A Q-body accurate construction method based on pre-stack gather data

Abstract

The present invention provides a method for accurately establishing a Q-body based on pre-stack gather data. The method comprises: inputting corresponding pre-stack gather data according to different seismic data processing stages, wherein the pre-stack gather data includes complete trace header information; performing Q value calculation on common midpoint gathers during the stacking stage; interpolating the Q value sequence calculated for each common midpoint gather to establish a three-dimensional Q-body; performing Q value calculation on common reflection point gathers during the pre-stack time migration stage; performing Q value calculation on all input common reflection point gathers, and performing Q value calculation on CIP gathers during the pre-stack depth migration stage; interpolating the Q value sequence calculated for each CIP gather to establish a three-dimensional Q-body, and using the Q-body calculated on the common midpoint gather as the basic Q-body of the CIP gathers. This method effectively improves the accuracy, fidelity, and stability of the three-dimensional Q-body.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas geophysical exploration, and in particular to a method for accurately establishing a Q-body based on pre-stack gather data. Background Art

[0002] During 3D seismic exploration, reflection wave information from underground strata is obtained by artificially stimulating seismic waves. As these waves propagate through the strata, their energy, frequency, and phase are affected by absorption attenuation, a process that occurs due to the viscoelastic nature of the strata. These attenuations include spherical diffusion of seismic waves, reflection loss, transmission loss, multiple reflections between layers, and inherent absorption attenuation. Seismic exploration has entered a phase of high-density seismic data, placing increasing demands on the resolution and imaging accuracy of seismic data. This, in turn, creates a growing need for Q-volumes of underground strata. This urgency necessitates the establishment of precise 3D Q-volumes to enable detailed exploration and development.

[0003] Subsurface Q-values ​​play an important role. They can be used for processes such as Q-body absorption attenuation compensation and inverse Q filtering, thereby improving the resolution of seismic data. Furthermore, the established three-dimensional Q-values ​​can be used for processes such as Q-compensated prestack depth migration and reverse time migration for viscoelastic media. This not only improves the resolution of seismic data but also enhances the accuracy of structural imaging and the identification of thin-bedded lithologic reservoirs. Currently, commonly used Q-value estimation methods include the spectral ratio method, the centroid frequency method, and the attribute combination method. Conventional methods use only the spectral characteristics of seismic data, calculating Q-values ​​based on attributes such as attenuation frequency, peak frequency, or centroid frequency. The spectral ratio method suffers from poor noise immunity when calculating Q-values, while the centroid frequency method requires the amplitude spectrum of the seismic wavelet to be a Gaussian function. Conventional methods fail to fully utilize the complete information of three-dimensional seismic data, resulting in unstable calculations and low accuracy. Three-dimensional Q-volumes can be calculated using full waveform inversion, but this requires the known artificially excited seismic wavelet and a high signal-to-noise ratio (SNR) in the seismic data. Due to the relatively low quality and high noise levels of onshore seismic data, full waveform inversion is less applicable to onshore seismic data and is susceptible to the adverse effects of low SNR. Given the shortcomings of current Q-volume construction methods, a precise Q-volume construction method based on prestack gather data is proposed. This method fully utilizes information such as amplitude, frequency, phase, offset, azimuth, and coverage of the seismic data, leveraging the complete information provided by the seismic data to effectively improve the accuracy of the three-dimensional Q-volume.

[0004] Conventional methods such as the spectral ratio method, the centroid frequency method, and the spectral simulation method calculate Q values ​​based solely on the spectral characteristics of seismic data. These methods, based on properties such as decay frequency, peak frequency, or centroid frequency, suffer from large errors in the calculated results and unstable calculation processes. Full-waveform Q-value inversion methods require known artificially excited seismic wavelets and high signal-to-noise ratios in the seismic data. Land seismic data generally have low signal-to-noise ratios, and seismic wavelets are difficult to accurately determine, limiting the accuracy of full-waveform Q-value inversion. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a method for accurately establishing a Q-body based on pre-stack gather data, which overcomes the above problems or at least partially solves the above problems.

