Large-offset seismic data dynamic correction method and system, electronic equipment and storage medium

Abstract

The invention provides a large-offset seismic data dynamic correction method and system, electronic equipment and a storage medium. Belongs to the technical field of seismic exploration data processing. The method adopts a step-by-step dynamic correction strategy and comprises the following steps of: firstly, accurately imaging a high-speed layer top and an overlying stratum structure of the high-speed layer top by adopting a conventional hyperbolic dynamic correction method on near-offset data; next, near-trace components in the far-offset data are removed by utilizing a strict internal excision method, and a linear dynamic correction method is adopted for the reserved far-offset data to analyze a deep stratum structure below a high-speed layer according to the characteristic that a large-offset time curve presents near linearity; and finally, overlapping and fusing the two parts of data. According to the method, the problem of stretching distortion generated at a large offset distance in conventional dynamic correction is effectively solved, shallow information loss caused by a traditional cutting method is avoided, wide-angle reflection information is fully utilized, the energy, the signal-to-noise ratio and the continuity of a main target layer are remarkably improved, and the deep imaging quality is improved.

Description

Technical Field

[0001] This invention relates to the field of seismic exploration data processing, and in particular to a method, system, electronic device, and storage medium for dynamic correction of large offset seismic data. Background Technology

[0002] As oil and gas exploration advances into deeper, ultra-deeper layers and complex mountainous terrain, seismic exploration technology continues to develop, and long-offset seismic data acquisition has become commonplace. Long-offset data contains rich wide-angle reflection and refraction information, which is crucial for imaging deep geological structures.

[0003] However, processing long-offset seismic data presents significant technical challenges. Conventional dynamic correction (NMO) methods are typically based on the hyperbolic assumption (i.e., assuming the subsurface medium is horizontally layered and isotropic), which works well at short offsets. However, as the offset increases, the actual time-distance curve deviates from the hyperbolic curve, especially in the presence of high-velocity shielding layers or strong anisotropy. Forcing conventional hyperbolic dynamic correction onto long-offset data causes severe "NMO stretching" distortion, leading to reduced frequency, decreased resolution, and even spurious frequencies, severely impacting the fidelity of the seismic data and the quality of shallow imaging.

[0004] In existing technologies, two strategies are typically employed to eliminate the effects of dynamic stretching distortion: 1. Muting: Directly removes large offset data with severe stretching (external removal). Although this method is simple, it leads to the loss of effective reflection information in the shallow and middle layers, and completely wastes the deep wide-angle reflection information carried by the far offset, making it impossible to achieve effective illumination of deep targets.

[0005] 2. Higher-order dynamic correction: Introducing anisotropic parameters and employing fourth- or sixth-order non-hyperbolic dynamic correction formulas. Although this method can reduce stretching distortion to some extent, it is computationally complex, and for extremely long offset distances (wide-angle reflection areas), the time-distance curve shape is already close to linear, so higher-order fitting still cannot fundamentally eliminate distortion and is prone to introducing fitting errors.

[0006] Given the physical characteristic that the time-distance curve at large offsets is almost a straight line at the far end, conventional methods are inadequate. Therefore, a new dynamic correction method is urgently needed that can both preserve high-resolution information in shallow layers and effectively utilize wide-angle reflection information at long offsets to improve the imaging quality of deep target layers.

[0007] The above technical issues urgently need to be resolved. Summary of the Invention

[0008] The purpose of this invention is to provide a large offset dynamic correction method. By adopting a "two-step" strategy, the physical characteristics of near offset and far offset data are processed differently, thereby reducing dynamic correction distortion and improving the quality of deep imaging.

[0009] The first aspect of this invention discloses a dynamic correction method for large offset seismic data, the method comprising: Step S1: Acquire seismic acquisition data and, based on a preset offset threshold, divide the seismic data into near offset data and far offset data. Step S2: The near-offset data portion is processed using a hyperbolic motion correction method to image the high-velocity top interface and its overlying strata structure; Step S3: Perform an inner cut-off operation on the far offset data portion to remove near offset information, and process it using a linear dynamic correction method based on the linear characteristics of the far offset time-distance curve to image the formation structure below the high-velocity layer. Step S4: Overlay and fuse the dynamically corrected near offset data with the dynamically corrected far offset data to obtain the final ground motion correction profile.

