A Compensation Method for Near-Surface Absorption of Vibroseis in Time-Frequency Domain

Abstract

The invention provides a near-surface absorption compensation method for a time-frequency domain controllable seismic source for controllable seismic source data processing during petroleum seismic exploration. The method comprises the following steps: performing seismic wave data decomposition in the time-frequency domain, and performing common-shot-gather frequency domain median filtering on fractional frequency data of each frequency band, so as to generate a shot-gather model trace; adopting a high-order exponential function with e as the base number; getting statistics absorption reduction function of each shot at all frequency bands by utilizing shot-gather model trace data fitting; decomposing scanning signals into different frequency bands in the time-frequency domain; applying a least square algorithm to a vibroseis analog wavelet of containing the near-surface absorption of each shot to obtain a deconvolution factor; applying the deconvolution factor to corresponding shot-gather data; processing all the shot data to realize the near-surface absorption compensation method for the time-frequency domain controllable seismic source. Due to the adoption of the method, processing quality and imaging precision of seismic data of the controllable seismic source can be effectively improved, the provided well location is relatively accurate, and drilling success ratio is obviously improved.

Description

technical field [0001] The invention relates to the field of seismic data processing acquired by a vibrator in petroleum seismic exploration and oilfield development seismic, in particular to a time-frequency domain vibrator near-surface absorption compensation method. Background technique [0002] Vibroseis is an artificial source device that uses mechanical vibration to excite seismic waves. It has the characteristics of artificially controlling the scanning time and frequency of vibration signals, and is more flexible and efficient than explosive sources. Since the early 1970s when the vibroseis was used in seismic exploration, it has been fully affirmed and widely used for its advantages of flexibility, economy, and environmental protection. However, there is often a special kind of harmonic interference in the data collected by the vibrator, which is also called resonance interference, which makes the initial arrival of the vibrator data unclear and affects the pickup o...

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Problems solved by technology

[0004] However, for the vibroseis data actually affected by near-surface absorption, the relevant wavelet of the vibrator is no longer zero phase, and there is a large mixed phase problem in the wavelet phase conversion using the above pure phase conversion factor. Its effect increases as absorption near the surface increases

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