Earthquake attenuation parameter extraction and compensation method for target stratum and related equipment

Abstract

The invention discloses a target stratum-oriented seismic attenuation parameter extraction and compensation method and related equipment, and the method comprises the steps: collecting seismic wave field data in a well through a zero well spacing VSP technology, accurately extracting an upward wave and a downward wave through fidelity wave field separation, and fusing the attenuation characteristics of the upward wave and the downward wave to obtain a high-precision comprehensive seismic attenuation coefficient. On the basis of the coefficient and VSP data, the excitation-target stratum-receiving full-path attenuation process of the ground earthquake is precisely restored, a well-ground attenuation parameter migration model is constructed, and effective extrapolation of the in-well attenuation parameters to the ground earthquake data is achieved. The attenuation coefficient field obtained through migration is used for self-adaptive compensation, the amplitude and the frequency spectrum of seismic waves are effectively recovered, the longitudinal resolution and the transverse consistency of ground seismic data are remarkably improved, and reliable support is provided for fine exploration of oil and gas.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geophysical exploration, in particular to a target formation-oriented seismic attenuation parameter extraction and compensation method and related equipment. BACKGROUND

[0002] Seismic wave attenuation parameters are key geophysical parameters for characterizing the non-elastic characteristics of underground media, lithology changes and oil and gas reservoir distribution. Their accurate extraction and application are of great significance for oil and gas resource exploration, complex geological structure interpretation and seismic disaster assessment. In the field of oil and gas exploration, as the exploration target extends to deep and complex hidden oil and gas reservoirs, traditional surface seismic exploration faces problems such as strong signal attenuation and distortion of stratum information. The accuracy of attenuation parameters directly affects the inversion accuracy of seismic data and the reliability of reservoir prediction. According to statistics, about 70% of oil and gas resources in the world are buried in complex geological structures. Therefore, there is an urgent need for high-precision attenuation parameter extraction technology.

[0003] The prior art has the defect of insufficient attenuation parameter extraction accuracy. Existing attenuation parameter extraction methods mainly rely on surface seismic data or conventional logging data, which have significant limitations: the surface seismic signal has a long propagation path, is affected by near-surface loose stratum attenuation (which can lose more than 70% of signal energy), wave field scattering and noise interference, resulting in distortion of amplitude and frequency information, making it difficult to accurately separate inherent attenuation and additional effects such as scattering attenuation, wave front divergence; although conventional logging data can obtain local stratum parameters, the coverage is limited, the application cost in large-scale work area is extremely high, and it cannot reflect the attenuation difference caused by lateral heterogeneity. In addition, although background noise tomography technology can extract attenuation information, it has problems such as large amplitude data error, unknown temporal and spatial distribution of noise sources, and insufficient quality factor extraction accuracy.

[0004] Therefore, using zero well source VSP technology as a high-resolution seismic exploration method, the well seismic wave field data collected are highly consistent with the actual stratum conditions, and can directly reflect the wave propagation characteristics of the target stratum, providing a data basis for accurate extraction of attenuation parameters. However, how to use this technical advantage to realize the targeted extraction of attenuation coefficients through wave field separation with fidelity and amplitude preservation, and establish the attenuation parameter migration mechanism between well and surface seismic data to restore the full-path attenuation process of "surface excitation-target stratum-surface reception", and then break through the bottleneck of traditional compensation technology, has become a key problem to be solved in the current seismic exploration field. Therefore, developing a target formation-oriented high-precision seismic attenuation parameter extraction and application method has important practical significance for improving the accuracy of seismic data processing in complex strata and ensuring the success rate of oil and gas resource exploration. SUMMARY

[0005] Based on the problems proposed in the above background art, the purpose of the present application is to provide a target formation-oriented seismic attenuation parameter extraction and compensation method and related equipment, which solves the problem that the current technology cannot effectively migrate the high-precision attenuation parameters in the well to the surface seismic data to realize precise compensation of the full-path attenuation.

[0006] The present application is realized by the following technical solutions:

[0007] The present application provides a target formation-oriented seismic attenuation parameter extraction and compensation method in the first aspect, which includes the following steps:

[0008] Collect zero-offset VSP original data covering the target formation;

[0009] Separate the wave field of the zero-offset VSP original data to obtain upgoing wave field data and downgoing wave field data;

[0010] Extract and fuse the coefficients of the upgoing wave field data and the downgoing wave field data to obtain comprehensive seismic attenuation coefficients;

[0011] Restore the surface seismic full-path attenuation process based on the zero-offset VSP original data and the comprehensive seismic attenuation coefficients, and generate a surface seismic full-path attenuation function;

[0012] Use the comprehensive seismic attenuation coefficients and the surface seismic full-path attenuation function as constraint conditions to construct a well-to-ground attenuation parameter migration model, and use the well-to-ground attenuation parameter migration model to generate an attenuation coefficient field;

[0013] Calculate the attenuation compensation according to the attenuation coefficient field.