[0010] Preferably, in step S1, the method for determining the preset offset threshold includes: Construct a seismic geological model of the target work area; Forward modeling based on the wave equation was performed to analyze the wave field characteristics at different offsets. The effective gun-receiver distance range of wide-angle reflections was determined through ultra-long array tests. The offset distance corresponding to the transition area between conventional reflection and wide-angle reflection is selected as the offset distance threshold.

[0011] Preferably, step S2 specifically includes: Step S21: Perform velocity spectrum analysis on the near offset data and pick the stacked velocity; Step S22: Using the hyperbolic time-distance equation Initial dynamic correction of near offset data Where t is the reflection time, t0 is the zero offset time, x is the offset distance, and v is the root mean square velocity, thus obtaining preliminary structural imaging; Step S23: Based on the preliminary structure, perform residual velocity analysis or anisotropic parameter extraction, and perform high-precision hyperbolic motion correction on the near offset data.

[0012] Preferably, in step S3, the specific method of the internal resection operation is as follows: Based on the depth or time position of the high-velocity layer top interface determined in step S2, and the offset threshold, determine the inner cutoff function; In the far offset data, the data sample values ​​within the offset threshold are set to zero or removed, while the wide-angle reflection information greater than the offset threshold is retained.

[0013] Preferably, in step S3, the linear dynamic correction method specifically includes: Step S31: For the far offset data after internal resection, identify the in-phase axis under large offset; Step S32: Based on the characteristic that the large offset time-distance curve is almost a straight line, construct a linear time-distance equation: or , Where v app τ is the apparent velocity, p is the ray parameter, and τ is the intercept time; Step S33: Calculate the correction amount for each far offset channel using the linear time-distance equation, and correct the far offset data to the zero offset position; In step S3, if the near offset data has anisotropic characteristics, a non-hyperbolic motion correction formula is used for processing. The non-hyperbolic motion correction formula includes fourth-order or sixth-order anisotropic parameter terms.

[0014] Preferably, step S4 specifically includes: Energy equalization processing is performed on the dynamically corrected near-offset data and far-offset data. Within the transition zone near the offset threshold, a weighted superposition method is used for splicing to eliminate the boundary effect at the data splicing point; The output is a full-offset overlay profile containing both shallow high-resolution information and deep wide-angle reflection information; The process after step S4 also includes: Determine whether the energy, signal-to-noise ratio, and continuity of the main target layer in the stacked profile meet the preset quality standards; If the condition is not met, the offset threshold is adjusted or the linear correction parameters in step S3 are re-acquired, and the process is returned to step S3 for reprocessing.

[0015] Preferably, the seismic geological model of the target work area further includes: For deep or ultra-deep low signal-to-noise ratio areas, a velocity model including high-velocity and low-velocity layers is established by combining well logging data and geological stratification information. Based on wide-angle imaging theory, the parameters of the observation system are designed, including the maximum shot-receiver distance and the number of coverages, to ensure that the wide-angle reflection information has a preset number of coverages in the long-offset data.

[0016] A second aspect of the present invention discloses a dynamic correction system for large offset seismic data, the system comprising: The first processing module is configured to acquire seismic acquisition data and, based on a preset offset threshold, divide the seismic data into near offset data and far offset data. The second processing module is configured to process the near offset data portion using a hyperbolic motion correction method to image the high-velocity top interface and its overlying strata structure. The third processing module is configured to perform an inner cut-off operation on the far offset data portion to remove near offset information, and to process it using a linear dynamic correction method based on the linear characteristics of the far offset time-distance curve, so as to image the stratigraphic structure below the high-velocity layer. The fourth processing module is configured to superimpose and fuse the dynamically corrected near offset data portion with the dynamically corrected far offset data portion to obtain the final ground motion correction profile.

[0017] In some specific embodiments, the first processing module 101 is further configured to determine the preset offset threshold by: Construct a seismic geological model of the target work area; Forward modeling based on the wave equation was performed to analyze the wave field characteristics at different offsets. The effective gun-receiver distance range of wide-angle reflections was determined through ultra-long array tests. The offset distance corresponding to the transition area between conventional reflection and wide-angle reflection is selected as the offset distance threshold.

