VTI anisotropic parameter inversion method based on cross-well earthquake and VSP

Abstract

The invention relates to the technical field of intelligent sensing systems, and provides a cross-well earthquake and VSP-based VTI anisotropic parameter inversion method, which comprises the following steps: acquiring first arrival information and speed information recorded by a zero well spacing VSP in a target exploration area, and establishing a near-well initial vertical speed model; acquiring first arrival information of excitation points at different depths of an inter-well earthquake in the area, and calculating to obtain the transverse velocity of a VTI anisotropic medium at each depth; solving the anisotropic medium value of each depth VTI; obtaining a VTI anisotropic medium delta value; and performing interpolation smoothing along a geologic horizon by using the epsilon value and the delta value of the VTI anisotropic medium to obtain an epsilon field and a delta field of the VTI anisotropic medium so as to form a VTI anisotropic body. The objective of the invention is to solve the problem of low accuracy of sedimentary rock feature analysis caused by poor matching of a velocity model and anisotropy parameters in traditional VTI anisotropy research.

Description

Technical Field

[0001] This invention relates to the field of intelligent sensing system technology, specifically to a method for inverting VTI anisotropy parameters based on well-to-well seismic data and VSP. Background Technology

[0002] Vertical-lateral isotropic (VTI) characteristics are prevalent in most sedimentary rocks. Therefore, accurate estimation of VTI anisotropy parameters is a key factor affecting the accuracy of seismic data anisotropic migration processing. Inter-well and in-well seismic observation systems provide a means to evaluate formation anisotropy parameters. Accurate lateral formation velocities can be obtained from the first arrival times of direct waves recorded in inter-well seismic records, and accurate vertical formation velocities can be obtained from the first arrival times of direct waves recorded in zero-source-distance VSP records. The first arrival times of inter-well seismic records at varying depths and VSP records at varying offsets reflect the influence of medium anisotropy on incident waves at different angles.

[0003] Currently, existing research includes: Ma Yechi, "Research on Seismic Wavefield and Parameter Analysis of Anisotropic Media in Inter-well Seismic [D]. Chang'an University, 2012," which analyzes the wavefield characteristics of different geological models in anisotropic media and the changes in waves with variations in anisotropic parameters; and Sun Jiayu, "Research on Travel-Time Tomography Method for Anisotropic Media in Inter-well Seismic [D]. Chang'an University, 2019," which studies the travel-time tomography method for anisotropic media in inter-well seismic. However, the above studies have not fully integrated anisotropic analysis with inter-well and in-well seismic data. In particular, in-well seismic data lacks effective methods for estimating lateral strata velocity, and the accuracy of anisotropic parameter calculation is limited, failing to accurately reflect the true propagation law of sedimentary seismic waves. Furthermore, since inter-well seismic data only focus on local anisotropic parameters at the target layer depth, the limitations of the observation system and assumptions in calculating anisotropic parameters result in poor matching between the velocity model and anisotropic parameters, leading to lower imaging accuracy and affecting the accuracy of sedimentary rock characteristic analysis. Summary of the Invention

[0004] This invention provides a method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP (Very Special Purpose Seismic Study), to address the problem of low accuracy in sedimentary rock characteristic analysis caused by poor matching between velocity models and anisotropy parameters in existing traditional VTI anisotropy studies. The specific technical solution adopted is as follows:

[0005] This invention proposes a method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP data. The method includes the following steps:

[0006] Acquire the initial arrival information and velocity information of the zero-well source distance VSP record in the target exploration area, and establish an initial vertical velocity model near the well.

[0007] Several P-wave signals are obtained by separating the first arrival information at the same depth. The differences between the modal components with the same number obtained by the decomposition of the P-wave signals and the differences in their center frequencies are analyzed to obtain the comprehensive deviation value of each P-wave signal number at the same depth, as well as the deviation vector of each P-wave signal. Based on the differences between the deviation vectors and the differences between the comprehensive deviation values, the deviation characteristic value caused by interference in the frequency range corresponding to each P-wave signal and each modal component number is obtained. Then, each P-wave signal is reconstructed to obtain the transverse velocity of the VTI anisotropic medium at each depth in the target exploration area.

[0008] Based on the vertical and lateral velocities of the VTI anisotropic medium, the VTI anisotropic medium at various depths can be obtained by solving the problem. value;

[0009] Based on the aforementioned initial vertical velocity model, and according to the first arrival information of different excitation points in inter-well or in-well seismic events, combined with the VTI anisotropic medium... The values ​​of the VTI anisotropic medium are obtained through ray tracing forward and inverse iterative methods. value;

[0010] Utilizing VTI anisotropic media Value and Values ​​were interpolated and smoothed along geological strata to obtain VTI anisotropic media. field and The field then forms a VTI anisotropic body.

[0011] Optionally, the specific method for separating the first arrival information at the same depth to obtain several longitudinal wave signals includes:

[0012] The acquired raw seismic data between wells was preprocessed, and P-wave and S-wave interference was separated by FK filtering to obtain several P-wave signals. The P-wave signals before separation originated from multiple repeated excitations at the same excitation and receiving points at the same depth.

[0013] Optionally, the specific method for obtaining the comprehensive deviation value of each P-wave signal number at the same depth includes:

[0014] For each P-wave signal at the same depth, calculate the DTW distance between each P-wave signal and the modal components with the same number from each other; and calculate the difference in center frequency between each P-wave signal and the modal components with the same number from each other.

[0015] Calculate the product of the DTW distance and difference values ​​of the modal components with the same number between each P-wave signal and every other P-wave signal, and take the mean of all the products calculated between each P-wave signal and all other P-wave signals under each number as a comprehensive deviation value.

[0016] Optionally, the difference in center frequencies of modal components with the same number between each P-wave signal and every other P-wave signal is obtained by the following method: ; in, The difference value, and They represent the first The longitudinal wave signal and other... The center frequencies of modal components with the same number among the longitudinal wave signals.

[0017] Optionally, the deviation vector of each longitudinal wave signal is obtained by the following method:

[0018] The vector formed by combining the combined deviation values ​​of all modal components under each number for each longitudinal wave signal in numerical order is used as the deviation vector.

