A method, apparatus, equipment and medium for simultaneous inversion of P-waves and S-waves before stacking.

Abstract

This application discloses a method, apparatus, equipment, and medium for simultaneous pre-stack inversion of P-waves and S-waves, relating to the field of seismic inversion technology. The method includes: interpreting stratigraphic layers of both S-wave and P-wave pre-stack time migration profiles to establish a geological framework model; the S-wave pre-stack time migration profile is obtained by sequentially performing polarization rotation, common-detector S-wave velocity analysis, and S-wave pre-stack time migration processing on seismic data received by a seafloor seismograph; well-seismic calibration is performed based on the geological framework model, the average seismic wavelet of the study area, and well logging curves to obtain calibrated seismic data; the well logging curves include P-wave logging curves, S-wave logging curves, and density curves; simultaneous pre-stack inversion is performed based on the well-seismic calibrated seismic data and the initial low-frequency model of the study area to obtain more accurate inversion results, which are then used to identify natural gas hydrates.

Description

Technical Field

[0001] This invention relates to the field of seismic inversion technology, and in particular to a method, apparatus, equipment and medium for simultaneous pre-stack inversion of P-waves and S-waves. Background Technology

[0002] Natural gas hydrates (referred to as "hydrates") are solid minerals formed by water and natural gas under low temperature and high pressure. They are widely found in seabed sediments and permafrost zones along continental margins and are an ideal alternative energy source for the future.

[0003] When performing inversion on a study area, conventional P-wave inversion only utilizes single P-wave information, resulting in single inversion parameters, multiple solutions, and poor accuracy of the inversion results. Post-stack seismic inversion uses multiple stacks of seismic data from all angles. Although it requires less data and is faster, it loses information about subsurface reservoirs and weakens the sensitivity of seismic data to reflecting reservoir variation characteristics. Summary of the Invention

[0004] This invention provides a method, apparatus, equipment, and medium for simultaneous inversion of P-waves and S-waves before stacking, which can obtain inversion results with higher accuracy.

[0005] According to one aspect of the present invention, a method for simultaneous pre-stack inversion of P-waves and S-waves is provided, the method comprising: Stratigraphic interpretation was performed on the pre-stack time migration profiles of shear waves and p-waves to establish a geological framework model. The pre-stack time migration profiles of shear waves were obtained by sequentially performing polarization rotation, common receiver shear wave velocity analysis, and pre-stack time migration processing on the seismic data received by the seafloor seismograph. Well-seismic calibration was performed based on the geological framework model, the average seismic wavelet of the study area, and the well logging curves to obtain calibrated seismic data; the well logging curves included: P-wave logging curves, S-wave logging curves, and density curves. Pre-stack simultaneous inversion was performed based on well-calibrated seismic data and the initial low-frequency model of the study area to obtain inversion results, which were then used to identify natural gas hydrates.

[0006] According to another aspect of the present invention, a simultaneous P-wave and S-wave pre-stack inversion apparatus is provided, comprising: The stratigraphic interpretation module is used to interpret the stratigraphic profiles of the pre-stack shear wave and pre-stack p-wave, and to establish a geological framework model. The pre-stack shear wave profile is obtained by sequentially performing polarization rotation, common receiver point shear wave velocity analysis, and pre-stack shear wave time migration processing on the seismic data received by the seafloor seismometer. The well-seismic calibration module is used to perform well-seismic calibration based on the geological framework model, the average seismic wavelet of the study area, and well logging curves to obtain calibrated seismic data; the well logging curves include: P-wave logging curves, S-wave logging curves, and density curves. The pre-stack simultaneous inversion module is used to perform pre-stack simultaneous inversion based on well-calibrated seismic data and the initial low-frequency model of the study area to obtain inversion results, which are then used to identify natural gas hydrates.

[0007] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the simultaneous inversion method of P-wave and S-wave stacking according to any embodiment of the present invention.

[0008] According to another aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions for causing a processor to execute and implement the simultaneous inversion method of P-wave and S-wave stacking as described in any embodiment of the present invention.

