Method and apparatus for improving converted wave resolution
By using forward modeling of P-waves and converted waves from multi-component seismic data, combined with frequency domain filtering, the problem of low converted wave resolution was solved, thereby improving the converted wave resolution and the accuracy of thin reservoir identification.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- PETROCHINA CO LTD
- Filing Date
- 2024-04-30
- Publication Date
- 2026-07-03
Smart Images
Figure CN120871239B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of petroleum geophysical exploration technology, and in particular to a method and apparatus for improving converted wave resolution. Background Technology
[0002] As oil and gas exploration becomes increasingly challenging, traditional P-wave seismic exploration is facing growing difficulties. Multi-component seismic exploration, which involves P-wave excitation and combined P- and S-wave reception, is gaining importance due to the added S-wave information. In multi-component seismic exploration, the signal received by P-wave excitation is called a PP wave, or P-wave; the signal received by S-wave excitation is called a PS wave, or converted wave.
[0003] Because shear waves attenuate more severely than p-waves during underground propagation, converted waves have a narrow bandwidth and significantly lower resolution than p-waves. This is one of the most significant problems hindering the development of multi-component seismic analysis, and there is a lack of effective solutions. Lower converted wave resolution leads to various reservoir prediction problems, such as increased uncertainty in converted wave attribute analysis, calculation errors due to different resolutions in combined p-wave and shear wave attribute analysis, and reduced resolution in combined p-wave and shear wave inversion.
[0004] Current methods for improving converted wave resolution typically follow the same approach used to improve P-wave resolution, broadening the frequency band of seismic data through mathematical methods to achieve this goal. However, this method neglects the intrinsic relationship between converted waves and P-waves in multi-component seismic data. Summary of the Invention
[0005] This invention addresses the technical challenge of low converted wave resolution by providing a method and apparatus for improving converted wave resolution. This invention relates to a technique for oil and gas exploration using multi-component seismic data. To achieve the above objective, this invention provides the following technical solution:
[0006] This invention provides a method for improving the resolution of converted waves, the method comprising:
[0007] Based on well logging data and multi-component seismic data of the study area, the time-depth relationship of P-wave, the time-depth relationship of converted wave, and the location of the target layer are obtained. The multi-component seismic data includes P-wave stacked data volume processed by pre-stack time migration, P-wave pre-stack gather data volume processed by pre-stack time migration, and converted wave stacked data volume processed by pre-stack time migration.
[0008] Based on the time-depth relationship of P-waves, the time-depth relationship of converted waves, and the location of the target layer, the stratigraphic interpretation of the P-wave marker layer and the stratigraphic interpretation of the converted wave marker layer are determined.
[0009] Based on the stratigraphic interpretation of the P-wave marker layer and the converted wave marker layer, the converted wave data volume in the P-wave time domain is obtained;
[0010] Based on well logging data of the study area, P-wave pre-stack gather data volume processed by pre-stack time migration, and the stratigraphic interpretation of P-wave marker layers, converted wave forward modeling seismic data volume was obtained.
[0011] Based on the converted wave data volume in the P-wave time domain and the converted wave forward modeling seismic data volume, a high-resolution converted wave data volume is obtained to improve the converted wave resolution.
[0012] Furthermore, the well logging data for the study area includes P-wave velocity curves, S-wave velocity curves, density logging curves, and stratified data.
[0013] Furthermore, the stratigraphic interpretation based on the P-wave marker layer and the converted wave marker layer yields the converted wave data volume in the P-wave time domain, including:
[0014] The interpretation time of the P-wave marker layer on the P-wave data is set to PPhorizon, and the interpretation time of the converted wave marker layer on the converted wave data is set to PShorizon. The P-wave and S-wave velocity ratio data volume is calculated and obtained.
[0015] Based on P-wave and S-wave velocity ratio data The time of the converted wave data is converted to the P-wave time to obtain the converted wave data volume in the P-wave time domain.
[0016] Furthermore, the calculation formula for the converted wave data volume in the longitudinal wave time domain is as follows:
[0017]
[0018] In the formula, T PP T is the time required for the converted wave to be corrected to the longitudinal wave. PS For the time of wave conversion, Vp represents the P-wave velocity, and Vs represents the S-wave velocity.
[0019] Furthermore, the P-wave and S-wave velocities are greater than the data volume. The calculation formula is:
[0020]
[0021] In the formula, Vp represents the longitudinal wave velocity and Vs represents the transverse wave velocity.
[0022] Furthermore, the converted wave forward modeling seismic data volume is obtained, including:
[0023] Based on well logging data of the study area, P-wave pre-stack gather data volume processed by pre-stack time migration, and stratigraphic interpretation of P-wave marker layers, shear wave impedance volume was obtained.
[0024] Seismic forward modeling is performed on the shear wave impedance volume to obtain converted wave forward modeling seismic data.
[0025] Furthermore, based on the well logging data of the study area, the P-wave pre-stack gather data volume processed by pre-stack time migration, and the stratigraphic interpretation results of the P-wave marker layers, the shear wave impedance volume is obtained, including:
[0026] Based on the P-wave velocity curve, S-wave velocity curve, and density logging curve in the well logging data of the study area, P-wave impedance and S-wave impedance are obtained.
