CN-122018008-A - VTI anisotropic parameter inversion method based on well-to-well earthquake and VSP

CN122018008ACN 122018008 ACN122018008 ACN 122018008ACN-122018008-A

Abstract

The invention relates to the technical field of intelligent sensing systems and provides a VTI anisotropic parameter inversion method based on an interwell earthquake and a VSP, which comprises the steps of obtaining first arrival information and speed information recorded by the VSP of a zero well source distance of a target exploration area, establishing an underground initial vertical speed model, obtaining first arrival information of excitation points of different depths of the interwell earthquake of the area, calculating to obtain transverse speeds of VTI anisotropic media of various depths, and obtaining the VTI anisotropic media of various depths And interpolating and smoothing along a geological horizon by utilizing the epsilon value and the delta value of the VTI anisotropic medium to obtain epsilon field and delta field of the VTI anisotropic medium so as to form a VTI anisotropic body. The invention aims to solve the problem that the accuracy of the sedimentary rock characteristic analysis is lower due to the fact that the speed model is not well matched with the anisotropic parameters in the traditional VTI anisotropic research.

Inventors

CAI DONGMEI
CHENG SHUNGUO
Fu Xiandi
ZHU YAN
BAI JUNHUI
YANG HUIDONG

Assignees

大庆油田有限责任公司
中国石油天然气股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260203

Claims (16)

