. The application approximates a real geological condition as much as possible based on multiple wave forward simulation, and realizes seismic wave forward simulation records containing surface-related multiple waves and not containing surface-related multiple waves by controlling a boundary absorption condition of the surface, and the records are closer to actual seismic data, which provides a good data basis for a qualitative / quantitative analysis, identification and suppression method test of the multiple waves, effectively guides multiple wave suppression, and improves imaging quality of a geological target.

Description

Technical Field

[0001] This invention relates to the field of seismic exploration technology for oil and gas in complex exploration areas, and more specifically, to an improved method and apparatus for analyzing the formation mechanism of multiple waves. Background Technology

[0002] In the exploration of Ordovician oil and gas in the southern Tarim Basin, it was found that the predicted carbonate fracture-vuggy reservoirs based on existing seismic data often did not match the actual drilled wells, posing a severe challenge to the identification and description of the target reservoir's scale. To address this problem, the existing seismic data was first analyzed. It was found that some seismic reflections in the target layer showed significant inconsistencies with geological understanding in terms of frequency and occurrence. Furthermore, well calibration revealed that the Ordovician interface between two wells was cross-axis; "platform" reflections appeared on large thrust structures; no obvious anomalies were observed in the seismic data of the drilled reservoirs; and "arc-like" characteristics were visible in pre-stack flattened CMP and CRP gathers. In short, seismic imaging exhibits high ambiguity, and reflections do not necessarily represent true reflection characteristics. A comprehensive analysis combining well calibration, VSP, and gather data revealed that the main cause of these issues was the development of multiples. To better suppress multiples, it is necessary to analyze and study their formation mechanism.

[0003] Currently, the analysis of multiple formation mechanisms mainly relies on forward modeling techniques. For example, Zhang Xianghui et al. established a geological model of a horizontally layered medium containing coal seams and then used a self-excitation and self-reception method for forward modeling to theoretically study the generation mechanism of multiples. Duan Hongyou et al. used a forward modeling method based on the elastic wave equation algorithm to analyze the characteristics of multiples, providing reliable data for optimizing seismic acquisition parameters and for indoor suppression of multiples, thereby improving deep reflection energy and the signal-to-noise ratio of the data. However, these methods are all based on simple models for the simulation and qualitative analysis of inter-layer multiples, without considering the actual seismic data and complex geological conditions, and without quantitative analysis of multiples.

[0004] To address the problems of existing technologies, this invention provides an improved method and apparatus for analyzing the formation mechanism of multiple waves. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides an improved method for analyzing the formation mechanism of multiple waves, the method comprising the following steps:

[0006] For the study area, a complex seismic geological model was constructed using the four approximation principles;

[0007] A forward modeling quantitative analysis of the multiple generation mechanism was performed on the complex seismic geological model to determine the basic conditions and wavefield characteristics of free surface multiples and interlayer multiples.

[0008] According to one embodiment of the present invention, constructing a complex earthquake geological model includes step S1: extracting the dominant earthquake frequencies based on geological targets to obtain a dominant frequency volume.

[0009] According to one embodiment of the present invention, constructing a complex seismic geological model includes step S2: performing fine well-seismic calibration on the dominant frequency volume, and obtaining the layer velocities of all strata and key lithologies by square-wave conversion of the sonic curves.

[0010] According to one embodiment of the present invention, constructing a complex seismic geological model includes step S3: establishing a time-domain tectonic model, and using this as a constraint to establish a velocity field model under the constraints of the tectonic model.

[0011] According to one embodiment of the present invention, constructing a complex seismic geological model includes:

[0012] S4. Based on the constraints of the velocity field model, establish a complex construction model framework that conforms to reality in order to achieve depth-construction approximation;

[0013] S5. Use the layer velocity to fill the framework model constraints of the complex structure model to achieve depth-velocity approximation and obtain the initial layer velocity model.

[0014] S6. Using velocity spectrum data and the distribution characteristics of low-velocity zones, extract velocity spectrum data above the water table and fuse it with the initial layer velocity model to obtain the final layer velocity model that conforms to reality, thereby achieving the approximation of the surface-low-velocity zone.

[0015] S7. Based on the actual seismic acquisition and observation system, the seismic acquisition is simulated by forward modeling using the elastic wave equation to achieve approximation of the observation system and acquisition parameters.