[0009] The technical solution of this application includes: interpreting the stratigraphic sequence of the pre-stack time migration profiles of shear waves and the pre-stack time migration profiles of p-waves to establish a geological framework model; the pre-stack time migration profiles of shear waves are obtained by sequentially performing polarization rotation, common receiver shear wave velocity analysis, and pre-stack time migration processing on the seismic data received by the seafloor seismometer; well-seismic calibration is performed based on the geological framework model, the average seismic wavelet of the study area, and well logging curves to obtain calibrated seismic data; the well logging curves include p-wave logging curves, shear wave logging curves, and density curves; pre-stack simultaneous inversion is performed based on the well-seismic calibrated seismic data and the initial low-frequency model of the study area to obtain more accurate inversion results, so as to identify natural gas hydrates based on the inversion results.

[0010] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a flowchart of a pre-stack simultaneous inversion method for P-waves and S-waves provided in Embodiment 1 of this application; Figure 2 This is a flowchart of a method for simultaneous inversion of P-waves and S-waves before stacking, according to Embodiment 2 of this application; Figure 3 This is an energy plane distribution diagram before polarization rotation provided in Embodiment 2 of this application; Figure 4 This is a planar energy distribution diagram after polarization rotation provided in Embodiment 2 of this application; Figure 5 It is the R-component gather before multiple wave suppression provided according to Embodiment 2 of this application; Figure 6 It is the R-component gather after multiple wave suppression according to Embodiment 2 of this application; Figure 7 This is a schematic diagram of the shear wave velocity field according to Embodiment 2 of this application; Figure 8 This is a schematic diagram of the pre-stack time migration profile of shear waves provided according to Embodiment 2 of this application; Figure 9 This is a schematic diagram of a geological lattice model according to Embodiment 2 of this application; Figure 10 This is a schematic diagram of the velocity field obtained from conventional velocity analysis; Figure 11 This is a schematic diagram of the velocity field obtained from the high-density velocity analysis provided in Embodiment 2 of this application; Figure 12 This is a schematic diagram of longitudinal wave impedance according to Embodiment 2 of this application; Figure 13 This is a schematic diagram of transverse wave impedance provided according to Embodiment 2 of this application; Figure 14 This is a schematic diagram of the longitudinal and transverse wave velocity ratio provided in Embodiment 2 of this application; Figure 15 This is a flowchart of pre-stack simultaneous inversion of natural hydrogen hydrates provided in Embodiment 2 of this application; Figure 16 This is a schematic diagram of the structure of a simultaneous inversion device for longitudinal and transverse waves before stacking, according to Embodiment 3 of this application; Figure 17This is a schematic diagram of the structure of an electronic device that implements a simultaneous inversion method for longitudinal and transverse waves according to an embodiment of this application. Detailed Implementation

[0013] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0014] It should be noted that the terms "first," "second," "target," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0015] Example 1 Figure 1 This application provides a flowchart of a method for simultaneous P-wave and S-wave pre-stack inversion in Embodiment 1. This embodiment is applicable to situations involving simultaneous P-wave and S-wave pre-stack inversion. The method can be executed by a simultaneous P-wave and S-wave pre-stack inversion device, which can be implemented in hardware and / or software. This device can be configured in an electronic device with data processing capabilities. Figure 1 As shown, the method includes: S110, perform stratigraphic interpretation on the pre-stack time migration profiles of shear waves and p-waves, and establish a geological framework model; the pre-stack time migration profiles of shear waves are obtained by sequentially performing polarization rotation, common receiver point shear wave velocity analysis, and pre-stack time migration processing on the seismic data received by the seafloor seismograph.

[0016] The pre-stack time migration profile of shear waves is obtained by high-precision imaging of shear waves. The process of obtaining the pre-stack time migration profile can be as follows: polarization rotation is sequentially performed on the seismic data received by the seafloor seismograph to distribute the shear wave (SV wave) energy on the radial component; then, the radial component seismic data is denoised, herar wave velocity is analyzed at common receiver points, and pre-stack time migration processing is performed to obtain the pre-stack time migration profile of shear waves. The process of determining the pre-stack time migration profile of p-waves is not described in detail in this embodiment.

[0017] Specifically, after obtaining the pre-stack time migration profiles of shear waves and P-waves, stratigraphic interpretation is performed on the shear wave and P-wave pre-stack time migration profiles to obtain stratigraphic information of the study area, and then a geological framework model is established.

