Picking method of three-dimensional VSP data first-motion wave

Abstract

The invention relates to a high-precision picking method of three-dimensional VSP data first-motion wave in seismic exploration data processing, comprising the following steps of: initially picking the first-motion wave to form a relational table of offset and first-motion time of observation point depth, obtaining a pilot first-motion of the path by cubic spline interpolation, re-sampling module path data by a cubic spline algorithm according to a new sampling rate, calculating product of neighboring amplitude difference of each sampling point of the module path, determining peaks with ratio more than alpha, and determining a first peak value, calculating a ratio of B to the data before B by a scale factor less than 1, determining a sampling point of which ratio is less than beta and distance from B is nearest, and picking the first-motion wave at corresponding time. The method of the invention improves accuracy and noise immunity, improves picking precision and efficiency and ensures the precision and the reliability of the first-motion wave picking in each path.

Description

Technical field [0001] The invention relates to seismic exploration data processing technology, and is a method for picking up first arrival waves of three-dimensional VSP data. Background technique [0002] In seismic exploration, the earliest arrival time of the wave field is the first arrival time, and in VSP exploration it is the arrival time of the downward longitudinal wave. The accurate picking of this time is crucial for the use of first arrivals to obtain velocity and anisotropy parameters and wave field separation. important. [0003] At present, there are many methods for picking up seismic waves. The first picking generally uses energy ratio method, fractal dimension method, neural network method, and cross-correlation method. The energy ratio method uses the difference in seismic energy characteristics before and after the first arrival to pick up. First, select the appropriate time window length according to the actual situation, and divide the seismic trace into man...

AI Technical Summary

Problems solved by technology

The energy ratio method is simple to implement, but its picking accuracy is difficult to meet the requirements of VSP data processing

[0004] VSP data tends to have the strongest downgoing wave energy, and the first arrival is easier to identify and pick up. At the same time, the accuracy of the pick-up is higher (less than the sampling rate). The existing first-arrival pick-up technology does not consider the characteristics of VSP data, and it is difficult to automatically pick up the accuracy of VSP data. requirements

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