[0006] According to one aspect of the present invention, a method for accurately establishing a Q-body based on pre-stack gather data is provided, the method comprising:

[0007] According to different seismic data processing stages, corresponding pre-stack gather data are input respectively, wherein the pre-stack gather data includes complete trace header information;

[0008] In the stacking stage, the Q value of the common center point gather is calculated, and the matching pursuit wavelet decomposition residual parameter, wavelet decomposition signal ratio parameter and coverage times are introduced;

[0009] The Q value sequence calculated from each common center point gather is interpolated to establish a three-dimensional Q body, and three interpolation control factors, namely offset, azimuth and number of coverages, are introduced.

[0010] Calculate the Q value of the common reflection point gathers in the pre-stack time migration stage;

[0011] Calculate the Q value of all input common reflection point gathers.

[0012] In the pre-stack depth migration stage, the Q value of CIP gathers is calculated by comprehensively utilizing amplitude, frequency and phase information, and introducing quality constraints and correction parameters.

[0013] The Q value sequence calculated from each CIP gather is interpolated to establish a three-dimensional Q body, and the Q body calculated from the common center point gather is used as the basic Q body of the CIP gather.

[0014] Optionally, inputting corresponding pre-stack gather data according to different seismic data processing stages specifically includes:

[0015] Input the common center point gather data in the superposition stage CMP ;

[0016] Input common reflection point gather data in the prestack time migration stage CRP ;

[0017] Input the common imaging point gather data in the prestack depth migration stage CIP .

[0018] Optionally, the Q value calculation of the common center point gathers in the superposition stage specifically includes:

[0019] Perform matching pursuit wavelet decomposition on the gather data of each offset distance, decomposing the seismic trace into a series of seismic wavelets, each of which contains the amplitude, frequency, and phase information of the corresponding position;

[0020] The Q value sequence of each seismic trace from shallow to deep is calculated using amplitude, frequency and phase information;

[0021] The formula is as follows: Q i (t) = Wave it (Amp i ,Fre i ,θ i ), where: i is the offset, i = 50, 100, ..., 5500, in meters; t is the propagation time, in seconds; Amp i is the wavelet amplitude; Fre i is the wavelet frequency; θ i is the wavelet phase.

[0022] Optionally, the introduction of matching pursuit wavelet decomposition residual parameter, wavelet decomposition signal ratio parameter, and coverage times specifically includes:

[0023] In the process of calculating the Q value of each offset data in the common center point gather, the matching pursuit wavelet decomposition residual parameter er and the wavelet decomposition signal ratio parameter ra are used as the quality constraints of the Q value calculation;

[0024] Matching pursuit wavelet decomposition residual parameter er i =Data CMP (i)-Wave i , where: i is the offset, Data CMP (i) is the original gather data, Wave i It is the seismic wavelet obtained by matching pursuit wavelet decomposition;

[0025] Wavelet decomposition signal ratio parameter ra i =Wave i [fa,fb] / Data CMP (i), where: fa is the effective frequency band start frequency, fb is the effective frequency end frequency, Wave i [fa,fb] is the effective signal component of the seismic wavelet;

[0026] Based on the wavelet decomposition signal proportion parameters and the wavelet decomposition signal proportion parameters, the Q value sequence calculated using the amplitude, frequency and phase information is guaranteed to have high fidelity;

[0027] The calculation formula of Q value after constraint is as follows: Q i (t) = Wave it (Amp i ,Fre i ,θ i ,er i ,ra i ), where: i is the offset distance, in meters; t is the propagation time, in seconds; Amp i is the wavelet amplitude; Fre i is the wavelet frequency; θ i is the wavelet phase; er i is the residual parameter of matching pursuit wavelet decomposition; ra i is the wavelet decomposition signal ratio parameter;

[0028] Considering the propagation path of seismic waves and introducing offset information, the common center point gather is based on the assumption of horizontal layered media to calculate the Q value sequence of different offset distances.

[0029] Each common center point gather has a different number of coverage times fo. In the process of calculating the Q value of the common center point gather, the number of coverage times fo is used as a correction parameter to ensure the stability of the Q value calculation of the common center point gather data at different offsets.

