A Calculation Method of Plane Wave Reflection Coefficient in Elastic Multilayer Media

Abstract

The invention discloses a method for calculating the plane wave reflection coefficient in an elastic multi-layer medium. The steps are as follows: (1) Assuming that the plane harmonic wave is incident from the medium n+1 to the target layer system, reflection will be generated in the n+1 medium The longitudinal wave and the transverse wave generate the transmitted longitudinal wave and transverse wave in the medium 1, and each layer of medium can be written in the form of scalar bit and vector bit; (2) determine the relationship between displacement, stress and displacement; (3) put step (1) The scalar bit and the vector bit in step (2) are obtained in the n+1th layer and the displacement and stress relational expressions of the first layer; (4) according to the n+1th layer obtained in (3) and The displacement and stress relational expressions of the first layer obtain the displacement and stress transfer matrix including the elastic coefficients of each layer, and solve it to obtain the reflection and transmission coefficients. The invention fully considers the effects of elastic layer multiple waves and converted wave thicknesses and frequencies on reflection coefficients, is suitable for thin-layer AVO analysis and simulation, and has high calculation efficiency.

Description

technical field [0001] The invention relates to a calculation method of plane wave reflection coefficient in an elastic multi-layer medium, belonging to the technical field of thin-layer AVO simulation. Background technique [0002] Simulated thin-layer AVO is divided into two categories, (1) time-domain convolution model, for a certain angle, the reflection coefficient is calculated for the time-domain sampling points one by one, and the wavelet and reflection coefficient are used to convolve to form the angle Corresponding to seismic traces, although this method is fast in calculation, simple in formula and easy to implement, it is difficult to reflect the thin layer effect and the simulation accuracy is low. (2) Using the integral solution finite difference method of the elastic wave equation to simulate the thin-layer wave field can simulate the thin-layer effect, but the calculation efficiency is low, which is greatly affected by the modeling, and it is difficult to be ...

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Problems solved by technology

[0002] Simulated thin-layer AVO is divided into two categories, (1) time-domain convolution model, for a certain angle, the reflection coefficient is calculated for the time-domain sampling points one by one, and the wavelet and reflection coefficient are used to convolve to form the angle Corresponding to seismic traces, although this method is fast in calculation, simple in formula and easy to implement, it is difficult to reflect the thin layer effect and the simulation accuracy is low

(2) Using the integral solution finite difference method of the elastic wave equation to simulate the thin-layer wave field can simulate the thin-layer effect, but the calculation efficiency is low, and it is greatly affected by the modeling, and it is difficult to be practical in industrial production

[0003] The conventional Zoeppritz equation calculates the reflection coefficient based on a single interface and has no thickness variable. Although it can also calculate AVO characteristics, it cannot directly analyze the effect of thickness on each frequency component.

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