Diffracted wave field separation method based on Kirchhoff integral method

Abstract

The invention provides a diffracted wave field separation method based on a Kirchhoff integral method. In seismic exploration, subsurface information can be inferred through responses of seismic waves to subsurface media; when a subsurface medium catastrophe happens, diffracted waves usually are response to the subsurface medium catastrophe. Main oil gas storage spaces in carbonate rock regions (such as Tarim and Sichuan) are secondary corroded holes and cracks, the sizes of the holes and the cracks are smaller than the wavelength of the seismic waves; the seismic response of the holes and the cracks is mainly diffraction, therefore the research on the diffracted waves has significant theoretical and practical meanings. However, in common deviation, the diffracted waves are converged to be one point on a profile and are submerged in a plurality of events and cannot be recognized. In a common reflection point (CRP) trace gather, since diffraction points and reflection points are the flattening of the events, the diffraction points cannot be recognized in the trace gather. Therefore, the invention provides a method for outputting an inclined angle trace gather through Kirchhoff deviation and hole diffracted waves and interface reflection waves can be rapidly and efficiently separated through obvious difference between the reflection waves and the diffracted waves in the inclined angle trace gather.

Description

technical field [0001] The invention relates to the technical field of oil and gas field exploration, belongs to the category of seismic signal analysis, and specifically relates to a fracture-cavity imaging technology based on the Kirchhoff integral method. Background technique [0002] For complex media, such as the Tarim Basin, oil and gas are stored in the ancient Cambrian and Ordovician carbonate formations. The buried depth of these formations is below 5,000 meters, and the primary pores have been compacted and filled. Today The reservoir space is the secondary pores formed by dissolution, fracture and other effects. The distribution of these pores is not controlled by sedimentary facies, and the scale of distribution is extremely uneven. Therefore, the only way to find these cave-fracture reservoirs is through seismic means. [0003] The size of the dissolved pores is often much smaller than the wavelength of the seismic wave, which can be considered as the abrupt c...

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Problems solved by technology

But in this way, the sudden change information of the underground medium will be lost, and the resolution of seismic exploration will also decrease.

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