[0014] In the above technical solution, the zero-offset VSP technology is used to collect the zero-offset VSP original data of the target formation, i.e., the seismic wave field data in the well; then the upgoing wave and the downgoing wave in the zero-offset VSP original data are accurately separated by the fidelity and amplitude-preserving wave field separation technology, and the seismic attenuation coefficients of the upgoing wave and the downgoing wave are extracted and fused to obtain comprehensive seismic attenuation coefficients; then, based on the advantages of the high consistency of the well data with the actual situation of the formation, the zero-offset VSP original data and the comprehensive seismic attenuation coefficients are used to restore the surface seismic full-path attenuation process, thereby restoring the full-path attenuation process of the surface seismic "surface excitation-target formation-ground receiving" mode; based on the restored full-path attenuation process and in combination with the zero-offset VSP original data, a well-to-ground attenuation parameter migration model is constructed to realize the effective migration of the high-precision attenuation parameters in the well to the surface seismic data; finally, the attenuation compensation is calculated through the attenuation coefficient field obtained by migration, thereby optimizing the attenuation compensation effect of the surface seismic data, improving its longitudinal resolution and lateral consistency, and providing more reliable technical support for oil and gas exploration.

[0015] In an alternative embodiment, the wave field separation of the zero offset VSP raw data comprises:

[0016] The zero offset VSP raw data is denoised, amplitude corrected and phase corrected to obtain pre-processed data.

[0017] Based on the difference in propagation direction and apparent velocity between downgoing and upgoing waves, i.e. polarization characteristics, a wave field identification criterion is established.

[0018] Based on the long wave identification criterion, the wave field separation is performed on the pre-processed data to obtain upgoing wave field data and downgoing wave field data.

[0019] In an alternative embodiment, the coefficient extraction and fusion of the upgoing wave field data and the downgoing wave field data comprises:

[0020] Based on the upgoing wave field data and the downgoing wave field data, the amplitude attenuation and frequency attenuation characteristics of upgoing and downgoing waves on the propagation path are calculated along the depth direction of the borehole at each depth point.

[0021] The spectral ratio method combined with the time domain logarithmic attenuation method is used to extract the upgoing wave attenuation coefficient and the downgoing wave attenuation coefficient at different depths from the amplitude attenuation and the frequency attenuation characteristics.

[0022] In an alternative embodiment, the ground seismic full-path attenuation process restoration based on the zero offset VSP raw data and the comprehensive seismic attenuation coefficient comprises:

[0023] The geological structure information of the target formation is obtained, and a formation depth-thickness model is constructed in combination with the zero offset VSP raw data.

[0024] The comprehensive seismic attenuation coefficient is fused into the formation depth-thickness model to construct a formation attenuation model.

[0025] The upgoing path attenuation process and the downgoing path attenuation process are restored according to the formation attenuation model to obtain the total attenuation function of ground seismic on the full propagation path.

[0026] In an alternative embodiment, the upgoing path attenuation process and the downgoing path attenuation process are restored according to the formation attenuation model to obtain the total attenuation function of ground seismic on the full propagation path, comprising:

[0027] The formation position where the seismic wave is located at the propagation time is determined, and the comprehensive seismic attenuation coefficient corresponding to the formation position is obtained.

[0028] integrate the comprehensive seismic attenuation coefficient corresponding to the formation position by an integral operator on the whole propagation time of the uplink path attenuation process and the downlink path attenuation process;

[0029] determine the total attenuation function of the seismic wave on the whole propagation path through the integration.

[0030] In an optional embodiment, the comprehensive seismic attenuation coefficient and the surface seismic full-path attenuation function are taken as constraint conditions to construct a well-to-surface attenuation parameter migration model, which comprises:

[0031] The amplitude spectrum and the phase spectrum of the surface seismic data are taken as observation data to establish an objective function.

[0032] The comprehensive seismic attenuation coefficient is taken as a true value constraint, and the surface seismic full-path attenuation function is taken as a physical law constraint to constrain the objective function, so as to construct a well-to-surface attenuation parameter migration model.

[0033] In an optional embodiment, the attenuation compensation is calculated according to the attenuation coefficient field, which comprises:

[0034] According to the wave equation attenuation theory, the attenuation coefficient field is taken as input to construct an adaptive attenuation compensation operator varying with depth and lateral position.

[0035] The adaptive attenuation compensation operator is used for post-stack surface seismic data to inversely compensate the energy attenuation and high-frequency loss in the seismic wave propagation process.

[0036] The second aspect of the present application provides a seismic attenuation parameter extraction and compensation system for a target formation, which comprises:

[0037] A collection module is configured to collect zero-offset VSP original data covering the target formation.

[0038] A wave field separation module is configured to perform wave field separation on the zero-offset VSP original data to obtain uplink wave field data and downlink wave field data.

[0039] A coefficient extraction module is configured to perform coefficient extraction and fusion on the uplink wave field data and the downlink wave field data to obtain a comprehensive seismic attenuation coefficient.

[0040] An attenuation restoration module is configured to perform surface seismic full-path attenuation process restoration based on the zero-offset VSP original data and the comprehensive seismic attenuation coefficient, and generate a surface seismic full-path attenuation function.

[0041] A parameter migration module is configured to take the comprehensive seismic attenuation coefficient and the surface seismic full-path attenuation function as constraint conditions to construct a well-to-surface attenuation parameter migration model, and generate an attenuation coefficient field by using the well-to-surface attenuation parameter migration model.

[0042] an attenuation compensation module configured to calculate attenuation compensation according to the attenuation coefficient field.

[0043] The third aspect of the present application provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method for extracting and compensating seismic attenuation parameters of a target formation when executing the computer program.