[0027] Based on the logging curves of P-wave impedance, S-wave impedance, and density, as well as the results of the stratigraphic interpretation of the P-wave marker layer, a low-frequency model of P-wave impedance, S-wave impedance, and density is established.
[0028] The P-wave pre-stack gather data volume, which has undergone pre-stack time migration processing, is divided into several parts and then stacked to form several parts of the stack.
[0029] Each part of the superposition was subjected to well seismic calibration, and the wavelet of each part of the superposition was extracted.
[0030] Using the low-frequency model, each part of the superposition, and the wavelet corresponding to each part of the superposition as inputs, pre-stack sparse pulse inversion is performed to obtain the transverse wave impedance volume.
[0031] Furthermore, seismic forward modeling is performed on the shear wave impedance volume to obtain converted wave forward modeling seismic data, including:
[0032] Seismic wavelets are extracted from P-wave stacking data;
[0033] The seismic wavelet is convolved with the shear wave impedance volume to obtain the converted wave forward modeling seismic data volume.
[0034] Furthermore, based on the converted wave data volume in the P-wave time domain and the converted wave forward modeling seismic data volume, a high-resolution converted wave data volume is obtained to improve the converted wave resolution, including:
[0035] By combining the converted wave data volume in the P-wave time domain with the converted wave forward modeling seismic data volume in the frequency domain, a high-resolution converted wave data volume is obtained to improve the converted wave resolution.
[0036] Furthermore, based on the converted wave data volume in the P-wave time domain and the converted wave forward modeling seismic data volume, a high-resolution converted wave data volume is obtained to improve the converted wave resolution, which also includes:
[0037] The frequency band range of the converted wave data volume in the time domain of the longitudinal wave is obtained by analyzing the spectrum of the converted wave data volume in the time domain of the longitudinal wave.
[0038] The converted wave data volume in the longitudinal wave time domain is low-pass filtered, and the high-frequency cutoff value is selected as the maximum value of the frequency band range of the converted wave data volume in the longitudinal wave time domain to obtain the low-pass filtered converted wave data volume in the longitudinal wave time domain.
[0039] High-pass filtering is performed on the converted wave forward modeling seismic data volume. The low-frequency cutoff value is selected as the maximum value of the frequency band range of the converted wave data volume in the P-wave time domain to obtain the high-pass filtered converted wave forward modeling seismic data volume.
[0040] By applying Fourier transform, the converted wave data volume of the low-pass filtered P-wave time domain and the converted wave forward modeling seismic data volume of the high-pass filtered P-wave are transformed to obtain the frequency domain data volume corresponding to the converted wave data volume of the low-pass filtered P-wave time domain and the frequency domain data volume corresponding to the converted wave forward modeling seismic data volume of the high-pass filtered P-wave.
[0041] The frequency domain data corresponding to the converted wave data volume in the time domain of the low-pass filtered P-wave and the frequency domain data corresponding to the converted wave forward modeling seismic data volume of the high-pass filtered are added together, and then converted back to the time domain by inverse Fourier transform to obtain the high-resolution converted wave data volume.
[0042] The present invention also provides an apparatus for improving the resolution of converted waves, the apparatus comprising,
[0043] The first acquisition module is used to acquire the P-wave time-depth relationship, the converted wave time-depth relationship, and the target layer location based on well logging data and multi-component seismic data of the study area. The multi-component seismic data includes P-wave stacked data volume processed by pre-stack time migration, P-wave pre-stack gather data volume processed by pre-stack time migration, and converted wave stacked data volume processed by pre-stack time migration.
[0044] The determination module is used to determine the stratigraphic interpretation of the P-wave marker layer and the stratigraphic interpretation of the converted wave marker layer based on the P-wave time-depth relationship, the converted wave time-depth relationship, and the target layer location;
[0045] The first module is used for the layer interpretation based on the P-wave marker layer and the converted wave marker layer to obtain the converted wave data volume in the P-wave time domain;
[0046] The second module is used to obtain converted wave forward modeling seismic data based on well logging data of the study area, P-wave pre-stack gather data volume processed by pre-stack time migration, and the stratigraphic interpretation of P-wave marker layers.
[0047] The second acquisition module is used to acquire high-resolution converted wave data volume based on the converted wave data volume in the P-wave time domain and the converted wave forward modeling seismic data volume, in order to improve the converted wave resolution.
[0048] Furthermore, the second module includes:
[0049] The first submodule is used to obtain the shear wave impedance volume based on the well logging data of the study area, the pre-stack P-wave gather data volume processed by pre-stack time migration, and the stratigraphic interpretation results of the P-wave marker layer.
[0050] The second submodule is used to perform seismic forward modeling on the shear wave impedance volume to obtain converted wave forward modeling seismic data.
[0051] Furthermore, the steps performed by the second acquisition module include:
[0052] The frequency band range of the converted wave data volume in the time domain of the longitudinal wave is obtained by analyzing the spectrum of the converted wave data volume in the time domain of the longitudinal wave.
[0053] Low-pass filtering is performed on the converted wave data volume in the longitudinal wave time domain. The high-frequency cutoff value is selected as the maximum value of the frequency band range of the converted wave data volume in the longitudinal wave time domain to obtain the low-pass filtered converted wave data volume in the longitudinal wave time domain.