1. The VTI anisotropic parameter inversion method based on the well earthquake and the VSP is characterized by comprising the following steps: acquiring first arrival information and speed information recorded by a zero well source distance VSP of a target exploration area, and establishing an initial vertical speed model beside a well; The method comprises the steps of separating first arrival information under the same depth to obtain a plurality of longitudinal wave signals, analyzing differences among modal components of the same number and differences of center frequencies of the modal components, which are obtained by decomposing the longitudinal wave signals, to obtain comprehensive deviation values of each serial number of each longitudinal wave signal under the same depth and deviation vectors of each longitudinal wave signal; solving and obtaining each depth of VTI anisotropic medium according to the vertical speed and the transverse speed of the VTI anisotropic medium A value; based on the initial vertical velocity model, according to the first arrival information of different excitation points of the well earthquake or the well earthquake, the VTI anisotropic medium is combined The value is obtained by a ray tracing forward modeling and inversion iteration method to obtain the VTI anisotropic medium A value; utilizing VTI anisotropic media Value sum The value is interpolated and smoothed along the geological horizon to obtain the VTI anisotropic medium Fields and methods of use The field, and thus the VTI anisotropy.
2. The VTI anisotropic parameter inversion method based on an interwell earthquake and a VSP of claim 1, wherein the separating the first arrival information at the same depth to obtain a plurality of longitudinal wave signals comprises the following specific steps: Preprocessing the acquired original data of the well earthquake, and separating the interference of longitudinal waves and transverse waves through F-K filtering to obtain a plurality of longitudinal wave signals, wherein the longitudinal wave signals before separation are repeatedly excited for a plurality of times under the same depth excitation point and receiving point positions.
3. The VTI anisotropic parameter inversion method based on the well-to-well earthquake and the VSP of claim 1, wherein the obtaining the comprehensive deviation value of each serial number of each longitudinal wave signal under the same depth comprises the following specific steps: For each longitudinal wave signal under the same depth, calculating the DTW distance of the modal component with the same number between each longitudinal wave signal and other longitudinal wave signals respectively, and calculating the difference value of the center frequency of the modal component with the same number between each longitudinal wave signal and other longitudinal wave signals; And calculating the product of the DTW distance and the difference value of the modal components with the same number between each longitudinal wave signal and each other longitudinal wave signal, and taking the average value of all the products calculated between each longitudinal wave signal and all other longitudinal wave signals under each number as a comprehensive deviation value.
4. The VTI anisotropic parameter inversion method based on the well-to-well earthquake and the VSP of claim 3, wherein the specific obtaining method is that: Wherein, the As a result of the value of the difference, And Respectively represent the first Longitudinal wave signals and other first The center frequencies of modal components of the same number between the longitudinal wave signals.
5. The VTI anisotropic parameter inversion method based on the well-to-well earthquake and the VSP of claim 1, wherein the deviation vector of each longitudinal wave signal is specifically obtained by: and taking a vector formed by the comprehensive deviation values of the modal components under all numbers of each longitudinal wave signal according to the number sequence as a deviation vector.
6. The VTI anisotropic parameter inversion method based on the well-to-well earthquake and the VSP according to claim 1, wherein the obtaining the deviation eigenvalue caused by the interference effect in the frequency range corresponding to each numbered modal component of each longitudinal wave signal comprises the following specific steps: calculating a deviation characteristic value caused by interference influence in a frequency range corresponding to each numbered modal component of each longitudinal wave signal, wherein the calculated relation is as follows: Wherein, the Represent the first The deviation characteristic value of each longitudinal wave signal caused by interference influence in the frequency range corresponding to any numbered modal component; And Respectively represent the first And (b) Comprehensive deviation values of the longitudinal wave signals in the frequency range corresponding to the numbered modal components; Representing the number of longitudinal wave signals received at the same depth; Represent the first And (b) Cosine similarity of deviation vectors among the longitudinal wave signals; Representing an absolute value function; is an exponential function with a base of natural constant.
7. The VTI anisotropic parameter inversion method based on the well-to-well earthquake and the VSP of claim 1, wherein the reconstructing each longitudinal wave signal comprises the following specific steps: For each longitudinal wave signal received under the same depth, taking each modal component of modal decomposition as input, and carrying out noise reduction treatment by utilizing a wavelet threshold denoising algorithm; And carrying out signal reconstruction on each longitudinal wave signal based on the modal component of the wavelet threshold denoising process and the corresponding reconstruction weight.
8. The VTI anisotropic parameter inversion method based on the well-to-well earthquake and the VSP of claim 7, wherein the reconstruction weight of each modal component is obtained by the following specific method: Taking the deviation characteristic values of all the modal components as input, obtaining processing results of all the deviation characteristic values by using a Softmax function, and determining reconstruction weight of each modal component based on the processing results, wherein a specific calculation formula is as follows: Wherein, the Represent the first Reconstruction weights of the individual modal components; And Respectively represent the first And (b) Softmax function processing results of the individual modal component deviation characteristic values; Representing the number of decomposed modal components.