[0044] The fourth aspect of the present application provides a computer readable storage medium, which stores a computer program, wherein the computer program is executable on a processor to implement the method for extracting and compensating seismic attenuation parameters of a target formation.

[0045] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0046] The present method directly extracts and fuses upgoing and downgoing wave attenuation coefficients through zero-offset VSP data, constructs a high-precision well-to-ground attenuation parameter migration model, realizes quantifiable restoration and accurate compensation of the whole-path attenuation process of ground seismic "excitation-formation-reception", and significantly improves the vertical resolution and lateral consistency of seismic data. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as a limitation to the scope. Other related drawings can also be obtained by those skilled in the art without creative labor. In the drawings:

[0048] Figure 1 The flowchart of the method for extracting and compensating seismic attenuation parameters of a target formation provided for the embodiment 1 of the present application is shown in the figure;

[0049] Figure 2 The wavefield single-shot record comparison chart before and after the fidelity and amplitude-preserved wavefield separation provided for the embodiment 1 of the present application is shown in the figure;

[0050] Figure 3 The logic chart of the comprehensive seismic attenuation coefficient weighted fusion calculation provided for the embodiment 1 of the present application is shown in the figure;

[0051] Figure 4 The flowchart of the well-to-ground attenuation parameter migration model iterative inversion provided for the embodiment 1 of the present application is shown in the figure;

[0052] Figure 5 The spectrum comparison chart before and after the attenuation compensation of the ground seismic data provided for the embodiment 1 of the present application is shown in the figure; wherein, Figure 5(a) Nyquist multiple diagram before deep compensation for ground earthquakes; Figure 5 (b) is the Nyquist multiple diagram after deep compensation for ground earthquakes;

[0053] Figure 6 This is a schematic diagram of the structure of an electronic device provided in Embodiment 3 of the present invention. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0055] Example 1

[0056] Figure 1 This is a flowchart illustrating the seismic attenuation parameter extraction and compensation method for target strata provided in Embodiment 1 of the present invention, as shown below. Figure 1 As shown, the method for extracting and compensating seismic attenuation parameters for the target stratum includes the following steps:

[0057] Collect raw VSP data with zero well source distance covering the target formation;

[0058] Wavefield separation was performed on the raw VSP data with zero well source distance to obtain up-wave wavefield data and down-wave wavefield data;

[0059] The coefficients of the up-wave and down-wave data are extracted and fused to obtain the comprehensive seismic attenuation coefficient.

[0060] Based on the original VSP data with zero well source distance and the comprehensive seismic attenuation coefficient, the surface seismic full-path attenuation process is reconstructed, and the surface seismic full-path attenuation function is generated.

[0061] Using the comprehensive seismic attenuation coefficient and the surface seismic full-path attenuation function as constraints, a well-to-surface attenuation parameter migration model is constructed, and an attenuation coefficient field is generated using the well-to-surface attenuation parameter migration model.

[0062] Attenuation compensation is calculated based on the attenuation coefficient field.

[0063] It should be noted that the zero-source-spacing VSP technology is used to acquire raw zero-source-spacing VSP data of the target formation, i.e., the seismic wavefield data in the well. Then, the up-going and down-going waves in the raw zero-source-spacing VSP data are accurately separated using a fidelity-preserving and amplitude-preserving wavefield separation technique. The seismic attenuation coefficients of the up-going and down-going waves are extracted and then fused to obtain a comprehensive seismic attenuation coefficient. Next, taking advantage of the high degree of close correlation between the well data and the actual formation conditions, the full path attenuation process of the surface seismic data is reconstructed based on the raw zero-source-spacing VSP data and the comprehensive seismic attenuation coefficient, thereby reconstructing the full path attenuation process of the surface seismic data under the "surface excitation-target formation-surface reception" mode. Based on the reconstructed full path attenuation process and combined with the raw zero-source-spacing VSP data, a well-to-surface attenuation parameter migration model is constructed to achieve effective migration of high-precision attenuation parameters from the well to the surface seismic data. Finally, attenuation compensation is calculated using the attenuation coefficient field obtained from the migration, thereby optimizing the attenuation compensation effect of the surface seismic data, improving its vertical resolution and lateral consistency, and providing more reliable technical support for oil and gas exploration.

[0064] This embodiment uses a deep carbonate reservoir in a basin as the target area, with a burial depth of 6000-8000m. The lithology is mainly composed of grainy limestone and dolomite, containing dissolution cavities and fracture systems, exhibiting extremely strong lateral heterogeneity. Due to the influence of the deep high-temperature and high-pressure environment, the original surface seismic data suffers from severe high-frequency energy attenuation (dominant frequency only 15Hz), severe ambiguity of deep wave groups, and difficulty in distinguishing the boundary between reservoir and non-reservoir areas. The attenuation compensation optimization method in this embodiment is required. The target well is a deep exploration well deployed in this area, with a depth of 9000m, fully covering the target carbonate reservoir.

[0065] Zero-source-distance VSP raw data includes mixed wavefield information of downflowing waves (propagating from the ground to the well) and upflowing waves (reflected from the well to the ground). Acquiring zero-source-distance VSP raw data covering the target formation includes: deploying a zero-source-distance VSP acquisition system for the preset target formation area, setting up geophone arrays at different depths of the target well, and ensuring that the geophones are tightly coupled with the well wall to ensure data reception stability by synchronously receiving seismic wavefield signals; and generating seismic waves at a ground excitation point near the wellhead and synchronously acquiring zero-source-distance VSP raw data covering the target formation through the geophone array.