[0018] In some specific embodiments, the second processing module 102 is further configured to, Perform velocity spectrum analysis on near offset data to pick up the stacking velocity; Using the hyperbolic time distance equation Initial dynamic correction of near offset data Where t is the reflection time, t0 is the zero offset time, x is the offset distance, and v is the root mean square velocity, thus obtaining preliminary structural imaging; Based on the preliminary structure, residual velocity analysis or anisotropic parameter extraction is performed, and high-precision hyperbolic motion correction is carried out on the near offset data.

[0019] In some specific embodiments, the third processing module 103 is further configured such that the internal resection operation specifically comprises: Based on the depth or time position of the high-speed layer top interface determined above, and the offset threshold, the inner cut-off function is determined; In the far offset data, the data sample values ​​within the offset threshold are set to zero or removed, while the wide-angle reflection information greater than the offset threshold is retained.

[0020] Preferably, the third processing module is further configured such that the linear dynamic correction specifically includes: Identify the in-phase axis under large offset for the far offset data after internal resection; Based on the characteristic that the time-distance curve with large offset is almost a straight line, a linear time-distance equation is constructed: or , Where v app τ is the apparent velocity, p is the ray parameter, and τ is the intercept time; The correction amount for each far offset channel is calculated using the linear time-distance equation, and the far offset data is corrected to the zero offset position. Preferably, the third processing module is further configured to process the near offset data using a non-hyperbolic motion correction formula if the near offset data exhibits anisotropic characteristics. The non-hyperbolic motion correction formula includes fourth-order or sixth-order anisotropic parameter terms.

[0021] Preferably, the fourth processing module is further configured to specifically include: Energy equalization processing is performed on the dynamically corrected near-offset data and far-offset data. Within the transition zone near the offset threshold, a weighted superposition method is used for splicing to eliminate the boundary effect at the data splicing point; The output is a full-offset overlay profile containing both shallow high-resolution information and deep wide-angle reflection information; In some specific embodiments, the system further includes a fifth processing module, configured to, Determine whether the energy, signal-to-noise ratio, and continuity of the main target layer in the stacked profile meet the preset quality standards; If the condition is not met, the offset threshold is adjusted or the linear correction parameters in the third module are re-acquired, and the process is returned to the third module for reprocessing.

[0022] A third aspect of this invention discloses an electronic device. The electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of a large-offset seismic data dynamic correction method according to any one of the first aspects of this disclosure.

[0023] A fourth aspect of this invention discloses a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a large-offset seismic data dynamic correction method according to any one of the first aspects of this disclosure.

[0024] The beneficial effects of this invention are as follows: 1. Completely eliminates stretching distortion: This invention abandons the approach of trying to fit the entire offset with a single hyperbola, and instead processes the data in segments according to the wavefield characteristics. Linear dynamic correction is used for long offset data, which conforms to the physical propagation law of wide-angle reflection / refraction, fundamentally eliminating the stretching distortion caused by forced hyperbolic correction.

[0025] 2. Make full use of wide-angle information: Avoid the information waste caused by traditional dynamic set excision (external excision), especially by preserving and correcting wide-angle reflection information at long offset distances, which significantly improves the energy, signal-to-noise ratio and continuity of deep and ultra-deep target layers.

[0026] 3. Improved imaging quality: Combining the advantages of high-frequency details at near offset and deep illumination at far offset, the final profile maintains high resolution in shallow layers and clear structure in deep layers, with a high signal-to-noise ratio.

[0027] 4. High efficiency and practicality: Compared with complex high-order anisotropic inversion and correction, the linear correction calculation in this method is simple, has high stability, does not require complex inverse operator calculation and recursive correction, and is easy to implement in industrial production. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a flowchart of a large-offset seismic data dynamic correction method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the effect of unconventional hyperbolic motion correction (2nd order anisotropy) in the existing technology; it can be seen that the data beyond 8km still has the problem of unevenness.

[0030] Figure 3 This is a schematic diagram illustrating the effect of the two-step dynamic correction method in an embodiment of the present invention; it shows the combination of near-track hyperbolic correction and far-track linear correction, with the in-phase axis achieving leveling across the entire offset range.