[0016] According to an embodiment of the present invention, the forward modeling quantitative analysis of the multiple wave generation mechanism of the complex seismic geological model includes step S8: abstracting and simplifying a certain point of the complex seismic geological model in order to analyze the generation conditions of multiple waves through forward modeling.

[0017] According to an embodiment of the present invention, determining the basic conditions for the generation of free surface multiples and interlayer multiples and their wavefield characteristics includes step S9: based on step S8, through all interfaces whose reflection coefficients meet the conditions according to the drilled statistics, the wavefield characteristics of multiples in the complex seismic geological model are accurately analyzed to clarify the wavefield characteristics of all multiples in the target layer.

[0018] According to an embodiment of the present invention, the method further includes step S10: based on step S9, the multiple wave distribution characteristics of the target layer are finally determined in order to carry out targeted multiple wave identification and suppression.

[0019] According to another aspect of the invention, a storage medium is also provided, which includes a series of instructions for performing the steps of the method described in any of the preceding claims.

[0020] According to another aspect of the invention, an improved apparatus for analyzing the formation mechanism of multiple waves is also provided, performing the method as described in any of the preceding claims, the apparatus comprising:

[0021] The model building module is used to construct complex seismic geological models for the study area using the four approximation principles.

[0022] The multiples module is used to perform forward modeling and quantitative analysis of the multiples generation mechanism of the complex seismic geological model, so as to determine the basic conditions and wavefield characteristics of the generation of free surface multiples and interlayer multiples.

[0023] The improved method and apparatus for analyzing the formation mechanism of multiples provided by this invention have the following advantages and beneficial effects compared with existing technologies: Existing forward modeling methods for multiple mechanisms based on simple models often only qualitatively analyze the formation mechanism and wavefield characteristics of multiples due to insufficient consideration of actual geological conditions. Under conditions of extremely low signal-to-noise ratio in Ordovician seismic data from the South Tarim Basin, they cannot effectively guide the identification and suppression of multiples in actual seismic data. This invention starts from the foundation of multiple forward modeling, namely model construction, to approximate the actual geological conditions as closely as possible. By controlling the boundary absorption conditions of the Earth's surface, it specifically realizes forward modeling simulation records of seismic waves including and excluding surface-correlated multiples, and more closely resembles actual seismic data. This provides a good data foundation for testing methods of qualitative / quantitative analysis, identification, and suppression of multiples, effectively guides multiple suppression, and improves the imaging quality of geological targets.

[0024] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0026] Figure 1 A flowchart of an improved method for analyzing the formation mechanism of multiple waves according to an embodiment of the present invention is shown;

[0027] Figure 2A flowchart of an improved method for analyzing the formation mechanism of multiple waves according to another embodiment of the present invention is shown;

[0028] Figure 3 The diagram shows a comparison of the dominant frequency volume extraction before and after according to an embodiment of the present invention;

[0029] Figure 4 A detailed wellbore calibration diagram is shown according to an embodiment of the present invention;

[0030] Figure 5 A diagram illustrating the temporal domain construction according to an embodiment of the present invention is shown;

[0031] Figure 6 A partial view of the depth construction modeling according to an embodiment of the present invention is shown;

[0032] Figure 7 A diagram showing the generation of a well control velocity filling construction model according to an embodiment of the present invention is displayed;

[0033] Figure 8 A low-speed band velocity fill plot is shown according to an embodiment of the present invention;

[0034] Figure 9 A diagram illustrating the conditions for generating multiple waves according to an embodiment of the present invention is shown.

[0035] Figure 10 This shows a multi-wave field characteristic analysis diagram according to an embodiment of the present invention;

[0036] Figure 11 The diagram shows a test image of a free surface multiple wave identification and suppression method according to an embodiment of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0038] The development of multiples in the Tarim Basin is difficult to suppress, severely affecting the imaging quality of Ordovician geological targets. To better suppress multiples, it is necessary to conduct a quantitative analysis of their formation mechanism, which can be applied to the mechanism analysis of multiple generation in seismic data imaging processing.