[0018] S120, well-seismic calibration is performed based on the geological framework model, the average seismic wavelet of the study area, and the well logging curves to obtain calibrated seismic data; the well logging curves include: P-wave logging curves, S-wave logging curves, and density curves.

[0019] The average seismic wavelet of the study area can be obtained by extracting wavelets from seismic data at different offsets, resulting in seismic wavelets at near offset, medium offset, and far offset, and then merging them to obtain the average seismic wavelet.

[0020] For example, since simultaneous P-wave and S-wave inversion before stacking requires P-wave and S-wave data from each well involved in the calculation, if only a few wells in the study area have S-wave logging data, the other wells need to use a fitting method to calculate the S-wave data. The P-wave velocity Gardner formula can be used to convert the velocity curve into a density curve, and based on the experience of the study area, the S-wave logging curve can be converted with a Vp / Vs velocity ratio of 2.

[0021] Specifically, after obtaining the geological framework model, the average seismic wavelet of the study area, and the well logging curves, well-seismic calibration is performed to obtain calibrated seismic data. In this case, calibration can be performed separately for near-offset seismic data, medium-offset seismic data, and far-offset seismic data.

[0022] S130, based on the seismic data after well-seismic calibration and the initial low-frequency model of the study area, performs pre-stack simultaneous inversion to obtain inversion results, which are then used to identify natural gas hydrates.

[0023] The initial low-frequency model of the study area contains low-frequency information, which can be an initial low-frequency model established using the layer velocity of the study area.

[0024] The inversion method described in this application allows for exploration, exploitation, and other operations of natural gas hydrates based on the inversion results.

[0025] The technical solution of this application includes: interpreting the stratigraphic sequence of the pre-stack time migration profiles of shear waves and the pre-stack time migration profiles of p-waves to establish a geological framework model; the pre-stack time migration profiles of shear waves are obtained by sequentially performing polarization rotation, common receiver shear wave velocity analysis, and pre-stack time migration processing on the seismic data received by the seafloor seismometer; well-seismic calibration is performed based on the geological framework model, the average seismic wavelet of the study area, and well logging curves to obtain calibrated seismic data; the well logging curves include p-wave logging curves, shear wave logging curves, and density curves; pre-stack simultaneous inversion is performed based on the well-seismic calibrated seismic data and the initial low-frequency model of the study area to obtain more accurate inversion results, so as to identify natural gas hydrates based on the inversion results.

[0026] Example 2 Figure 2 This is a flowchart of a method for simultaneous inversion of P-waves and S-waves before stacking, provided in Embodiment 2 of this application. This embodiment is an optimization based on the above embodiment.

[0027] like Figure 2 As shown, the method in this embodiment specifically includes S210-S280: Before executing S210, this application embodiment can determine the hydrate filling mode to perform pre-stack simultaneous inversion of P-waves and S-waves (P-waves and S-waves) based on the filling model. Since hydrates can both fill pores as fluids and support the sediment skeleton, it is necessary to analyze the hydrate filling mode before establishing the rock physics template. This application calculates the P-wave and S-wave velocities under the two filling modes according to the effective medium model, and then compares them with the actual well logging P-wave and S-wave velocities to analyze the hydrate filling mode. The mineral composition, porosity, and saturation parameters required to estimate the P-wave and S-wave velocities are obtained from well logging interpretation results. The elastic modulus parameters of mineral composition and pore fluid are obtained from laboratory rock physics data. It can be seen that the calculated P-wave and S-wave velocities of the hydrate as skeleton support model are more consistent with the measured data than when hydrates are pore fluids. Therefore, it is believed that the hydrate filling mode in the study area is mainly skeleton support.

[0028] Furthermore, since there may be fewer shear wave logging curves in the well logging data, and the simultaneous inversion of P-wave and S-wave logs requires P-wave and S-wave data from each well involved in the calculation, other wells need to use a fitting method to calculate the S-wave data. The P-wave velocity curve is converted into a density curve using the Gardner formula, and based on the experience of the study area, the S-wave logging curve is converted with a Vp / Vs velocity ratio of 2.

[0029] S210 performs polarization rotation processing on the shear wave seismic data received by the seabed seismograph.