[0031] Figure 4 The above image shows a comparison of the superimposed cross-sections before and after dynamic correction in an embodiment of the present invention. The top image shows the result without utilizing wide-angle information, while the bottom image shows the effect after utilizing the method of the present invention. The energy and continuity of the main target layer are significantly improved.

[0032] Figure 5 This is a structural diagram of a large-offset seismic data dynamic correction system according to an embodiment of the present invention; Figure 6 This is a structural diagram of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0034] The first aspect of this invention discloses a dynamic correction method for large offset seismic data.

[0035] This invention employs a two-step dynamic correction method. For near-offset data, a conventional hyperbolic dynamic correction method is used to accurately determine the structure of the top of the high-velocity layer and its overlying strata. Then, a rigorous "internal cut" method is used to cut off the near-offset data, and a linear dynamic correction method is used for the far-offset data to clarify the stratigraphic structure beneath the high-velocity layer. This reduces dynamic correction distortion and error, and utilizes the profile of wide-angle reflection information. The energy, signal-to-noise ratio, and continuity of the main target layer are significantly improved, thus enhancing the quality of deep imaging.

[0036] Example 1: Figure 1 This is a flowchart of a large-offset seismic data dynamic correction method according to an embodiment of the present invention, such as... Figure 1 As shown, the method includes: Step S1: Acquire seismic acquisition data and, based on a preset offset threshold, divide the seismic data into near offset data and far offset data. In step S1, the method for determining the preset offset threshold includes: Construct a seismic geological model of the target work area; Forward modeling based on the wave equation was performed to analyze the wave field characteristics at different offsets. The effective gun-receiver distance range of wide-angle reflections was determined through ultra-long array tests. The offset distance corresponding to the transition area between conventional reflection and wide-angle reflection is selected as the offset distance threshold.

[0037] Step S2: The near-offset data portion is processed using a hyperbolic motion correction method to image the high-velocity top interface and its overlying strata structure; Step S2 specifically includes: Step S21: Perform velocity spectrum analysis on the near offset data and pick the stacked velocity; Step S22: Using the hyperbolic time-distance equation Initial dynamic correction of near offset data Where t is the reflection time, t0 is the zero offset time, x is the offset distance, and v is the root mean square velocity, thus obtaining preliminary structural imaging; Step S23: Based on the preliminary structure, perform residual velocity analysis or anisotropic parameter extraction, and perform high-precision hyperbolic motion correction on the near offset data.

[0038] Step S3: Perform an inner cut-off operation on the far offset data portion to remove near offset information, and process it using a linear dynamic correction method based on the linear characteristics of the far offset time-distance curve to image the formation structure below the high-velocity layer. In step S3, the specific method for the internal resection operation is as follows: Based on the depth or time position of the high-velocity layer top interface determined in step S2, and the offset threshold, determine the inner cutoff function; In the far offset data, the data sample values ​​within the offset threshold are set to zero or removed, while the wide-angle reflection information greater than the offset threshold is retained.

[0039] In step S3, the linear dynamic correction method specifically includes: Step S31: For the far offset data after internal resection, identify the in-phase axis under large offset; Step S32: Based on the characteristic that the large offset time-distance curve is almost a straight line, construct a linear time-distance equation: or , Where v app τ is the apparent velocity, p is the ray parameter, and τ is the intercept time; Step S33: Calculate the correction amount for each far offset channel using the linear time-distance equation, and correct the far offset data to the zero offset position; In step S3, if the near offset data has anisotropic characteristics, a non-hyperbolic motion correction formula is used for processing. The non-hyperbolic motion correction formula includes fourth-order or sixth-order anisotropic parameter terms.

[0040] Step S4: Overlay and fuse the dynamically corrected near offset data with the dynamically corrected far offset data to obtain the final ground motion correction profile.

[0041] Step S4 specifically includes: Energy equalization processing is performed on the dynamically corrected near-offset data and far-offset data. Within the transition zone near the offset threshold, a weighted superposition method is used for splicing to eliminate the boundary effect at the data splicing point; The output is a full-offset overlay profile containing both shallow high-resolution information and deep wide-angle reflection information; The process after step S4 also includes: Determine whether the energy, signal-to-noise ratio, and continuity of the main target layer in the stacked profile meet the preset quality standards; If the condition is not met, the offset threshold is adjusted or the linear correction parameters in step S3 are re-acquired, and the process is returned to step S3 for reprocessing.