[0039] This invention is based on establishing a realistic seismic geological model that conforms to the principle of "four approximations"—approximating surface conditions, structure, velocity, and observation system—based on the general laws of the model and actual geological conditions. It conducts simulations of multiple waves based on the theory of elastic wave equations, and performs qualitative and quantitative analyses on the classification, distribution characteristics, and influence range of multiple wave types. Ultimately, it clarifies the generation mechanism and necessary conditions of multiple waves, providing targeted guidance for subsequent suppression of multiple waves.

[0040] Figure 1 This paper presents a flowchart of an improved method for analyzing the formation mechanism of multiples according to an embodiment of the present invention. The present invention primarily determines the "source," "mirror," and "image" of multiples through well-seismic calibration or VSP data (Vertical Seismic Profiling, VSP). It then focuses on key issues and, based on forward modeling of the elastic wave theory equations of a complex geological model constructed using the "four approximations" principle, achieves a quantitative analysis of the formation mechanism and generation conditions of Ordovician multiples in the vast desert region.

[0041] like Figure 1 As shown, in step S101, a complex seismic geological model is constructed for the study area using the four approximation principles.

[0042] In one embodiment, in step S101, a complex structural model framework that conforms to reality is established. Specifically, the selected time-domain profile is converted to depth using the velocity difference of the study area, and the lithology of the strata encountered in the actual well is used as a basis to perform complex structural modeling, forming a framework model that conforms to the actual burial depth and achieves "depth-structure" approximation.

[0043] In one embodiment, in step S101, rock physical parameters that conform to reality are filled in. Specifically, using VSP data or drilled well data, vertically varying layer velocities are generated, and velocity and density are filled in within the framework model constraints to achieve an approximation of the "depth-velocity" velocity parameter filling.

[0044] In one embodiment, in step S101, parameters such as the velocity of the low-velocity zone are fitted. Specifically, the velocity of the layer above the water table is replaced with the actual processed velocity spectrum data to achieve an approximation of the "surface-low-velocity zone".

[0045] In one embodiment, step S101 defines a realistic acquisition and observation system and parameters. Specifically, forward modeling acquisition parameters are used to determine the actual system's acquisition and observation system and parameters, further refining the approximation of the "acquisition and observation system and parameters".

[0046] like Figure 1As shown, in step S102, a forward modeling quantitative analysis of the multiple generation mechanism is performed on the complex seismic geological model to determine the basic conditions and wavefield characteristics of the generation of free surface multiples and interlayer multiples.

[0047] In one embodiment, step S1021 analyzes the generation mechanism and basic conditions of multiples. Specifically, based on the "four approximations" complex seismic geological model obtained in step S101, the model is further adjusted and simplified, the relationship between the intensity of multiples and the reflection coefficient is quantitatively analyzed, and the minimum critical value of the reflection coefficient for generating multiples in the study area is determined by combining the actual reflection coefficient of the drilled strata.

[0048] In one embodiment, step S1022 involves a precise analysis of the wavefield characteristics of multiple waves. Specifically, based on the fundamental conditions for the generation of multiple waves in the study area determined in step S1021, a forward modeling based on the elastic wave equation is performed using a "four-approximation" complex seismic geological model. Targeted analysis of the multiple wave mechanism is then conducted to further clarify the propagation path and wavefield characteristics of multiple waves under complex geological conditions.

[0049] This invention, through quantitative analysis based on the forward modeling results of the "four approximations" model that conforms to reality, further clarifies the necessary conditions for generating multiples, the minimum reflection coefficient interface, and the variation law of the gather domain, providing an important basis for the suppression of multiples in actual seismic data.

[0050] Figure 2 A flowchart of an improved method for analyzing the formation mechanism of multiple waves according to another embodiment of the present invention is shown.

[0051] like Figure 2 As shown, in step S1, based on geological targets, the dominant seismic frequencies are extracted to obtain the dominant frequency body. First, based on the collection of seismic acquisition observation parameters and result data (seismic data, velocity spectra), the reflection characteristics of already determined faults or carbonate fracture-vuggy reservoirs are selected as the basis. For low signal-to-noise ratio seismic data, a seismic dominant frequency information analysis based on geological target constraints is conducted. Frequency information that reflects the stratigraphic structure is selected and fused as the dominant frequency body for the area (e.g., ...). Figure 3 This lays the foundation for the establishment of subsequent models.

