Method, system, medium and equipment for determining OBN acquisition maximum offset

Abstract

The invention provides a method, a system, a medium and equipment for determining OBN acquisition maximum offset, and belongs to the technical field of seismic exploration. The method comprises the following steps: constructing a three-dimensional geological model of a target region according to geological measured data and interpretation result data of the target region; seismic wave forward illumination analysis is carried out on the target layer, and the maximum receiving distance of the target layer is determined; calculating the maximum offset distance corresponding to the offset aperture, meeting the offset imaging requirement, of the target layer; carrying out data forward modeling according to the constructed three-dimensional geologic model, and simulating a single shot by adopting a parameter with a relatively large offset distance; performing FWI inversion by using different offset data subjected to forward modeling as input, and comparing FWI inversion results to determine the maximum offset; and comprehensively analyzing and selecting the maximum offset suitable for the target region. According to the method, the maximum offset value required by later AVO analysis, migration imaging, FWI inversion and the like for the acquired data is considered when the OBN acquisition scheme is designed, and the high requirement of OBN acquisition for the data is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of seismic exploration, and in particular relates to a method, a system, a medium and a device for determining a maximum offset distance of OBN acquisition. Background Art

[0002] In recent years, Ocean Bottom Node (OBN) exploration technology has been widely used in oil and gas field exploration in various sea areas around the world, and has achieved good results. The seabed node is less affected by sea conditions and the surrounding environment, and the received data has a higher signal-to-noise ratio, and the data is more comprehensive and undistorted. In addition, OBN seismic acquisition technology can simultaneously obtain longitudinal and transverse wave data, and can achieve wide azimuth (all-round), ultra-high coverage, and ultra-large offset seismic data acquisition. High-quality longitudinal and transverse wave data are combined for lithology identification and reservoir prediction, which can greatly improve the accuracy of oil and gas reservoir identification. OBN technology represents the development direction of marine seismic exploration technology. From a long-term development perspective, it is necessary to master OBN acquisition design, construction and processing technology.

[0003] Due to the unique working mode of OBN exploration, it is very necessary to carry out targeted research on acquisition technology scheme design during the acquisition process. The maximum offset is one of the key parameters in the acquisition scheme, and its size has a great influence on the imaging of the target layer. At present, targeted degradation analysis is generally carried out by establishing a velocity model of the exploration area and using forward simulation imaging analysis methods, but this method is insufficient for later analysis of lithology identification, reservoir prediction, etc. Summary of the invention

[0004] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and to provide a method, system, medium and device for determining the maximum offset distance of OBN acquisition, which can determine the maximum offset distance of OBN acquisition in the target area, improve the imaging effect of OBN acquisition in the target area, and lay the foundation for subsequent analysis work.

[0005] The present invention is achieved through the following technical solutions:

[0006] A first aspect of the present invention provides a method for determining a maximum offset distance of OBN acquisition, comprising the following steps:

[0007] Step 1: construct a three-dimensional geological model of the target area based on the geological measured data and interpretation results of the target area;

[0008] Step 2, performing seismic wave forward illumination analysis on the target layer to determine the maximum receiving distance of the target layer;

[0009] Step 3, calculating the maximum offset distance corresponding to the offset aperture that satisfies the offset imaging requirements of the target layer;

[0010] Step 4: Perform data forward modeling based on the constructed 3D geological model and use parameters with larger offset distance to simulate single shot;

[0011] Step 5, using different offset data of forward simulation as input to perform FWI inversion, comparing the FWI inversion results, and determining the appropriate maximum offset;

[0012] Step 6: Comprehensively analyze and select the maximum offset distance suitable for the target area.

[0013] A further improvement of the present invention is:

[0014] The specific steps of step 1 are:

[0015] A three-dimensional geological model of the target area is constructed based on the depth domain interpretation profile data and depth domain stratigraphic data information of the target area's previous collected data.

[0016] A further improvement of the present invention is:

[0017] In step 2, the seismic wave forward illumination analysis is performed on the target layer to determine the maximum receiving distance of the target layer. The specific operations include:

[0018] Excitation points are arranged on the horizontal plane above the complex structural areas of the 3D geological model to simulate Gaussian ray irradiation of the deepest target layer; in order to ensure the accuracy of parameter selection, it is also necessary to simulate Gaussian ray irradiation in different areas;

[0019] Because OBN acquisition is a method of acquisition in which the excitation point is located under the water surface and the receiving point is located on the seabed, the shot point is placed under the water surface and used as the source point to simulate Gaussian ray irradiation to the target layer in the 3D geological model. The maximum shot offset is determined based on the reflection position of the Gaussian ray irradiation of the target layer received on the seabed when the incident angle meets the 45-degree angle analysis.