[0054] High-pass filtering is performed on the converted wave forward modeling seismic data volume. The low-frequency cutoff value is selected as the maximum value of the frequency band range of the converted wave data volume in the P-wave time domain to obtain the high-pass filtered converted wave forward modeling seismic data volume.
[0055] By applying Fourier transform, the converted wave data volume of the low-pass filtered P-wave time domain and the converted wave forward modeling seismic data volume of the high-pass filtered P-wave are transformed to obtain the frequency domain data volume corresponding to the converted wave data volume of the low-pass filtered P-wave time domain and the frequency domain data volume corresponding to the converted wave forward modeling seismic data volume of the high-pass filtered P-wave.
[0056] The frequency domain data volumes corresponding to the low-pass filtered P-wave time-domain converted wave data volume and the high-pass filtered converted wave forward modeling seismic data volume are added together and then converted back to the time domain by inverse Fourier transform to obtain the high-resolution converted wave data volume.
[0057] The present invention also provides an electronic device, the electronic device comprising at least one processor and at least one memory, the memory being data-connected to the processor, wherein,
[0058] The memory stores instructions executable by the at least one processor, which, when executed, enable the at least one processor to perform the described method. Technical effects and advantages of the present invention:
[0059] The technical approach of this invention is mainly to utilize pre-stack inversion technology of longitudinal waves to invert transverse wave information, simulate converted waves through forward modeling, and then fuse the actual converted wave with the high-frequency end of the inverted converted wave. The overall trend of the fusion result is consistent with the actual acquired converted wave, but the resolution is higher than that of the actual acquired converted wave.
[0060] This invention broadens the frequency band of converted wave seismic data and improves the accuracy of converted wave identification of thin reservoirs, which has significant practical implications for multi-component seismic exploration.
[0061] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description
[0062] Figure 1a This is a flowchart of a method for improving the resolution of converted waves according to an embodiment of the present invention;
[0063] Figure 1b This is a flowchart illustrating an embodiment of the method for improving converted wave resolution according to the present invention.
[0064] Figure 2a This is a P-wave well seismic calibration diagram according to an embodiment of the present invention;
[0065] Figure 2b This is a converted wave well seismic calibration diagram according to an embodiment of the present invention;
[0066] Figure 3 This is a schematic diagram of the marker layer based on the interpretation of longitudinal waves and converted waves in an embodiment of the present invention, which corrects the converted wave from the converted wave time domain to the longitudinal wave time domain;
[0067] Figure 4 A cross-sectional view of the transverse wave impedance body S obtained by longitudinal wave pre-stack inversion in an embodiment of the present invention;
[0068] Figure 5 This is a cross-sectional view of the converted wave forward modeling seismic data volume RPS according to an embodiment of the present invention;
[0069] Figure 6 This is a comparison diagram of the converted wave data volume PS2 and the high-resolution converted wave data volume PSH according to an embodiment of the present invention;
[0070] Figure 7 A block diagram of an electronic device structure according to an embodiment of the present disclosure is shown. Detailed Implementation
[0071] The technical solutions of the embodiments of the present invention 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 are within the scope of protection of the present invention.
[0072] To address the shortcomings of existing technologies, this invention discloses a method for improving the resolution of converted waves, such as... Figure 1a As shown, the method includes,
[0073] Step 1: Obtain well logging data and multi-component seismic data for the study area. Well logging data includes P-wave velocity, S-wave velocity, density logging curves, and layered data. Multi-component seismic data typically consists of P-wave stacked data volume PP processed by pre-stack time migration, P-wave pre-stack gather data CRP processed by pre-stack time migration, and converted wave stacked data volume PS1 processed by pre-stack time migration.
[0074] Step 2: Based on well logging data and multi-component seismic data of the study area, obtain the time-depth relationship of P-waves, the time-depth relationship of converted waves, and the location of the target layer;
[0075] Step 3: Based on the P-wave time-depth relationship, the converted wave time-depth relationship, and the target layer location, determine the stratigraphic interpretation of the P-wave marker layer and the stratigraphic interpretation of the converted wave marker layer;
[0076] Step 4: Based on the stratigraphic interpretation of the P-wave marker layer and the stratigraphic interpretation of the converted wave marker layer, obtain the converted wave data volume in the P-wave time domain;
[0077] Step 5: Based on well logging data of the study area, P-wave pre-stack gather data volume processed by pre-stack time migration, and stratigraphic interpretation of P-wave marker layers, the converted wave forward modeling seismic data volume is obtained;
[0078] Step 6: Based on the converted wave data volume in the P-wave time domain and the converted wave forward modeling seismic data volume, obtain a high-resolution converted wave data volume to improve the converted wave resolution.
[0079] In a specific embodiment of the present invention, step 2 is as follows:
[0080] In P-wave well-seismic calibration, the P-wave impedance curve is obtained by multiplying the P-wave velocity curve and density curve, and then the reflection coefficient sequence is obtained. Wavelets are extracted from the P-wave seismic data, and the P-wave seismic wavelets and the P-wave reflection sequence are convolved to obtain the P-wave composite record. The P-wave composite record is compared with the P-wave well-side seismic data to achieve the best match between the P-wave composite record and the P-wave well-side seismic data, and to determine the P-wave time-depth relationship and the location of the target layer.
