Direct prestack time migration method for three-dimensional seismic data acquired from irregular surfaces

Abstract

The invention discloses a direct prestack time migration method for three-dimensional seismic data acquired from irregular surfaces, and the method is applied to the processing on reflected seismic information in seismic exploration. The method can be used for directly carrying out three-dimensional seismic data migration imaging (at different elevations) on shot points and geophone points acquired from irregular surfaces without statically correcting a processing process. In the method, no vertical emergence and incidence assumption is performed on nearsurface seismic wave propagation, therefore, the method can adapt to the situations which have no obvious low velocity region and velocity-reduction region such as high-velocity rock outcropping, and the like. In the method, the seismic wave propagation in near surfaces or stratums is described by using two equivalent speed parameters; and the two equivalent speed parameters can be determined according to the straightness of lineups inmigrated gathers, thereby avoiding the difficulties in near-surface velocity modeling. By using the method disclosed by the invention, the gathers subjected to migration can be subjected to remainingstatic correction, thereby effectively compensating the inherent errors existing in a land acquisition technology. The method has important application value in oil, gas and mineral resource exploration in complex surface areas.

Description

technical field [0001] The invention belongs to the technical field of reflection seismic data processing in seismic exploration, relates to the category of pre-stack migration imaging technology in the process of seismic data processing, and is a pre-stack time without static correction for three-dimensional seismic data collected on undulating surfaces offset method. Background technique [0002] When seismic exploration is carried out in areas with complex surface conditions, the acquisition of seismic data is carried out on the undulating surface, and generally the shot point and the receiver point are not on the same elevation; while the current pre-stack time migration method uses dual The square root equation is used to obtain the travel time of seismic waves, which requires that the shot point and the receiver point are on the same horizontal plane. There are two methods to solve this problem. One is to apply static correction technology, that is, apply static corre...

AI Technical Summary

Problems solved by technology

However, there are two problems with this method: one is that a more accurate near-surface velocity model is required, and because the signal-to-noise ratio of seismic data collected on undulating surfaces is generally low, it is a very difficult task to obtain an accurate near-surface velocity; The "static correction" method of surface reconstruction leads to a sharp increase in the number of seismic channels of the reconstructed seismic data, which increases the calculation amount of subsequent pre-stack migration processing

However, there is no effective method

Images