[0030] S220, Multiple wave suppression is applied to the rotated target component shear wave seismic data to obtain multiple wave suppressed target component seismic data; the target component is the component that satisfies the shear wave energy distribution condition.

[0031] S230: Based on the target component seismic data, P-wave velocity, and vertical velocity ratio, the shear wave velocity of the common receiver point is analyzed to obtain the shear wave velocity.

[0032] S240, based on the shear wave velocity, perform shear wave pre-stack time migration processing to obtain a shear wave pre-stack time migration profile.

[0033] In this embodiment of the application, optionally, S210-S240 is the process of determining the pre-stack time offset profile of the shear wave.

[0034] In this embodiment of the application, optionally, the target component is the radial component; the polarization rotation processing of the shear wave seismic data received by the seafloor seismograph includes: polarizing the horizontal component data of the shear wave seismic data received by the seafloor seismograph so that the shear wave energy is located on the radial component; correspondingly, the shear wave seismic data of the rotated target component is subjected to multiple wave suppression to obtain the target component seismic data after multiple wave suppression, including: the shear wave seismic data of the radial component is subjected to multiple wave suppression to obtain the radial component seismic data after multiple wave suppression.

[0035] This application's embodiments polarize the seismic data of the horizontal component, enabling the shear wave energy to be distributed across the radial component. The shear wave energy converges from two horizontal components to a single radial component, resulting in more focused energy, a clearer waveform, and suppression of stray energy, thus solving the problems of weak shear wave signals and susceptibility to noise masking. This technical solution, by suppressing the radial component seismic waves through multiple waves, facilitates the identification of effective shear wave information in subsequent conversion.

[0036] For example, the process of determining the pre-stack time migration profile of the shear wave can be: 1. Polarization Rotation: The seafloor seismograph receives three components of information: the horizontal component X is parallel to the receiver line, and the horizontal component Y is perpendicular to the receiver line. Since the line connecting the shot point and the receiver point generally forms an angle with the receiver line, the SV wave reaching the receiver will project onto both the X and Y components. This results in the observed X and Y component records containing both the radial component R and the tangential component T of the SV wave. To obtain the SV wave, the X and Y components need to be rotated. The purpose of polarization rotation is to concentrate the energy of the SV wave as much as possible on the radial component R and to ensure a uniform energy distribution of the gathers within the positive and negative offsets. Figure 3 The diagram shows the energy plane distribution before polarization rotation (from left to right, the horizontal components X and Y). Figure 4 The diagram shows the planar energy distribution after polarization rotation (from left to right: radial component R and tangential component T).

[0037] 2. Shear wave denoising. After rotation processing, the shear wave energy is mainly concentrated in the R component. However, the R component has significant multiples, which can affect the identification of effective information from the converted shear wave. Figure 5 For multiple wave suppression of the R component gather; Figure 6 This is the R-component gather after multiple wave suppression.

[0038] 3. SEM velocity analysis at common receiver points. SEM velocity analysis is primarily based on common receiver gather data, calculating the up-travel time and down-travel time separately. This approach accommodates situations where the shot and receiver points differ significantly, and also adapts to the characteristic of down-travel P-waves incident and up-travel SEMs exiting. SEM velocity analysis is mainly based on target component seismic data, P-wave velocity, and gamma value (vertical velocity ratio). Figure 7 This is a schematic diagram of the transverse wave velocity field.

[0039] 4. Shear wave pre-stack time migration. Shear wave migration is mainly based on shear wave velocity parameters. Figure 8 This is a schematic diagram of the pre-stack time migration profile of a shear wave.

[0040] S250, stratigraphic interpretation of pre-stack time migration profiles of shear waves and pre-stack time migration profiles of p-waves, and establishment of a geological framework model.

[0041] For example, Figure 9 This is a schematic diagram of a geological lattice model.

[0042] S260, well-seismic calibration is performed based on the geological framework model, the average seismic wavelet of the study area, and the well logging curves to obtain calibrated seismic data; the well logging curves include: P-wave logging curves, S-wave logging curves, and density curves.

[0043] Optionally, in this embodiment of the application, the process of determining the average seismic wavelet of the study area includes: extracting seismic wavelets at different offsets from the seismic traces near the well, and merging the wavelets corresponding to each offset into the average seismic wavelet of the study area.