[0042] In addition, the seismic geological model of the target work area also includes: For deep or ultra-deep low signal-to-noise ratio areas, a velocity model including high-velocity and low-velocity layers is established by combining well logging data and geological stratification information. Based on wide-angle imaging theory, the parameters of the observation system are designed, including the maximum shot-receiver distance and the number of coverages, to ensure that the wide-angle reflection information has a preset number of coverages in the long-offset data.

[0043] Example 2: This embodiment addresses the low signal-to-noise ratio problem in ultra-deep Neoproterozoic strata within the Tianhuan Depression of the Ordos Basin. This region has complex surface conditions (loess hills) and a high-speed shielding layer underground, resulting in weak deep-seated reflected signals.

[0044] Step S1: Acquire seismic acquisition data and, based on a preset offset threshold, divide the seismic data into near offset data and far offset data. In step S1, the method for determining the preset offset threshold includes: Construct a seismic geological model of the target work area; Forward modeling based on the wave equation was performed to analyze the wave field characteristics at different offsets. The effective gun-receiver distance range of wide-angle reflections was determined through ultra-long array tests. The offset distance corresponding to the transition area between conventional reflection and wide-angle reflection is selected as the offset distance threshold.

[0045] Wide-angle imaging observation: For the target area, a seismic geological model was established. Using wide-angle imaging theory and wave equation forward modeling technology, parameters such as maximum shot-receiver offset and coverage number were analyzed.

[0046] Through forward modeling and ultra-long array tests of wide-angle reflections, the shot-receiver distance range for wide-angle reflections in the work area was determined. In this embodiment, it was found that data with offsets greater than 6 km exhibited obvious wide-angle reflection characteristics, and the time-distance curve showed obvious linear characteristics in the range of 8 km to 16 km. Therefore, the threshold (or transition zone) for separating near and far offsets was determined to be between 6 km and 8 km.

[0047] Comparative analysis of existing technologies: like Figure 2 As shown, if the existing unconventional hyperbolic motion correction method (such as second-order anisotropic motion correction) is used, although it can level the data at around 6km, the data still cannot be leveled well in the ultra-large offset range of 8km-16km, and there are residual time difference and stretching distortion.

[0048] Step S2: The near-offset data portion is processed using a hyperbolic motion correction method to image the high-velocity top interface and its overlying strata structure; Step S2 specifically includes: Step S21: Perform velocity spectrum analysis on the near offset data and pick the stacked velocity; Step S22: Using the hyperbolic time-distance equation Initial dynamic correction of near offset data Where t is the reflection time, t0 is the zero offset time, x is the offset distance, and v is the root mean square velocity, thus obtaining preliminary structural imaging; Step S23: Based on the preliminary structure, perform residual velocity analysis or anisotropic parameter extraction, and perform high-precision hyperbolic motion correction on the near offset data.

[0049] In a specific embodiment, the near offset is typically handled as follows: For near offset data with an offset of less than 6km (or a threshold set according to actual conditions), the conventional hyperbolic dynamic correction method (or high-precision dynamic correction combined with anisotropic parameters) is used.

[0050] The specific operation involves: performing a velocity scan, picking up the root mean square velocity, and applying the hyperbolic motion correction formula. The main purpose of this step is to accurately determine the structure of the high-velocity layer top and its overlying strata, ensuring high resolution and high fidelity in shallow and intermediate layer imaging.

[0051] Step S3: Perform an inner cut-off operation on the far offset data portion to remove near offset information, and process it using a linear dynamic correction method based on the linear characteristics of the far offset time-distance curve to image the formation structure below the high-velocity layer. In step S3, the specific method for the internal resection operation is as follows: Based on the depth or time position of the high-velocity layer top interface determined in step S2, and the offset threshold, determine the inner cutoff function; In the far offset data, the data sample values ​​within the offset threshold are set to zero or removed, while the wide-angle reflection information greater than the offset threshold is retained.