[0081] In converted wave well-seismic calibration, the range of converted wave incident angles is determined based on the acquisition of multi-component seismic data. For example, if the range of converted wave incident angles is 0-60 degrees, the converted wave reflection coefficient within the 0-60 degree range is calculated according to formula (1). Wavelets are extracted from the converted wave seismic data and convolved with the converted wave reflection coefficients within the 0-60 degree range to generate pre-stack converted wave gathers. The gathers are then stacked to generate a converted wave composite record. The converted wave composite record is compared with the converted wave well-side seismic data to achieve the best match between the two, thus determining the converted wave time-depth relationship and the location of the target layer.
[0082]
[0083] In the formula: θ is the incident angle of the longitudinal wave, For the converted wave reflection angle, v s ρ and Δv are the average velocity of the transverse wave and the average density of the medium, respectively. s Δρ and Δρ represent the difference in transverse wave velocity and density, respectively, and γ is the ratio of transverse wave velocity to longitudinal wave velocity.
[0084] In a specific embodiment of the present invention, step 4: obtaining the converted wave data volume PS2 based on the stratigraphic interpretation of the P-wave marker layer and the stratigraphic interpretation of the converted wave marker layer includes:
[0085] Step 401: Set the interpretation time of the P-wave marker layer on the P-wave data to PPhorizon, and the interpretation time of the converted wave marker layer on the converted wave data to PShorizon, and calculate and obtain the P-wave and S-wave velocity ratio data volume. The P-wave and S-wave velocity ratio data volume The calculation formula is:
[0086]
[0087] In the formula, Vp represents the longitudinal wave velocity and Vs represents the transverse wave velocity.
[0088] Step 402: Based on the P-wave and S-wave velocity ratio data volume The converted wave data time is converted to P-wave time to obtain the converted wave data volume in the P-wave time domain. The calculation formula is as follows:
[0089]
[0090] In the formula, T PP T is the time required for the converted wave to be corrected to the longitudinal wave. PS For the time of wave conversion, Vp represents the P-wave velocity, and Vs represents the S-wave velocity.
[0091] In a specific embodiment of the present invention, step 5: obtaining the converted wave forward modeling seismic data volume (RPS) based on well logging data of the study area, P-wave pre-stack gather data volume, and stratigraphic interpretation of P-wave marker layers includes:
[0092] Step 501: Based on well logging data, P-wave pre-stack gather data, and the stratigraphic interpretation of P-wave marker layers, the shear wave impedance volume S is obtained; the specific steps are as follows:
[0093] Step 5011: Based on the P-wave velocity curve, S-wave velocity curve, and density logging curve in the well logging data of the study area, obtain the P-wave impedance and S-wave impedance; Step 5012: Based on the P-wave impedance, S-wave impedance, and density logging curves, and the stratigraphic interpretation results of the P-wave marker layer obtained in Step 3, establish a low-frequency model for P-wave impedance, S-wave impedance, and density; Step 5013: Divide the P-wave pre-stack gather data volume CRP into several parts, and stack them to form several partial stacks; Step 5014: Perform well-seismic calibration on each partial stack and extract the wavelet of each partial stack; Step 5015: Use the low-frequency model, each partial stack, and the corresponding wavelet of each partial stack as input to perform pre-stack sparse pulse inversion to obtain the S-wave impedance volume S.
[0094] Step 502: Perform seismic forward modeling on the shear wave impedance volume to obtain converted wave forward modeling seismic data volume, including: extracting seismic wavelets from the P-wave stacking data; and convolving the seismic wavelets with the shear wave impedance volume to obtain the converted wave forward modeling seismic data volume RPS.
[0095] In a specific embodiment of the present invention, step 6: obtaining a high-resolution converted wave data volume for improving the converted wave resolution based on the converted wave data volume in the P-wave time domain and the converted wave forward seismic data volume includes: combining the converted wave data volume in the P-wave time domain and the converted wave forward seismic data volume in the frequency domain to obtain a high-resolution converted wave data volume for improving the converted wave resolution. The specific steps are as follows:
[0096] Step 601: Analyze the spectrum of the converted wave data volume in the time domain of the longitudinal wave to obtain the frequency band range of the converted wave data volume in the time domain of the longitudinal wave;
[0097] Step 602: Perform low-pass filtering on the converted wave data volume in the longitudinal wave time domain. Select the maximum value of the frequency band range of the converted wave data volume in the longitudinal wave time domain as the high-frequency cutoff value to obtain the low-pass filtered converted wave data volume in the longitudinal wave time domain.
[0098] Step 603: Perform high-pass filtering on the converted wave forward modeling seismic data volume. Select the maximum value of the frequency band range of the converted wave data volume in the P-wave time domain as the low-frequency cutoff value to obtain the high-pass filtered converted wave forward modeling seismic data volume.
[0099] Step 604: By applying Fourier transform, the converted wave data volume of the low-pass filtered P-wave time domain and the converted wave forward modeling seismic data volume of the high-pass filtered P-wave are transformed to obtain the frequency domain data volume corresponding to the converted wave data volume of the low-pass filtered P-wave time domain and the frequency domain data volume corresponding to the converted wave forward modeling seismic data volume of the high-pass filtered P-wave.
