A method and system for identifying abnormal first arrivals based on offset range

Abstract

The present invention provides a method and system for identifying abnormal first arrivals based on the offset range domain. The method includes: collecting seismic data; extracting a plurality of offset pairs from the seismic data, and the offset pairs include The first arrival, the midpoint coordinates, the excitation point and the receiving point; apply the basic static correction to the first arrivals of the extracted multiple shot detection pairs to obtain the first time of the shot detection pair; obtain a preset threshold; according to The first time, the extracted multiple shot detection pairs, and the threshold value identify an abnormal first arrival from the first arrivals of the extracted multiple shot detection pairs. The present invention utilizes the principle that the first arrival time of the applied basic static correction is a smooth plane in the common offset gather in a central point plane, and avoids the deficiency of polynomial fitting for the first arrival in the common excitation point gather. , suitable for two-dimensional exploration and three-dimensional exploration.

Description

technical field [0001] The present invention relates to the technical field of geophysical exploration, in particular to static correction processing technology in seismic exploration, and specifically to a method and system for identifying anomaly first arrivals based on offset domains. Background technique [0002] The static correction processing technology in seismic exploration is mainly used to solve the problem that the change of seismic wave travel time in the near-surface medium affects the reflection wave stacking imaging. After an earthquake occurs, the first wave received by the seismic observation point is called the first arrival wave. Due to the different propagation speeds of various seismic waves, the time of propagation to the observation point also has a sequence. Using the refraction static correction method or tomographic static correction method of the first arrival wave can invert a relatively accurate near-surface model to solve the static correction...

AI Technical Summary

Problems solved by technology

[0004] In the process of curve fitting by the above method, due to the presence of anomalous first arrivals, the shape of the fitted curve does not conform to the propagation law of first arrivals, so that the normal first arrivals are deleted, and sometimes the abnormal first arrivals are retained.

In order to avoid the situation that the first arrivals of the same offset come from different layers or the refraction interface is inclined, it is required to distinguish the left and right branches of the first arrivals during the calculation process, and perform polynomial fitting on the first arrivals of each branch, and the power of the polynomial is due to abnormal The existence of the first arrival, it is difficult to choose in actual operation

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