[0020] The maximum offset is the distance between the excitation point and the farthest receiving point. In Gaussian ray analysis, the maximum offset is approximately considered to be the maximum receiving distance of the target layer.

[0021] A further improvement of the present invention is:

[0022] The maximum offset distance corresponding to the offset aperture that satisfies the offset imaging requirements of the target layer in step 3 is calculated, and the specific operations include:

[0023] The distance that satisfies the diffraction homing of the target layer structure is calculated based on the average velocity, reflection time and dip angle of the target layer, and the diffraction homing distance at the maximum steep dip angle is used as a reference to determine the design that satisfies the offset aperture. According to experience, the maximum offset distance that satisfies the offset aperture design is recommended to be greater than twice the diffraction homing distance at the maximum steep dip angle.

[0024] The diffraction homing distance of the maximum steep angle is calculated according to the following calculation expression of the diffraction homing distance of the target layer:

[0025]

[0026] Among them, dx is the diffraction homing distance of the target layer, v is the average velocity of the target layer, t is the reflection time of the target layer, θ max The steepest formation dip.

[0027] The present invention is further improved in that:

[0028] In step 4, data forward modeling is performed based on the constructed three-dimensional geological model, and single shot simulation is performed using parameters with a larger offset. The specific operations include:

[0029] According to the constructed three-dimensional geological model, finite element wave equation forward modeling is carried out. The forward modeling observation system is arranged with the shot points located below the water surface and the detection points located on the seabed. The maximum shot offset is set to a larger value. A certain distance is added on the basis of satisfying the lighting analysis and offset aperture to increase the amount of redundant analysis.

[0030] A further improvement of the present invention is:

[0031] In step 5, different offset data of forward modeling are used as input to perform FWI inversion, and the FWI inversion results are compared to determine the appropriate maximum offset. The specific operations include:

[0032] According to the data of forward simulation, different offset data are used as input to perform FWI inversion velocity model;

[0033] Compare the FWI inversion results of different offset distances, and determine the maximum offset distance required for FWI inversion based on the accuracy of the inverted velocity model and the comparison with the 3D geological model constructed in step 1.

[0034] A further improvement of the present invention is:

[0035] In step 6, comprehensive analysis is performed to select the maximum offset distance suitable for the target area. The specific operations include:

[0036] Select a distance that can simultaneously meet the forward ray illumination results, offset aperture requirements and FWI inversion results as the maximum offset distance for target area OBN acquisition.

[0037] A second aspect of the present invention provides a system for determining a maximum offset distance of OBN acquisition, comprising:

[0038] A three-dimensional geological model building unit is used to build a three-dimensional geological model of the target area based on the geological measured data and interpretation results data of the target area;

[0039] A forward illumination analysis unit, used to perform forward illumination analysis of seismic waves on the target layer and determine the maximum receiving distance of the target layer;

[0040] A migration aperture analysis unit is used to calculate the maximum migration distance corresponding to the migration aperture of the target layer that meets the migration imaging requirements;

[0041] The forward simulation unit is used to perform data forward modeling based on the constructed three-dimensional geological model and simulate single shot using parameters with larger offset distances;

[0042] The FWI inversion unit is used to use different offset data of the forward simulation as input to perform FWI inversion, compare the FWI inversion results, and determine the appropriate maximum offset;

[0043] The maximum offset determination unit is used for comprehensive analysis and selection of the maximum offset suitable for the target area.

[0044] A third object of the present invention is to provide a computer-readable storage medium, wherein the computer-readable storage medium stores at least one program executable by a computer, and when the at least one program is executed by the computer, the computer executes the steps in the method for determining the maximum offset distance of OBN acquisition as described above.