[0030] The calculation formula of the corrected Q value is as follows: Q i (t) = Wave it (Amp i ,Fre i ,θ i ,er i ,ra i ,fo i ), where: i is the offset distance, in meters; t is the propagation time, in seconds; Amp i is the wavelet amplitude; Fre i is the wavelet frequency; θ i is the wavelet phase; er i is the residual parameter of matching pursuit wavelet decomposition; ra i is the wavelet decomposition signal ratio parameter; fo i Correction parameter for the number of coverages.

[0031] Optionally, the Q value sequence calculated from each common center point gather is interpolated to establish a three-dimensional Q body, and the three-parameter interpolation control factors of offset, azimuth, and number of coverages are introduced, specifically including:

[0032] The Q value sequence calculated from each common center point gather is interpolated to establish a three-dimensional Q body. In the process of establishing the Q body, information such as offset, azimuth, and number of coverages are fully considered. Three interpolation control factors are introduced: offset i, azimuth α, and number of coverages fo. The offset can reflect the propagation path of the seismic wave, the azimuth can reflect the spatial variation of the Q body, and the number of coverages can reflect the stability of the Q value.

[0033] The common center point gather is based on the assumption of horizontal layered media. In areas with simple geological structures, the calculated Q value has a high accuracy. In areas with complex geological structures, the calculated Q value has deviations. As a basic Q body, it is used in the prestack time migration or prestack depth migration process. After calculation and correction of the common reflection point gather and the CIP gather, accurate calculation of the Q value in areas with complex geological structures can be achieved.

[0034] Optionally, the performing Q value calculation on the common reflection point gathers in the pre-stack time migration stage specifically includes:

[0035] In the pre-stack time migration stage, the Q value of the common reflection point gather is calculated. First, the gather data of each offset distance is decomposed into a series of seismic wavelets by matching pursuit wavelet decomposition. Each seismic wavelet contains the amplitude, frequency, and phase information of the corresponding position. The Q value sequence of each seismic trace from shallow to deep can be calculated by combining the amplitude, frequency, and phase information.

[0036] In the process of calculating the Q value of each offset data in the common reflection point gather, the matching pursuit wavelet decomposition residual parameter er and the wavelet decomposition signal ratio parameter ra are used as the quality constraints of the Q value calculation;

[0037] Considering the propagation path of seismic waves, the offset information is introduced. Since each common reflection point gather has a different coverage number fo, the coverage number fo is used as a correction parameter in the process of calculating the Q value of the common reflection point gather to ensure the stability of the Q value calculation.

[0038] Optionally, the Q value calculation for all input common reflection point gathers specifically includes: interpolating the Q value sequence calculated for each common reflection point gather, establishing a three-dimensional Q body, and using the Q body calculated for the common center point gather as the basic Q body of the common reflection point gather.

[0039] Optionally, interpolating the Q value sequence calculated from each common reflection point gather to establish a three-dimensional Q body, and using the Q body calculated from the common center point gather as the basic Q body of the common reflection point gather specifically includes:

[0040] In the process of establishing the Q body, the information such as offset distance, azimuth angle, and number of coverages is fully considered, and three parameter interpolation control factors, namely offset distance i, azimuth angle α, and number of coverages fo, are introduced. The offset distance can reflect the propagation path of the seismic wave, the azimuth angle can reflect the spatial variation of the Q body, and the number of coverages can reflect the stability of the Q value.

[0041] Optionally, the Q value calculation of the CIP gathers in the pre-stack depth migration stage is performed by comprehensively utilizing amplitude, frequency, and phase information, and introducing quality constraints and correction parameters, specifically including:

[0042] During the pre-stack depth migration phase, the Q value of the CIP gather is calculated. First, matching pursuit wavelet decomposition is performed on the gather data at each offset distance, decomposing the seismic trace into a series of seismic wavelets. Each seismic wavelet contains the amplitude, frequency, and phase information at the corresponding position. The Q value sequence of each seismic trace from shallow to deep can be calculated by comprehensively utilizing the amplitude, frequency, and phase information.

