Ghost common shot point (GCSP) ray tracing dynamic and static correction method

Abstract

The invention discloses a ghost common shot point (GCSP) ray tracing dynamic and static correction method, which is a non-surface consistency static correction method for solving the problem of coalfield seismic exploration static correction of a complex near-surface structure. According to the method, the deviation of rays in a near-surface layer is considered; a static correction amount is dynamic, is changed along with reflection time, offset distance and azimuth, and is in accordance with a wave field propagation law; and the influence on a reflected wave caused by near-surface abnormities can be eliminated effectively. The method comprises the following steps of: first, converting common midpoint (CMP) gathers into GCSP trace gathers, performing forward modeling by adopting a critical path method based on the GCSP trace gathers, and tracking the path and the travel time of the rays in the near-surface layer; then, correcting seismic data to the wave front surface at the time when a seismic wave is propagated to an intermediate reference plane; and finally, replacing the speed of the near-surface layer by the speed of the high-speed layer, and correcting the seismic data to a final reference plane. By the method, zero-offset distance conversion of non-zero offset CMP gathers can be further realized; and the CMP gathers can be stacked directly to form a stacked section without performing speed analysis and dynamic correction.

Description

technical field [0001] The invention relates to a geophysical exploration method, which is a non-surface consistent static correction method for complex near-surface coal field seismic exploration. Background technique [0002] The surface-consistent static correction assumes that the ray propagates vertically in the near-surface layer, and performs a simple static time-shift on the seismic trace. At this time, the static correction is consistent with the surface and only related to the location of the excitation point and the receiving point. In the complex area near the surface, the surface undulates violently, the thickness of the low-velocity-decelerating layer varies erratically, and the lateral velocity changes sharply. At this time, the assumption of surface consistency cannot be satisfied. The static correction is dynamic and varies with reflection time, offset and azimuth angle. The static time shift does not conform to the law of wave field propagation, causing sec...

AI Technical Summary

Problems solved by technology

[0003] Aiming at the non-surface consistency of the static correction problem in complex near-surface coalfield seismic exploration, the present invention considers the deflection of rays, corrects the seismic data according to the actual propagation path of rays in the near-surface layer, and proposes a virtual common shot point (Ghost Common- Source Point, GCSP) ray tracing dynamic static correction method

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