Method for establishing simulated earth surface depth domain velocity model

Abstract

The invention discloses a method for establishing a simulated earth surface depth domain velocity model. The method comprises the following steps: smoothing a tomography static correction value or a high-range static correction value of a seismic pre-stack gather, extracting a low-frequency component and a high-frequency component, and reflecting the low-frequency component for the pre-stack gather; according to the full-offset first arrival of the work area, obtaining a shallow velocity model through a chromatography inversion iteration method, and carrying out smoothing processing on the shallow velocity model; smoothing the real ground surface of the work area to obtain a simulated ground surface, and replacing the real ground surface of the shallow velocity model with the simulated ground surface; correcting the seismic pre-stack gather from the floating reference surface to the simulated ground surface, the correction time being obtained through a two-side depth difference and a replacement speed; and selecting a splicing surface, splicing the shallow velocity model and the middle-deep velocity model, smoothing the splicing surface, obtaining a simulated earth surface depth domain velocity model, carrying out chromatography inversion updating on the middle-deep velocity, and improving the velocity precision is improved.

Description

technical field [0001] The invention relates to the technical field of pre-stack depth migration imaging in the process of oil exploration reflected wave seismic data processing, in particular to a method for establishing a simulated surface depth domain velocity model. Background technique [0002] At present, domestic shale gas exploration and development are in the ascendant, and shale gas resources have great potential. However, the thickness of high-quality shale reservoirs is relatively thin, and the development process relies on horizontal well technology, which requires high depth accuracy. Prestack depth migration technology is an ideal technology to solve the problem of seismic data imaging in areas with complex structures and severe lateral velocity changes. Depth domain imaging results of seismic data can play an important supporting role in high-precision exploration and development of shale gas (fine structure interpretation, precise fault location, oil and ga...

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to overcome the problem in the prior art that the low accuracy of the velocity model affects the final imaging accuracy, and to provide a simulation of the establishment of a velocity model in the depth domain of the surface for the undulating surface areas with low signal-to-noise ratio and inaccurate velocity method

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