[0043] In the process of calculating the Q value of each offset data in the CIP gather, the matching pursuit wavelet decomposition residual parameter er and the wavelet decomposition signal ratio parameter ra are used as the quality constraints for the Q value calculation;

[0044] Considering the propagation path of seismic waves, the offset information is introduced. Since each CIP gather has a different coverage number fo, the coverage number fo is used as a correction parameter in the process of calculating the Q value of the CIP gather to ensure the stability of the Q value calculation.

[0045] Optionally, interpolating the Q value sequence calculated for each CIP gather to establish a three-dimensional Q body, and using the Q body calculated for the common center point gather as the basic Q body for the CIP gather specifically includes:

[0046] In the process of establishing the Q body, the offset distance, azimuth angle, and coverage number information are fully considered, and three parameter interpolation control factors, namely offset distance i, azimuth angle α, and coverage number fo, are introduced. The offset distance can reflect the propagation path of the seismic wave, the azimuth angle can reflect the spatial variation of the Q body, and the coverage number can reflect the stability of the Q value.

[0047] The present invention provides a method for accurately establishing a Q-body based on pre-stack gather data. The method comprises: inputting corresponding pre-stack gather data according to different seismic data processing stages, wherein the pre-stack gather data includes complete trace header information; performing Q value calculation on the common midpoint gathers in the stacking stage, introducing matching pursuit wavelet decomposition residual parameters, wavelet decomposition signal ratio parameters, and coverage times; interpolating the Q value sequence calculated for each common midpoint gather to establish a three-dimensional Q-body, and introducing three interpolation control factors: offset, azimuth, and coverage times; performing Q value calculation on the common reflection point gathers in the pre-stack time migration stage; performing Q value calculation on all input common reflection point gathers, and performing Q value calculation on the CIP gathers in the pre-stack depth migration stage, comprehensively utilizing amplitude, frequency, and phase information, and introducing quality constraints and correction parameters; interpolating the Q value sequence calculated for each CIP gather to establish a three-dimensional Q-body, and using the Q-body calculated from the common midpoint gather as the basic Q-body of the CIP gathers. This effectively improves the accuracy, fidelity, and stability of the three-dimensional Q-body.

[0048] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0050] Figure 1 Provided in accordance with an embodiment of the present invention;

[0051] Figure 2 The common center point gather provided by the embodiment of the present invention;

[0052] Figure 3 The two-dimensional time-frequency spectrum of the common center point gather provided in an embodiment of the present invention;

[0053] Figure 4 The three-dimensional Q-body obtained by calculation provided by the embodiment of the present invention. DETAILED DESCRIPTION

[0054] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0055] The terms "comprises" and "comprising" and any variations thereof in the description, embodiments, claims and drawings of the present invention are intended to cover non-exclusive inclusions, for example, including a series of steps or units.

[0056] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0057] like Figure 1 As shown, the present invention is a method for accurately establishing a Q body based on pre-stack gather data, comprising the following steps:

[0058] Step 1: For different seismic data processing stages, input the corresponding pre-stack gather data respectively. The input gather data contains complete trace header information.

[0059] like Figure 2 The following is a schematic diagram of the common center point gather. The common center point gather Data is input in the superposition stage. CMP , input the common reflection point gather (common reflection point gather) Data in the pre-stack time migration stage CRP , input CIP gather (common imaging point gather) Data in the pre-stack depth migration stage CIP ;

[0060] like Figure 3 As shown in Figure 2, it is a schematic diagram of the two-dimensional time-frequency spectrum of the common center point gather.

[0061] Step 2: Calculate the Q value of the common center point gathers in the stacking stage. First, perform matching pursuit wavelet decomposition on the gather data of each offset distance, and decompose the seismic trace into a series of seismic wavelets. Each seismic wavelet contains the amplitude, frequency, and phase information of the corresponding position. The Q value sequence of each seismic trace from shallow to deep can be calculated by comprehensively utilizing the amplitude, frequency, and phase information. The formula is as follows: Q i (t) = Wave it (Amp i ,Fre i ,θ i ), where: i is the offset, i = 50, 100, ..., 5500, in meters; t is the propagation time, in seconds; Amp i is the wavelet amplitude; Fre i is the wavelet frequency; θ iis the wavelet phase.