[0019] Optionally, the specific method for obtaining the deviation characteristic value caused by interference in the frequency range corresponding to each numbered mode component of each longitudinal wave signal includes:

[0020] The characteristic value of the deviation caused by interference in the frequency range corresponding to each numbered mode component of each longitudinal wave signal is calculated using the following formula: ; in, Indicates the first The deviation characteristic value of a longitudinal wave signal due to interference in the frequency range corresponding to any numbered mode component; and They represent the first The and the first The comprehensive deviation value of a longitudinal wave signal within the frequency range corresponding to the numbered mode component; This indicates the number of longitudinal wave signals received at the same depth; Indicates the first The and the first Cosine similarity of the deviation vectors between longitudinal wave signals; Represents the absolute value function; It is an exponential function with the natural constant as its base.

[0021] Optionally, the specific method for reconstructing each longitudinal wave signal includes:

[0022] For each longitudinal wave signal received at the same depth, each modal component of the mode decomposition is used as input, and noise reduction is performed using a wavelet threshold denoising algorithm; and the reconstruction weight of each modal component is calculated.

[0023] Based on the modal components processed by wavelet threshold denoising and the corresponding reconstruction weights, signal reconstruction is performed on each longitudinal wave signal.

[0024] Optionally, the reconstruction weights of each modal component are obtained using the following method:

[0025] Using the deviation eigenvalues ​​of all modal components as input, the Softmax function is used to obtain the processing results of all deviation eigenvalues. Based on the processing results, the reconstruction weight of each modal component is determined. The specific calculation formula is as follows: ; in, Indicates the first Reconstruction weights of each modal component; and They represent the first The and the first The result of processing the Softmax function for the eigenvalues ​​of the modal component deviations; This indicates the number of modal components in the decomposition.

[0026] Optionally, the specific method for obtaining the VTI anisotropic medium lateral velocity at each depth in the target exploration area includes:

[0027] For the reconstructed P-wave signal, notch filtering is used to remove 50Hz power frequency and harmonic interference, and wellhead consistency static correction is performed. The arrival time of the P-wave direct wave corresponding to each depth excitation point is recorded.

[0028] Determine the spatial coordinates of the excitation point and the receiver point at the same depth. The coordinates of the excitation point are: The coordinates of the receiving point are It adopts the same depth excitation-reception method, therefore Calculate the horizontal distance between two points using the Pythagorean theorem. ;

[0029] Based on the horizontal propagation mode of direct waves in a horizontally layered medium, and according to the formula for calculating transverse velocity... ,in Given the initial arrival time of the P-wave for excitation-reception at the same depth, the transverse velocity at the corresponding depth is calculated. The arithmetic mean of the calculation results for multiple excitation-reception pairs at the same depth is taken, and the transverse velocity is discarded. With vertical velocity The ratio of outliers exceeding the preset range is filled with missing values ​​using a linear interpolation method to obtain the transverse velocity of the VTI anisotropic medium at each depth in the target exploration area.

[0030] Optionally, the VTI anisotropic medium at each depth The value is obtained using the following method: ; in, For lateral velocity, Indicates vertical velocity, The parameters represent the VTI anisotropic medium.

[0031] Optionally, based on the initial vertical velocity model, and according to the first arrival information of different excitation points in inter-well or in-well seismic events, combined with the VTI anisotropic medium... The values ​​of the VTI anisotropic medium are obtained through ray tracing forward and inverse iterative methods. The value, including the specific methods, is as follows:

[0032] The first arrival time of the direct wave from the excitation point at different depths to the receiver point in the adjacent well was calculated using the horizontal layered medium ray tracing method. ;

[0033] Based on the epicentral distance equation and the isotropic velocity model, calculate the isotropic initial ray parameters. And determine the initial ray angle based on the isotropic initial ray parameters;

[0034] The ray path is calculated iteratively based on the epicentral distance equation, and the first arrival time of the direct wave is also considered. and the initial ray angle of each layer and anisotropic velocity The relational expression is used to obtain the initial anisotropy parameters. value;

[0035] Based on the initial ray angle and anisotropy parameters Value and The values ​​are updated using the weak anisotropy approximation formula to update the anisotropic velocity of each layer;

[0036] Travel time forward modeling is performed based on the first arrival time of the direct wave, and then the actual first arrival curve is fitted; the initial anisotropy parameters are adjusted based on the actual first arrival curve. value.

[0037] Optionally, the epicentral distance equation is: ; in, For ray parameters; Indicates the number of seismic waves at the 1st twentieth ... The propagation isotropic velocity of the layer is obtained through an initial isotropic velocity model, which is constructed by extrapolating the initial vertical velocity model near the well to the inter-well region based on the assumption of a horizontal layered medium. Indicates the first The thickness of the layer, which is obtained through geological stratification data of the target area; The total number of media layers is obtained by statistically analyzing the target layer and the number of layers of the surrounding rock above and below it using geological stratification data. The epicentral distance is the distance from the epicenter of an earthquake to a ground observation point, and the epicenter is the projected location of the earthquake source on the ground.

[0038] Optionally, the specific method for determining the initial ray angle based on the isotropic initial ray parameters includes:

[0039] The initial ray angle is determined based on the acquired isotropic initial ray parameters, wherein the geometric relationship between the ray parameters and the propagation angle is considered. Determine the initial ray angle .

[0040] Optionally, the specific method for updating the anisotropic velocity of each layer includes: ; in, This indicates that the updated seismic wave is in the [number]th [phase]. The propagation velocity of the layer is isotropic; This represents the corrected anisotropy parameter value. Indicates the anisotropy parameter value; Indicates the first The initial ray angle of the layer; Indicates the number of seismic waves at the 1st twentieth ... The propagation velocity of the layer is isotropic.

[0041] Optionally, the specific method for performing travel time forward modeling based on the first arrival time of the direct wave, and then fitting the actual first arrival curve, includes:

[0042] According to the established The anisotropic velocities of each layer are updated, and ray tracing is then performed again based on the updated velocities to calculate the first arrival time of the direct wave. Then, curve fitting is performed based on the obtained actual arrival time to obtain the actual arrival curve.

