Search

CN-121995489-A - Optimal parameter calculation method, device and medium for synchronous extrusion transformation

CN121995489ACN 121995489 ACN121995489 ACN 121995489ACN-121995489-A

Abstract

The invention provides a method, a device and a medium for calculating optimal parameters of synchronous extrusion transformation, and belongs to the field of oil-gas geophysical exploration. The method comprises the steps of inputting seismic data, constructing an analysis time window and calculating optimal parameters based on a time-frequency focusing criterion. The method obtains the optimal variance and time window length through iterative optimization calculation based on the time-frequency focusing criterion, does not need manual experiments or experience, and improves the accuracy of signal analysis.

Inventors

  • WANG XIAOPIN
  • DONG QIANQIAN

Assignees

  • 中国石油化工股份有限公司
  • 中石化石油物探技术研究院有限公司

Dates

Publication Date
20260508
Application Date
20241105

Claims (10)

  1. 1. The method for calculating the optimal parameters of the synchronous extrusion transformation is characterized by comprising the following steps of: Inputting seismic data; Constructing an analysis time window; and calculating optimal parameters based on the time-frequency focusing criteria.
  2. 2. The method of claim 1, wherein the constructing the analysis time window comprises: Let the expression of the gaussian function be: Let the length of the analysis time window be h, then h=h+1-h% 2, where% is the remainder sign, The time sequence after discretization is t= [ -0.5:1/h:0.5], and the Gaussian window sequence after discretization is: Where σ 2 is the variance, t=n×Δt, Δt is the discrete sampling interval, Δt=1/h.
  3. 3. The method of claim 1, wherein the time-frequency focusing criteria is: wherein, the parameter alpha is 3, and p (t, f) is the synchronous extrusion transformation result of the analysis signal.
  4. 4. The method of claim 4, wherein the calculating the optimal parameters based on the time-frequency focusing criteria comprises: Step 301, setting the analysis signal length of the seismic data, setting the initial value of variance and the variance searching range, and setting the initial value of time window length and the searching range of time window length; Step 302, taking the initial value of variance as an input value, and obtaining a synchronous extrusion conversion result of an analysis signal in the search range of the analysis time window length, substituting the synchronous extrusion conversion result of the analysis signal into a formula (3) to calculate to obtain H α (p), and selecting the analysis time window length corresponding to the minimum H α (p), namely the optimal analysis time window length; Step 303, taking the optimal analysis time window length obtained in step 302 as an input value, obtaining a synchronous extrusion conversion result of an analysis signal in a variance searching range, substituting the synchronous extrusion conversion result of the analysis signal into a formula (3) to calculate to obtain H α (p), and selecting a variance corresponding to the minimum H α (p) as an optimal variance; step 304, taking the optimal variance obtained in step 322 as an input value, and repeating step 302 and step 303 until the set iteration number is reached.
  5. 5. The method of claim 4, wherein the variance value initial value is set to 0.3 and the variance search range is set to (0.1, 1).
  6. 6. The method of claim 4, wherein the initial value of the analysis window length is set to 1/5 of the analysis signal length of the seismic data; the search range of the analysis time window is set as (1,2N), and N is the number of sampling points of the seismic data.
  7. 7. An optimal parameter calculation device for synchronous extrusion transformation, comprising: an input unit for inputting seismic data; The time window construction unit is used for constructing an analysis time window; And the optimal parameter calculation unit is used for calculating optimal parameters based on the time-frequency focusing criteria.
  8. 8. The apparatus of claim 7, wherein the time-frequency focusing criteria is: wherein, the parameter alpha is 3, and p (t, f) is the synchronous extrusion transformation result of the analysis signal.
  9. 9. The apparatus according to claim 8, wherein the optimal parameter calculation unit specifically performs the following operations: Step 301, setting the analysis signal length of the seismic data, setting the initial value of variance and the variance searching range, and setting the initial value of time window length and the searching range of time window length; Step 302, taking the initial value of variance as an input value, and obtaining a synchronous extrusion conversion result of an analysis signal in the search range of the analysis time window length, substituting the synchronous extrusion conversion result of the analysis signal into a formula (3) to calculate to obtain H α (p), and selecting the analysis time window length corresponding to the minimum H α (p), namely the optimal analysis time window length; Step 303, taking the optimal analysis time window length obtained in step 302 as an input value, obtaining a synchronous extrusion conversion result of an analysis signal in a variance searching range, substituting the synchronous extrusion conversion result of the analysis signal into a formula (3) to calculate to obtain H α (p), and selecting a variance corresponding to the minimum H α (p) as an optimal variance; Step 304, repeating steps 302 and 303 with the optimal variance obtained in step 322 as an input value until the set number of iterations is reached.
  10. 10. A computer-readable storage medium storing at least one program executable by a computer, which when executed by the computer, causes the computer to perform the steps in the optimal parameter calculation method of synchronous extrusion transformation according to any one of claims 1-6.