[0100] Step 605: Add the frequency domain data volume corresponding to the converted wave data volume of the low-pass filtered P-wave in the time domain and the frequency domain data volume corresponding to the converted wave forward modeling seismic data volume of the high-pass filtered P-wave, and then convert it back to the time domain through inverse Fourier transform to obtain the high-resolution converted wave data volume corresponding to the time domain.
[0101] In a specific embodiment of the present invention, the calculation formula for the frequency domain data volume corresponding to the converted wave data volume of the low-pass filtered longitudinal wave in step 604 is as follows:
[0102]
[0103] In the formula, S(ω1) represents the frequency domain seismic data corresponding to the converted wave data volume of the low-pass filtered P-wave in the time domain, ω1 = 2πf1, f1 is the frequency of the seismic data corresponding to the converted wave data volume of the low-pass filtered P-wave in the time domain, t1 is the time of the seismic data corresponding to the converted wave data volume of the low-pass filtered P-wave in the time domain, and s(t1) is the time domain seismic data corresponding to the converted wave data volume of the low-pass filtered P-wave in the time domain.
[0104] In a specific embodiment of the present invention, the calculation formula for the frequency domain data volume corresponding to the high-pass filtered converted wave forward modeling seismic data volume in step 604 is as follows:
[0105]
[0106] In the formula, S(ω2) represents the frequency domain seismic data corresponding to the high-pass filtered converted-wave forward modeling seismic data volume, ω2 = 2πf2, f2 is the frequency of the seismic data corresponding to the high-pass filtered converted-wave forward modeling seismic data volume, t2 is the time of the seismic data corresponding to the high-pass filtered converted-wave forward modeling seismic data volume, and s(t2) is the time domain seismic data corresponding to the high-pass filtered converted-wave forward modeling seismic data volume.
[0107] In a specific embodiment of the present invention, in step 605, the two data volumes are added in the frequency domain and then converted back to the time domain using an inverse Fourier transform to obtain the high-resolution converted wave data volume corresponding to the time domain. The inverse Fourier transform formula is:
[0108]
[0109] Where S(ω)=S(ω1)+S(ω2), ω=ω1+ω2, t=t1+t2, and S(t) represents the high-resolution converted wave data volume corresponding to the time domain.
[0110] The present invention proposes a method to improve the resolution of converted waves, which can broaden the bandwidth of converted wave seismic data and improve the resolution of converted waves, thereby laying a good foundation for subsequent seismic data interpretation.
[0111] The present invention also provides an apparatus for improving the resolution of converted waves, the apparatus comprising,
[0112] The first acquisition module is used to acquire the P-wave time-depth relationship, the converted wave time-depth relationship, and the location of the target layer based on well logging data and multi-component seismic data of the study area.
[0113] The determination module is used to determine the stratigraphic interpretation of the P-wave marker layer and the stratigraphic interpretation of the converted wave marker layer based on the P-wave time-depth relationship, the converted wave time-depth relationship, and the target layer location;
[0114] The first module is used for the layer interpretation based on the P-wave marker layer and the converted wave marker layer to obtain the converted wave data volume in the P-wave time domain;
[0115] The second module is used to obtain converted wave forward modeling seismic data based on well logging data of the study area, P-wave pre-stack gather data volume processed by pre-stack time migration, and the stratigraphic interpretation of P-wave marker layers.
[0116] The second acquisition module is used to acquire high-resolution converted wave data volume based on the converted wave data volume in the P-wave time domain and the converted wave forward modeling seismic data volume, in order to improve the converted wave resolution.
[0117] In one specific embodiment of the present invention, the second obtaining module includes:
[0118] The first submodule is used to obtain the shear wave impedance volume based on the well logging data of the study area, the pre-stack P-wave gather data volume processed by pre-stack time migration, and the stratigraphic interpretation results of the P-wave marker layer.
[0119] The second submodule is used to perform seismic forward modeling on the shear wave impedance volume to obtain converted wave forward modeling seismic data.
[0120] In a specific embodiment of the present invention, the steps performed by the second acquisition module include:
[0121] The frequency band range of the converted wave data volume in the time domain of the longitudinal wave is obtained by analyzing the spectrum of the converted wave data volume in the time domain of the longitudinal wave.
[0122] The converted wave data volume in the longitudinal wave time domain is low-pass filtered, and the high-frequency cutoff value is selected as the maximum value of the frequency band range of the converted wave data volume in the longitudinal wave time domain to obtain the low-pass filtered converted wave data volume in the longitudinal wave time domain.
[0123] High-pass filtering is performed on the converted wave forward modeling seismic data volume. The low-frequency cutoff value is selected as the maximum value of the frequency band range of the converted wave data volume in the P-wave time domain to obtain the high-pass filtered converted wave forward modeling seismic data volume.
[0124] By combining the low-pass filtered converted wave data volume with the high-pass filtered converted wave forward modeling seismic data volume in the frequency domain, a high-resolution converted wave data volume is obtained.
[0125] The technical solution of the present invention will be further described below with reference to specific embodiments.
