Suppressing method suitable for loess plateau out-of-line ground roll wave

Abstract

The invention provides a suppressing method suitable for loess plateau out-of-line ground roll waves. The suppressing method comprises the steps of: 1) performing offset geometric transformation on X to obtain X'; 2) determining an apparent velocity range of ground roll waves; 3) determining a ground roll wave frequency band range on the X'; 4) acquiring G' via G; 5) seeking an orthogonal projection vector matrix of the single shot seismic record G', and performing K-L transformation on the G'; 6) reconstructing a ground roll wave model G'' by utilizing the K-L transformation; 7) acquiring a ground roll wave final model G''' via the G''; acquiring a single shot seismic record X'' after suppressing the ground roll waves; 9) repeating the steps from step 3) to step 8) to obtain a single shot seismic record X''' after suppressing the ground roll waves finally; and 10) performing offset geometric inverse transformation on the single shot seismic record X''' to obtain X'''', and finishing the suppression of the ground roll waves. The suppressing method adopts frequency division processing, automatically adjusts and tracks change features of the ground roll waves under different geological conditions, so as to achieve the wave field separation and de-noising, can increase the continuity of a mesozoic tight oil target layer, and has amplitude fidelity characteristics.

Description

technical field [0001] The invention belongs to the technical field of geophysical exploration, and in particular relates to a ground-roll suppressing method suitable for non-longitudinal survey lines in loess tablelands, and is a fidelity denoising method for improving the signal-to-noise ratio of oil and gas exploration data. Background technique [0002] Waves are the propagation of disturbances along space. There are two kinds of body waves, longitudinal wave and transverse wave, which propagate in the infinite solid medium. They propagate independently in the medium. When encountering an elastic interface, reflection, refraction, and transmission will occur. Under certain conditions, the body waves will interfere with each other and superimpose. , Conversion variation. Then the synthesis of particle vibration will be formed by the combination of different types of waves. Near the surface, Rayleigh waves (also known as ground roll waves) are synthesized by the SV compo...

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Problems solved by technology

[0009] However, there are some problems in practical application. The non-longitudinal line acquisition method implemented for the Mesozoic tight oil target layer in the huge thick loess plateau of the Ordos Basin can suppress the near shot point by increasing the distance between the excitation point line and the receiving point line. Ground roll avoids the secondary interference propagating along the bottom of the dry and thick loess layer, further improving the quality of seismic data, but there are still strong ground roll waves in the single shot record, and the non-longitudinal distance of 600 meters makes the ground The roll wave presents a hyperbolic noise shape, which limits the applicable conditions of the K-L transform to suppress the ground roll wave

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