9. The VTI anisotropic parameter inversion method based on well-to-well earthquake and VSP of claim 1, wherein the obtaining the VTI anisotropic medium lateral velocity of each depth of the target exploration area comprises the following specific steps: removing 50Hz power frequency and harmonic interference from the reconstructed longitudinal wave signal by combining notch filtering, performing wellhead consistency static correction, and recording the first arrival time of the longitudinal wave direct wave corresponding to each depth excitation point; Defining the space coordinates of the excitation point and the receiving point with the same depth, wherein the coordinates of the excitation point are as follows The coordinates of the receiving points are In the same depth excitation-reception mode, thus Calculating the horizontal distance between two points by Pythagorean theorem ; Based on the direct wave horizontal propagation mode in the horizontal lamellar medium, calculating the formula according to the transverse speed Wherein For the first arrival time of longitudinal waves excited and received at the same depth, solving the transverse speed at the corresponding depth, taking arithmetic average value of calculation results of a plurality of excitation-receiving pairs at the same depth segment, and eliminating the transverse speed And vertical velocity And (3) the ratio of the two values exceeds an abnormal value in a preset range, and filling the missing value by adopting a linear interpolation method to obtain the transverse speed of the VTI anisotropic medium at each depth of the target exploration area.
10. The method for inverting the VTI anisotropic parameters based on the well-to-well earthquake and the VSP of claim 1, wherein each depth of the VTI anisotropic medium The specific acquisition method comprises the following steps: Wherein, the In order to be a transverse velocity, Which is indicative of the vertical velocity of the beam, Representing parameters of the VTI anisotropic medium.
11. The method for inverting the VTI anisotropic parameters based on the well earthquake and the VSP according to claim 1, wherein the initial vertical velocity model is based on the first arrival information of different excitation points of the well earthquake or the well earthquake, and is combined with the VTI anisotropic medium The value is obtained by a ray tracing forward modeling and inversion iteration method to obtain the VTI anisotropic medium The values include the following specific methods: Calculating the first arrival time of direct waves from excitation points with different depths to receiving points of adjacent wells by adopting a horizontal lamellar medium ray tracing method ; Calculating isotropic initial ray parameters according to the epicenter equation and the isotropic velocity model Determining an initial ray angle according to the isotropic initial ray parameters; Iteratively calculating a ray path according to a midjolt equation, and according to the first arrival time of the direct wave Initial ray angles of each layer And anisotropic velocity in each direction Is used for the relation of (a), obtaining initial anisotropic parameters A value; According to the initial ray angle and the anisotropic parameter Value sum Value, using weak anisotropic approximation formula to update anisotropic speed of each layer; forward modeling is performed when walking according to the first arrival time of the direct wave, so as to fit an actual first arrival curve, and initial anisotropic parameters are adjusted according to the actual first arrival curve Values.
12. The VTI anisotropic parameter inversion method based on well-to-well seismic and VSP of claim 11, wherein the epicenter distance equation is: Wherein, the Is a ray parameter; Representing seismic waves at the first The propagation isotropy speed of the layer is obtained through an initial isotropy speed model, and the isotropy speed model is constructed by extrapolation of an initial vertical speed model beside the well to an interwell area according to a horizontal lamellar medium hypothesis; Represent the first The thickness of the layer, the thickness is obtained through geological stratification data of the target area; Counting the number of layers of the medium by using geological stratification data to obtain the layering number of the target layer and the upper and lower surrounding rocks; The epicenter distance is represented as the distance from the epicenter to the ground observation point, and the epicenter is the projection position of the seismic source on the ground.
13. The VTI anisotropic parameter inversion method based on the well-to-well earthquake and the VSP of claim 12, wherein the determining the initial ray angle from the isotropic initial ray parameters comprises the specific steps of: determining an initial ray angle based on the acquired isotropic initial ray parameters, wherein the initial ray angle is determined based on the geometrical relationship of the ray parameters to the propagation angle Determining an initial ray angle 。
14. The VTI anisotropic parameter inversion method based on well-to-well earthquake and VSP of claim 13, wherein the updating the anisotropic velocity of each layer comprises the following specific steps: Wherein, the Representing updated seismic waves at the first Propagation isotropic velocity of the layer; The value of the modified anisotropic parameter is indicated, Representing an anisotropic parameter value; Represent the first An initial ray angle of the layer; Representing seismic waves at the first Propagation isotropic velocity of the layer.
15. The VTI anisotropic parameter inversion method based on an interwell seismic and a VSP of claim 11, wherein the forward modeling is performed when traveling according to the first arrival time of the direct wave, and further fitting the actual first arrival curve, comprises the following specific steps: According to the determination The anisotropic speed of each layer is updated by the value, then ray tracing is carried out again according to the updated speed, and the first arrival time of the direct wave is calculated And further performing curve fitting according to the obtained actual first arrival time to obtain an actual first arrival curve.
16. The method for inverting a VTI anisotropic parameter based on an inter-well seismic and VSP of claim 1, wherein the VTI anisotropic medium is utilized Value sum The value is interpolated and smoothed along the geological horizon to obtain the VTI anisotropic medium Fields and methods of use The field comprises the following specific methods: Acquiring seismic data in the well of the target exploration area comprises acquiring WALKAWAY VSP and 3D-VSP data reflecting propagation responses of seismic waves at different offset distances and different incidence angles, and further carrying out analysis and calculation on correlation of wave velocity characteristics and anisotropic parameters at different incidence angles according to WALKAWAY VSP and 3D-VSP data to obtain shallow-deep layer-by-layer anisotropic parameters Value sum Value, combining geologic layering information, anisotropic parameters for each layer Value sum Value edge layer interpolation smoothing, taking geological stratification as a constraint unit, and dispersing in layers based on observation point data of interwell earthquake and borehole earthquake Value sum Performing spatial interpolation on the values, and performing mean filtering on the interpolation result to form the VTI anisotropic medium Fields and methods of use A field.

