Method of using seismic reflection waves to detect ultra-shallow layer fault

Abstract

The invention discloses a method of using seismic reflection waves to detect an ultra-shallow layer fault. A single-well multi-shot excitation and ground multichannel receiving mode is adopted to directly acquire, analyze and translate the shallow fault plane information. The method of the invention can directly detect the development condition of a newly-constructed movement track-ultra-shallow layer active fault, intuitive seismic and geological data can be provided for analysis and prediction on the development and the happening, and the problem that a near-surface active fault is hard to detect can be solved.

Description

technical field [0001] The invention relates to a method for detecting ultra-shallow faults by using seismic reflection waves, belonging to the field of seismic geological exploration. Background technique [0002] The current artificial seismic reflection technology is very difficult to detect ultra-shallow (mainly within 20m underground) faults, and it is difficult to describe and characterize the shallow development of faults. The main reasons are as follows: [0003] (1) The current method mainly uses the seismic reflection wave exploration technology of surface excitation and surface reception to receive the seismic wave reflection information of the subsurface wave impedance interface. The wave impedance interface mainly refers to the reflection interface of different formations. The detection of faults mainly uses the migration and homing of diffracted waves at breakpoints to generate breakpoints, and generates fault planes by connecting and connecting breakpoints ins...

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Problems solved by technology

[0004] (2) Constrained by the current surface excitation and surface reception observation system, the surface information of the underground reflection wave detected by the observation system is hyperbolic in the single shot record, and the long-distance reflection information is seriously attenuated, especially for the shallow weak reflection interface The detection is very unfavorable, which makes it difficult to superimpose imaging on the shallow weak reflection interface;

[0005] (3) The reflection wave travel time of the ultra-shallow layer is small, and its reflection information is easily disturbed by ground waves and is difficult to distinguish, which cannot effectively detect ultra-shallow reflection imaging, hindering the analysis and research of ultra-shallow faults

[0006] The main reason is that the ultra-shallow reflected waves are submerged in the direct waves, which cannot be separated and explained

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