[0052] In a specific implementation, inner mulching is used to process data with far offsets, first requiring the removal of the influence of data with near offsets. A strict inner mulching method is employed to mulch data with offsets less than a set threshold (e.g., 6km). At this point, only data with far offsets between 6km and 16km remains in the dataset.

[0053] In step S3, the linear dynamic correction method specifically includes: Step S31: For the far offset data after internal resection, identify the in-phase axis under large offset; Step S32: Based on the characteristic that the large offset time-distance curve is almost a straight line, construct a linear time-distance equation: or , Where v app τ is the apparent velocity, p is the ray parameter, and τ is the intercept time; Step S33: Calculate the correction amount for each far offset channel using the linear time-distance equation, and correct the far offset data to the zero offset position; In step S3, if the near offset data has anisotropic characteristics, a non-hyperbolic motion correction formula is used for processing. The non-hyperbolic motion correction formula includes fourth-order or sixth-order anisotropic parameter terms.

[0054] In a specific embodiment, the long offset data retained in step S2 is analyzed. Since the distance curve is nearly a straight line when the offset is large, and no longer conforms to the hyperbolic law, a linear dynamic correction method is adopted.

[0055] The specific steps are as follows: 1) Identify in-phase axes at large offsets; 2) Constructing a linear correction function , where v lin The apparent velocity is linear and is determined by the slope of the time-distance curve; 3) Correct the data and clarify the stratigraphic structure beneath the high-velocity layer.

[0056] like Figure 3 As shown, after linear dynamic correction, the long offset data (especially the 8-16km range) was well leveled, and the waveform did not suffer from severe stretching distortion.

[0057] Step S4: Overlay and fuse the dynamically corrected near offset data with the dynamically corrected far offset data to obtain the final ground motion correction profile.

[0058] Step S4 specifically includes: Energy equalization processing is performed on the dynamically corrected near-offset data and far-offset data. Within the transition zone near the offset threshold, a weighted superposition method is used for splicing to eliminate the boundary effect at the data splicing point; The output is a full-offset overlay profile containing both shallow high-resolution information and deep wide-angle reflection information.

[0059] In some specific embodiments, the near offset data processed in step S1 (mainly reflecting the shallow and middle layers and the top of the high-velocity layer) is superimposed with the far offset data processed in step 3 (mainly using wide-angle information to reflect the deep structure below the high-velocity layer).

[0060] During the overlay process, weighted fusion technology can be used to smoothly splice the layers in the 6km-8km transition zone, avoiding splicing marks.

[0061] The process after step S4 also includes: Determine whether the energy, signal-to-noise ratio, and continuity of the main target layer in the stacked profile meet the preset quality standards; If the condition is not met, the offset threshold is adjusted or the linear correction parameters in step S3 are re-acquired, and the process is returned to step S3 for reprocessing.

[0062] In addition, the seismic geological model of the target work area also includes: For deep or ultra-deep low signal-to-noise ratio areas, a velocity model including high-velocity and low-velocity layers is established by combining well logging data and geological stratification information. Based on wide-angle imaging theory, the parameters of the observation system are designed, including the maximum shot-receiver distance and the number of coverages, to ensure that the wide-angle reflection information has a preset number of coverages in the long-offset data.

[0063] Implementation results: like Figure 4 As shown, compare the two cross-sections: The top profile (without utilizing wide-angle reflection information / conventional processing): the middle and deep wave groups are blurred, with low signal-to-noise ratio and poor continuity.

[0064] The following cross-section (using the two-step method of this invention, utilizing wide-angle reflection information) shows that the energy of the main target layer (Middle Neoproterozoic) is significantly enhanced, the signal-to-noise ratio is greatly improved, the continuity of the phase axis is significantly improved, and the quality of deep imaging has achieved a qualitative leap.

[0065] This invention cleverly solves the problems in processing large-offset seismic data through a segmented processing and linear correction strategy, providing strong technical support for deep oil and gas exploration.