Description

VTI anisotropic parameter inversion method based on well-to-well earthquake and VSP Technical Field The invention relates to the technical field of intelligent sensing systems, in particular to a VTI anisotropic parameter inversion method based on well-to-well earthquake and VSP. Background In the process of carrying out seismic data anisotropic migration, accurate estimation of VTI anisotropic parameters is a key factor influencing the processing accuracy, an inter-well seismic and in-well seismic observation system is used for estimating stratum anisotropic parameters, accurate transverse stratum velocity can be obtained through the direct wave first arrival time of inter-well seismic records, accurate vertical stratum velocity can be obtained through the direct wave first arrival time of zero-well source distance VSP records, and the influence of medium anisotropy on incident waves of different angles is reflected through the first arrival time of inter-well seismic variable depth records and variable migration distance VSP records. In the prior study, the horse is relaxed, the well-to-well seismic anisotropic medium seismic wave field and parameter analysis study [ D ]. Changan university 2012. Wave changes when different geological models in anisotropic media and anisotropic parameters change are analyzed in the literature, sun Jia, the well-to-well seismic anisotropic medium travel time tomography method study [ D ]. Changan university 2019. The well-to-well seismic anisotropic medium travel time tomography method is studied, but the above-mentioned research process is not fully combined with well-to-well seismic data to conduct anisotropic analysis, wherein the well-to-well seismic is supported by a stratum transverse velocity estimation method which is insufficient and effective, the accuracy of the anisotropic parameter calculation is limited, the true propagation rule of the sedimentary layer seismic waves cannot be accurately reflected, and the limitation of the observation system and conditions is caused in the process of calculating the anisotropic parameters because the well-to-well seismic is only focused on the local anisotropic parameters of the depth of a destination layer, so that the velocity model is not well-to-well anisotropic parameters are well matched, the imaging accuracy of the later imaging hypothesis is lower, and the accuracy of the sedimentary rock characteristic analysis is affected. Disclosure of Invention The invention provides a VTI anisotropic parameter inversion method based on well-to-well earthquake and VSP, which solves the problem of lower accuracy of sedimentary rock characteristic analysis caused by poor matching of a velocity model and an anisotropic parameter in the traditional VTI anisotropic research, and adopts the following technical scheme: the invention provides a VTI anisotropic parameter inversion method based on well-to-well earthquake and VSP, which comprises the following steps: acquiring first arrival information and speed information recorded by a zero well source distance VSP of a target exploration area, and establishing an initial vertical speed model beside a well; The method comprises the steps of separating first arrival information under the same depth to obtain a plurality of longitudinal wave signals, analyzing differences among modal components of the same number and differences of center frequencies of the modal components, which are obtained by decomposing the longitudinal wave signals, to obtain comprehensive deviation values of each serial number of each longitudinal wave signal under the same depth and deviation vectors of each longitudinal wave signal; solving and obtaining each depth of VTI anisotropic medium according to the vertical speed and the transverse speed of the VTI anisotropic medium A value; based on the initial vertical velocity model, according to the first arrival information of different excitation points of the well earthquake or the well earthquake, the VTI anisotropic medium is combined The value is obtained by a ray tracing forward modeling and inversion iteration method to obtain the VTI anisotropic mediumA value; utilizing VTI anisotropic media Value sumThe value is interpolated and smoothed along the geological horizon to obtain the VTI anisotropic mediumFields and methods of useThe field, and thus the VTI anisotropy. Optionally, the method for separating first arrival information under the same depth to obtain a plurality of longitudinal wave signals includes the following specific steps: Preprocessing the acquired original data of the well earthquake, and separating the interference of longitudinal waves and transverse waves through F-K filtering to obtain a plurality of longitudinal wave signals, wherein the longitudinal wave signals before separation are repeatedly excited for a plurality of times under the same depth excitation point and receiving point positions. Optionally, the method for obtaining the