[0066] Specifically, a zero-source-distance VSP observation system was deployed in the deep well where the target reservoir was located. High-temperature, high-pressure resistant three-component digital geophones were used, with a deployment depth range of 20-8200m and an overall base spacing of 20m. Intensified acquisition was conducted in the target reservoir and adjacent transition zone (5800m-8200m), reducing the point spacing to 10m to ensure complete capture of the target layer's wavefield characteristics. Seismic sources were deployed within an 80m radius around the wellhead, using an EV56 high-energy controllable seismic source with an excitation frequency range of 3-96Hz (adapted to the attenuation characteristics of deep seismic wave propagation), an excitation energy of 280kN·m, a recording length of 8s (meeting the propagation time requirements of deep wavefields), and a sampling rate of 0.25ms (adapted to the capture of high-frequency signals in deep formations). The acquired seismic wavefield data included downlink direct waves, uplink reflected waves, and deep formation interference signals (such as multiples and converted waves), with a signal-to-noise ratio ≥25dB.

[0067] In one optional embodiment, wavefield separation is performed on the raw zero-well-spacing VSP data, including:

[0068] The raw VSP data with zero well source distance is subjected to denoising, amplitude correction, and phase correction to obtain preprocessed data;

[0069] Based on the differences in propagation direction and apparent velocity between down-going and up-going waves, i.e., polarization characteristics, a wave field identification criterion is established.

[0070] Based on the long-wave identification criterion, wavefield separation is performed on the preprocessed data to obtain up-wave wavefield data and down-wave wavefield data.

[0071] In this embodiment, the raw VSP data of zero-well source distance is preprocessed, including:

[0072] The noise reduction process includes removing environmental noise, instrument noise, and interference waves. Specifically, the original noise components are classified and analyzed, and occasional noise that affects the wave field separation process is suppressed. The noise reduction steps in this method are used to analyze the noise type and its impact, and to eliminate casing noise, wellbore wave noise, etc. that do not affect the wave field separation process.

[0073] Amplitude correction, including compensation for detector coupling differences and propagation geometry diffusion effects;

[0074] Phase correction includes correcting phase distortion in wave field propagation.

[0075] The above preprocessing ensures the data's fidelity and amplitude retention.

[0076] Based on the difference in propagation direction between downlink and uplink waves, and considering velocity differences and polarization characteristics, a wavefield identification criterion is established. Based on the wavelength identification criterion, the preprocessed mixed wavefield data is separated to obtain clean downlink and uplink wavefield data respectively, ensuring the authenticity and integrity of the separated wavefield. Single-shot wavefield records before and after separation are shown below. Figure 2 As shown.

[0077] It should be noted that the wavefield separation process can employ separation algorithms such as median filtering wavefield separation, FK domain wavefield separation, and amplitude-preserving separation algorithm based on the wave equation, and can be implemented using existing seismic processing software, such as the seismic processing software Geoeast.

[0078] In one optional embodiment, coefficient extraction and fusion are performed on the up-wave wavefield data and the down-wave wavefield data, including:

[0079] Based on the up-wave field data and the down-wave field data, the amplitude attenuation and frequency attenuation characteristics of the up-wave and down-wave along the propagation path are calculated at each depth point along the well depth direction.

[0080] By employing the spectral ratio method combined with the time-domain logarithmic attenuation method, the up-wave attenuation coefficient and down-wave attenuation coefficient at different depths are extracted from the amplitude attenuation and the frequency attenuation characteristics.

[0081] Attenuation coefficient extraction and fusion, such as Figure 3 As shown, the extraction principles of the upward wave attenuation coefficient and the downward wave attenuation coefficient are the same. Taking the downward wave attenuation coefficient as an example: the separated downward wave field data is used to calculate the amplitude attenuation and frequency attenuation characteristics of the downward wave along the propagation path at each depth point. The algorithm of combining the spectrum ratio method with the logarithmic attenuation method in the time domain is used to accurately extract the downward wave attenuation coefficient α_d of the target formation at different depths.

[0082] Among them, the spectrum ratio method combined with the time-domain logarithmic attenuation method refers to the use of the fact that when seismic waves propagate in viscoelastic strata, the energy attenuation simultaneously satisfies two laws: the frequency domain law and the time domain law. By combining the methods of "first calculating the attenuation by frequency division and then verifying the fitting in the time domain", the influence of wave field distortion is considered.

[0083] Specifically, the extraction of downwave attenuation coefficients at different depths includes: processing each depth point along the borehole depth direction according to the actual spacing of the geophones (20 meters or 10 meters); for each depth point, analyzing the effective signal within 200 milliseconds after the initial arrival of the downwave (due to the long wave propagation path in deeper layers, the effective signal time window can be appropriately extended to ensure information integrity). First, the amplitude spectrum ratio of the downwave signal at the current depth point and the adjacent previous depth point is calculated using the spectral ratio method to initially obtain the frequency-varying attenuation characteristics; then, the attenuation curve of the amplitude envelope of the initial arrival segment of the downwave is fitted using the time-domain logarithmic attenuation method to constrain the overall attenuation trend; finally, the downwave attenuation coefficient α corresponding to each depth is extracted through joint optimization. d Actual data processing results show that in the well section from 20 meters to 5800 meters, α d The value ranges from 0.005 dB / m to 0.028 dB / m; while in the target layer (deep carbonate rock strata) at depths of 5800 to 8200 meters, α d The range of values ​​increased to 0.008 dB / m to 0.035 dB / m, reflecting that the attenuation effect of deep carbonate rock formations is significantly stronger than that of shallow formations, and the absorption attenuation characteristics of the target layer are more prominent.

