A kinematic-based method for suppressing multiple reflection and refraction waves with two vertical sources

Abstract

The invention discloses a kinematics-based method for suppressing multiple reflection refraction waves with vertical dual seismic sources. The method is based on the propagation path of multiple reflection refraction waves, and deduces the time distance between multiple reflection refraction waves and target layer reflection waves when there is an excitation well depth. curve, on the basis of the curve, a vertical dual-source combined excitation method is proposed. Set a combined dual seismic source at different depths at the same position on the ground, control the vertical relative distance of the two seismic sources, and simultaneously excite, the two columns of seismic waves generated by the two seismic sources have time-lag interference and cancellation during propagation, so as to suppress multiple reflections The purpose of reducing the impact of reflected waves on the target layer. From the source of multiple reflection and refraction waves, it solves the problem of low resolution and signal-to-noise ratio of target layer reflection waves in seismic records caused by the development of low-velocity zones in seismic exploration work areas such as loess tablelands and sandy lands, and improves the overall seismic exploration The work efficiency is conducive to the fine interpretation of coal and coalbed methane reservoirs.

Description

technical field [0001] The invention relates to a kinematics-based method for suppressing multiple reflection and refraction waves with vertical double seismic sources, and belongs to the technical field of oil and gas seismic exploration. Background technique [0002] China is the country with the widest loess distribution and the largest thickness in the world. Under the loess cover, there are abundant energy resources, mainly coal, coal bed methane, and oil and natural gas. These fossil energy sources are mainly explored by means of artificial earthquakes. Due to the unique physical properties of the loess plateau, the pores are developed, loose and dry, the density is low, and the wave velocity is low, which leads to serious attenuation of seismic wave energy, serious high-frequency attenuation caused by low signal-to-noise ratio, and strong interference such as surface waves, ringing earthquakes, and multiple waves. And other issues. With the transformation of energy ...

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Problems solved by technology

[0031] The main function and purpose of this horizontal seismic combination excitation is to suppress random interference through the combination of signals. It increases the energy of seismic waves propagating downward through large base distances and small doses, suppresses interference waves, and improves signal-to-noise In contrast, the multiple reflection and refraction waves have not been eliminated purposefully, and the multiple reflection and refraction wave information still exists in the seismic data volume, which will still affect the refined interpretation of the seismic section after stacking

[0032] The existing seismic processing and seismic acquisition methods do not suppress and eliminate the multiple reflection and refraction waves from the source of the multiple reflection and refraction waves, but take remedial measures after the multiple reflection and refraction waves are generated

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