Description

Optimal parameter calculation method, device and medium for synchronous extrusion transformation Technical Field The invention belongs to the field of oil and gas geophysical exploration, and particularly relates to a method, a device and a medium for calculating optimal parameters of synchronous extrusion transformation. Background Time-frequency analysis is a signal processing method for simultaneously studying the time-domain and frequency-domain characteristics of a signal, which can provide detailed information about how the signal varies in time and frequency. Common time-frequency analysis methods for seismic signals include 1) Short-time fourier transform (Short-Time Fourier Transform, STFT), which divides the signal into a series of Short-time windows and then fourier transforms each window to obtain frequency components of the signal in different time periods, 2) wavelet transform (Wavelet Transform), which uses wavelet functions as basic functions to have local properties in time and frequency domains and thus better describe time-frequency characteristics of non-stationary signals, 3) Wigner-Ville distribution (Wigner-Ville Distribution, WVD), which directly applies autocorrelation and cross-correlation functions of the signal to the time-frequency domain and provides high-resolution time-frequency information, and 4) Cohen distribution (Cohen's class distribution), which is an improvement and expansion of the WVD and which can improve cross-term problems in the signal by introducing different window functions and smoothing techniques. In recent years, a seismic signal analysis method with high time-frequency focusing, i.e. an extrusion transformation method, is increasingly widely applied, firstly, a basic window function, such as a hanning window, is selected, secondly, a local bandwidth (local bandwidth) corresponding to each frequency point is calculated according to frequency distribution of signals, a higher frequency corresponds to a smaller local bandwidth, a lower frequency corresponds to a larger local bandwidth, finally, fourier transformation is performed on each adjusted window to obtain time-frequency information, and then all results are combined into a time-frequency representation. The synchronous extrusion transformation can provide higher time resolution and frequency resolution and can better accommodate signals with larger frequency variations than STFT. However, compared with the conventional STFT, the synchronous extrusion transformation is large in calculation amount, so that the calculation complexity and the required time-frequency precision need to be balanced in practical application. There are two important parameters when analyzing seismic signals using the synchro-squeeze transformation, one is the choice of gaussian window function, the other is the analysis time window parameter, and specific experiments are needed to give the two parameters when analyzing the signals, but seismic data, especially prestack seismic data, are huge, each of which is impractical, it is common practice to choose any one of the seismic traces to do an experiment to give the optimal parameters, but such parameters are likely to be unsuitable for other seismic traces. It is therefore necessary to study a method for adaptive synchronous extrusion transformation optimal parameter selection. Disclosure of Invention The invention aims to solve the problems in the prior art and provide an optimal parameter calculation method, device and medium for synchronous extrusion transformation, which improve the accuracy of signal analysis. The invention is realized by the following technical scheme: in a first aspect of the present invention, there is provided a method for calculating optimal parameters for synchronous extrusion transformation, comprising: Inputting seismic data; Constructing an analysis time window; and calculating optimal parameters based on the time-frequency focusing criteria. The invention further improves that: the construction analysis time window comprises the following specific operations: Let the expression of the gaussian function be: Let the length of the analysis time window be h, then h=h+1-h% 2, where% is the remainder sign, The time sequence after discretization is t= [ -0.5:1/h:0.5], and the Gaussian window sequence after discretization is: Where σ 2 is the variance, t=n×Δt, Δt is the discrete sampling interval, Δt=1/h. The invention further improves that: The time-frequency focusing criterion is as follows: wherein, the parameter alpha is 3, and p (t, f) is the synchronous extrusion transformation result of the analysis signal. The invention further improves that: the time-frequency focusing criterion-based optimal parameter calculation comprises the following specific operations: Step 301, setting the analysis signal length of the seismic data, setting the initial value of variance and the variance searching range, and setting the initial value of time window length