[0044] For example, multiple wavelets are first extracted from the near-offset seismic data and averaged to obtain the wavelets corresponding to the near-offset seismic data. The same process is applied to the intermediate / far-offset seismic data to obtain wavelets corresponding to the three offset seismic data. These three wavelets are then combined into an average seismic wavelet. For example, a synthetic seismic record can be output based on the average seismic wavelet and well logging reflection coefficients. This synthetic record is then used to simultaneously calibrate three sets of real seismic data from near, intermediate, and far offset locations to obtain calibrated seismic data.

[0045] In a specific example, the wavelet estimation and calibration process is as follows: For seismic data volumes stacked at different offsets, based on the data conditions of each well in the study area, wavelets from well-side channels with high seismic data quality and well curve quality are extracted. Then, different wavelets are merged into an average wavelet. The bandwidth of the seismic data at near, medium, and far offsets is basically consistent. The amplitude spectrum of the wavelet at far offset is the largest, followed by the amplitude spectrum of the wavelet at medium offset, and the amplitude spectrum of the wavelet at near offset is the smallest. The phase of the corresponding wavelet in the stacked seismic data at far, medium, and near offsets is basically stable, indicating that the data can be used for the next step of joint inversion. To improve the accuracy of the inversion results and the ability to resolve reservoirs, it is necessary to combine seismic and well logging data, that is, to perform joint calibration of well logging, seismic, and geological data under the control of seismic data stacked at different angles. During the calibration process, it is necessary to consider the time-depth correspondence between different gather data and well logging results, as well as the optimal matching of amplitude, frequency, etc.

[0046] S270, based on the calibrated seismic data, velocity analysis is performed to obtain layer velocities and generate an initial low-frequency model of the study area; the analysis density during the velocity analysis meets the high-density condition.

[0047] In this embodiment, S270 is the process of determining the initial low-frequency model. The high-density condition involves performing velocity analysis on each spatial trace and each temporal sample point. This maximizes the utilization of data travel time and provides an initial low-frequency model with richer low-frequency components and higher resolution for inversion.

[0048] For example, the process of establishing the initial low-frequency model is as follows: the initial model used for pre-stack simultaneous inversion should contain low-frequency information. Since seismic waveform data lacks low-frequency information, well logging information is generally used to provide low-frequency constraints during inversion. However, in the study area, layer velocity is usually used to establish the initial model, but conventional velocity analysis methods have low density and low accuracy, resulting in insufficient low-frequency information components for compensation. To address this deficiency, this application uses a high-density velocity analysis method to obtain layer velocity and establish the initial model. Using pre-stack time migration data, every spatial trace and every temporal sample point is analyzed, making full use of the data travel time, which can provide an initial model with richer low-frequency components and higher resolution for inversion.

[0049] For example, Figure 10 This is a schematic diagram of the velocity field obtained from conventional velocity analysis. Figure 11 This is a schematic diagram of the velocity field obtained from the high-density velocity analysis of this application.

[0050] S280, based on the seismic data after well-seismic calibration and the initial low-frequency model of the study area, performs pre-stack simultaneous inversion to obtain inversion results, which are then used to identify natural gas hydrates.

[0051] In this embodiment of the application, optionally, pre-stack simultaneous inversion is performed based on the well-seismic calibration seismic data and the initial low-frequency model of the study area to obtain the inversion results, including: pre-stack simultaneous inversion is performed based on the well-seismic calibration seismic data and the initial low-frequency model of the study area to obtain the target elastic parameters.

[0052] The target elastic parameters include, but are not limited to: the ratio of P-wave to S-wave velocity, and the P-wave and S-wave impedance.

[0053] In this embodiment of the application, elastic parameters such as the P-wave velocity ratio and P-wave impedance can be obtained by simultaneously inverting P-waves and S-waves before stacking. The specific elastic parameters can be selected according to actual needs. This setting can obtain more and more accurate elastic parameters compared to methods such as P-wave inversion before stacking.

[0054] In this embodiment of the application, optionally, pre-stack simultaneous inversion is performed based on the well-calibrated seismic data and the initial low-frequency model of the study area to obtain the inversion results, including: pre-stack simultaneous inversion is performed based on the well-calibrated near-offset seismic data, medium-offset seismic data, far-offset seismic data and the initial low-frequency model of the study area to obtain the inversion results.