[0043] Optionally, the use of VTI anisotropic media Value and Values ​​were interpolated and smoothed along geological strata to obtain VTI anisotropic media. field and The specific methods included in the field are as follows:

[0044] Acquiring well-drilled seismic data for the target exploration area includes acquiring Walkaway VSP and 3D-VSP data, which reflect the propagation response of seismic waves at different offsets and incident angles. Then, based on the Walkaway VSP and 3D-VSP data, the correlation between wave velocity characteristics and anisotropy parameters at different incident angles is analyzed and calculated to obtain anisotropy parameters layer by layer from shallow to deep. Value and Values; combined with geological stratification information, anisotropy parameters of each layer are analyzed. Value and Values ​​are interpolated and smoothed along the layer, using geological stratification as the constraint unit. Based on observation data from inter-well and intra-well seismic points, the values ​​are discretized within the layer. Value and Spatial interpolation is performed on the values, and mean filtering is applied to the interpolation results to form the VTI anisotropic medium. field and field.

[0045] The beneficial effects of this invention are as follows: This invention obtains initial vertical velocity information near the wellbore through zero-source-distance seismic records in the wellbore, accurately analyzes the differences in location interference at different depths using inter-well seismic record data, and accurately calculates lateral velocity information. Based on the assumption of vertical and lateral velocities in VTI anisotropic media, it obtains VTI anisotropic media at each depth. The calculation is more reliable and accurate, improving the accuracy of velocity modeling in VTI anisotropic media, which is beneficial to improving imaging accuracy and effect. At the same time, it fully leverages the advantages of high lateral accuracy of inter-well seismic and high longitudinal velocity accuracy of in-well seismic. Through layer-by-layer forward and inverse iterative modeling from shallow to deep, outliers are eliminated and errors in inversion results caused by differences between the two observation systems are adjusted. In relatively overlapping well sections, the calculation results of inter-well seismic are used as the main reference; for observation well sections that do not overlap with inter-well seismic, the calculation results of in-well seismic are used as the main reference. The inter-well and in-well seismic calculations are fully combined in terms of VTI anisotropic media calculation and analysis, achieving complementary advantages. It can not only give full play to the advantages of inter-well and in-well seismic velocity bridges and high-precision travel time of one-way waves, but also reasonably and objectively drive surface seismic to improve imaging accuracy and effect. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 A schematic diagram of the process for inverting VTI anisotropy parameters based on inter-well seismic data and VSP, provided in an embodiment of the present invention;

[0048] Figure 2 A schematic diagram of establishing an initial vertical velocity model around the well for zero-source-distance VSP velocity;

[0049] Figure 3 A schematic diagram showing the setting of seismic excitation and receiving points at the same depth between wells in the exploration area;

[0050] Figure 4 A schematic diagram illustrating the initial arrival information obtained by stimulating different locations at the stimulating points in the exploration area and receiving it at the receiving point.

[0051] Figure 5 A schematic diagram of the forward evolution of anisotropic vectors;

[0052] Figure 6 This is a schematic diagram of the forward modeling of isotropic travel time and the observed anisotropic travel time. Detailed Implementation

[0053] 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.

[0054] Please see Figure 1 The diagram illustrates a flowchart of a method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP, according to an embodiment of the present invention. The method includes the following steps:

[0055] Step S001: Obtain the initial arrival information and velocity information of the zero-well source distance VSP record in the target exploration area, and establish an initial vertical velocity model near the well, such as... Figure 2 As shown.

[0056] As an example, this embodiment uses borehole seismic zero-source-distance (VSP) technology to obtain velocity information of the target exploration area. This velocity information includes the vertical propagation velocity of P-waves and the vertical propagation velocity of S-waves. Based on this velocity information, an initial vertical velocity model is constructed near the well, such as... Figure 2As shown, the specific construction process includes: First, extracting velocity information within a preset distance range from the wellhead in the zero-well source distance VSP data. In this embodiment, the preset distance range is described as 10m. The velocity information is then subjected to mean filtering to eliminate velocity fluctuations caused by random noise, ensuring that the velocity change rate of adjacent depth points is less than or equal to the change threshold. In this embodiment, the change threshold is described as 5%. This yields smoothed P-wave vertical propagation velocity data and smoothed S-wave vertical propagation velocity data. Finally, combining regional geological stratification data (such as lithological interfaces, reservoir top and bottom plate depths, etc.), the smoothed velocity data is divided into layers, and the top and bottom depths and average velocities of each layer are extracted to form a structured wellhead initial vertical velocity model. The specific model construction process is a well-known technique in the field and will not be described in detail in this embodiment.

[0057] As another example, implementers can also calculate the initial vertical velocity around the well using the arrival time of the direct wave, the location of the excitation point, and the location of the receiver point recorded in the zero-source-distance VSP of the well-hole seismic system. Figure 2 As shown; the initial vertical velocity near the well is calculated using the Pythagorean theorem combined with the direct wave propagation path analysis method, i.e., the coordinates of the excitation point and the receiver point are determined. The excitation point is located directly above the wellhead, with its horizontal coordinates consistent with the wellhead and its vertical depth being 0; the receiver point is located at a predetermined depth inside the well. The horizontal coordinates are consistent with the wellhead; thus, the vertical propagation distance between the two can be determined. Then, based on the first arrival time of the direct wave recorded by the VSP... By calculating the relational formula Calculate the vertical velocity of the longitudinal wave The vertical velocity can be used as the vertical velocity for the corresponding depth segment; vertical velocity information can also be obtained by sonic logging. The specific process of smoothing and stratifying the sonic logging velocity to obtain the initial vertical velocity near the well is a well-known technology in the field, and will not be described in detail in this embodiment.

[0058] Step S002: Separate the first arrival information at the same depth to obtain several P-wave signals, and analyze the differences between the modal components with the same number obtained from the P-wave signal decomposition and the differences in their center frequencies to obtain the comprehensive deviation value of each P-wave signal number at the same depth, as well as the deviation vector of each P-wave signal; based on the differences between the deviation vectors and the differences between the comprehensive deviation values, obtain the deviation characteristic value caused by interference in the frequency range corresponding to each P-wave signal number modal component, and then reconstruct each P-wave signal to obtain the VTI anisotropic medium transverse velocity at each depth in the target exploration area.

[0059] It should be noted that, firstly, it is necessary to obtain the first arrival information of the inter-well seismic excitation points at different depths in the target exploration area. Then, based on the first arrival information of the inter-well seismic excitation points at the same depth in the target exploration area, the transverse velocity of the VTI anisotropic medium at the corresponding depth is calculated. The specific settings for the excitation and receiving points are as follows: Figure 3 As shown; due to the influence of formation lateral heterogeneity, near-surface velocity differences, and surrounding medium disturbances during the propagation of the P-waves corresponding to the excitation points at various depths in the actual processing, the signal propagation is significantly interfered with. If the interference is significant, it may increase background noise, leading to false start points and masking the true first arrival time's start characteristics, resulting in picking errors due to premature or delayed first arrival times. The accuracy of determining the first arrival time of the direct P-waves at each depth directly affects the accuracy of lateral velocity calculation, and thus impacts... Value derivation and follow-up Reliability of value inversion.