[0062] In the process of calculating the Q value of each offset data in the common center point gather, the matching pursuit wavelet decomposition residual parameter er and the wavelet decomposition signal ratio parameter ra are used as the quality constraints of the Q value calculation.

[0063] Matching pursuit wavelet decomposition residual parameter er i =Data CMP (i)-Wave i , where: i is the offset, Data CMP (i) is the original gather data, Wave i It is the seismic wavelet obtained by matching pursuit wavelet decomposition.

[0064] Wavelet decomposition signal ratio parameter ra i =Wave i [fa,fb] / Data CMP (i), where: fa is the effective frequency band start frequency, fb is the effective frequency end frequency, Wave i [fa,fb] is the effective signal component of the seismic wavelet.

[0065] Based on the wavelet decomposition signal ratio parameters and the wavelet decomposition signal ratio parameters, the Q value sequence calculated using amplitude, frequency, and phase information is guaranteed to have high fidelity. The constrained Q value calculation formula is as follows: Q i (t) = Wave it (Amp i ,Fre i ,θ i ,er i ,ra i ), where: i is the offset distance, in meters; t is the propagation time, in seconds; Amp i is the wavelet amplitude; Fre i is the wavelet frequency; θ i is the wavelet phase; er i is the residual parameter of matching pursuit wavelet decomposition; ra i is the signal ratio parameter of the wavelet decomposition.

[0066] Considering the propagation path of seismic waves and introducing offset information, the common center point gather can calculate the Q value sequence of different offset distances based on the assumption of horizontal layered media. Since each common center point gather has a different number of coverages fo, in the process of calculating the Q value of the common center point gather, the number of coverages fo is used as a correction parameter to ensure the stability of the Q value calculation of the common center point gather data with different offset distances. The corrected Q value calculation formula is as follows: Q i (t) = Wave it (Ampi ,Fre i ,θ i ,er i ,ra i ,fo i ), where: i is the offset distance, in meters; t is the propagation time, in seconds; Amp i is the wavelet amplitude; Fre i is the wavelet frequency; θ i is the wavelet phase; er i is the residual parameter of matching pursuit wavelet decomposition; ra i is the wavelet decomposition signal ratio parameter; fo i Correction parameter for the number of coverages.

[0067] Step 3: Calculate the Q value of all input common center point gathers, interpolate the Q value sequence calculated for each common center point gather, and establish a three-dimensional Q body, such as Figure 4 In the process of establishing the Q-body, the offset, azimuth, and coverage times are fully considered, and three interpolation control factors are introduced: offset i, azimuth α, and coverage times fo. The offset can reflect the propagation path of the seismic wave, the azimuth can reflect the spatial variation of the Q-body, and the coverage times can reflect the stability of the Q value.

[0068] The common center point gather is based on the assumption of a horizontal layered medium. In areas with simple geological structures, the calculated Q value has a high accuracy. In areas with complex geological structures, the calculated Q value has deviations. It can be used as a basic Q body and applied to the prestack time migration or prestack depth migration process. After calculation and correction of the common reflection point gather and the CIP gather, accurate calculation of the Q value in areas with complex geological structures can be achieved.

[0069] Step 4: Q values ​​are calculated for the common reflection point gathers during prestack time migration. First, matching pursuit wavelet decomposition is performed on the gather data at each offset, decomposing the seismic trace into a series of seismic wavelets. Each wavelet contains amplitude, frequency, and phase information at the corresponding position. This information is combined to calculate a Q value sequence for each seismic trace from shallow to deep. During the Q value calculation for each offset in the common reflection point gather, the matching pursuit wavelet decomposition residual parameter er and the wavelet decomposition signal ratio parameter ra are used as quality constraints for the Q value calculation.