[0055] For example, the pre-stack simultaneous inversion method utilizes near, medium and far offset stacked gathers to obtain important elastic parameters such as P-wave velocity ratio and P-wave impedance through pre-stack simultaneous inversion (Formula 1). It can effectively reduce the non-uniqueness of simple P-wave inversion and has the advantages of stable algorithm, strong noise resistance, and no requirement for equalization processing of pre-stack gathers.

[0056] Formula 1 is: ; Where EI is the elastic impedance function, and θ is the angular variable. For the longitudinal wave velocity, For transverse wave velocity, This represents the density of the rock.

[0057] For example, Figure 12 This is a schematic diagram of longitudinal wave impedance. Figure 13 This is a schematic diagram of transverse wave impedance. Figure 14 This is a schematic diagram of the P-wave and S-wave velocity ratio. Figure 15 This is a flowchart of the pre-stack simultaneous inversion process for natural gas hydrates.

[0058] The technical solution of this application establishes a stratigraphic framework through high-precision P-wave and S-wave imaging, and constructs a high-precision initial low-frequency model using high-density velocity analysis for simultaneous pre-stack inversion of hydrates using P-wave and S-wave. This overcomes two shortcomings of commonly used methods: first, poor P-wave and S-wave data imaging leads to inaccurate stratigraphic interpretation, affecting the accuracy of the geological framework model; second, conventional velocity spectra have low spatial density and low precision, resulting in low accuracy in establishing the initial low-frequency model, with the error increasing at deeper layers. This application demonstrates good adaptability to different hydrate study areas, and the predicted P-wave and S-wave impedance, P-wave and S-wave velocity ratio, and other important elastic parameters are more accurate.

[0059] This application establishes a stratigraphic framework through high-precision P- and S-wave imaging and constructs a more accurate initial low-frequency model using high-density velocity analysis for simultaneous pre-stack inversion of hydrate P- and S-waves. This method demonstrates good adaptability to different hydrate study areas and provides higher accuracy in predicting important elastic parameters such as P- and S-wave impedance and P- and S-wave velocity ratios. Based on the elastic parameters such as P- and S-wave impedance and P- and S-wave velocity ratios inverted in this application, areas with significant velocity anomalies and high impedance anomalies are suspected to be related to hydrate ore bodies. Figure 12 The low P-wave impedance region below the seabed, circled in red in the P-wave impedance profile, is similar to the characteristics of a high-velocity methane hydrate ore body. Figure 13 In the suspected hydrate region at the same location, the change in transverse wave impedance was found to be relatively small, especially... Figure 14 The low P-wave velocity ratio anomaly region indicated by the P-wave velocity ratio profile is likely caused by the presence of a free gas layer beneath the hydrate layer. These conclusions are in good agreement with the drilling results, proving that the method described in the embodiments of this application is practical and effective.

[0060] Example 3 Figure 16 This is a schematic diagram of a pre-stack inversion device for both P-waves and S-waves provided in Embodiment 3 of this application. This device can execute the pre-stack inversion method for both P-waves and S-waves provided in any embodiment of this invention, and possesses the corresponding functional modules and beneficial effects for executing the method. For example... Figure 16 As shown, the device includes: The stratigraphic interpretation module 310 is used to interpret the stratigraphic profiles of the pre-stack shear wave and the pre-stack p-wave, and to establish a geological framework model. The pre-stack shear wave profile is obtained by sequentially performing polarization rotation, common receiver point shear wave velocity analysis, and pre-stack shear wave time migration processing on the seismic data received by the seafloor seismograph. The well-seismic calibration module 320 is used to perform well-seismic calibration based on the geological framework model, the average seismic wavelet of the study area, and well logging curves to obtain calibrated seismic data; the well logging curves include: P-wave logging curves, S-wave logging curves, and density curves. The pre-stack simultaneous inversion module 330 is used to perform pre-stack simultaneous inversion based on the seismic data after well-seismic calibration and the initial low-frequency model of the study area to obtain inversion results, so as to identify natural gas hydrates based on the inversion results.