[0045] A fourth aspect of the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for determining the maximum offset distance of OBN acquisition as described above.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The method of the present invention takes into account the maximum offset value required for the acquired data by the later AVO analysis, migration imaging and FWI inversion when designing the OBN acquisition scheme, thus ensuring the high data requirements of OBN acquisition. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 The present invention provides a flow chart of a method for determining a maximum offset distance of OBN acquisition;

[0049] Figure 2 To analyze the seismic wave forward illumination of the target layer;

[0050] Figure 3 It is one of the two-dimensional geological models in the actual geological model of the target area;

[0051] Figure 4 This is the FWI inversion result diagram of 6000m offset data;

[0052] Figure 5 This is the FWI inversion result diagram of 7000m offset data;

[0053] Figure 6 This is the FWI inversion result diagram of 8000m offset data. DETAILED DESCRIPTION

[0054] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0055] The present invention establishes a three-dimensional geological model of the target area to be collected, performs seismic wave forward illumination analysis on the target layer, and determines the maximum receiving distance of the target layer; then, according to the velocity and structural characteristics of the target layer in the target area, calculates the maximum offset distance corresponding to the offset aperture that meets the offset imaging requirements of the target layer; then, forward modeling is used for the geological model of the target area, and different offset distance data of the forward modeling data are used for FWI inversion, and the maximum offset distance value required to be adopted is determined by comparing the FWI inversion accuracy; finally, the maximum offset distance parameter value of the OBN acquisition of the target area is determined by comprehensively analyzing the forward ray illumination results, the offset aperture requirement results, and the maximum offset distance value determined by the FWI inversion results. This method takes into account the maximum shot distance value required for the acquisition data by the later AVO analysis, offset imaging, and FWI inversion when designing the OBN acquisition plan, ensuring the high requirements of OBN acquisition for data.

[0056] The present invention provides a method for determining the maximum offset distance of OBN acquisition, and an embodiment of the method is as follows:

[0057] [Example 1]

[0058] like Figure 1 As shown, the method comprises the following steps:

[0059] Step 1: construct a three-dimensional geological model of the target area based on the geological measured data and interpretation results of the target area;

[0060] A three-dimensional geological model of the target area is constructed based on the depth domain interpretation profile data, depth domain stratigraphic data and other information of the previously collected data of the target area.

[0061] Step 2, performing seismic wave forward illumination analysis on the target layer to determine the maximum receiving distance of the target layer;

[0062] Excitation points are arranged on the horizontal plane above the complex structural areas of the 3D geological model, and Gaussian ray irradiation is simulated for the deepest target layer. The purpose is to better reflect the particularity of the maximum offset distance parameter in the complex structural areas and ensure the imaging effect in the complex structural areas.

[0063] In order to ensure the accuracy of parameter selection, it is also necessary to simulate Gaussian ray irradiation in different areas, and finally statistically analyze the results of each observation point, comprehensively consider, and select the appropriate maximum offset parameter value. Because there may be multiple strata in the target layer area and the structural changes may also be variable, different strata need to be irradiated when simulating Gaussian ray irradiation to ensure that the selected maximum offset parameter value is the most effective.

[0064] Because OBN acquisition is a collection method in which the excitation point is located below the water surface and the receiving point is located on the seabed, the shot point (excitation point) is placed below the water surface and used as the source point to simulate Gaussian ray irradiation to the target layer in the three-dimensional geological model. The analysis is performed from the perspective of the incident angle satisfying 45 degrees, and the maximum shot distance is determined based on the reflection position of the Gaussian ray irradiation of the target layer received on the seabed.

[0065] The maximum offset is the distance between the excitation point and the farthest receiving point. In Gaussian ray analysis, it can be approximately considered that the maximum offset is the maximum receiving distance of the target layer.

[0066] Step 3, calculating the maximum offset distance corresponding to the offset aperture that satisfies the offset imaging requirements of the target layer;

[0067] The distance that satisfies the diffraction homing of the target layer structure is calculated based on the average velocity, reflection time, dip angle and other parameters of the target layer, and the diffraction homing distance at the maximum steep dip angle is used as a reference to determine the design that satisfies the offset aperture. According to experience, the maximum offset distance that satisfies the offset aperture design is recommended to be greater than twice the diffraction homing distance at the maximum steep dip angle.

[0068] Optionally, the diffraction homing distance of the maximum steep inclination angle is calculated according to the following calculation expression of the diffraction homing distance of the target layer:

[0069]

[0070] Among them, dx is the diffraction homing distance of the target layer, v is the average velocity of the target layer, t is the reflection time of the target layer, θ max The steepest formation dip.

[0071] Step 4: Perform data forward modeling based on the constructed 3D geological model and use parameters with larger offset distance to simulate single shot;

[0072] Based on the constructed three-dimensional geological model, finite element wave equation forward modeling is carried out. The forward modeling observation system is arranged with the shot points located below the water surface and the detection points located on the seabed. The maximum shot offset is set to a larger value. On the basis of satisfying the lighting analysis and offset aperture, a certain distance is added (there is no specific requirement for this increased distance. In actual implementation, 1000-2000m is added to the previous analysis for redundant analysis) to increase the amount of redundant analysis.