[0070] Considering the propagation path of seismic waves, the offset information is introduced. Since each common reflection point gather has a different coverage number fo, the coverage number fo is used as a correction parameter in the process of calculating the Q value of the common reflection point gather to ensure the stability of the Q value calculation.

[0071] Step 5: Calculate the Q value for all input common reflection point gathers, interpolate the Q value sequence calculated for each common reflection point gather, establish a three-dimensional Q volume, and use the Q volume calculated for the common center point gather as the basic Q volume for the common reflection point gather. In the process of establishing the Q volume, full consideration is given to information such as offset, azimuth, and number of coverages. The three interpolation control factors of offset i, azimuth α, and number of coverages fo are introduced. The offset can reflect the propagation path of the seismic wave, the azimuth can reflect the spatial variation of the Q volume, and the number of coverages can reflect the stability of the Q value.

[0072] Step 6: Q-value calculation for CIP gathers during prestack depth migration. First, matching pursuit wavelet decomposition is performed on the gather data at each offset, decomposing the seismic trace into a series of seismic wavelets. Each wavelet contains amplitude, frequency, and phase information at the corresponding position. This combined information is used to calculate a Q-value sequence for each seismic trace from shallow to deep. During the Q-value calculation for each offset in the CIP gather, the matching pursuit wavelet decomposition residual parameter er and the wavelet decomposition signal ratio parameter ra are used as quality constraints for the Q-value calculation.

[0073] Considering the propagation path of seismic waves, the offset information is introduced. Since each CIP gather has a different coverage number fo, the coverage number fo is used as a correction parameter in the process of calculating the Q value of the CIP gather to ensure the stability of the Q value calculation.

[0074] Step 7: Calculate Q values ​​for all input CIP gathers, interpolate the Q value sequences calculated for each CIP gather, establish a 3D Q-volume, and use the Q-volume calculated for the common center point gather as the base Q-volume for the CIP gathers. In establishing the Q-volume, full consideration is given to information such as offset, azimuth, and number of overlaps. Three interpolation control factors are introduced: offset i, azimuth α, and number of overlaps fo. The offset reflects the propagation path of seismic waves, the azimuth reflects the spatial variation of the Q-volume, and the number of overlaps reflects the stability of the Q value.

[0075] Beneficial effects: (1) The present invention makes full use of the amplitude, frequency, phase, offset, azimuth, coverage times and other information of seismic data, gives full play to the role of complete information of seismic data, and effectively improves the accuracy of three-dimensional Q body.

[0076] (2) The present invention adopts the matching pursuit wavelet decomposition residual parameter and the wavelet decomposition signal ratio parameter as the quality constraint conditions for Q value calculation, which can effectively ensure the fidelity of Q value calculation.

[0077] (3) The number of coverages is used as a correction parameter for Q value calculation to ensure the stability of Q value calculation.

[0078] (4) The three interpolation control factors of offset distance, azimuth angle and number of coverage are introduced. The offset distance can reflect the propagation path of seismic waves, the azimuth angle can reflect the spatial variation of Q body, and the number of coverage can reflect the stability of Q value, thus finally establishing a real, reliable and stable three-dimensional Q body.