[0126] Figure 1b This is a flowchart illustrating a method for improving converted wave resolution according to an embodiment of the present invention. Figure 1b As shown, the method includes the following steps:
[0127] S101: Obtain well logging data and multi-component seismic data for the study area. Sidetracking data includes, but is not limited to, P-wave velocity, S-wave velocity, density logging curves, and layered data; in this embodiment, the multi-component seismic data consists of P-wave stacked data PP processed by pre-stack time migration, P-wave pre-stack gather data CRP processed by pre-stack time migration, and converted wave stacked data PS1 processed by pre-stack time migration.
[0128] S102: Conduct well-seismic calibration using both P-wave and converted-wave data to determine the time-depth of the target layer in both P-wave and converted-wave data. Specifically, in P-wave well-seismic calibration, the P-wave velocity curve and density curve are multiplied to obtain the P-wave impedance curve, which in turn yields the reflection coefficient sequence. Wavelets are extracted from the P-wave seismic data, and convolution operations are performed on the P-wave seismic wavelets and the P-wave reflection sequence to obtain the P-wave composite record. The P-wave composite record is compared with the P-wave well-side seismic data to achieve the best match between the two, determining the time-depth relationship and the location of the target layer, such as... Figure 2a As shown in the figure, the peaks of the P-wave stacked data volume (PP) after pre-stack time migration correspond to the peaks of the synthetic record, and the troughs of the P-wave stacked data volume (PP) after pre-stack time migration correspond to the troughs of the synthetic record. This indicates that the synthetic record and the P-wave well-side seismic data achieve optimal matching, thus allowing the correlation between time and depth, i.e., the depth relationship. Furthermore, the pre-stack time migration times of the P-wave stacked data volume (PP) corresponding to well layers H1, H2, and H3 can be determined.
[0129] In converted-wave well seismic calibration, the range of converted-wave incident angles is determined based on the acquisition of multi-component seismic data. In this embodiment, the range is 0-60 degrees. The converted-wave reflection coefficient within this range is calculated using a formula. Wavelets are extracted from the converted-wave seismic data and convolved with the converted-wave reflection coefficient within the 0-60 degree range to generate pre-stack converted-wave gathers. These gathers are then stacked to generate a converted-wave composite record. The composite record is compared with the converted-wave well-side seismic data to achieve optimal matching, determining the time-depth relationship and the target layer location, such as... Figure 2b As shown in the figure, the peaks of the converted wave seismic data correspond to the peaks of the synthetic record, and the troughs of the converted wave seismic data correspond to the troughs of the synthetic record. This indicates that the synthetic record and the converted wave well-side seismic data achieve optimal matching, thus allowing us to obtain the correspondence between time and depth, i.e., the depth relationship. Furthermore, the converted wave seismic times corresponding to well layers H1, H2, and H3 can be determined.
[0130]
[0131] In the formula: θ is the incident angle of the longitudinal wave, For the converted wave reflection angle, v s ρ and Δv are the average velocity of the transverse wave and the average density of the medium, respectively. s Δρ and Δρ represent the difference in transverse wave velocity and density, respectively, and γ is the ratio of transverse wave velocity to longitudinal wave velocity.
[0132] S103: Interpretation of the P-wave marker layers and the converted wave marker layers are performed separately. In this embodiment, H1, H2, and H3 exhibit strong trough reflections in both P-waves and converted waves, and can be used as marker layers. Therefore, the layers H1, H2, and H3 are interpreted on the pre-stack time-migrated P-wave stacked data volume PP and the pre-stack time-migrated converted wave stacked data volume PS1, respectively. Figure 3 As shown in (a) and 3(b).
[0133] S104: Based on the marker layer interpreted by P-wave and converted wave, the converted wave stacked data volume PS1, after pre-stack time migration processing, is corrected from the converted wave time domain to the P-wave time domain to obtain the converted wave data volume PS2 in the P-wave time domain. First, assuming the time interpreted by the marker layer on the P-wave data is PPhorizon and the time interpreted by the marker layer on the converted wave data is PShorizon, the P-wave and S-wave velocity ratio data volume is calculated according to the formula.
[0134]
[0135] The second step is to analyze the P-wave and S-wave velocity ratio data. The time of the converted wave data is converted to the P-wave time, resulting in the converted wave data volume PS2 in the P-wave time domain.
[0136] Specifically, in this embodiment, the H1, H2, and H3 interpreted on the converted wave stacking data PS1 after pre-stack time migration processing are aligned with the H1, H2, and H3 interpreted on the P-wave stacking data PP after pre-stack time migration processing, respectively, to obtain the converted wave data PS2 in the P-wave time domain, as follows. Figure 3 As shown in (c).
[0137] S105: Based on well logging data and the pre-stack P-wave gather data volume (CRP) processed by pre-stack time migration, a pre-stack P-wave inversion is performed to obtain the shear wave impedance volume (S). In this embodiment, the constrained sparse pulse method is used to perform the pre-stack P-wave inversion to obtain the shear wave impedance volume (S), as follows: Figure 4 As shown.
[0138] S106: Perform seismic forward modeling to obtain the converted-wave forward modeled seismic data volume RPS. Based on the seismic wavelet extracted from the P-wave in step S102, convolve it with the S-wave impedance volume S to generate the converted-wave forward modeled seismic data volume RPS, as follows... Figure 5 As shown.