[0084] Extracting the upflow wave attenuation coefficient at different depths involves: analyzing 80 milliseconds of effective data segments before and after the center time of the reflected wave group at each receiver point along the well depth direction, based on the upflow wave reflection signal (including the reflection response of geological targets such as dissolution cavities and fractures). The same combined calculation method as for extracting the downflow wave attenuation coefficient is used: first, the spectral difference of the upflow wave signal at adjacent depths is analyzed using the spectral ratio method; then, the attenuation curve of the upflow wave amplitude envelope is fitted using the time-domain logarithmic attenuation method; and finally, the upflow wave attenuation coefficient α at each depth is extracted through joint optimization. u Because the upward wave propagation path is the upward process reflected from the target formation at 6000-8000 meters to each detector, its attenuation characteristics exhibit a clear segmented feature: in the well section from 20 meters to 5800 meters, α u The value ranges from 0.007 dB / m to 0.032 dB / m; while in the target layer section from 5800 meters to 8200 meters, α u The attenuation of the up-going wave increased significantly from 0.010 dB / m to 0.042 dB / m, reflecting that the up-going wave encountered stronger scattering and absorption when passing through the fracture development zone, resulting in a more significant attenuation than the down-going wave.

[0085] Furthermore, considering the propagation paths of the downlink and uplink waves, the attenuation coefficient α of the downlink wave is... d and the upward wave attenuation coefficient α u Weighted fusion calculations are performed to obtain the comprehensive seismic attenuation coefficient α at each depth of the target stratum. The weighting coefficients are adaptively determined based on the signal-to-noise ratio and energy intensity of the two types of wavefields.

[0086] The formula for calculating the weighted fusion is as follows:

[0087]

[0088] in These are the weighting coefficients for the downlink attenuation coefficient. These are the weighting coefficients for the up-wave attenuation coefficient. ; and Based on the signal-to-noise ratio of the two types of wave fields , Adaptive determination.

[0089] Furthermore, the adaptive adjustment is as follows:

[0090]

[0091]

[0092] Specifically, calculate the downwave signal-to-noise ratio. =38dB, Upward wave field signal-to-noise ratio =31dB, calculate the weighting coefficient according to the formula. =38 / (38+31)=0.551, =31 / (38+31)=0.449, calculated using the weighted fusion logic of the comprehensive seismic attenuation coefficient: Substituting into the weighted fusion formula α=0.551×α d +0.449×α u The comprehensive seismic attenuation coefficient α at various depths of the target stratum (6000-8000m) was obtained, with values ​​ranging from 0.0089 to 0.038 dB / m. Figure 3 As shown.

[0093] In one optional embodiment, the surface seismic full-path attenuation process is reconstructed based on the original zero-well-source-distance VSP data and the integrated seismic attenuation coefficient, including:

[0094] Obtain geological structure information of the target formation and construct a formation depth-thickness model by combining the raw VSP data from the zero-well source distance.

[0095] The comprehensive seismic attenuation coefficient is incorporated into the formation depth-thickness model to construct a formation attenuation model;

[0096] Based on the formation attenuation model, the attenuation processes of the uplink and downlink paths are reconstructed to obtain the total attenuation function of the ground earthquake along the entire propagation path.

[0097] In this embodiment, a corresponding formation depth-thickness model is established by combining the acquired zero-source-distance VSP raw data with the geological structure information of the target strata (such as formation thickness and lithological distribution). The comprehensive seismic attenuation coefficient is integrated into the formation depth-thickness model to construct a formation attenuation model. Based on the propagation path of the ground earthquake from "ground excitation to ground reception", the downlink attenuation process of the seismic wave propagating from the ground excitation point to the target stratum and the uplink attenuation process of the seismic wave reflected from the target stratum to the ground reception point are reconstructed respectively, resulting in the total attenuation function A(z,t) of the ground earthquake on the entire propagation path, where z is the depth and t is the propagation time. This expands the "point-based high-precision attenuation data" in the well to the "continuous attenuation law throughout the entire path" of the ground earthquake, which builds a bridge between well data and ground earthquake data and realizes the accurate reconstruction of the attenuation process of the entire path of the ground earthquake.

[0098] In an optional embodiment, the uplink and downlink attenuation processes are reconstructed based on the formation attenuation model to obtain the total attenuation function of the ground earthquake along the entire propagation path, including:

[0099] Determine the location of the seismic wave in the stratigraphic layer at the propagation time, and obtain the comprehensive seismic attenuation coefficient corresponding to that stratigraphic location;

[0100] The integral operator is used to integrate the comprehensive seismic attenuation coefficient corresponding to the stratum location over the entire propagation time of the up-path attenuation process and the down-path attenuation process.

