Irregular-size space-variant grid tomography imaging statics correction method

Abstract

The invention discloses an irregular-size space-variant grid tomography imaging statics correction method in geophysical exploration. The method is characterized by: arranging different grid lengths along a horizontal direction during performing mesh generation; arranging novel nodes on four sides of the grid; performing equal layout on a same distance in a horizontal direction or a vertical direction; or carrying out the equal layout of the nodes on the each grid side in the horizontal direction or the vertical direction; initializing a model speed and performing ray path forward modeling; calculating a difference value between actual picked first break time and ray travelling time and the speed of an inversion model; completing imaging statics correction till inversion speed field is stable. By using the method of the invention, a near surface characteristic of an actual stratum can be better described; propagation rules of a first break wave on the near surface can be better reflected; forward and inversion precision of the speed model can be raised and a statics correction effect can be raised too.

Description

technical field [0001] The invention relates to a geophysical exploration method, which is a static correction method for space-variable grid tomographic imaging with irregular dimensions. Background technique [0002] Static correction processing in seismic exploration is mainly to solve the problem that the travel time change of seismic waves in the near-surface medium affects the reflection wave stacking imaging problem. The first arrival wave reflects the change of the near-surface strata, and using the first arrival wave to obtain the static correction value has become the main technical means of static correction. Tomographic forward and inversion methods can be used to establish relatively accurate near-surface models that can reflect vertical and horizontal velocity changes. In recent years, tomographic methods have been widely used in production and have achieved good results in many complex areas. [0003] Conventional tomographic methods currently used in static ...

AI Technical Summary

Problems solved by technology

This condition limits the authenticity and rationality of the tomographic inversion model

Especially when there are undulations on the interface between the surface and the subsurface or pinch-outs in the strata, the equal-sized regular grid cannot accurately describe the boundary position of the geological body or the velocity body, and the boundary of the geological body or the velocity body can only be stepped.

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