[0073] Step 5, using different offset data of forward simulation as input to perform FWI inversion, comparing the FWI inversion results, and determining the appropriate maximum offset;

[0074] According to the data of forward simulation, different offset data are used as input for FWI inversion velocity model. OBN acquisition data has the advantages of long offset and full range, which is more suitable for the needs of FWI inversion. Therefore, it is very important to ensure the data integrity required for FWI inversion in OBN acquisition.

[0075] By comparing the FWI inversion results of different offset distances, the maximum offset distance value required for FWI inversion can be determined based on the accuracy of the inverted velocity model and the comparison with the 3D geological model constructed in step 1.

[0076] Step 6: Comprehensively analyze and select the maximum offset distance suitable for the target area.

[0077] The forward ray illumination results, offset aperture requirements, and FWI inversion results are comprehensively analyzed, and the maximum offset distance suitable for OBN acquisition in the target area is finally selected.

[0078] Finally, a distance that can simultaneously meet the forward ray illumination results, offset aperture requirements, and FWI inversion results is selected as the maximum offset distance for OBN acquisition in the target area.

[0079] The embodiments of the method of the present invention are as follows:

[0080] [Example 2]

[0081] A target area needs to be OBN seismic acquisition, and an observation system for the geological features and target layers of the target area needs to be designed. In the design of the observation system, the optimization of key acquisition parameters is very important. Among them, the optimization of the maximum offset distance is one of the very important acquisition parameters, which directly affects the imaging effect of the acquired data and the subsequent inversion modeling. The method of the present invention is used to determine the maximum offset distance of OBN acquisition in a target area, including the following steps:

[0082] 1) Construct a 3D geological model based on the depth domain interpretation results and stratigraphic data collected in the target area in the past. In the process of constructing the geological model, it is necessary to try to be consistent with the actual situation, including structural characteristics, depth and velocity of each stratigraphic layer, so that the subsequent analysis is more in line with the actual situation.

[0083] 2) An excitation source is arranged on the horizontal plane above the area with more complex structures in the model, and Gaussian ray irradiation is simulated for the deepest target layer. The purpose is to better reflect the particularity of the maximum offset distance parameter in the area with complex structures and ensure the imaging effect of the complex structural area. In order to ensure the accuracy of parameter selection, it is also necessary to simulate Gaussian ray irradiation in different areas, and finally statistically analyze the results of each observation point, and comprehensively consider and select the appropriate maximum offset distance parameter value. Because there may be multiple sets of strata in the target layer area and the structural changes may also be variable, it is necessary to irradiate different strata when simulating Gaussian ray irradiation to ensure that the selected maximum offset distance parameter value is the most effective. It is generally believed that if AVO analysis and elastic impedance inversion are to be performed on the target layer, the incident angle is generally required to reach more than 40°. Figure 2 This is the result of irradiating the target layer with rays that meet an incident angle of 45 degrees with the sea surface excitation and the seabed reception in this embodiment. When calculating the offset, the result is calculated based on the reflection of the sea surface excitation to the receiving position of the seabed detector, and the result is 6900m.

[0084] 3) Use the target layer's requirements for the offset aperture to select the maximum offset parameter value. The pre-stack migration's requirements for data should be guaranteed during the data acquisition process. In particular, the maximum offset and the maximum longitudinal offset are the decisive factors in improving the quality of mid-deep data. If these two parameters are selected to be small, simply increasing the offset aperture during the post-processing process will not produce the ideal offset effect. During the processing, pre-stack migration comprehensively determines the optimal offset aperture based on the target layer's regional velocity and the steepest formation dip. Therefore, in this embodiment, the optimal offset aperture is determined based on the target layer's average velocity (3825.21 m / s), the target layer's reflection time (2974 ms) and the maximum dip (30 0 ) is used to calculate the diffraction homing distance as 3281m. In order to meet the requirements of the offset aperture, the maximum offset distance is selected to be twice greater than this value, that is, greater than 3281x2=6562m.

[0085] 4) According to the established three-dimensional geological model, a single shot wave equation simulation is performed. Before the simulation, it is necessary to establish a simulated observation method. The observation method of this embodiment adopts a shot point located 5m below the water surface and a detection point located on the seabed, trying to simulate the actual field acquisition method. In the setting of the maximum shot offset, a larger value of 9000m is selected, which is basically to increase a certain distance on the basis of meeting the lighting analysis and offset aperture, in order to increase the redundant analysis amount and ensure that the selected maximum offset meets the various analysis requirements in the later stage.