[0101] The total attenuation function of the seismic wave along its entire propagation path is determined by the integral.

[0102] The total attenuation function is:

[0103]

[0104] in, This represents the ratio of the remaining energy to the initial energy when the seismic wave has propagated to a depth z and a total time t.

[0105] Since seismic wave attenuation follows an "exponential decay law," an exponential function is used to fit this characteristic. The integral from the start of propagation to the total time is the accumulation of the "instantaneous attenuation contribution" throughout the entire process. The negative sign ensures that the attenuation function value decreases as the propagation time increases. t is the propagation time variable used for integration throughout the entire propagation process. z(t) is the stratum depth corresponding to the propagation time τ, reflecting the stratum location of the seismic wave at different times. α(z(t)) is the comprehensive seismic attenuation coefficient at depth z(t).

[0106] Specifically, the attenuation process of the entire path of ground earthquakes is reconstructed using the iterative inversion method of the well-to-surface attenuation parameter migration model, such as... Figure 4As shown, based on the deep geological data of the target area (drilling logs, imaging logging curves, and core analysis data), a formation depth-thickness model was established. The model includes four main formations: upper clastic formation (2000-4000m, 2000m thick), middle gypsum-salt formation (4000-6000m, 2000m thick, strong shielding layer), carbonate reservoir (6000-8000m, 2000m thick), and lower formation (8000-9000m, 1000m thick).

[0107] Calculation of the full-path attenuation function: Based on the ground earthquake propagation path of "ground excitation-ground reception", it is decomposed into three segments: "ground-6000m (top of the target stratum)", "6000-8000m (target stratum)" and "8000m-ground". Considering the strong attenuation characteristics of the gypsum-salt layer in the middle (assigned a separate attenuation coefficient αgypsum=0.025dB / m), the comprehensive attenuation coefficient α(z(t)) obtained in step 3-3 is substituted, and the full-path attenuation function is calculated by integration.

[0108] For example, at the top of the target stratum (z=6000m, t=3.8s).

[0109] This indicates that when the seismic wave propagates to this deep location, the remaining energy is only 45% of the initial energy (significant attenuation at depth).

[0110] In an optional embodiment, the integrated seismic attenuation coefficient and the surface seismic full-path attenuation function are used as constraints to construct a well-to-surface attenuation parameter migration model, including:

[0111] An objective function is established using the amplitude and phase spectra of ground seismic data as observation data.

[0112] By using the comprehensive seismic attenuation coefficient as a truth constraint and the ground seismic full-path attenuation function as a physical law constraint to constrain the objective function, a well-to-ground attenuation parameter migration model is constructed.

[0113] The construction of the objective function in the migration model includes: using the amplitude spectrum and phase spectrum of ground seismic data as observation data, establishing the objective function, whereby the objective function is established as follows:

[0114]

[0115] in, The overall error of the ground seismic attenuation parameter inversion results is measured by summing the squares of the Euclidean norms; The desired ground seismic attenuation parameters are... Based on the parameters to be determined The theoretical amplitude spectrum calculated using the full-path attenuation function A(z,t); is the regularization parameter (range 0.001-0.01, used to balance the weights of observation data fitting and truth constraints); L is the second-order Laplace smoothing operator (ensuring...). (The spatial distribution is continuous and reasonable) Let α be the comprehensive seismic attenuation coefficient in the well.

[0116] Then, the well-to-surface attenuation parameter migration model is constructed by using the comprehensive seismic attenuation coefficient as a truth constraint and the surface seismic full-path attenuation function as a physical law constraint to constrain the objective function. The purpose of using the comprehensive seismic attenuation coefficient as a truth constraint is to ensure that the surface parameters do not deviate from the actual formation attenuation level; the purpose of using the surface seismic full-path attenuation function as a physical law constraint is to ensure that the migration process conforms to the seismic wave attenuation mechanism and avoids deviation from the actual propagation situation during migration.

[0117] Finally, using pre-stack or post-stack data from ground seismic data, the high-precision integrated seismic attenuation coefficient α from the well is transferred to the target stratigraphic region corresponding to the ground seismic data through an iterative inversion algorithm, thus obtaining a high-precision attenuation parameter field of the ground seismic data.

[0118] Specifically, ground seismic post-stack data (dominant frequency 15Hz, trace spacing 20m) within a 40km×30km range of the target area are selected. The comprehensive seismic attenuation coefficient is used as the true value constraint, and the ground seismic full-path attenuation function is used as the physical law constraint to constrain the target function.

[0119] Then, set the regularization parameter λ=0.008 (enhancing the truth constraint weight) and the second-order Laplace smoothing operator L.

[0120] initialization The mean value of α in the well (0.023 dB / m); calculated using forward modeling. →Comparison and Error → Correction The loop iterates until the objective function is achieved. Convergence (convergence threshold is a difference of less than 10⁻ J values ​​between two iterations) 6 ), to obtain the optimal ground seismic attenuation parameters The value of this parameter field in the target carbonate reservoir area ranges from 0.008 to 0.040 dB / m, with a relative error of ≤7% compared to α in the well (the migration accuracy of the deep parameter is better than that of the shallow parameter).

[0121] In one optional embodiment, calculating attenuation compensation based on the attenuation coefficient field includes:

[0122] Based on the wave equation decay theory, an adaptive decay compensation operator that varies with depth and lateral position is constructed using the decay coefficient field as input.