[0061] The technical solution of this application embodiment includes: a stratigraphic interpretation module 310, used to interpret the stratigraphic profiles of the pre-stack shear wave and pre-stack p-wave, and establish a geological framework model; the pre-stack shear wave profile is obtained by sequentially performing polarization rotation, common receiver shear wave velocity analysis, and pre-stack shear wave time migration processing on the seismic data received by the seafloor seismometer; a well-seismic calibration module 320, used to perform well-seismic calibration based on the geological framework model, the average seismic wavelet of the study area, and well logging curves to obtain calibrated seismic data; the well logging curves include: p-wave logging curves, shear wave logging curves, and density curves; and a pre-stack simultaneous inversion module 330, used to perform pre-stack simultaneous inversion based on the well-seismic calibrated seismic data and the initial low-frequency model of the study area to obtain more accurate inversion results, so as to identify natural gas hydrates based on the inversion results.

[0062] Optionally, in this embodiment of the application, the apparatus further includes: a pre-stack time migration profile determination module for shear waves, comprising: The polarization rotation unit is used to perform polarization rotation processing on the shear wave seismic data received by the seabed seismograph. The multiple wave suppression unit is used to suppress the shear wave seismic data of the rotated target component with multiple waves, so as to obtain the target component seismic data after multiple wave suppression; the target component is the component that satisfies the shear wave energy distribution condition. The shear wave velocity analysis unit is used to perform shear wave velocity analysis at the common receiver point based on the target component seismic data, P-wave velocity, and vertical velocity ratio to obtain the shear wave velocity. The pre-stack time migration processing unit is used to perform pre-stack time migration processing of shear waves based on the shear wave velocity to obtain a pre-stack time migration profile of shear waves.

[0063] Optionally, in this embodiment of the application, the polarization rotating unit includes: The polarization rotation sub-unit is used to polarize and rotate the horizontal component of the shear wave seismic data received by the seabed seismograph so that the shear wave energy is located on the radial component. Correspondingly, the multiple suppression unit includes: The multiple wave suppression sub-unit is used to suppress the radial component of shear wave seismic data with multiple waves, resulting in radial component seismic data after multiple wave suppression.

[0064] Optionally, in this embodiment of the application, the device further includes: an initial low-frequency model determination module, specifically used for: Velocity analysis is performed based on the calibrated seismic data to obtain layer velocities and generate an initial low-frequency model of the study area; the analysis density during the velocity analysis meets the high-density condition.

[0065] Optionally, in this embodiment of the application, the device further includes: a module for determining the average seismic wavelet of the study area, specifically used for: In the seismic traces near the well, seismic wavelets at different offsets are extracted, and the wavelets corresponding to each offset are merged into the average seismic wavelet of the study area.

[0066] Optionally, in this embodiment of the application, the pre-stack simultaneous inversion module 330 includes: The target elastic parameter determination unit is used to perform pre-stack simultaneous inversion based on well-calibrated seismic data and the initial low-frequency model of the study area to obtain the target elastic parameters.

[0067] Optionally, in this embodiment of the application, the pre-stack simultaneous inversion module 330 includes: The pre-stack simultaneous inversion unit is used to perform pre-stack simultaneous inversion based on the near-offset seismic data, medium-offset seismic data, far-offset seismic data after well-seismic calibration, and the initial low-frequency model of the study area to obtain the inversion results.

[0068] The simultaneous P-wave and S-wave inversion apparatus provided in this application embodiment can execute the simultaneous P-wave and S-wave inversion method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0069] Example 4 Figure 17 A schematic diagram of an electronic device 10, which can be used to implement embodiments of the present invention, is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0070] like Figure 17As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0071] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0072] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the simultaneous inversion method before P-wave and S-wave stacking.

[0073] In some embodiments, the simultaneous P-wave and S-wave pre-stack inversion method can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the simultaneous P-wave and S-wave pre-stack inversion method described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to perform the simultaneous P-wave and S-wave pre-stack inversion method by any other suitable means (e.g., by means of firmware).