[0086] 5) FWI inversion velocity model is carried out by simulating a single shot, and the velocity model accuracy of the single shot data FWI inversion at different offsets is compared to study the maximum offset required. As a high-precision quantitative seismic imaging method, the FWI inversion method has achieved very good results in oil and gas exploration in complex areas today. But to make the FWI inversion method really play its due value, it is first necessary to ensure the integrity of seismic data. In this embodiment, different offset distances (5000m, 6000m, 7000m, 8000m, 9000m) data of the forward simulation data of the target area are used as input data for FWI inversion, and the inversion results of different offset distance data are compared. When the inversion accuracy is not obvious after the offset value increases, it can be considered that the offset value satisfies the integrity of the FWI inversion data, and a larger offset value is considered unnecessary.

[0087] Figure 3 It is one of the two-dimensional geological models in the actual geological model of the target area in this embodiment. Figure 4 This is the inversion result of the 6000m offset data, from which we can see that the shallow layer has obtained a better inversion model result. Figure 5 This is the inversion result of the 7000m offset data. It can be seen that the accuracy of deep velocity inversion is further improved. Figure 6 This is the inversion result of the 8000m offset data. It can be seen that the improvement in inversion accuracy is not obvious. Therefore, based on the accuracy comparison of FWI inversion, it is believed that the maximum offset of the target area should be above 7000m.

[0088] 6) Comprehensively analyze the forward ray illumination results, offset aperture requirements and FWI inversion results, and finally select the maximum offset distance value of more than 7000m suitable for OBN acquisition in the target area.

[0089] The present invention also provides a system for determining the maximum offset distance of OBN acquisition, and an embodiment of the system is as follows:

[0090] [Example 3]

[0091] The system comprises:

[0092] A three-dimensional geological model building unit is used to build a three-dimensional geological model of the target area based on the geological measured data and interpretation results data of the target area;

[0093] A forward illumination analysis unit, used to perform forward illumination analysis of seismic waves on the target layer and determine the maximum receiving distance of the target layer;

[0094] A migration aperture analysis unit is used to calculate the maximum migration distance corresponding to the migration aperture of the target layer that meets the migration imaging requirements;

[0095] The forward simulation unit is used to perform data forward modeling based on the constructed three-dimensional geological model and simulate single shot using parameters with larger offset distances;

[0096] The FWI inversion unit is used to use different offset data of the forward simulation as input to perform FWI inversion, compare the FWI inversion results, and determine the appropriate maximum offset;

[0097] The maximum offset determination unit is used for comprehensive analysis and selection of the maximum offset suitable for the target area.

[0098] The present invention also provides a computer-readable storage medium, and an embodiment of the computer-readable storage medium is as follows:

[0099] [Example 4]

[0100] The computer-readable storage medium stores at least one program executable by a computer. When the at least one program is executed by the computer, the computer is caused to execute the steps in the method for determining the maximum offset distance of OBN acquisition as described in the first embodiment.

[0101] The present invention also provides a computer device, and the embodiments of the computer device are as follows:

[0102] [Example 5]

[0103] The computer device includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor executes the steps of the method for determining the maximum offset distance of OBN acquisition as described in the first embodiment.

[0104] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0105] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A method for determining the maximum offset of OBN acquisition, characterized in that: The steps include: Step 1: construct a three-dimensional geological model of the target area based on the geological measured data and interpretation results of the target area; Step 2, performing seismic wave forward illumination analysis on the target layer to determine the maximum receiving distance of the target layer; Step 3, calculating the maximum offset distance corresponding to the offset aperture that satisfies the offset imaging requirements of the target layer; Step 4: Perform data forward modeling based on the constructed 3D geological model and use parameters with larger offset distance to simulate single shot; Step 5, using different offset data of forward simulation as input to perform FWI inversion, comparing the FWI inversion results, and determining the appropriate maximum offset; Step 6: Comprehensively analyze and select the maximum offset distance suitable for the target area.

2. The method for determining the maximum offset distance of OBN acquisition according to claim 1, characterized in that: The specific steps of step 1 are: A three-dimensional geological model of the target area is constructed based on the depth domain interpretation profile data and depth domain stratigraphic data information of the target area's previous collected data.