[0139] S107: Combine the P-wave time-domain converted wave data volume PS2 with the converted wave forward modeling seismic data volume RPS in the frequency domain to generate the high-resolution converted wave data volume PSH. Analyze the spectrum of the P-wave time-domain converted wave data volume PS2 to obtain its frequency band range; perform low-pass filtering on the P-wave time-domain converted wave data volume PS2, selecting the maximum value of the frequency band range at the high-frequency end cutoff, to obtain the frequency domain data volume corresponding to the low-pass filtered P-wave time-domain converted wave data volume; perform high-pass filtering on RPS, selecting the maximum value of the frequency band range at the low-frequency end cutoff, to obtain the frequency domain data volume corresponding to the high-pass filtered converted wave forward modeling seismic data volume; combine the frequency domain data volume corresponding to the low-pass filtered P-wave time-domain converted wave data volume with the frequency domain data volume corresponding to the high-pass filtered converted wave forward modeling seismic data volume in the frequency domain, and then return to the time domain to obtain the high-resolution converted wave data volume PSH.
[0140] according to Figure 6 The comparison between the converted wave data volume PS2 in the P-wave time domain and the high-resolution converted wave data volume PSH shows that, within the same time range, the high-resolution converted wave data volume PSH has significantly more reflection axes than the converted wave data volume PS2 in the P-wave time domain, resulting in a substantial increase in resolution and reflecting more stratigraphic information.
[0141] Based on the above disclosure, this disclosure also provides an electronic device. For example... Figure 7As shown, the electronic device of this disclosure includes at least one processor electrically connected to the present invention and at least one memory electrically connected to the processor, wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the method steps as executed by the controller above.
[0142] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for improving the resolution of converted waves, characterized in that, The method includes, Based on well logging data and multi-component seismic data of the study area, the time-depth relationship of P-wave, the time-depth relationship of converted wave, and the location of the target layer are obtained. The multi-component seismic data includes P-wave stacked data volume processed by pre-stack time migration, P-wave pre-stack gather data volume processed by pre-stack time migration, and converted wave stacked data volume processed by pre-stack time migration. Based on the time-depth relationship of P-waves, the time-depth relationship of converted waves, and the location of the target layer, the stratigraphic interpretation of the P-wave marker layer and the stratigraphic interpretation of the converted wave marker layer are determined. Based on the stratigraphic interpretation of the P-wave marker layer and the converted wave marker layer, the converted wave data volume in the P-wave time domain is obtained; Based on well logging data from the study area, P-wave pre-stack gather data volume processed by pre-stack time migration, and stratigraphic interpretation of P-wave marker layers, converted wave forward modeling seismic data volume was obtained, including: Based on the P-wave velocity curve, S-wave velocity curve and density logging curve in the well logging data of the study area, P-wave impedance and S-wave impedance are obtained. Based on the logging curves of P-wave impedance, S-wave impedance, and density, as well as the results of the stratigraphic interpretation of the P-wave marker layer, a low-frequency model of P-wave impedance, S-wave impedance, and density is established. The P-wave pre-stack gather data volume, which has undergone pre-stack time migration processing, is divided into several parts and then stacked to form several parts of the stack. Each part of the superposition was subjected to well seismic calibration, and the wavelet of each part of the superposition was extracted. Using the low-frequency model, each partial superposition, and the wavelet corresponding to each partial superposition as input, pre-stack sparse pulse inversion is performed to obtain the transverse wave impedance volume. Seismic wavelets are extracted from P-wave stacking data; The seismic wavelet is convolved with the shear wave impedance volume to obtain the converted wave forward modeling seismic data volume. By combining the converted wave data volume in the P-wave time domain with the converted wave forward modeling seismic data volume in the frequency domain, a high-resolution converted wave data volume is obtained to improve the converted wave resolution.
2. The method for improving converted wave resolution according to claim 1, characterized in that, The well logging data for the study area includes P-wave velocity curves, S-wave velocity curves, density logging curves, and stratified data.
3. The method for improving converted wave resolution according to claim 1, characterized in that, The stratigraphic interpretation based on the P-wave marker layer and the converted wave marker layer yields the converted wave data volume in the P-wave time domain, including: The interpretation time of the P-wave marker layer on the P-wave data is set to PPhorizon, and the interpretation time of the converted wave marker layer on the converted wave data is set to PShorizon. The P-wave and S-wave velocity ratio data volume is calculated and obtained. ; Based on P-wave and S-wave velocity ratio data The time of the converted wave data is converted into the P-wave time, thus obtaining the converted wave data volume in the P-wave time domain.
4. The method for improving converted wave resolution according to claim 3, characterized in that, The formula for calculating the converted wave data volume in the longitudinal wave time domain is: In the formula, The time required to correct the converted wave to the longitudinal wave. For the time of wave conversion, The ratio of P-wave to S-wave velocity, Indicates the longitudinal wave velocity. This indicates the velocity of the transverse wave.
5. The method for improving converted wave resolution according to claim 4, characterized in that, The P-wave and S-wave velocity ratio data volume The calculation formula is: ； In the formula, Indicates the longitudinal wave velocity. This indicates the velocity of the transverse wave.