[0052] like Figure 2 As shown, in step S2, the dominant frequency body is finely calibrated using wellbore seismic data, and the sonic waveform is square-wave converted to obtain the layer velocities for all formations and key lithologies. Specifically, the dominant frequency body is finely calibrated using drilled sonic waveforms or VSP data (e.g., Figure 4 The main stratigraphic interfaces were determined, and the sonic curves were square-wave converted to obtain the layer velocities of all strata and key lithologies (including gypsum, igneous rocks and limestone).

[0053] like Figure 2 As shown, in step S3, a time-domain tectonic model is established, and a velocity field model constrained by this model is built. Specifically, based on the fine calibration in step S2, a tectonic style is established under the guidance of a geological model, and key stratigraphic interfaces are finely interpreted, ultimately establishing the time-domain tectonic model (e.g., Figure 5 ), and use this as a constraint to establish the velocity field under the constraints of the construction model.

[0054] like Figure 2 As shown, in step S4, based on the constraints of the velocity field model, a complex structural model framework that conforms to reality is established to achieve depth-structure approximation. Specifically, based on the velocity field model constraints established in step S3, the selected time-domain profile is transformed using the velocity difference in the study area to perform time-depth transformation, and the time-depth transformation of the time-domain structural model is carried out to establish a depth-domain structural model (such as...). Figure 6 This forms a framework model that matches the actual burial depth and structure, achieving a "depth-structure" approximation.

[0055] like Figure 2 As shown, in step S5, the layer velocity is used to fill the frame model constraints of the complex structural model, achieving depth-velocity approximation to obtain an initial layer velocity model. Specifically, the layer velocity obtained through fine calibration in step S2 is used to fill the frame model constraints of the complex structural model in step S4 with velocity and density, achieving depth-velocity approximation of the velocity parameter filling, and obtaining an initial layer velocity model (e.g., ...). Figure 7 ).

[0056] like Figure 2 As shown, in step S6, velocity spectrum data and the distribution characteristics of the low-velocity gradient zone are used to extract velocity spectrum data above the water table and fuse it with the initial layer velocity model to obtain a final layer velocity model that conforms to reality, thus achieving surface-low-velocity gradient zone approximation. Specifically, by using the collected velocity spectrum data and the distribution characteristics of the low-velocity gradient zone, velocity spectrum data above the water table is extracted and fused with the initial layer velocity model in step S5 to obtain a final layer velocity model that conforms to reality, effectively solving the problem of insufficient acoustic data and difficulty in simulating velocity variation patterns in shallow layers (such as...). Figure 8 This allows for the approach of the "surface-low speed zone".

[0057] like Figure 2As shown, in step S7, based on the actual seismic acquisition system, forward modeling using the elastic wave equation is employed to simulate seismic acquisition, thereby approximating the acquisition system and acquisition parameters. Specifically, based on the actual seismic acquisition system (4875-200-50-200-4875), forward modeling using the elastic wave equation is employed to simulate seismic acquisition, thereby approximating the "acquisition system and acquisition parameters".

[0058] like Figure 2 As shown, in step S8, a certain point of the complex seismic geological model is abstracted and simplified to analyze the generation conditions of multiple waves through forward modeling. Specifically, a certain point of the above model is abstracted and simplified (e.g., Figure 9 a) to facilitate forward modeling analysis of multiple wave generation conditions and changes in reflection coefficients (e.g.) Figure 9 b) and its relationship with effective wave energy (e.g.) Figure 9 c), thereby better guiding subsequent multiple wave analysis.

[0059] The results show that interlayer multiples always exist, and the amplitude of multiples gradually increases with the increase of the reflection coefficient. When the reflection coefficient reaches about 0.6, the amplitude of multiples reaches its extreme value. Then, as the reflection coefficient continues to increase, the amplitude of multiples gradually weakens due to the influence of transmission. In actual seismic data, the maximum value of the reflection coefficient generally does not exceed 0.5. Therefore, the amplitude of multiples gradually increases with the increase of the reflection coefficient, and only when the reflection coefficient of the downstream interface is >0.18 does it have an impact on the primary wave. The impact of the second-order multiples is relatively small. This further illustrates that in actual data processing, it is sufficient to find and analyze and suppress multiples with a reflection coefficient greater than 0.18, which achieves more accurate analysis and identification of multiples and effectively improves work efficiency.