[0079] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A Q-body accurate establishment method based on pre-stack gather data, characterized in that: The establishment method comprises: According to different seismic data processing stages, corresponding pre-stack gather data are input respectively, wherein the pre-stack gather data includes complete trace header information; In the stacking stage, the Q value of the common center point gather is calculated, and the matching pursuit wavelet decomposition residual parameter, wavelet decomposition signal ratio parameter and coverage times are introduced; The Q value calculation of the common center point gathers in the superposition stage specifically includes: Perform matching pursuit wavelet decomposition on the gather data of each offset distance, and decompose the seismic trace into a series of seismic wavelets. Each seismic wavelet contains the amplitude, frequency, and phase information of the corresponding position. The Q value sequence of each seismic trace from shallow to deep is calculated using amplitude, frequency and phase information; The formula is as follows: Q i (t) = Wave it (Amp i ,Fre i ,θ i ), where: i is the offset, i = 50, 100, ..., 5500, in meters; t is the propagation time, in seconds; Amp i is the wavelet amplitude; Fre i is the wavelet frequency; θ i is the wavelet phase; The Q value sequence calculated from each common center point gather is interpolated to establish a three-dimensional Q body. The three interpolation control factors of offset, azimuth, and number of coverages are introduced, including: In the process of calculating the Q value of each offset data in the common center point gather, the matching pursuit wavelet decomposition residual parameter er and the wavelet decomposition signal ratio parameter ra are used as the quality constraints of the Q value calculation; Matching pursuit wavelet decomposition residual parameter er i =Data CMP (i)-Wave i , where: i is the offset, Data CMP (i) is the original gather data, Wave i It is the seismic wavelet obtained by matching pursuit wavelet decomposition; Wavelet decomposition signal ratio parameter ra i =Wave i [fa,fb]Data CMP (i), where: fa is the effective frequency band start frequency, fb is the effective frequency end frequency, Wave i [fa,fb] is the effective signal component of the seismic wavelet; Based on the wavelet decomposition signal proportion parameter, the Q value sequence calculated using amplitude, frequency and phase information is guaranteed to have high fidelity; The calculation formula of Q value after constraint is as follows: Q i (t) = Wave it (Amp i ,Fre i ,θ i ,er i ,ra i ), where: i is the offset distance, in meters; t is the propagation time, in seconds; Amp i is the wavelet amplitude; Fre i is the wavelet frequency; θ i is the wavelet phase; er i is the residual parameter of matching pursuit wavelet decomposition; ra i is the wavelet decomposition signal ratio parameter; Considering the propagation path of seismic waves and introducing offset information, the common center point gather is based on the assumption of horizontal layered media to calculate the Q value sequence of different offset distances. Each common center point gather has a different number of coverage times fo. In the process of calculating the Q value of the common center point gather, the number of coverage times fo is used as a correction parameter to ensure the stability of the Q value calculation of the common center point gather data at different offsets. The calculation formula of the corrected Q value is as follows: Q i (t) = Wave it (Amp i ,Fre i ,θ i ,er i ,ra i ,fo i ), where: i is the offset distance, in meters; t is the propagation time, in seconds; Amp i is the wavelet amplitude; Fre i is the wavelet frequency; θ i is the wavelet phase; er i is the residual parameter of matching pursuit wavelet decomposition; ra i is the wavelet decomposition signal ratio parameter; fo i Correction parameters for the number of coverages; Calculate the Q value of the common reflection point gathers in the pre-stack time migration stage; Calculate the Q value of all input common reflection point gathers. In the pre-stack depth migration stage, the Q value of CIP gathers is calculated by comprehensively utilizing amplitude, frequency and phase information, and introducing quality constraints and correction parameters. The Q value sequence calculated from each CIP gather is interpolated to establish a three-dimensional Q body, and the Q body calculated from the common center point gather is used as the basic Q body of the CIP gather.

2. The method for accurately establishing a Q-body based on pre-stack gather data according to claim 1, characterized in that: According to different stages of seismic data processing, inputting corresponding pre-stack gather data specifically includes: Input the common center point gather data in the superposition stage CMP ; Input common reflection point gather data in the prestack time migration stage CRP ; Input the common imaging point gather data in the prestack depth migration stage CIP .

3. The method for accurately establishing a Q-body based on pre-stack gather data according to claim 1, characterized in that: The Q value sequence calculated from each common center point gather is interpolated to establish a three-dimensional Q body, and the three interpolation control factors of offset, azimuth, and number of coverages are introduced. Specifically, the following are the factors: Interpolate the Q value sequence calculated from each common center point gather to establish a three-dimensional Q body; In the process of establishing the Q-body, the offset, azimuth, and coverage times are fully considered, and three interpolation control factors are introduced: offset i, azimuth α, and coverage times fo. The offset can reflect the propagation path of the seismic wave, the azimuth can reflect the spatial variation of the Q-body, and the coverage times can reflect the stability of the Q value. The common center point gather is based on the assumption of horizontal layered media. In areas with simple geological structures, the calculated Q value has a high accuracy. In areas with complex geological structures, the calculated Q value has deviations. As a basic Q body, it is used in the prestack time migration or prestack depth migration process. After calculation and correction of the common reflection point gather and the CIP gather, accurate calculation of the Q value in areas with complex geological structures can be achieved.