[0066] The second aspect of this invention discloses a dynamic correction system for large offset seismic data. Figure 5 This is a structural diagram of a large-offset seismic data dynamic correction system according to an embodiment of the present invention; as shown below. Figure 5 As shown, the system 100 includes: The first processing module 101 is configured to acquire seismic acquisition data and, based on a preset offset threshold, divide the seismic data into near offset data and far offset data. The second processing module 102 is configured to process the near offset data portion using a hyperbolic motion correction method to image the high-velocity top interface and its overlying strata structure. The third processing module 103 is configured to perform an inner cut-off operation on the far offset data portion to remove near offset information, and to process it using a linear dynamic correction method based on the linear characteristics of the far offset time-distance curve, so as to image the formation structure below the high-velocity layer. The fourth processing module 104 is configured to superimpose and fuse the dynamically corrected near offset data portion with the dynamically corrected far offset data portion to obtain the final ground motion correction profile.

[0067] In some specific embodiments, the first processing module 101 is further configured to determine the preset offset threshold by: Construct a seismic geological model of the target work area; Forward modeling based on the wave equation was performed to analyze the wave field characteristics at different offsets. The effective gun-receiver distance range of wide-angle reflections was determined through ultra-long array tests. The offset distance corresponding to the transition area between conventional reflection and wide-angle reflection is selected as the offset distance threshold.

[0068] In some specific embodiments, the second processing module 102 is further configured to, Perform velocity spectrum analysis on near offset data to pick up the stacking velocity; Using the hyperbolic time distance equation Initial dynamic correction of near offset data Where t is the reflection time, t0 is the zero offset time, x is the offset distance, and v is the root mean square velocity, thus obtaining preliminary structural imaging; Based on the preliminary structure, residual velocity analysis or anisotropic parameter extraction is performed, and high-precision hyperbolic motion correction is carried out on the near offset data.

[0069] In some specific embodiments, the third processing module 103 is further configured such that the internal resection operation specifically comprises: Based on the depth or time position of the high-speed layer top interface determined above, and the offset threshold, the inner cut-off function is determined; In the far offset data, the data sample values ​​within the offset threshold are set to zero or removed, while the wide-angle reflection information greater than the offset threshold is retained.

[0070] In some specific embodiments, the third processing module 103 is further configured such that the linear dynamic correction specifically includes: Identify the in-phase axis under large offset for the far offset data after internal resection; Based on the characteristic that the time-distance curve with large offset is almost a straight line, a linear time-distance equation is constructed: or , Where v app τ is the apparent velocity, p is the ray parameter, and τ is the intercept time; The correction amount for each far offset channel is calculated using the linear time-distance equation, and the far offset data is corrected to the zero offset position. In some specific embodiments, the third processing module 103 is further configured to process the near offset data using a non-hyperbolic motion correction formula if the near offset data exhibits anisotropic characteristics. The non-hyperbolic motion correction formula includes fourth-order or sixth-order anisotropic parameter terms.

[0071] In some specific embodiments, the fourth processing module 104 is further configured to include: Energy equalization processing is performed on the dynamically corrected near-offset data and far-offset data. Within the transition zone near the offset threshold, a weighted superposition method is used for splicing to eliminate the boundary effect at the data splicing point; The output is a full-offset overlay profile containing both shallow high-resolution information and deep wide-angle reflection information; In some specific embodiments, the system further includes a fifth processing module, configured to, Determine whether the energy, signal-to-noise ratio, and continuity of the main target layer in the stacked profile meet the preset quality standards; If the condition is not met, the offset threshold is adjusted or the linear correction parameters in the third module are re-acquired, and the process is returned to the third module for reprocessing.

[0072] A third aspect of this invention discloses an electronic device. The electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the large-offset seismic data dynamic correction method according to any one of the first aspects of this invention.

[0073] Figure 6 This is a structural diagram of an electronic device according to an embodiment of the present invention, such as... Figure 6 As shown, the electronic device includes a processor, memory, communication interface, display screen, and input device connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, Near Field Communication (NFC), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input device can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the device's casing, or an external keyboard, touchpad, or mouse.

[0074] Those skilled in the art will understand that Figure 6 The structure shown is merely a structural diagram of the part related to the technical solution of this disclosure and does not constitute a limitation on the electronic device to which the solution of this application is applied. The specific electronic device may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0075] A fourth aspect of this invention discloses a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a large-offset seismic data dynamic correction method according to any one of the first aspects of this invention.