[0060] like Figure 2 As shown, in step S9, based on step S8, by statistically analyzing all interfaces whose reflection coefficients meet the conditions from drilled wells, the wavefield characteristics of multiple waves in the complex seismic geological model are accurately analyzed to clarify the wavefield characteristics of all multiple waves in the target layer. Specifically, based on the understanding in step S8, by statistically analyzing all interfaces whose reflection coefficients meet the conditions (e.g., greater than 0.18) from drilled wells, the wavefield characteristics of multiple waves in the complex structural model of the "four approximations" are accurately analyzed. Figure 10 In the context of the T50 strong reflective interface, where the reflection coefficient is greater than the 0.18 threshold, the forward modeling of the free surface multiple waves and effective wave field generated by this interface (e.g.) is presented. Figure 10 This allows us to observe the propagation characteristics of multiple waves and their impact on the effective wave at the target layer. By analogy, we can clarify the wavefield characteristics of all multiple waves at the target layer.

[0061] like Figure 2As shown, in step S10, based on step S9, the multiple distribution characteristics of the target layer are finally determined in order to carry out targeted multiple identification and suppression. Specifically, multiple identification and suppression are performed using actual seismic data, that is, based on the multiple well-seismic analysis in step S9, the multiple distribution characteristics of the target layer are finally determined, and targeted multiple identification and suppression are carried out (e.g., Figure 11 ).

[0062] like Figure 11 From the forward modeling results, the forward modeling results based on the "four approximations" principle are closer to the actual seismic reflection characteristics. They clarify the basic conditions and wavefield characteristics of free surface multiples and inter-layer multiples, and effectively guide the application test of multiple identification and suppression technology.

[0063] This invention discloses an improved method for analyzing the formation mechanism of multiples. Combining a simplified model with quantitative analysis of the multiple generation mechanism, it clarifies the basic conditions for multiple generation and the minimum threshold value at which multiples can affect effective wave imaging. Taking into full account actual geological structures, burial depths, surface velocity conditions, and actual seismic acquisition and observation systems, it accurately quantifies and analyzes the wavefield characteristics of multiples, effectively simulating the wavefield characteristics of free-surface multiples and interlayer multiples. This method serves as a bridge for verifying the effectiveness of actual multiple mechanism analysis, identification, and suppression techniques, effectively promoting the improvement of actual seismic data imaging quality.

[0064] The advantages of the multiple wave post-stack identification and suppression in this invention are as follows: By adopting the "four approximations" principle, it considers key factors affecting the propagation of seismic wavefields, such as actual depth, structural morphology, key stratum thickness, layer velocity, and low-velocity zones at the surface, and establishes a geological model that closely approximates actual conditions. The corresponding seismic wavefield is closer to the actual wavefield. At the same time, through quantitative analysis of multiple wave generation conditions, it is possible to generate the main interface combination of multiple waves. Especially in areas with low signal-to-noise ratios where effective wavefields and interfering wavefields are difficult to identify, it can effectively and quickly guide the suppression of multiple waves.

[0065] The improved method and apparatus for analyzing the formation mechanism of multiple waves provided by this invention can also be used in conjunction with a computer-readable storage medium. The storage medium stores a computer program, which is executed to run the improved method for analyzing the formation mechanism of multiple waves. The computer program is capable of executing computer instructions, which include computer program code. The computer program code can be in the form of source code, object code, executable file, or some intermediate form.

[0066] Computer-readable storage media may include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0067] It should be noted that the contents of computer-readable storage media may be appropriately added to or subtracted from the contents according to the requirements of legislation and patent practice in a jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media may not include electrical carrier signals and telecommunication signals.

[0068] The present invention also provides an improved apparatus for analyzing the formation mechanism of multiple waves, which performs an improved method for analyzing the formation mechanism of multiple waves. The apparatus includes a model building module and a multiple wave module.

[0069] Specifically, the model building module is used to construct complex seismic geological models for the study area using the four approximation principles; the multiples module is used to perform forward modeling and quantitative analysis of the multiple generation mechanism of complex seismic geological models in order to determine the basic conditions and wavefield characteristics of free surface multiples and interlayer multiples.