6. The method for improving converted wave resolution according to claim 1, characterized in that, Based on the P-wave time-domain converted wave data volume and the converted wave forward modeling seismic data volume, a high-resolution converted wave data volume is obtained to improve the converted wave resolution, which also includes: The frequency band range of the converted wave data volume in the time domain of the longitudinal wave is obtained by analyzing the spectrum of the converted wave data volume in the time domain of the longitudinal wave. The converted wave data volume in the longitudinal wave time domain is low-pass filtered, and the high-frequency cutoff value is selected as the maximum value of the frequency band range of the converted wave data volume in the longitudinal wave time domain to obtain the low-pass filtered converted wave data volume in the longitudinal wave time domain. High-pass filtering is performed on the converted wave forward modeling seismic data volume. The low-frequency cutoff value is selected as the maximum value of the frequency band range of the converted wave data volume in the P-wave time domain to obtain the high-pass filtered converted wave forward modeling seismic data volume. By applying Fourier transform, the converted wave data volume of the low-pass filtered P-wave time domain and the converted wave forward modeling seismic data volume of the high-pass filtered P-wave are transformed to obtain the frequency domain data volume corresponding to the converted wave data volume of the low-pass filtered P-wave time domain and the frequency domain data volume corresponding to the converted wave forward modeling seismic data volume of the high-pass filtered P-wave. The frequency domain data corresponding to the converted wave data volume in the time domain of the low-pass filtered P-wave and the frequency domain data corresponding to the converted wave forward modeling seismic data volume of the high-pass filtered are added together, and then converted back to the time domain by inverse Fourier transform to obtain the high-resolution converted wave data volume.
7. A device for improving the resolution of converted waves, characterized in that, The device includes, The first acquisition module is used to acquire the P-wave time-depth relationship, the converted wave time-depth relationship, and the target layer location based on well logging data and multi-component seismic data of the study area. The multi-component seismic data includes P-wave stacked data volume processed by pre-stack time migration, P-wave pre-stack gather data volume processed by pre-stack time migration, and converted wave stacked data volume processed by pre-stack time migration. The determination module is used to determine the stratigraphic interpretation of the P-wave marker layer and the stratigraphic interpretation of the converted wave marker layer based on the P-wave time-depth relationship, the converted wave time-depth relationship, and the target layer location; The first module is used for the layer interpretation based on the P-wave marker layer and the converted wave marker layer to obtain the converted wave data volume in the P-wave time domain; The second module is used to obtain converted wave forward modeling seismic data based on well logging data of the study area, P-wave pre-stack gather data, and the stratigraphic interpretation of P-wave marker layers; it includes: Based on the P-wave velocity curve, S-wave velocity curve and density logging curve in the well logging data of the study area, P-wave impedance and S-wave impedance are obtained. Based on the logging curves of P-wave impedance, S-wave impedance, and density, as well as the results of the stratigraphic interpretation of the P-wave marker layer, a low-frequency model of P-wave impedance, S-wave impedance, and density is established. The P-wave pre-stack gather data volume, which has undergone pre-stack time migration processing, is divided into several parts and then stacked to form several parts of the stack. Each part of the superposition was subjected to well seismic calibration, and the wavelet of each part of the superposition was extracted. Using the low-frequency model, each partial superposition, and the wavelet corresponding to each partial superposition as input, pre-stack sparse pulse inversion is performed to obtain the transverse wave impedance volume. Seismic wavelets are extracted from P-wave stacking data; The seismic wavelet is convolved with the shear wave impedance volume to obtain the converted wave forward modeling seismic data volume. The second acquisition module is used to combine the converted wave data volume in the P-wave time domain with the converted wave forward modeling seismic data volume in the frequency domain to acquire a high-resolution converted wave data volume for improving the converted wave resolution.
8. The apparatus for improving the resolution of converted waves according to claim 7, characterized in that, The second step of the acquisition module includes: The frequency band range of the converted wave data volume in the time domain of the longitudinal wave is obtained by analyzing the spectrum of the converted wave data volume in the time domain of the longitudinal wave. Low-pass filtering is performed on the converted wave data volume in the longitudinal wave time domain. The high-frequency cutoff value is selected as the maximum value of the frequency band range of the converted wave data volume in the longitudinal wave time domain, and the low-pass filtered converted wave data volume in the longitudinal wave time domain is obtained. High-pass filtering is performed on the converted wave forward modeling seismic data volume. The low-frequency cutoff value is selected as the maximum value of the frequency band range of the converted wave data volume in the P-wave time domain to obtain the high-pass filtered converted wave forward modeling seismic data volume. By applying Fourier transform, the converted wave data volume of the low-pass filtered P-wave time domain and the converted wave forward modeling seismic data volume of the high-pass filtered P-wave are transformed to obtain the frequency domain data volume corresponding to the converted wave data volume of the low-pass filtered P-wave time domain and the frequency domain data volume corresponding to the converted wave forward modeling seismic data volume of the high-pass filtered P-wave. The frequency domain data volumes corresponding to the low-pass filtered P-wave time-domain converted wave data volume and the high-pass filtered converted wave forward modeling seismic data volume are added together and then converted back to the time domain by inverse Fourier transform to obtain the high-resolution converted wave data volume.
9. An electronic device comprising at least one processor and at least one memory, the memory being data-connected to the processor, wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-6.