Method and device for determining fracture strike

Abstract

The invention provides a method and a device for determining fracture strike. The method comprises the steps of acquiring three-component seismic data comprising two-horizontal-component data and vertical-component data from multiwave seismic measurement data of the fracture strike; performing polarization analysis on the two-horizontal-component data for determining polarizing angles and polarizing angle variance; determining a feature vector azimuth angle corresponding to the maximum eigenvalue of a covariance matrix and feature vector azimuth angle variance; determining a travel time-difference azimuth angle of the vertical-component data and azimuth angle variance; performing acceleration analysis and ellipse fitting on the vertical-component data for determining an azimuth angle of an ellipse long shaft and fitting variance; performing data fusion on the polarizing angles, the feature vector azimuth angle corresponding to the maximum eigenvalue, the travel time-difference azimuth angle and the azimuth angle of the ellipse long shaft for determining a fracture azimuth angle. The method and the device have the advantages that the uncertainty of a seismic fracture measurement result is reduced, and the stability and the precision of the measurement result are improved.

Description

technical field [0001] The invention relates to the technical field of seismic exploration, in particular to a method and device for determining the orientation of cracks and cracks. Background technique [0002] Fissures and fractures are oil and gas storage spaces and percolation channels, as well as places where water and coalbed methane are enriched, stored, and migrated. Ascertaining the direction of underground fissures and cracks and improving the accuracy of seismic detection are very important for oil and gas prediction, increasing oil and gas production, and preventing gas explosions and roof / floor water inrush. [0003] The use of seismic waves to study the internal structure of rocks has made significant progress in theory, laboratory and field observations, especially seismic shear waves. The effect of directional fractures on shear waves has been documented for many years. When the medium model consists of a single vertically oriented fracture, the azimuthal ...

AI Technical Summary

Problems solved by technology

Due to the complex underground environment, incomplete seismic data collection and measurement errors, there are two defects in using only one wave type data or one method to measure formation cracks and cracks: one is weak anti-interference ability, and the other is that it cannot make full use of multi-component The longitudinal and shear wave data provided by the data are redundant and the crack information is poor, and the measurement results are poor in stability and low in accuracy

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