[0123] The adaptive attenuation compensation operator is used in post-stack ground seismic data to inversely compensate for energy attenuation and high-frequency loss during seismic wave propagation.

[0124] In this embodiment, based on the attenuation theory of the wave equation, an adaptive attenuation compensation operator that varies with depth and lateral position is constructed using the attenuation coefficient field as input. The adaptive attenuation compensation operator is based on the attenuation theory of the wave equation and transforms the migrated high-precision attenuation coefficient field into a mathematical model that can be directly applied to ground seismic data to achieve personalized compensation that is "dynamically adjusted with spatial position".

[0125] Specifically, the core principle of the adaptive attenuation compensation operator is that the attenuation process of seismic waves propagating underground follows the viscoelastic wave equation. Its amplitude attenuation satisfies a quantifiable relationship with frequency, propagation path, and formation attenuation coefficient (Q value). That is, for a seismic wave of a certain frequency component, the amplitude after propagation is: ;in The initial amplitude at the epicenter; The angular frequency of the seismic wave is , denoted as , where is the seismic wave frequency; r is the one-way distance of the seismic wave propagation; v is the propagation speed of the seismic wave in the target stratum; e is the natural constant; and Q is the attenuation coefficient of the seismic wave propagating from the ground to the (x,y) position, specifically referring to the comprehensive attenuation coefficient in this embodiment. That is, Q(x,z)=αground(x,z).

[0126] Then, an adaptive attenuation compensation operator is applied to the post-stack ground seismic data to inversely compensate for energy attenuation and high-frequency loss during seismic wave propagation, restoring the original amplitude and spectral characteristics of the seismic waves, ultimately improving data resolution and consistency. The compensated data is shown below. Figure 5 ( Figure 5 (a) and Figure 5 As shown in (b), the main frequency of the compensated data is increased to 24Hz, and the high-frequency components (30-50Hz) are enhanced with energy, resulting in a significant effect on deep high-frequency recovery.

[0127] Example 2

[0128] Embodiment 2 of the present invention provides a seismic attenuation parameter extraction and compensation system for target strata, comprising:

[0129] The acquisition module is used to acquire raw VSP data with zero well source distance covering the target formation;

[0130] The wave field separation module is used to perform wave field separation on the raw VSP data with zero well source distance to obtain up-wave wave field data and down-wave wave field data.

[0131] The coefficient extraction module is used to extract and fuse the coefficients of the up-wave wavefield data and the down-wave wavefield data to obtain the comprehensive seismic attenuation coefficient.

[0132] The attenuation restoration module is used to restore the surface earthquake full-path attenuation process based on the original zero-well-source-distance VSP data and the comprehensive seismic attenuation coefficient, and generate the surface earthquake full-path attenuation function.

[0133] The parameter migration module is used to construct a well-to-surface attenuation parameter migration model by taking the comprehensive seismic attenuation coefficient and the surface seismic full-path attenuation function as constraints, and to generate an attenuation coefficient field using the well-to-surface attenuation parameter migration model.

[0134] The attenuation compensation module is used to calculate attenuation compensation based on the attenuation coefficient field.

[0135] Example 3

[0136] Figure 6 This is a schematic diagram of the structure of an electronic device provided in Embodiment 3 of the present invention, as shown below. Figure 6 As shown, the electronic device includes a processor 21, a memory 22, an input device 23, and an output device 24; the number of processors 21 in the computer device can be one or more. Figure 6 Taking a processor 21 as an example; the processor 21, memory 22, input device 23, and output device 24 in an electronic device can be connected via a bus or other means. Figure 6 Taking the example of a connection between China and Israel via a bus.

[0137] The memory 22, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and modules. The processor 21 executes various functional applications and data processing of the electronic device by running the software programs, instructions, and modules stored in the memory 22, thereby implementing the seismic attenuation parameter extraction and compensation method for the target stratum in Embodiment 1.

[0138] The memory 22 may primarily include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a given function; the data storage area may store data created based on terminal usage. Furthermore, the memory 22 may include high-speed random access memory and non-volatile memory, such as at least one disk storage device, flash memory, or other non-volatile solid-state storage device. In some instances, the memory 22 may further include memory remotely located relative to the processor 21, which can be connected to the electronic device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0139] Input device 23 can be used to receive user input such as ID and password. Output device 24 is used to output the network configuration page.

[0140] Example 4

[0141] Embodiment 4 of the present invention also provides a computer-readable storage medium, wherein the computer-executable instructions, when executed by a computer processor, are used to implement the seismic attenuation parameter extraction and compensation method for target strata as provided in Embodiment 1.

[0142] The storage medium containing computer-executable instructions provided in the embodiments of the present invention is not limited to the method operation provided in Embodiment 1, but can also perform related operations in the seismic attenuation parameter extraction and compensation method for target strata provided in any embodiment of the present invention.

