A Method for Separation of P- and S-waves without Separation Artifacts

Abstract

The invention relates to a longitudinal and transverse wave separation method without separation artifacts, and belongs to the technical field of seismic wave information processing. The invention mainly overcomes the defects in the prior art, and provides a longitudinal and transverse wave separation method without separation artifacts, which comprises the following specific steps: carrying out forward modeling by using a first-order speed-strain equation, and carrying out longitudinal and transverse wave decoupling based on the formula and a longitudinal and transverse wave decoupling equation to obtain a separated longitudinal and transverse wave speed field. According to the invention, the phase and the amplitude of the separation result are not changed, and the separation result has no separation artifact; accurate longitudinal and transverse wave separation provides support for forward modeling and understanding of seismic wave propagation, elastic waves are relatively complex due to the fact that the elastic waves include longitudinal and transverse waves, and coupling of the longitudinal and transverse waves causes inconvenience to understanding of propagation rules of a wave field during forward modeling of the wave field of the elastic waves. Accurate longitudinal and transverse wave separation provides support for elastic wave imaging, surface data longitudinal and transverse wave separation, microseism positioning and the like depending on elastic wave field continuation algorithms.

Description

technical field [0001] The invention relates to a method for separating longitudinal and transverse waves without separation artifacts, and belongs to the technical field of seismic wave information processing. Background technique [0002] Previous exploration often assumed that the earth medium was an acoustic wave model, and single-component geophones were used to collect seismic signals. However, as simple oil and gas reservoirs were discovered one after another, we had to look for more complex oil and gas reservoirs. Therefore, many work areas began to use multi-component data acquisition. The previous model based on the acoustic wave assumption is no longer applicable in some areas, and the earth medium must be regarded as an elastic medium. Therefore, our geophones on land have also changed from single-component to three-component, and at sea, hydrophones for monitoring water pressure have changed to four-component submarine cables (Yu et al., 2013, Ikeda, 1986). For...

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Problems solved by technology

At present, there are some methods for the separation of P- and S-waves, such as the separation of P- and S-waves based on the curl-divergence, and the decoupling of P- and S-waves based on the first-order velocity-stress equation, but these methods have the following shortcomings; The physical meaning and vector characteristics obtained by the method of separating the longitudinal and transverse waves are inconsistent with the original wave field; the method of decoupling the longitudinal and transverse waves based on the first-order velocity-stress equation has separation artifacts

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