[0076] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0077] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A dynamic correction method for large-offset seismic data, characterized in that, The method includes the following steps: Step S1: Acquire seismic acquisition data and, based on a preset offset threshold, divide the seismic data into near offset data and far offset data. Step S2: The near-offset data portion is processed using a hyperbolic motion correction method to image the high-velocity top interface and its overlying strata structure; Step S3: Perform an inner cut-off operation on the far offset data portion to remove near offset information, and process it using a linear dynamic correction method based on the linear characteristics of the far offset time-distance curve to image the formation structure below the high-velocity layer. Step S4: Overlay and fuse the dynamically corrected near offset data with the dynamically corrected far offset data to obtain the final ground motion correction profile.

2. The method for dynamic correction of large offset seismic data according to claim 1, characterized in that, In step S1, the method for determining the preset offset threshold includes: Construct a seismic geological model of the target work area; Forward modeling based on the wave equation was performed to analyze the wave field characteristics at different offsets. The effective gun-receiver distance range of wide-angle reflections was determined through ultra-long array tests. The offset distance corresponding to the transition area between conventional reflection and wide-angle reflection is selected as the offset distance threshold.

3. The method for dynamic correction of large offset seismic data according to claim 1, characterized in that, Step S2 specifically includes: Step S21: Perform velocity spectrum analysis on the near offset data and pick the stacked velocity; Step S22: Using the hyperbolic time-distance equation Initial dynamic correction of near offset data Where t is the reflection time, t0 is the zero offset time, x is the offset distance, and v is the root mean square velocity, thus obtaining preliminary structural imaging; Step S23: Based on the preliminary structure, perform residual velocity analysis or anisotropic parameter extraction, and perform high-precision hyperbolic motion correction on the near offset data.

4. The method for dynamic correction of large offset seismic data according to claim 1, characterized in that, In step S3, the specific method for the internal resection operation is as follows: Based on the depth or time position of the high-velocity layer top interface determined in step S2, and the offset threshold, determine the inner cutoff function; In the far offset data, the data sample values ​​within the offset threshold are set to zero or removed, while the wide-angle reflection information greater than the offset threshold is retained.

5. The method for dynamic correction of large offset seismic data according to claim 1, characterized in that, In step S3, the linear dynamic correction method specifically includes: Step S31: For the far offset data after internal resection, identify the in-phase axis under large offset; Step S32: Based on the characteristic that the large offset time-distance curve is almost a straight line, construct a linear time-distance equation: or , Where v app τ is the apparent velocity, p is the ray parameter, and τ is the intercept time; Step S33: Calculate the correction amount for each far offset channel using the linear time-distance equation, and correct the far offset data to the zero offset position.

6. The method for dynamic correction of large offset seismic data according to claim 1, characterized in that, Step S4 specifically includes: Energy equalization processing is performed on the dynamically corrected near-offset data and far-offset data. Within the transition zone near the offset threshold, a weighted superposition method is used for splicing to eliminate the boundary effect at the data splicing point; The output is a full-offset overlay profile containing both shallow high-resolution information and deep wide-angle reflection information.

7. The method for dynamic correction of large offset seismic data according to claim 2, characterized in that, The process after step S4 also includes: Determine whether the energy, signal-to-noise ratio, and continuity of the main target layer in the stacked profile meet the preset quality standards; If the condition is not met, the offset threshold is adjusted or the linear correction parameters in step S3 are re-acquired, and the process is returned to step S3 for reprocessing.

8. A dynamic correction system for large offset seismic data, characterized in that, The system includes: The first processing module is configured to acquire seismic acquisition data and, based on a preset offset threshold, divide the seismic data into near offset data and far offset data. The second processing module is configured to process the near offset data portion using a hyperbolic motion correction method to image the high-velocity top interface and its overlying strata structure. The third processing module is configured to perform an inner cut-off operation on the far offset data portion to remove near offset information, and to process it using a linear dynamic correction method based on the linear characteristics of the far offset time-distance curve, so as to image the formation structure below the high-velocity layer. The fourth processing module is configured to superimpose and fuse the dynamically corrected near offset data portion with the dynamically corrected far offset data portion to obtain the final ground motion correction profile.

9. An electronic device, characterized in that, The electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps in the large offset seismic data dynamic correction method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the large offset seismic data dynamic correction method according to any one of claims 1 to 7.

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