[0070] In summary, the improved method and apparatus for analyzing the formation mechanism of multiples provided by this invention have the following advantages and beneficial effects compared with existing technologies: Existing forward modeling methods for multiple mechanisms based on simple models often only qualitatively analyze the formation mechanism and wavefield characteristics of multiples due to insufficient consideration of actual geological conditions. Under conditions of extremely low signal-to-noise ratio in Ordovician seismic data from the southern Tarim Basin, they cannot effectively guide the identification and suppression of multiples in actual seismic data. This invention starts from the foundation of multiple forward modeling, namely model construction, to approximate the actual geological conditions as closely as possible. By controlling the boundary absorption conditions of the Earth's surface, it specifically realizes forward modeling simulation records of seismic waves including and excluding surface-correlated multiples, and more closely resembles actual seismic data. This provides a good data foundation for testing methods of qualitative / quantitative analysis, identification, and suppression of multiples, effectively guides multiple suppression, and improves the imaging quality of geological targets.

[0071] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0072] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0073] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0074] The phrase "an embodiment" or "an embodiment" as used in the specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0075] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

[0076] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. An improved multiple formation mechanism analysis method, characterized in that, The method is used to quantitatively analyze the formation mechanism of wave multiples, and includes the following steps: For the study area, a complex seismic geological model was constructed using the four approximation principles; A forward modeling quantitative analysis of the multiple generation mechanism was performed on the complex seismic geological model to determine the basic conditions and wavefield characteristics of free surface multiples and interlayer multiples. The construction of the complex seismic geological model includes: using the velocity difference of the study area to perform time-depth conversion on the selected time-domain profile; combining the lithology of the strata encountered in actual drilling with the constraints of the velocity field model, establishing a complex structural model framework that conforms to the actual burial depth and the actual structure to achieve depth-structure approximation; filling the framework model constraints of the complex structural model with layer velocities to achieve depth-velocity approximation and obtain an initial layer velocity model; using velocity spectrum data and the distribution characteristics of low-velocity zones, extracting velocity spectrum data above the water table and fusing it with the initial layer velocity model to obtain a final layer velocity model that conforms to reality, achieving surface-low-velocity zone approximation; and using the actual seismic acquisition and observation system, employing forward modeling of the elastic wave equation to simulate seismic acquisition, achieving approximation of the observation system and acquisition parameters.

2. The improved multiple forming mechanism analysis method of claim 1, wherein, Constructing complex seismic geological models also includes: extracting dominant seismic frequencies based on geological targets to obtain a dominant frequency volume.

3. The improved multi-wavefront generating mechanism analysis method of claim 2, wherein, Constructing a complex seismic geological model also includes: performing fine well-seismic calibration of the dominant frequency body, and obtaining the layer velocities of all strata and key lithologies by square-wave conversion of the sonic curves.

4. The improved multi-wavefront generating mechanism analysis method of claim 3, wherein, Constructing a complex seismic geological model also includes: establishing a time-domain tectonic model, and using this as a constraint to establish the velocity field model under the constraints of the tectonic model.

5. The improved multiple formation mechanism analysis method of claim 1, wherein, The forward modeling quantitative analysis of the multiple wave generation mechanism of the complex seismic geological model includes: abstracting and simplifying a certain point of the complex seismic geological model in order to analyze the generation conditions of multiple waves through forward modeling.

6. The improved multiple formation mechanism analysis method of claim 5, wherein, To determine the basic conditions and wavefield characteristics of free surface multiples and interlayer multiples, the following steps are taken: based on the forward modeling analysis of the multiple generation conditions, the wavefield characteristics of multiples are accurately analyzed for all interfaces whose reflection coefficients meet the conditions through drilling statistics, thereby clarifying the wavefield characteristics of all multiples in the target layer.

7. The improved method for analyzing the formation mechanism of multiple waves as described in claim 6, characterized in that, The method further includes: based on clarifying the wavefield characteristics of all multiples in the target layer, finally determining the distribution characteristics of multiples in the target layer in order to carry out targeted multiple identification and suppression.

8. A storage medium, characterized by It includes a series of instructions for performing the method steps as described in any one of claims 1-7.

9. An improved multiple wave formation mechanism analysis device, characterized by, The apparatus for performing the method as described in any one of claims 1-7 comprises: The model building module is used to construct complex seismic geological models for the study area using the four approximation principles. The multiples module is used to perform forward modeling and quantitative analysis of the multiples generation mechanism of the complex seismic geological model, so as to determine the basic conditions and wavefield characteristics of the generation of free surface multiples and interlayer multiples.

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