[0074] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), system-on-a-chip (SoCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0075] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0076] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0077] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0078] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or middleware components (e.g., application servers), or frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0079] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0080] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0081] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for simultaneous inversion of P-waves and S-waves before stacking, characterized in that, include: Stratigraphic interpretation was performed on the pre-stack time migration profiles of shear waves and p-waves to establish a geological framework model. The pre-stack time migration profiles of shear waves were obtained by sequentially performing polarization rotation, common receiver shear wave velocity analysis, and pre-stack time migration processing on the seismic data received by the seafloor seismograph. Well-seismic calibration was performed based on the geological framework model, the average seismic wavelet of the study area, and the well logging curves to obtain calibrated seismic data; the well logging curves included: P-wave logging curves, S-wave logging curves, and density curves. Pre-stack simultaneous inversion was performed based on well-calibrated seismic data and the initial low-frequency model of the study area to obtain inversion results, which were then used to identify natural gas hydrates.

2. The method according to claim 1, characterized in that, The process of determining the pre-stack time migration profile of the shear wave includes: The shear wave seismic data received by the seabed seismograph are subjected to polarization rotation processing. Multiple wave suppression is applied to the rotated target component shear wave seismic data to obtain multiple wave suppressed target component seismic data; the target component is the component that satisfies the shear wave energy distribution condition. Based on the target component seismic data, P-wave velocity, and vertical velocity ratio, the shear wave velocity of the common receiver point is analyzed to obtain the shear wave velocity. Based on the shear wave velocity, a pre-stack time migration process is performed to obtain a pre-stack time migration profile of the shear wave.

3. The method according to claim 2, characterized in that, Polarization rotation processing is performed on the shear wave seismic data received by the seabed seismograph, including: The horizontal component of the shear wave seismic data received by the seabed seismograph is polarized and rotated so that the shear wave energy is located on the radial component. Accordingly, the rotated target component shear wave seismic data is subjected to multiple wave suppression to obtain multiple-suppressed target component seismic data, including: Multiple wave suppression is applied to the radial component shear wave seismic data to obtain the multiple-suppressed radial component seismic data.

4. The method according to claim 1, characterized in that, The process of determining the initial low-frequency model includes: Velocity analysis is performed based on the calibrated seismic data to obtain layer velocities and generate an initial low-frequency model of the study area; the analysis density during the velocity analysis meets the high-density condition.

5. The method according to claim 1, characterized in that, The process of determining the average seismic wavelet of the study area includes: In the seismic traces near the well, seismic wavelets at different offsets are extracted, and the wavelets corresponding to each offset are merged into the average seismic wavelet of the study area.

6. The method according to claim 1, characterized in that, Pre-stack simultaneous inversion was performed based on well-calibrated seismic data and the initial low-frequency model of the study area to obtain inversion results, including: Pre-stack simultaneous inversion was performed based on well-calibrated seismic data and the initial low-frequency model of the study area to obtain the target elastic parameters.

7. The method according to claim 1, characterized in that, Pre-stack simultaneous inversion was performed based on well-calibrated seismic data and the initial low-frequency model of the study area to obtain inversion results, including: Pre-stack simultaneous inversion was performed based on the near-offset seismic data, medium-offset seismic data, and far-offset seismic data after well-seismic calibration, as well as the initial low-frequency model of the study area, to obtain the inversion results.

8. A device for simultaneous inversion of P-waves and S-waves before stacking, characterized in that, include: The stratigraphic interpretation module is used to interpret the stratigraphic profiles of the pre-stack shear wave and pre-stack p-wave, and to establish a geological framework model. The pre-stack shear wave profile is obtained by sequentially performing polarization rotation, common receiver point shear wave velocity analysis, and pre-stack shear wave time migration processing on the seismic data received by the seafloor seismometer. The well-seismic calibration module is used to perform well-seismic calibration based on the geological framework model, the average seismic wavelet of the study area, and well logging curves to obtain calibrated seismic data; the well logging curves include: P-wave logging curves, S-wave logging curves, and density curves. The pre-stack simultaneous inversion module is used to perform pre-stack simultaneous inversion based on well-calibrated seismic data and the initial low-frequency model of the study area to obtain inversion results, which are then used to identify natural gas hydrates.

9. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the simultaneous P-wave and S-wave pre-stack inversion method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that cause a processor to execute the simultaneous inversion method of P-wave and S-wave stacks as described in any one of claims 1-7.

Images