Retrieval method for chromatography speed based on undulating surface

Abstract

The invention provides a retrieval method for a chromatography speed based on an undulating surface. The retrieval method comprises the following steps of: performing Gaussian beam shifting imaging based on the undulating surface on an initial speed model, extracting an angle region co-imaging point channel set and judging the correctness of an initial speed; taking a plurality of points from an in-phase axis of an angle channel set, fitting the in-phase axis of the angle channel set according to a shifting depth formula of the in-phase axis of the angle channel set, calculating a residual depth difference, and converting the residual depth difference into a traveling residual error according to a quantitative relation between the residual depth difference of an imaging channel set and the traveling residual error; taking a position interface on a shifting profile, establishing a reference speed model required by ray tracing forward modeling, and improving a constant-speed gradient method to obtain a sensitivity matrix suitable for the undulating surface; on the basis of considering the retrieval precision and calculation efficiency, introducing a regularizing factor and performing chromatography retrieval according to an LSQR method to obtain speed updating volume and updating the speed model; and applying the speed model obtained after updating to pre-stack depth migration and extracting the angle region co-imaging point channel set.

Description

technical field [0001] The invention belongs to the field of seismic data processing, and is an accurate velocity inversion and modeling method suitable for complex surface conditions and complex underground structures in the piedmont zone. Background technique [0002] Velocity is one of the core issues in seismic data processing, which runs through the whole process of seismic data. With the increasing difficulty of seismic exploration and the increasing complexity of oil and gas reservoirs, the requirements for imaging precision of seismic data are getting higher and higher. Prestack depth migration velocity analysis is the focus of research on seismic data processing methods, and it is one of the key technologies that affect seismic imaging results. For double-complex areas with undulating surfaces and complex subsurface structures, the conventional pre-stack migration velocity analysis method is to correct the undulating surface to a fixed datum or perform surface mode...

AI Technical Summary

Problems solved by technology

Velocity update equations (or depth residual equations) of commonly used methods are all derived under the assumption of small reflective interface dip and small offset. There are certain limitations in the velocity analysis of complex geological structures, which affects the velocity analysis. (Liu, 1995, 1997; Sava, 2003; Xia, et. al., 2006; Prucha, et. al.1999)

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