4. The method for accurately establishing a Q-body based on pre-stack gather data according to claim 1, characterized in that: The Q value calculation of the common reflection point gathers in the pre-stack time migration stage specifically includes: In the pre-stack time migration stage, the Q value of the common reflection point gather is calculated. First, the gather data of each offset distance is decomposed into a series of seismic wavelets by matching pursuit wavelet decomposition. Each seismic wavelet contains the amplitude, frequency, and phase information of the corresponding position. The Q value sequence of each seismic trace from shallow to deep can be calculated by combining the amplitude, frequency, and phase information. In the process of calculating the Q value of each offset data in the common reflection point gather, the matching pursuit wavelet decomposition residual parameter er and the wavelet decomposition signal ratio parameter ra are used as the quality constraints of the Q value calculation; Considering the propagation path of seismic waves, the offset information is introduced. Since each common reflection point gather has a different coverage number fo, the coverage number fo is used as a correction parameter in the process of calculating the Q value of the common reflection point gather to ensure the stability of the Q value calculation.

5. The method for accurately establishing a Q-body based on pre-stack gather data according to claim 1, characterized in that: The Q value calculation for all input common reflection point gathers specifically includes: interpolating the Q value sequence calculated for each common reflection point gather to establish a three-dimensional Q body, and using the Q body calculated for the common center point gather as the basic Q body for the common reflection point gather.

6. The method for accurately establishing a Q-body based on pre-stack gather data according to claim 5, characterized in that: The interpolation of the Q value sequence calculated from each common reflection point gather to establish a three-dimensional Q body, and the use of the Q body calculated from the common center point gather as the basic Q body of the common reflection point gather specifically includes: In the process of establishing the Q body, the offset distance, azimuth angle, and coverage number information are fully considered, and three parameter interpolation control factors, namely offset distance i, azimuth angle α, and coverage number fo, are introduced. The offset distance can reflect the propagation path of the seismic wave, the azimuth angle can reflect the spatial variation of the Q body, and the coverage number can reflect the stability of the Q value.

7. The method for accurately establishing a Q-body based on pre-stack gather data according to claim 1, characterized in that: The Q value calculation of the CIP gathers in the pre-stack depth migration stage is performed by comprehensively utilizing amplitude, frequency, and phase information, and introducing quality constraints and correction parameters, specifically including: During the pre-stack depth migration phase, the Q value of the CIP gather is calculated. First, matching pursuit wavelet decomposition is performed on the gather data at each offset distance, decomposing the seismic trace into a series of seismic wavelets. Each seismic wavelet contains the amplitude, frequency, and phase information at the corresponding position. The Q value sequence of each seismic trace from shallow to deep can be calculated by comprehensively utilizing the amplitude, frequency, and phase information. In the process of calculating the Q value of each offset data in the CIP gather, the matching pursuit wavelet decomposition residual parameter er and the wavelet decomposition signal ratio parameter ra are used as the quality constraints for the Q value calculation; Considering the propagation path of seismic waves, the offset information is introduced. Since each CIP gather has a different coverage number fo, the coverage number fo is used as a correction parameter in the process of calculating the Q value of the CIP gather to ensure the stability of the Q value calculation.

8. The method for accurately establishing a Q-body based on pre-stack gather data according to claim 1, characterized in that: The interpolation of the Q value sequence calculated from each CIP gather to establish a three-dimensional Q body and the use of the Q body calculated from the common center point gather as the basic Q body of the CIP gather specifically include: In the process of establishing the Q body, the offset distance, azimuth angle, and coverage number information are fully considered, and three parameter interpolation control factors, namely offset distance i, azimuth angle α, and coverage number fo, are introduced. The offset distance can reflect the propagation path of the seismic wave, the azimuth angle can reflect the spatial variation of the Q body, and the coverage number can reflect the stability of the Q value.

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