Stratum oil-gas possibility prediction method with high time resolution

Abstract

The present invention provides a stratum oil-gas possibility prediction method with a high time resolution. By utilizing improved generalized S transform, a Gauss window function with a time window width in directly proportional change with frequency f is employed, the time window is narrow at a low frequency band, the high time resolution is obtained, and seismic wave low frequency absorption attenuation gradient is calculated; at the same time, by using generalized S transform, a Gauss window function with a time window width in inversely proportional change with the frequency f is employed, the time window is narrow at a high frequency band, the high time resolution is obtained, high frequency absorption attenuation gradient is calculated, and the low frequency absorption attenuation gradient and the high frequency absorption attenuation gradient are utilized comprehensively. The method has better time resolution at a low frequency band, an influence of high frequency interference is avoided, at the same time, the method has better time resolution at a high frequency band, an influence of low frequency interference is avoided, oil and gas prediction time resolution is raised greatly, an algorithm is simple, and computational efficiency is high.

Description

technical field [0001] The invention relates to a seismic exploration data processing technology, and is a method for predicting formation oil-gas content with high time resolution by using the frequency attribute of each sample point of the seismic data. Background technique [0002] Attenuation is the loss of the total energy of the seismic wave in the propagation of the underground medium, and it is an intrinsic property of the medium. After Domenic (1982) discovered the phenomenon of frequency attenuation caused by the increase of oil and gas saturation through experiments, Dilay and Eastwood (1995) analyzed the influence of oil and gas layers on the seismic signal spectrum. When the formation contains oil and gas, the energy of various frequency components of seismic waves will be significantly attenuated, and the high frequency components will attenuate faster, and this attenuation will be more obvious with the increase of oil and gas saturation. The energy attenuatio...

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Problems solved by technology

[0004] Due to the weak energy of high-frequency signals in seismic records, when there is strong high-frequency interference, the signal-to-noise ratio of high-frequency signals is low, and the calculation of the current absorption attenuation gradient only uses high-frequency signals, and only relies on high-frequency absorption The attenuation gradient cannot be a good indicator of oil and gas; at the same time, because the seismic records are mainly in the middle and low frequencies, the current time-frequency analysis method cannot achieve high time resolution in the low frequency band

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