Pre-stack seismic wide angle retrieval method

Abstract

The invention provides a pre-stack seismic wide angle retrieval method. The pre-stack seismic wide angle retrieval method comprises the following steps: inputting at least three angle stacking seismic data volumes, at least three corresponding wavelets, longitudinal wave speeds, a transverse wave speed and an initial density model; creating a pre-stack retrieval objective function; expanding the taylor series of the pre-stack retrieval objective function; deriving parameters through the matrix form of a Zoeppritz equation to obtain the partial derivatives of a reflection coefficient to the longitudinal wave speeds, the transverse wave speed and the density; according to actual data, decreasing computing amount through matrix partitioning; computing the perturbation of a retrieval parameter; and controlling the convergence of the retrieval objective function through the computed perturbation of the retrieval parameter to obtain a pre-stack retrieval parameter. The pre-stack seismic wide angle retrieval method solves the problems that the approximate conditions of the validity of the Zoeppritz equation are difficult to met and the error is great in the prior art, and has the advantages of wide application range, small error and high retrieval precision.

Description

technical field [0001] The invention relates to geophysical exploration technology, in particular to a pre-stack seismic wide-angle inversion method. Background technique [0002] Pre-stack seismic inversion can provide a variety of effective formation parameter data results, and is an important technique for complex reservoir description. [0003] The Zoeppritz equation describes the relationship between reflection and transmission of waves propagating in the upper and lower media, and is the theoretical basis of pre-stack seismic inversion. [0004] Due to the large amount of calculation to obtain the exact solution of the Zoeppritz equation, and the reason that the inversion coefficient matrix is ​​"ill-conditioned", problems such as unstable calculation and non-convergence of the objective function will be encountered in the actual application process. [0005] The current prestack inversion methods are almost all based on the approximate formula of the Zoeppritz equati...

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Problems solved by technology

[0005] The current prestack inversion methods are almost all based on the approximate formula of the Zoeppritz equation, which are only suitable for weakly reflective medium interfaces and reflection problems at medium and small angles (or small offsets), but the actual situation is often difficult to satisfy the approximation that the formula holds condition

[0006] In the range of small angles, as long as the formation parameters of the two layers of media change slightly, this approximation will produce a certain calculation error in the iterative calculation process, and the Zoeppritz equation approximation has a relatively large error when calculated at a large angle, which is difficult to improve. The pre-stack inversion accuracy of large-angle seismic data cannot meet the needs of high-precision research in exploration and development

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