[0060] It should be further noted that, for the seismic data obtained at the same depth after separation between wells, considering the characteristics of the interference effect of geological differences at the same depth, the interference effect differences of multiple sets of P-wave signal data received at the same depth are compared and analyzed, thereby reducing the impact of interference effect differences on the acquisition of the first arrival time of the P-wave direct wave. Here, multiple sets of P-wave signals refer to the calculation of the first arrival information obtained by repeated excitation at the same excitation point and receiving point.

[0061] Specifically, the acquired raw seismic data between wells is preprocessed, and P-wave and S-wave interference is separated by FK filtering to obtain several P-wave signals. The P-wave signals before separation are derived from multiple repeated excitations at the same excitation and receiving points at the same depth. For each separated P-wave signal at the same depth, empirical mode decomposition is used to perform mode decomposition on the P-wave signal, and the signals are numbered sequentially according to the decomposition order. The decomposed mode components correspond to P-wave signals in different frequency ranges.

[0062] It should be noted that due to the significant differences in interference during the propagation and reception of longitudinal waves at the same depth, longitudinal waves at the same depth may be greatly affected by interference from signals of different frequencies, resulting in a large error in picking up the first arrival time of the longitudinal waves.

[0063] Furthermore, for each P-wave signal at the same depth, the DTW distance of the modal components with the same number between each P-wave signal and every other P-wave signal is calculated; and the difference in center frequencies of the modal components with the same number between each P-wave signal and every other P-wave signal is calculated, the formula for calculating the difference is as follows: ,in The difference value, and They represent the first The longitudinal wave signal and other... The center frequencies of modal components with the same number among the longitudinal wave signals; where the center frequency of the modal component does not equal 0, the formula will not have a denominator of 0 that would render it meaningless.

[0064] It should be noted that the larger the DTW distance between modal components with the same number in the P-wave signal, the greater the difference caused by interference in the frequency range corresponding to the modal components with the same number at the same depth. The larger the calculated difference value, the larger the frequency range difference caused by interference, and the greater the possibility of deviation in the P-wave signal caused by interference. Introducing DTW distance and analyzing the center frequency difference is superior to the traditional average superposition method when dealing with non-stationary interference (such as intermittent noise).

[0065] Furthermore, in order to accurately analyze the characteristics of signal propagation at the same depth due to interference from geological differences, the product of the DTW distance and difference value of the modal components with the same number between each P-wave signal and every other P-wave signal is calculated, and the mean of all the products calculated between each P-wave signal with each number and all other P-wave signals is taken as a comprehensive deviation value.

[0066] It should be noted that the larger the overall deviation value, the greater the difference between each P-wave signal and other P-wave signals due to interference in each modal component. That is, during P-wave propagation at the same depth, due to interference deviation of noise signals, the currently received P-wave signal may have a large frequency range of deviation.

[0067] It should be further explained that, based on the comprehensive deviation value, and combined with the consistency characteristics of the P-wave signals received at different frequencies at the same depth, the deviation of interference effects between different P-wave signals received at the same depth is compared, thereby determining the deviation influence characteristics of each P-wave signal in different frequency ranges; by measuring the similarity between the comprehensive deviation value of each P-wave signal under all numbers and the comprehensive deviation values ​​of all other P-wave signals, the differences in the distribution of interference deviation due to noise signals during P-wave propagation at the same depth are compared; it should be noted that, in the similarity measurement process, the implementer can express the comprehensive deviation value of each P-wave signal as a vector, or as a sequence or set, and perform similarity analysis using existing similarity measurement methods, such as calculating the cosine similarity between vectors or the intersection-union ratio between sets.

[0068] Specifically, the vector formed by the combined deviation values ​​of all modal components under each P-wave signal in numerical order is used as the deviation vector. This deviation vector reflects the distribution of deviation due to noise interference during P-wave propagation at the same depth. The cosine similarity between the deviation vectors of each P-wave signal and every other P-wave signal is calculated. The larger the cosine similarity, the stronger the consistency under the comprehensive comparison of different P-wave signals, and the smaller the possibility of deviation due to interference. Then, the deviation characteristic value caused by interference in the frequency range corresponding to each modal component of each P-wave signal is calculated. The calculation relationship is as follows: ; in, Indicates the first The deviation characteristic value of a longitudinal wave signal due to interference in the frequency range corresponding to any numbered mode component; and They represent the first The and the first The comprehensive deviation value of a longitudinal wave signal within the frequency range corresponding to the numbered mode component; This indicates the number of longitudinal wave signals received at the same depth; Indicates the first The and the first Cosine similarity of the deviation vectors between longitudinal wave signals; Represents the absolute value function; The purpose of this function is to normalize the comprehensive comparison results of similarity between different longitudinal wave signals, since the result of cosine similarity -1 is always negative, thus achieving normalization.

[0069] It should be noted that, by combining the consistency of different P-wave signals received at the same depth, the interference influence characteristics of each P-wave signal in the frequency range corresponding to each numbered mode component are analyzed. The larger the calculated deviation characteristic value, the greater the signal difference of the currently received P-wave signal in the frequency range of the corresponding numbered mode component due to interference. Therefore, the weight of signal reconstruction can be reduced during the noise reduction process, thereby reducing the impact of interference differences on the P-wave direct arrival time analysis.

[0070] Furthermore, for each P-wave signal received at the same depth, each modal component of the mode decomposition is used as input, and noise reduction is performed using a wavelet threshold denoising algorithm; and the reconstruction weight of each modal component is calculated: the deviation feature values ​​of all modal components are used as input, and the processing results of all deviation feature values ​​are obtained using the Softmax function. Based on the processing results, the reconstruction weight of each modal component is determined, and the specific calculation formula is as follows: ; in, Indicates the first Reconstruction weights of each modal component; and They represent the first The and the first The result of processing the Softmax function for the eigenvalues ​​of the modal component deviations; The number of modal components decomposed is indicated; wherein the number of modes obtained by empirical mode decomposition is greater than or equal to 2; based on the modal components processed by wavelet threshold denoising and the corresponding reconstruction weights, signal reconstruction is performed on each longitudinal wave signal. The specific signal reconstruction process is a well-known technique and will not be described in detail in this embodiment.

