Microseism interference positioning method based on instantaneous phase cross-correlation weighting

Abstract

The invention discloses a microseism interference positioning method based on instantaneous phase cross-correlation weighting, and the method comprises the steps: obtaining N seismic waves of a microseism event through N detectors, and carrying out the component of the seismic waves; combining the detectors one by one to form non-repeated detector pairs; calculating a time domain cross-correlationtrace gather and an instantaneous phase cross-correlation trace gather in each component; weighting each time domain cross-correlation waveform in each component and the corresponding instantaneous phase cross-correlation waveform to obtain a corresponding weighted cross-correlation gather; in each component, performing offset superposition on each weighted cross-correlation waveform by utilizinga theoretical direct wave travel time difference to obtain an interference imaging profile; and multiplying the interference imaging profiles in the plurality of components to obtain a comprehensiveinterference imaging profile to determine the position of the microseism event. By means of the method, the problem of micro-seismic waveform polarity change caused by a complex seismic source mechanism is solved, and meanwhile the influence of high-amplitude noise on time domain cross-correlation and subsequent superposition calculation is reduced.

Description

technical field [0001] The invention relates to the technical field of microseismic monitoring and positioning, in particular to a microseismic interference positioning method based on instantaneous phase cross-correlation weighting. Background technique [0002] As the world's energy becomes increasingly severe, the focus of oil and gas exploration has gradually shifted from conventional oil and gas fields to unconventional oil and gas fields. Unconventional oil and gas fields are characterized by tightness and low permeability, and hydraulic fracturing technology is mainly used for exploration and development. Microseismic monitoring technology is one of the most effective methods for real-time monitoring of hydraulic fracturing effects. The basic process is that when the fracturing operation is carried out in the reservoir through the fracturing well, the ground stress changes to form fractures, accompanied by weak acoustic emission or seismic wave signals, and these sei...

AI Technical Summary

Problems solved by technology

Because this type of positioning method does not consider the influence of the complex focal mechanism on the amplitude and phase of the waveform, it may not be possible to obtain an accurate source location

At the same time, this kind of method needs to search the time of the earthquake and the location of the source at the same time, which will limit the accuracy and efficiency of positioning to a certain extent.

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