[0143] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for extracting and compensating seismic attenuation parameters for target strata, characterized in that, Includes the following steps: Collect raw VSP data with zero well source distance covering the target formation; Wavefield separation was performed on the raw VSP data with zero well source distance to obtain up-wave wavefield data and down-wave wavefield data; The coefficients of the up-wave and down-wave data are extracted and fused to obtain the comprehensive seismic attenuation coefficient. Based on the original VSP data with zero well source distance and the comprehensive seismic attenuation coefficient, the surface seismic full-path attenuation process is reconstructed, and the surface seismic full-path attenuation function is generated. Using the comprehensive seismic attenuation coefficient and the surface seismic full-path attenuation function as constraints, a well-to-surface attenuation parameter migration model is constructed, and an attenuation coefficient field is generated using the well-to-surface attenuation parameter migration model. Attenuation compensation is calculated based on the attenuation coefficient field.

2. The method for extracting and compensating seismic attenuation parameters for target strata according to claim 1, characterized in that, Wavefield separation is performed on the raw VSP data with zero well source distance, including: The raw VSP data with zero well source distance is subjected to denoising, amplitude correction, and phase correction to obtain preprocessed data; Based on the differences in propagation direction and apparent velocity between down-going and up-going waves, i.e., polarization characteristics, a wave field identification criterion is established. Based on the long-wave identification criterion, wavefield separation is performed on the preprocessed data to obtain up-wave wavefield data and down-wave wavefield data.

3. The method for extracting and compensating seismic attenuation parameters for target strata according to claim 1, characterized in that, The coefficients of the up-wave and down-wave field data are extracted and fused, including: Based on the up-wave field data and the down-wave field data, the amplitude attenuation and frequency attenuation characteristics of the up-wave and down-wave along the propagation path are calculated at each depth point along the well depth direction. By employing the spectral ratio method combined with the time-domain logarithmic attenuation method, the up-wave attenuation coefficient and down-wave attenuation coefficient at different depths are extracted from the amplitude attenuation and the frequency attenuation characteristics.

4. The method for extracting and compensating seismic attenuation parameters for target strata according to claim 1, characterized in that, Based on the aforementioned zero-well-source-distance VSP raw data and the aforementioned comprehensive seismic attenuation coefficient, the surface seismic full-path attenuation process is reconstructed, including: Obtain geological structure information of the target formation and construct a formation depth-thickness model by combining the raw VSP data from the zero-well source distance. The comprehensive seismic attenuation coefficient is incorporated into the formation depth-thickness model to construct a formation attenuation model; Based on the formation attenuation model, the attenuation processes of the uplink and downlink paths are reconstructed to obtain the total attenuation function of the ground earthquake along the entire propagation path.

5. The method for extracting and compensating seismic attenuation parameters for target strata according to claim 4, characterized in that, Based on the formation attenuation model, the attenuation processes of the uplink and downlink paths are reconstructed, yielding the total attenuation function of the ground earthquake along its entire propagation path, including: Determine the location of the seismic wave in the stratigraphic layer at the propagation time, and obtain the comprehensive seismic attenuation coefficient corresponding to that stratigraphic location; The integral operator is used to integrate the comprehensive seismic attenuation coefficient corresponding to the stratum location over the entire propagation time of the up-path attenuation process and the down-path attenuation process. The total attenuation function of the seismic wave along its entire propagation path is determined by the integral.

6. The method for extracting and compensating seismic attenuation parameters for target strata according to claim 1, characterized in that, Using the comprehensive seismic attenuation coefficient and the surface seismic full-path attenuation function as constraints, a well-to-surface attenuation parameter migration model is constructed, including: An objective function is established using the amplitude and phase spectra of ground seismic data as observation data. By using the comprehensive seismic attenuation coefficient as a truth constraint and the ground seismic full-path attenuation function as a physical law constraint to constrain the objective function, a well-to-ground attenuation parameter migration model is constructed.

7. The method for extracting and compensating seismic attenuation parameters for target strata according to claim 1, characterized in that, The attenuation compensation is calculated based on the attenuation coefficient field, including: Based on the wave equation decay theory, an adaptive decay compensation operator that varies with depth and lateral position is constructed using the decay coefficient field as input. The adaptive attenuation compensation operator is used in post-stack ground seismic data to inversely compensate for energy attenuation and high-frequency loss during seismic wave propagation.

8. A seismic attenuation parameter extraction and compensation system for a target stratum, used to implement the seismic attenuation parameter extraction and compensation method for a target stratum as described in any one of claims 1 to 7, characterized in that, include: The acquisition module is used to acquire raw VSP data with zero well source distance covering the target formation; The wave field separation module is used to perform wave field separation on the raw VSP data with zero well source distance to obtain up-wave wave field data and down-wave wave field data. The coefficient extraction module is used to extract and fuse the coefficients of the up-wave wavefield data and the down-wave wavefield data to obtain the comprehensive seismic attenuation coefficient. The attenuation restoration module is used to restore the surface earthquake full-path attenuation process based on the original zero-well-source-distance VSP data and the comprehensive seismic attenuation coefficient, and generate the surface earthquake full-path attenuation function. The parameter migration module is used to construct a well-to-surface attenuation parameter migration model by taking the comprehensive seismic attenuation coefficient and the surface seismic full-path attenuation function as constraints, and to generate an attenuation coefficient field using the well-to-surface attenuation parameter migration model. The attenuation compensation module is used to calculate attenuation compensation based on the attenuation coefficient field.

9. An electronic device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the seismic attenuation parameter extraction and compensation method for any of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the seismic attenuation parameter extraction and compensation method for target strata as described in any one of claims 1 to 7.

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