[0071] It should be noted that, based on the above processing, the impact of random noise interference differences is reduced, thereby reducing the impact of background noise and false start points on the judgment of the start characteristics of the true first arrival, and reducing the picking error when the first arrival time is early or late; by analyzing the consistency of signals excited multiple times, stable signals are given high weight and interference signals are given low weight, so as to retain the true first arrival information in the superposition.

[0072] Furthermore, for the reconstructed P-wave signal, notch filtering is used to remove 50Hz power frequency and harmonic interference, while wellhead consistency static correction is performed to eliminate travel time deviation caused by the difference in near-surface conditions between the two wells, and the first arrival time of the P-wave direct wave corresponding to each depth excitation point is recorded.

[0073] Furthermore, the spatial coordinates of the excitation point and the receiver point at the same depth are clarified, with the coordinates of the excitation point being... The coordinates of the receiving point are This embodiment uses a same-depth excitation-reception method, therefore Calculate the horizontal distance between two points using the Pythagorean theorem. Finally, based on the horizontal propagation mode of direct waves in a horizontally layered medium, the transverse velocity is calculated using the formula... ,in Given the initial arrival time of the P-wave for excitation-reception at the same depth, the transverse velocity at the corresponding depth is calculated. The arithmetic mean of the calculation results for multiple excitation-reception pairs at the same depth is taken, and the transverse velocity is discarded. With vertical velocity The ratio exceeding the preset range is an abnormal value; in this embodiment, the range is set to... By using linear interpolation to fill in missing values, the continuous and reliable transverse velocities of the VTI anisotropic medium at each depth in the target exploration area can be obtained.

[0074] Step S003: Based on the vertical and lateral velocities of the VTI anisotropic medium, solve for the VTI anisotropic medium at each depth. value.

[0075] It should be noted that, based on the assumption of vertical and lateral velocities in VTI anisotropic media, i.e., the VTI medium is a weakly anisotropic sedimentary rock stratum, seismic waves propagate in the medium according to Thomsen's weak anisotropy theory, and the vertical velocity ( ) reflects the longitudinal wave propagation characteristics of the medium along the vertical axis of symmetry, and the transverse velocity ( This reflects the longitudinal wave propagation characteristics of the medium along the horizontal direction (perpendicular to the axis of symmetry), and both types of velocities satisfy the assumption of a continuous distribution law of strata.

[0076] Specifically, the relationship between vertical velocity and lateral velocity is used to calculate the VTI anisotropic medium at the same depth. The value, specifically the calculation formula is:

[0077] ; in, For lateral velocity, Indicates vertical velocity, The parameters represent the VTI anisotropic medium.

[0078] It should be noted that the results were obtained through calculations of lateral and vertical velocities. The purpose of this value is to accurately quantify the difference in longitudinal wave velocity between the horizontal and vertical directions of the VTI medium, providing a basis for subsequent... Value inversion provides reliable constraints and establishes layers at various depths. The distribution profile of the values ​​provides a basis for subsequent construction of continuous... This lays the foundation for the separation and matching of the velocity field and the anisotropic field, thereby improving the accuracy of subsequent seismic migration imaging.

[0079] Step S004: Based on the initial vertical velocity model, and according to the first arrival information of different excitation points in inter-well or in-well seismic events, combined with the VTI anisotropic medium... The values ​​of the VTI anisotropic medium are obtained through ray tracing forward and inverse iterative methods. value.

[0080] It should be noted that, based on the inter-well seismic records, the VTI anisotropic medium of each layer is updated simultaneously using ray tracing forward and inverse iterative methods. Value and The value is ultimately obtained for the VTI anisotropic medium. Value and On the other hand, based on well-drilled seismic records, the VTI anisotropic medium of each layer is simultaneously updated using ray tracing forward and inverse iterative methods. Value and The value is ultimately obtained for the VTI anisotropic medium. Value and value.

[0081] In one embodiment of the present invention, based on the initial vertical velocity model near the well, and combined with the first arrival information of different excitation points of the inter-well seismic event and the obtained VTI anisotropic medium, The values ​​are calculated for VTI anisotropic media using ray tracing forward and inverse iterative methods. Value; such as Figure 3 As shown, the two wells are the excitation well and the receiving well, respectively. The excitation well is used to excite at different depths, and the receiving point at each depth records the first arrival information of different excitation points of the earthquake between the wells.

[0082] Specifically, an initial isotropic velocity model is constructed based on the initial vertical velocity model near the well. The specific construction process is as follows:

[0083] (1) First, the horizontal layered medium ray tracing method is used to calculate the first arrival time of the direct wave from the excitation point at different depths to the receiving point of the adjacent well. The purpose is to obtain a theoretical travel time reference under the isotropic assumption, so as to provide a reference for subsequent comparison with actual observation travel time and identification of travel time deviation caused by anisotropy. The process of obtaining the first arrival time of the direct wave based on the horizontal layered medium ray tracing method is a well-known technology in the art, and will not be described in detail in this embodiment.

[0084] (2) Calculate the isotropic initial ray parameters based on the epicentral distance equation and the isotropic velocity model. The initial ray angle is determined based on the isotropic initial ray parameters; the specific epicentral distance equation is as follows: ; in, For ray parameters; Indicates the number of seismic waves at the 1st twentieth ... The propagation isotropic velocity of the layer is obtained through an initial isotropic velocity model, which is constructed by extrapolating the initial vertical velocity model near the well to the inter-well region based on the assumption of a horizontal layered medium. Indicates the first The thickness of the layer is obtained through geological stratification data of the target area (including well logging stratification and surface seismic stratification interpretation results); The total number of media layers is obtained by statistically analyzing the target layer and the number of layers of the surrounding rock above and below it using geological stratification data. The epicentral distance is the distance from the earthquake epicenter to a ground observation point, where the epicenter is the projected location of the earthquake source on the ground. In one embodiment of the present invention, the isotropic and anisotropic ray paths of the inter-well seismic event are as follows: Figure 3As shown.

