Method for estimating stratum equivalent quality factor based on synchronous extrusion wavelet transform

Abstract

The invention discloses a method for estimating a stratum equivalent quality factor based on synchronous extrusion wavelet transform, and the method is a quality factor extraction method based on a Qcompensation principle. By using synchronous extrusion wavelet transform with extremely high time-frequency resolution and energy aggregation to transform seismic data of adjacent horizons (post-stackseismic data) or adjacent seismic records (vertical seismic sections) to a time-frequency domain first, then inverse Q filtering is carried out in a preset certain Q value range, and by calculating amean square error between a result after time-frequency domain Q compensation and a reference waveform frequency spectrum, a corresponding quality factor when the minimum mean square error is satisfied is searched as the best equivalent quality factor, thereby realizing optimal estimation of the quality factor. The method for estimating a stratum equivalent quality factor based on synchronous extrusion wavelet transform avoids the difficulty of frequency band selection for estimating a quality factor in a conventional spectral ratio method, the hypothesis that a seismic source frequency spectrum is a Gaussian spectrum in a centroid frequency method or the like does not exist, methods for quality factor estimation are expanded, and the estimation accuracy of the quality factor is improved.

Description

technical field [0001] The invention relates to the technical field of geophysical processing methods for oil and gas exploration, in particular to a method for estimating formation equivalent quality factors based on simultaneous squeeze wavelet transform. Background technique [0002] When the seismic wave propagates underground, it will be attenuated by the ground due to the inhomogeneity and anelasticity of the medium, which will lead to energy dissipation and velocity dispersion of high frequency components. This intrinsic dielectric property of attenuation that causes seismic wavelet distortion and amplitude attenuation is often expressed in terms of the quality factor Q. Q is sensitive to geological information such as lithology, porosity, saturation, and permeability, and Q estimation helps to improve the resolution of seismic data, enhance the fine details of formation characteristics, and be used as a direct hydrocarbon detection indicator, etc. [0003] Currently...

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Problems solved by technology

However, the spectral ratio method needs to select an appropriate frequency band range when calculating. The results of different frequency band ranges are very different, and at the same time it is very sensitive to noise; The peak frequency is easily affected by noise; the centroid frequency migration method is obtained under the assumption that the source spectrum is a Gaussian spectrum, but the sub-wave spectrum of the actual seismic data is usually non-Gaussian distribution, which will lead to calculation errors. It is also susceptible to noise when calculating the centroid frequency

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