Seismic wavelet attenuation spectrum-based oil and gas detecting method and device

Abstract

The embodiment of the invention provides a seismic wavelet attenuation spectrum-based oil and gas detecting method and device. The method comprises the following steps of: carrying out noise removal processing on seismic data by adopting an independent component analyzing method; carrying out top and bottom seismic layer tracing on a target layer on the seismic data obtained after noise removal processing; arranging upper and lower two time windows along the top and bottom of the target layer; carrying out frequency spectrum analysis on the seismic data in the upper and lower two time windows to obtain frequency spectrum distribution; carrying out complex cepstrum analysis on the frequency spectrum distribution to obtain a complex cepstrum of a seismic data amplitude spectrum; separating a complex cepstrum of a seismic wavelet amplitude spectrum from the complex cepstrum of the seismic data amplitude spectrum according to a preset low-pass time window; carrying out inverse transformation on the complex cepstrum of the seismic wavelet amplitude spectrum to obtain a seismic wavelet spectrum in the upper and lower two time windows; carrying out difference value calculation on the seismic wavelet spectrum to obtain a seismic wavelet attenuation spectrum; and detecting the oil and gas content of the stratum by analyzing the seismic wavelet attenuation spectrum. The invention can realize the aim of accurately and sensitively recognizing oil and gas.

Description

technical field [0001] The invention relates to the field of oil and gas detection in petroleum geophysical exploration, in particular to an oil and gas detection method and device based on seismic wavelet attenuation spectrum. Background technique [0002] Current research and practical applications show that when the pores in geological bodies are filled with oil and gas, seismic reflection absorption increases, seismic high-frequency energy absorption and attenuation intensify, and the absorption coefficient of oil-gas-bearing formations can be higher than that of oil-gas-free formations of the same lithology by one or even several orders of magnitude. Based on the above principles, Mitchell et al. (Mitchell J T, Derzhi N, Lichma E. Energy absorption analysis: A case study. Expanded Abstracts of 66th SEG Mtg, 1996) proposed an analysis method for calculating the energy attenuation of seismic signals (that is, EAA technology) , to carry out oil and gas detection of geolog...

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Problems solved by technology

[0004] 1. The seismic signal is composed of wavelet and reflection coefficient convolution, plus noise. Direct spectral analysis of seismic traces will be seriously affected by seismic noise and reflection coefficient, resulting in inaccurate estimation of seismic signal spectrum and large errors ;

[0005] 2. Using the Fourier transform method to calculate the signal spectrum requires a larger time window, but for smaller geological bodies, an excessively large time window will lead to large errors in the calculation results;

[0006] 3. Using a series of single-time windows to analyze the high-frequency attenuation of seismic signals, resulting in weak contrast and intuition for oil and gas identification

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