[0085] Furthermore, based on the calculation formula for epicentral distance, the isotropic initial ray parameters are calculated. Furthermore, the initial ray angle is determined based on the obtained isotropic initial ray parameters, wherein the geometric relationship between the ray parameters and the propagation angle is considered. Determine the initial ray angle This provides an angle constraint for subsequent updates of anisotropic velocities.

[0086] (3) Calculate the ray path iteratively based on the epicentral distance equation and the first arrival time of the direct wave. and the initial ray angle of each layer and anisotropic velocity The relational expression is used to obtain the initial anisotropy parameters. The value, specifically the calculation formula is: ; in, The theoretical travel time of a direct wave; Indicates the first Layer thickness; Indicates the number of seismic waves at the 1st twentieth ... The propagation velocity of the layer is isotropic; Indicates the first The initial ray angle of the layer is used to calculate the theoretical travel time under the isotropic assumption. Then, the initial anisotropy parameters are analyzed and calculated. The specific calculation and analysis process for the value is as follows: First, compare it with the theoretical time. Travel time compared with actual inter-well seismic observations Obtain the travel time residual Secondly, based on the weak anisotropy, the residual during the down-travel and correlation ,in The initial value is calculated based on the average ray angle of each layer. The purpose is to initially determine the value using the travel time residual. The range of values ​​for is used to provide initial values ​​for subsequent iterative optimization.

[0087] (4) Based on the initial ray angle and anisotropy parameters Value and The values ​​are updated using the weak anisotropy approximation formula to update the anisotropic velocity of each layer. The specific formula for the update process is as follows: ; in, This indicates that the updated seismic wave is in the [number]th [phase]. The propagation velocity of the layer is isotropic; This represents the corrected anisotropy parameter value. Indicates the anisotropy parameter value; Indicates the first The initial ray angle of the layer; Indicates the number of seismic waves at the 1st twentieth ... The propagation velocity of the layer is isotropic; the purpose is to... and The anisotropic effects are simultaneously incorporated into the velocity model, fully considering the VTI medium. (Horizontal-vertical velocity difference) and The synergistic effect of (medium-angle velocity deviation) improves the accuracy of anisotropic velocity field calculation and analysis.

[0088] (5) Perform travel time forward modeling based on the first arrival time of the direct wave, and then fit the actual first arrival curve, including: firstly, based on the determined first arrival time... The anisotropic velocities of each layer are updated, and ray tracing is then performed again based on the updated velocities to calculate the first arrival time of the direct wave. Then, curve fitting is performed based on the obtained actual first arrival time to obtain the actual first arrival curve; then, the initial anisotropy parameters are adjusted based on the actual first arrival curve. value.

[0089] Specifically, firstly, based on the calculated first arrival time of the direct wave... Compared with actual time Calculate the residual And then based on the residual Adjustment Value, if Then increase Conversely, it decreases. ,in The adjustment range for increasing or decreasing the value is described as 5% to 10% in this embodiment. After each adjustment, the root mean square error of the actual arrival curve is calculated. If the root mean square error is less than or equal to a preset threshold, it indicates that the current arrival time is closer to the actual observation. In this embodiment, the preset threshold is described as 0.8 ms. The accuracy of the values ​​is relatively high.

[0090] Furthermore, based on inversion iterative calculations and analysis, until the travel time error of the first arrival of the direct wave is minimized, the final anisotropy at different depths is obtained. The value; the specific process includes: repeating steps (4) and (5), updating after each iteration. The anisotropic velocity is then calculated, followed by continuous calculation of the RMS of the travel time residuals. A stopping residual threshold and a stopping number are preset. In this embodiment, the stopping residual threshold is described as 0.5ms and the stopping number is described as 10. The iteration terminates when the RMS is less than or equal to the stopping residual threshold, or when the number of iterations reaches the stopping number. Finally, the anisotropic parameters at different depths are obtained. value.

[0091] In another embodiment of the invention, based on the constructed well-side initial vertical velocity model, and according to the first arrival information of different excitation points of the Walkaway VSP in the well, combined with the already obtained VTI anisotropic medium... The values ​​of the VTI anisotropic medium are obtained through ray tracing forward and inverse iterative methods. Value; such as Figure 4 As shown, excitation is performed along different excitation points on the surface, and each depth receiver point records the first arrival information of different excitation points of the Walkaway VSP in the well.

[0092] Furthermore, an initial isotropic velocity model is constructed based on the initial vertical velocity model near the well. The specific construction process is as follows:

[0093] (1) First, the horizontal layered medium ray tracing method is used to calculate the first arrival time of the direct wave from the excitation point at different depths to the receiving point of the adjacent well. .

[0094] (2) Calculate the isotropic initial ray parameters based on the epicentral distance equation and the isotropic velocity model. The initial ray angle is determined based on the isotropic initial ray parameters.

[0095] (3) Calculate the ray path iteratively based on the epicentral distance equation and the first arrival time of the direct wave. and the initial ray angle of each layer and anisotropic velocity The relation is used to calculate the theoretical travel time under the isotropic assumption. Then, the initial anisotropy parameters are analyzed and calculated. value.

[0096] (4) Based on the initial ray angle and anisotropy parameters Value and The values ​​are updated using the weak anisotropy approximation formula to update the anisotropic velocity of each layer.

[0097] (5) Perform travel time forward modeling based on the first arrival time of the direct wave, then fit the actual first arrival time curve, and adjust the initial anisotropy parameters according to the actual first arrival curve. value.

[0098] It should be noted that the specific calculation and analysis processes (1) to (5) in the processing flow of the two embodiments of the present invention are the same. The difference is that in the other embodiment, based on the first arrival information of different excitation points of the Walkaway VSP in the well seismic test, combined with the VTI anisotropic medium that has been obtained, The values ​​of the VTI anisotropic medium are obtained through ray tracing forward and inverse iterative methods. value.

[0099] Step S005: Utilizing VTI anisotropic medium Value and Values ​​were interpolated and smoothed along geological strata to obtain VTI anisotropic media. field and The field then forms a VTI anisotropic body.

