Near-surface shear wave interval velocity model establishment method

Abstract

The invention discloses a near-surface shear wave interval velocity model establishment method. The method includes: A, sorting original shot point arrangement data according to a preset spatial sampling interval and source-receiver azimuth to acquire input data; B, analyzing the input data to acquire pure surface wave data; C, calculating surface wave dispersion data of a receiving point according to the pure surface wave data; D, correcting velocity parameters of the surface wave dispersion data of the receiving point from surface azimuth apparent velocity to true velocity according to a surface inclination angle of the source-receiver azimuth; E, subjecting surface wave dispersion data of each co-receiving point to true velocity curve statistics to form unique dispersion data of each co-receiving point; F, calculating a near-surface shear wave interval velocity model according to the unique dispersion data of each co-receiving point. The near-surface shear wave interval velocity model established according to the method is high in accuracy, three-dimensional seismic data surface waves can be effectively extracted while high-precision dispersion data are acquired, and converted shear wave correction accuracy in multiwave seismic data processing is improved.

Description

technical field [0001] The invention relates to the technical field of seismic data processing, in particular to a method for establishing a near-surface shear wave layer velocity model. Background technique [0002] In multi-wave seismic exploration, the shear-wave layer velocity model of the surface formation is directly related to converted wave imaging. Converted wave static correction is a difficult point in multi-wave imaging processing and one of the key links in converted wave data processing. [0003] In the static correction mechanism, the conversion wave static correction can be decomposed into the longitudinal wave static correction of the shot point and the shear wave static correction of the receiver point. The former can be solved by the conventional longitudinal wave static correction, and the latter is not affected by the pore fluid due to the propagation of the shear wave. The shear wave velocity is smaller than the longitudinal wave velocity, the thickness...

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Problems solved by technology

These converted wave static correction methods usually face the common problem that the converted shear wave surface velocity structure model cannot be finally determined, or the accuracy of the near-surface shear wave layer velocity model is low, which makes it difficult to obtain the first arrival of converted wave refraction, making the actual multi-wave seismic data Low effectiveness of converted shear wave statics in processing

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