3. The method for determining the maximum offset distance of OBN acquisition according to claim 1, characterized in that: In step 2, the seismic wave forward illumination analysis is performed on the target layer to determine the maximum receiving distance of the target layer. The specific operations include: Excitation points are arranged on the horizontal plane above the complex structural areas of the 3D geological model to simulate Gaussian ray irradiation of the deepest target layer; in order to ensure the accuracy of parameter selection, it is also necessary to simulate Gaussian ray irradiation in different areas; Because OBN acquisition is a method of acquisition in which the excitation point is located under the water surface and the receiving point is located on the seabed, the shot point is placed under the water surface and used as the source point to simulate Gaussian ray irradiation to the target layer in the 3D geological model. The maximum shot offset is determined based on the reflection position of the Gaussian ray irradiation of the target layer received on the seabed when the incident angle meets the 45-degree angle analysis. The maximum offset is the distance between the excitation point and the farthest receiving point. In Gaussian ray analysis, the maximum offset is approximately considered to be the maximum receiving distance of the target layer.

4. The method for determining the maximum offset of OBN acquisition according to claim 1, characterized in that: The maximum offset distance corresponding to the offset aperture that satisfies the offset imaging requirements of the target layer in step 3 is calculated, and the specific operations include: The distance that satisfies the diffraction homing of the target layer structure is calculated based on the average velocity, reflection time and dip angle of the target layer, and the diffraction homing distance at the maximum steep dip angle is used as a reference to determine the design that satisfies the offset aperture. According to experience, the maximum offset distance that satisfies the offset aperture design is recommended to be greater than twice the diffraction homing distance at the maximum steep dip angle. The diffraction homing distance of the maximum steep angle is calculated according to the following calculation expression of the diffraction homing distance of the target layer: Among them, dx is the diffraction homing distance of the target layer, v is the average velocity of the target layer, t is the reflection time of the target layer, θ max The steepest formation dip.

5. The method for determining the maximum offset distance of OBN acquisition according to claim 1, characterized in that: In step 4, data forward modeling is performed based on the constructed three-dimensional geological model, and single shot simulation is performed using parameters with a larger offset. The specific operations include: According to the constructed three-dimensional geological model, finite element wave equation forward modeling is carried out. The forward modeling observation system is arranged with the shot points located below the water surface and the detection points located on the seabed. The maximum shot offset is set to a larger value. On the basis of satisfying the lighting analysis and offset aperture, a certain distance is added to increase the amount of redundant analysis.

6. The method for determining the maximum offset distance of OBN acquisition according to claim 5, characterized in that: In step 5, different offset data of forward modeling are used as input to perform FWI inversion, and the FWI inversion results are compared to determine the appropriate maximum offset. The specific operations include: According to the data of forward simulation, different offset data are used as input to perform FWI inversion velocity model; Compare the FWI inversion results of different offset distances, and determine the maximum offset distance required for FWI inversion based on the accuracy of the inverted velocity model and the comparison with the 3D geological model constructed in step 1.

7. The method for determining the maximum offset distance of OBN acquisition according to claim 1, characterized in that: In step 6, comprehensive analysis is performed to select the maximum offset distance suitable for the target area. The specific operations include: Select a distance that can simultaneously meet the forward ray illumination results, offset aperture requirements and FWI inversion results as the maximum offset distance for target area OBN acquisition.

8. A system for determining the maximum offset of OBN acquisition, characterized in that: include: A three-dimensional geological model building unit is used to build a three-dimensional geological model of the target area based on the geological measured data and interpretation results data of the target area; A forward illumination analysis unit, used to perform forward illumination analysis of seismic waves on the target layer and determine the maximum receiving distance of the target layer; A migration aperture analysis unit is used to calculate the maximum migration distance corresponding to the migration aperture of the target layer that meets the migration imaging requirements; The forward simulation unit is used to perform data forward modeling based on the constructed three-dimensional geological model and simulate single shot using parameters with larger offset distances; The FWI inversion unit is used to use different offset data of the forward simulation as input to perform FWI inversion, compare the FWI inversion results, and determine the appropriate maximum offset; The maximum offset determination unit is used for comprehensive analysis and selection of the maximum offset suitable for the target area.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one computer-executable program, and when the at least one program is executed by the computer, the computer executes the steps of the method for determining the maximum offset distance of OBN acquisition according to any one of claims 1 to 7.

10. A computer device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for determining the maximum offset distance of OBN acquisition according to any one of claims 1 to 7.

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