[0100] It should be noted that after acquiring the inter-well seismic, borehole seismic, and surface seismic geological stratigraphic information data of the target exploration area, the VTI anisotropic medium calculated based on the inter-well and borehole seismic data is analyzed. Value and Comparative analysis of values ​​is performed to reduce the impact of abnormal results on the accuracy of calculation and analysis. The advantages of two observation systems are fully combined to correct errors in the inversion analysis caused by the influence of different observation systems. These observation systems include a borehole seismic migration distance observation system and an inter-well seismic observation system. Because the inter-well seismic system uses a dual-well, same-depth excitation-receiver mode, it has a short lateral propagation path and a high signal-to-noise ratio, directly reflecting horizontal velocity differences. This makes the calculation of lateral velocity in the inter-well seismic observation system more accurate, thus improving the accuracy of calculations for VTI anisotropic media. More accurate values; well-drilled seismic variable migration distance observation systems (such as Walkaway VSP) can cover multiple incident angles (10° to 70°) and are more sensitive to mid-angle wave velocity deviations, thus providing more accurate values ​​for VTI anisotropic media. The value is calculated more accurately.

[0101] It should be further explained that, based on the above analysis of the complementary advantages of the observation systems, since the well sections observed by inter-well seismic and in-well seismic systems do not completely overlap, and the inter-well seismic observation points are more closely spaced and the receiver intervals are smaller within the observation well section, resulting in higher resolution for the formation, the inter-well seismic calculation results are considered as the main reference for relatively overlapping well sections; for well sections mainly observed by the in-well seismic observation system, or for observation well sections that do not overlap with the inter-well seismic system, the in-well seismic calculation results are used as the main reference.

[0102] Specifically, to achieve spatial continuity and geological rationality of anisotropic parameters, this embodiment performs interpolation smoothing along geological strata to obtain VTI anisotropic media. field and The field forms a VTI anisotropic body; the specific process includes: firstly, acquiring well-drilled seismic data of the target exploration area, including Walkaway VSP and 3D-VSP data, which reflect the propagation response of seismic waves at different offsets and incident angles; then, based on the Walkaway VSP and 3D-VSP data, performing analysis and calculation of the correlation between wave velocity characteristics and anisotropic parameters at different incident angles, obtaining anisotropic parameters layer by layer from shallow to deep. Value and Values; combined with geological stratification information, anisotropy parameters of each layer are analyzed. Value and Values ​​are smoothed through interpolation along the layers. In this embodiment, Kriging interpolation is used for processing, with geological layers as the constraint unit. Based on observation point data from inter-well and intra-well seismic data, the values ​​are smoothed for discrete layers. Value and Spatial interpolation is performed on the values. In this embodiment, the horizontal interpolation interval is 10m and the vertical interpolation interval is 5m. At the same time, the interpolation results are mean filtered to form the VTI anisotropic medium. field and Field; in this embodiment, the anisotropic forward walk is as follows: Figure 5 As shown; finally, the boundary constraint optimization method is used to minimize the error between the forward travel time and the observed travel time, thereby obtaining the anisotropic parameters layer by layer from shallow to deep. Value and In this embodiment, the forward isotropic travel time and the observed anisotropic travel time are as follows: Figure 6 As shown.

[0103] This concludes the embodiment.

[0104] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP, characterized in that, The method includes the following steps: Acquire the initial arrival information and velocity information of the zero-well source distance VSP record in the target exploration area, and establish an initial vertical velocity model near the well. Several P-wave signals are obtained by separating the first arrival information at the same depth. The differences between the modal components with the same number obtained by the decomposition of the P-wave signals and the differences in their center frequencies are analyzed to obtain the comprehensive deviation value of each P-wave signal number at the same depth, as well as the deviation vector of each P-wave signal. Based on the differences between the deviation vectors and the differences between the comprehensive deviation values, the deviation characteristic value caused by interference in the frequency range corresponding to each P-wave signal and each modal component number is obtained. Then, each P-wave signal is reconstructed to obtain the transverse velocity of the VTI anisotropic medium at each depth in the target exploration area. Based on the vertical and lateral velocities of the VTI anisotropic medium, the VTI anisotropic medium at various depths can be obtained by solving the problem. value; Based on the aforementioned initial vertical velocity model, and according to the first arrival information of different excitation points in inter-well or in-well seismic events, combined with the VTI anisotropic medium... The values ​​of the VTI anisotropic medium are obtained through ray tracing forward and inverse iterative methods. value; Utilizing VTI anisotropic media Value and Values ​​were interpolated and smoothed along geological strata to obtain VTI anisotropic media. field and The field then forms a VTI anisotropic body.

2. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 1, characterized in that, The specific method for separating the first arrival information at the same depth to obtain several longitudinal wave signals includes: The acquired raw seismic data between wells was preprocessed, and P-wave and S-wave interference was separated by FK filtering to obtain several P-wave signals. The P-wave signals before separation originated from multiple repeated excitations at the same excitation and receiving points at the same depth.

3. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 1, characterized in that, The specific method for obtaining the comprehensive deviation value of each P-wave signal number at the same depth includes: For each P-wave signal at the same depth, calculate the DTW distance between each P-wave signal and the modal components with the same number from each other; and calculate the difference in center frequency between each P-wave signal and the modal components with the same number from each other. Calculate the product of the DTW distance and difference values ​​of the modal components with the same number between each P-wave signal and every other P-wave signal, and take the mean of all the products calculated between each P-wave signal and all other P-wave signals under each number as a comprehensive deviation value.

4. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 3, characterized in that, The difference in the center frequency of the modal components with the same number between each longitudinal wave signal and every other longitudinal wave signal is obtained by the following method: in, The difference value, and They represent the first The longitudinal wave signal and other... The center frequencies of modal components with the same number among the longitudinal wave signals.

5. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 1, characterized in that, The specific method for obtaining the deviation vectors of each longitudinal wave signal is as follows: The vector formed by combining the combined deviation values ​​of all modal components under each number for each longitudinal wave signal in numerical order is used as the deviation vector.

6. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 1, characterized in that, The specific method for obtaining the deviation characteristic value caused by interference in the frequency range corresponding to each numbered mode component of each longitudinal wave signal includes: The characteristic value of the deviation caused by interference in the frequency range corresponding to each numbered mode component of each longitudinal wave signal is calculated using the following formula: in, Indicates the first The deviation characteristic value of a longitudinal wave signal due to interference in the frequency range corresponding to any numbered mode component; and They represent the first The and the first The comprehensive deviation value of a longitudinal wave signal within the frequency range corresponding to the numbered mode component; This indicates the number of longitudinal wave signals received at the same depth; Indicates the first The and the first Cosine similarity of the deviation vectors between longitudinal wave signals; Represents the absolute value function; It is an exponential function with the natural constant as its base.

7. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 1, characterized in that, The specific method for reconstructing each longitudinal wave signal is as follows: For each longitudinal wave signal received at the same depth, each modal component of the mode decomposition is used as input, and the wavelet threshold denoising algorithm is used for noise reduction. And calculate the reconstruction weights for each modal component; Based on the modal components processed by wavelet threshold denoising and the corresponding reconstruction weights, signal reconstruction is performed on each longitudinal wave signal.

8. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 7, characterized in that, The reconstruction weights of each modal component are obtained using the following method: Using the deviation eigenvalues ​​of all modal components as input, the Softmax function is used to obtain the processing results of all deviation eigenvalues. Based on the processing results, the reconstruction weight of each modal component is determined. The specific calculation formula is as follows: in, Indicates the first Reconstruction weights of each modal component; and They represent the first The and the first The result of processing the Softmax function for the eigenvalues ​​of the modal component deviations; This indicates the number of modal components in the decomposition.

9. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 1, characterized in that, The specific method for obtaining the VTI anisotropic medium lateral velocity at each depth in the target exploration area includes: For the reconstructed P-wave signal, notch filtering is used to remove 50Hz power frequency and harmonic interference, and wellhead consistency static correction is performed. The arrival time of the P-wave direct wave corresponding to each depth excitation point is recorded. Determine the spatial coordinates of the excitation point and the receiver point at the same depth. The coordinates of the excitation point are: The coordinates of the receiving point are It adopts the same depth excitation-reception method, therefore Calculate the horizontal distance between two points using the Pythagorean theorem. ; Based on the horizontal propagation mode of direct waves in a horizontally layered medium, and according to the formula for calculating transverse velocity... ,in Given the initial arrival time of the P-wave for excitation-reception at the same depth, the transverse velocity at the corresponding depth is calculated. The arithmetic mean of the calculation results for multiple excitation-reception pairs at the same depth is taken, and the transverse velocity is discarded. With vertical velocity The ratio of outliers exceeding the preset range is filled with missing values ​​using a linear interpolation method to obtain the transverse velocity of the VTI anisotropic medium at each depth in the target exploration area.

10. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 1, characterized in that, The VTI anisotropic media at each depth The value, specifically, is obtained as follows: in, For lateral velocity, Indicates vertical velocity, The parameters represent VTI anisotropic media.

11. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 1, characterized in that, Based on the initial vertical velocity model, and according to the first arrival information of different excitation points in inter-well or in-well seismic events, combined with the VTI anisotropic medium... The values ​​of the VTI anisotropic medium are obtained through ray tracing forward and inverse iterative methods. The value, including the specific methods, is as follows: The first arrival time of the direct wave from the excitation point at different depths to the receiver point in the adjacent well was calculated using the horizontal layered medium ray tracing method. ; Based on the epicentral distance equation and the isotropic velocity model, calculate the isotropic initial ray parameters. And determine the initial ray angle based on the isotropic initial ray parameters; The ray path is calculated iteratively based on the epicentral distance equation, and the first arrival time of the direct wave is also considered. and the initial ray angle of each layer and anisotropic velocity The relational expression is used to obtain the initial anisotropy parameters. value; Based on the initial ray angle and anisotropy parameters Value and The values ​​are updated using the weak anisotropy approximation formula to update the anisotropic velocity of each layer; Travel time forward modeling is performed based on the first arrival time of the direct wave, and then the actual first arrival curve is fitted; the initial anisotropy parameters are adjusted based on the actual first arrival curve. value.

12. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 11, characterized in that, The equation for the epicentral distance is: in, For ray parameters; Indicates the number of seismic waves at the 1st twentieth ... The propagation isotropic velocity of the layer is obtained through an initial isotropic velocity model, which is constructed by extrapolating the initial vertical velocity model near the well to the inter-well region based on the assumption of a horizontal layered medium. Indicates the first The thickness of the layer, which is obtained through geological stratification data of the target area; The total number of media layers is obtained by statistically analyzing the target layer and the number of layers of the surrounding rock above and below it using geological stratification data. The epicentral distance is the distance from the epicenter of an earthquake to a ground observation point, and the epicenter is the projected location of the earthquake source on the ground.

13. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 12, characterized in that, The specific method for determining the initial ray angle based on the isotropic initial ray parameters is as follows: The initial ray angle is determined based on the acquired isotropic initial ray parameters, wherein the geometric relationship between the ray parameters and the propagation angle is considered. Determine the initial ray angle .

14. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 13, characterized in that, The specific method for updating the anisotropic velocity of each layer is as follows: in, This indicates that the updated seismic wave is in the 1st... The propagation velocity of the layer is isotropic; This represents the corrected anisotropy parameter value. Indicates the anisotropy parameter value; Indicates the first The initial ray angle of the layer; Indicates the number of seismic waves at the 1st twentieth ... The propagation velocity of the layer is isotropic.

15. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 11, characterized in that, The specific method for performing travel time forward modeling based on the first arrival time of the direct wave, and then fitting the actual first arrival curve, includes: According to the established The anisotropic velocities of each layer are updated, and ray tracing is then performed again based on the updated velocities to calculate the first arrival time of the direct wave. Then, curve fitting is performed based on the obtained actual arrival time to obtain the actual arrival curve.

16. The method for inverting VTI anisotropy parameters based on inter-well seismic data and VSP according to claim 1, characterized in that, The use of VTI anisotropic medium Value and Values ​​were interpolated and smoothed along geological strata to obtain VTI anisotropic media. field and The specific methods included in the field are as follows: Acquiring well-drilled seismic data for the target exploration area includes acquiring Walkaway VSP and 3D-VSP data, which reflect the propagation response of seismic waves at different offsets and incident angles. Then, based on the Walkaway VSP and 3D-VSP data, the correlation between wave velocity characteristics and anisotropy parameters at different incident angles is analyzed and calculated to obtain anisotropy parameters layer by layer from shallow to deep. Value and Values; combined with geological stratification information, anisotropy parameters of each layer are analyzed. Value and Values ​​are interpolated and smoothed along the layer, using geological stratification as the constraint unit. Based on observation data from inter-well and intra-well seismic points, the values ​​are discretized within the layer. Value and Spatial interpolation is performed on the values, and mean filtering is applied to the interpolation results to form the VTI anisotropic medium. field and field.

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